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  • richardmitnick 5:49 am on December 21, 2014 Permalink | Reply
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    From SPACE.com: “How Was the Moon Formed?” 2013 

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    SPACE.com

    After the sun spun to light, the planets of the solar system began to form. But it took another hundred million years for Earth’s moon to spring into existence. There are three theories as to how our planet’s satellite could have been created: the giant impact hypothesis, the co-formation theory and the capture theory.

    Giant impact hypothesis

    This is the prevailing theory supported by the scientific community. Like the other planets, the Earth formed from the leftover cloud of dust and gas orbiting the young sun. The early solar system was a violent place, and a number of bodies were created that never made it to full planetary status. According to the giant impact hypothesis, one of these crashed into Earth not long after the young planet was created.

    Known as Theia, the Mars-size body collided with Earth, throwing vaporized chunks of the young planet’s crust into space. Gravity bound the ejected particles together, creating a moon that is the largest in the solar system in relation to its host planet. This sort of formation would explain why the moon is made up predominantly of lighter elements, making it less dense than Earth — the material that formed it came from the crust, while leaving the planet’s rocky core untouched. As the material drew together around what was left of Theia’s core, it would have centered near Earth’s ecliptic plane, the path the sun travels through the sky, which is where the moon orbits today.

    Co-formation theory

    Moons can also form at the same time as their parent planet. Under such an explanation, gravity would have caused material in the early solar system to draw together at the same time as gravity bound particles together to form Earth. Such a moon would have a very similar composition to the planet, and would explain the moon’s present location. However, although Earth and the moon share much of the same material, the moon is much less dense than our planet, which would likely not be the case if both started with the same heavy elements at their core.

    Capture theory

    Perhaps Earth’s gravity snagged a passing body, as happened with other moons in the solar system, such as the Martian moons of Phobos and Deimos. Under the capture theory, a rocky body formed elsewhere in the solar system could have been drawn into orbit around the Earth. The capture theory would explain the differences in the composition of the Earth and its moon. However, such orbiters are often oddly shaped, rather than being spherical bodies like the moon. Their paths don’t tend to line up with the ecliptic of their parent planet, also unlike the moon.

    Although the co-formation theory and the capture theory both explain some elements of the existence of the moon, they leave many questions unanswered. At present, the giant impact hypothesis seems to cover many of these questions, making it the best model to fit the scientific evidence for how the moon was created.
    Conceptual illustrations of the birth of the moon.

    m1

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    m3

    m4

    m5

    m6

    See the full article, with video, here.

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  • richardmitnick 6:04 pm on December 20, 2014 Permalink | Reply
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    From SPACE.com: “Orion’s Belt: String of Stars & Region of Star Birth” 

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    SPACE.com

    December 20, 2014
    Elizabeth Howell

    Orion’s Belt is an asterism of three stars that appear about midway in the constellation Orion the Hunter. The asterism is so called because it appears to form a belt in the hunter’s outfit. It is one of the most famous asterisms used by amateur astronomers. Asterisms are patterns of stars of similar brightness. The stars may be part of a larger constellation or may be formed from stars in different constellations.

    Spotting the belt is actually one of the easiest ways to find the constellation Orion itself, which is among the brightest and most prominent in the winter sky. The three stars that traditionally make up the belt are, from west to east: Mintaka, Alnilam and Alnitak. The names of the outer two both mean “belt” in Arabic, while Alnilam comes from an Arabis word that mean “string of pearls,” which is the name of the whole asterism in Arabic, according to astronomer Jim Kaler.

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    The stars Alnilam, Mintaka and Alnitak form Orion’s belt.
    Credit: Martin Mutti, Astronomical Image Data Archive

    Hanging down from Orion’s Belt is his sword, which is made up of three fainter stars. The central “star” of the sword is actually the Orion Nebula (M42), a famous region of star birth. The Horsehead Nebula (IC 434), which is a swirl of dark dust in front of a bright nebula, is also nearby.

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    In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

    NASA Hubble Telescope
    NASA Hubble schematic
    Hubble

    Looking north of the belt, Orion’s “shoulders” are marked by Betelgeuse and Bellatrix and south, his “knees” are Saiph and Rigel.

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    Skywatcher Per-Magnus Heden wondered if the Vikings gazed at the same starry sky, which includes the constellation Orion at bottom, when he took this photo in Feb. 2011.
    Credit: P-M Hedén/TWAN

    Cultural references and notable features

    “The only real legend that is sometimes referred to in Western Culture with Orion’s Belt is the Three Kings,” said Tom Kerss, an astronomer with the Royal Observatory Greenwich, in a Space.com interview. This is a direct reference to the Biblical tale of the three kings who offered gifts to the Baby Christ shortly after his birth.

    Because Orion’s Belt is so easy to find in the sky, it can be used as a pointer to bring amateur astronomers to other interesting objects. Move northwest of the star complex and eventually the line will bring you to the Pleiades star cluster, a collection of dozens of stars that are sometimes called the Seven Sisters (after those that are the most easily visible to the naked eye.)

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    The Pleiades, an open cluster consisting of approximately 3,000 stars at a distance of 400 light-years (120 parsecs) from Earth in the constellation of Taurus. It is also known as “The Seven Sisters”, or the astronomical designations NGC 1432/35 and M45.

    http://hubblesite.org/newscenter/archive/releases/2004/20/image/a/

    Following southwest of the stars will lead you to Sirius, the brightest star in the sky in both the Northern and Southern hemispheres. Part of its brightness in the sky comes because it is so close to us, just 8.7 light-years away.

    Kerss said the shape is also interesting astronomically. Some of the stars themselves are physically close together (which is not always true of stars in the sky, which only appear to be nearby.)
    Recent astronomical news

    Although the Orion Nebula has been studied thoroughly by both amateur and professional astronomers, surprises continue with further observations.

    In 2013, a Chilean European Southern Observatory telescope spotted signs of a cosmic “ribbon” in the nebula that is more than 1,000 light-years away. The track contains cold gas and dust, and astronomers also noted they may have found 15 young stars or protostars while making these observations.

    Even closer looks at the nebula have revealed features such as this bow shock from the young star LL Ori, which is sending out wind that strikes gas leaving the heart of the star-forming region.

    See the full article here.

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  • richardmitnick 3:16 pm on December 15, 2014 Permalink | Reply
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    From SPACE.com: “Will We Ever Find Dark Matter?” Previously Covered Elsewhere, But K.T. is an Excellent Exponent of her Material 

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    SPACE.com

    December 11, 2014
    Kelen Tuttle, The Kavli Foundation

    Scientists have long known about dark matter, a mysterious substance that neither emits nor absorbs light. But despite decades of searching, they have not yet detected dark matter particles.

    With ten times the sensitivity of previous detectors, three recently funded dark matter experiments — the Axion Dark Matter eXperimen Gen 2, LUX-ZEPLIN and the Super Cryogenic Dark Matter Search at the underground laboratory SNOLAB — have scientists crossing their fingers that they may finally glimpse these long-sought particles.

    AXION DME
    University of Washington physicists Gray Rybka (right) and Leslie Rosenberg examine the primary components of the ADMX detector.
    Credit: Mary Levin, University of Washington

    LUX Dark matter
    LUX-ZEPLIN

    SUPER CDMS
    Super Cryogenic Dark Matter Search

    Late last month, The Kavli Foundation hosted a Google Hangout so that scientists on each of those experiments could discuss just how close we are to identifying dark matter. In the conversation below are three of the leading scientists in the dark matter hunt:

    Enectali Figueroa-Feliciano: Figueroa-Feliciano is a member of the SuperCDMS collaboration and an associate professor of physics at the MIT Kavli Institute for Astrophysics and Space Research.

    Harry Nelson: Nelson is the science lead for the LUX-ZEPLIN experiment and is a professor of physics at the University of California, Santa Barbara.

    Gray Rybka: Rybka leads the ADMX Gen 2 experiment as a co-spokesperson and is a research assistant professor of physics at the University of Washington.

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    The SuperCDMS experiment at the Soudan Underground Laboratory uses five towers like the one shown here to search for WIMP dark matter particles.
    Credit: Reidar Hahn, Fermilab

    Below is a modified transcript of the discussion. Edits and changes have been made by the participants to clarify spoken comments recorded during the live webcast. To view and listen to the discussion with unmodified remarks, you can watch the original video.

    The Kavli Foundation: Let’s start with a very basic, yet far from simple question. One of our viewers asks how do we know for sure that dark matter even exists. Enectali, I’m hoping you can start us off. How do you know that there’s something out there for you to find?

    E.F.F.: The primary evidence telling us dark matter is out there is from astronomical observations. In the 1930s, evidence first came in the observations of the velocities of galaxies inside galaxy clusters. Then, in the 1970s, it came in the velocities of stars inside galaxies. One way to explain this is if you imagine tying a string around a rock and twirling it around. The faster you twirl the rock on the string, the more force you have to use to hold onto that string. When people looked at the velocity rotations of galaxies, they noticed that stars were moving way too fast around the center of the galaxy to be explained from the force you could see due to gravity from the mass that we knew was there from our observations. The implication was that if the stars are moving faster than gravity could hold them together, there must be more matter than we can see holding everything in place.

    Today, many different types of observations have been done at the very largest scales, using clusters of galaxies and what’s called the cosmic microwave background. Even when we look at the small scale of particle physics, we know that there are things about the Standard Model that aren’t quite right. We’re trying to find out what’s missing. That’s part of what’s being done at the Large Hadron Collider
    at CERN and other collider experiments. Some of the theories predict particles that would be good candidates for dark matter. So from the largest cosmic scales to the smallest particle physics scales there are reasons to believe that dark matter is there and there are candidates for what that dark matter can be.

    Cosmic Microwave Background  Planck
    CMB erp ESA/Planck

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    The Standard Model of elementary particles, with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

    TKF: Harry, I’m hoping that you can follow up on that a little bit. Your experiment and the one Enectali works on both look for the most promising type of theoretical particle, one that interacts so weakly with the matter in our world that it’s called the WIMP. In fact there are more than thirty dark matter experiments that are currently planned or underway, and the great majority of them search for this same type of particle. Why do all these experiments focus on the WIMP?

    H.N.: First I want to emphasize that WIMP is an acronym, W-I-M-P, which stands for weakly interacting massive particle. “Massive” means a mass that’s anywhere from a little smaller than the mass of a proton up to many times the mass of a proton. The WIMP is so popular in part because it’s easy to fit into descriptions of the Big Bang — maybe the easiest to fit. The concept to understand here is called thermal equilibrium, and that’s just when you put something in the refrigerator it ends up at the same temperature as the refrigerator. I had a leftover sandwich last night from when I went out to dinner and I put in my refrigerator, and now it’s cold. In much the same way, with WIMPs we hypothesize that dark matter in the early universe was in thermal equilibrium with our matter. But after the Big Bang, the universe gradually cooled down and our matter fell out of equilibrium with the dark matter. Then the dark matter keeps finding itself and, through a process called annihilation, turning into our matter. But the reverse process can no longer go on because our matter doesn’t have enough thermal energy.

    To explain the current abundance of dark matter, the interaction between dark matter and us numerically must be about the same as the weak interaction. That’s W-I in WIMP: weakly interacting. It implies a numerical strength that is consistent with beta decay in radioactivity or, for example, the production of the Higgs particle at the Large Hadron Collider. That the weak interaction appears from this idea about the Big Bang appeals to people. Occam’s Razor, the idea that you don’t want to make things any more complicated than they need to be, makes it attractive. But it doesn’t prove it.

    There are at least two other ways to detect the WIMP. One is at the Large Hadron Collider, as Enectali mentioned, and another is in these WIMP annihilations, where the WIMPs find each other and turn into our matter in certain places in the universe such as the center of stars or the center of our galaxy. If we get lucky, we could hit a trifecta; we could see the same particle with experiments like mine — LUX/LZ — or Enectali’s SuperCDMS, we could see it in the Large Hadron Collider, and we could also see it astrophysically. That would be the trifecta.

    Of course there’s a second reason why so many people are building these WIMP experiments, and that’s that we’ve made a lot of progress in how to build them. There’s been a lot of creativity using many techniques to look for these things. I will say that’s partly true because they’re a little easier to look for than the axion, for which you need really talented and expert people like Gray and Leslie Rosenberg.

    TKF: That’s a nice segue into Gray’s experiment. Gray, you don’t look for the WIMP; instead, you look for something called the axion. It’s a very lightweight particle, with no electric charge and no spin that interacts with our world very rarely. Can you tell us a little bit more about your experiment and why you look for the axion?

    G.R.: I look for the axion because if I looked for WIMPs then I would have to compete with very smart people like Harry and Enectali! But there are other really good reasons as well. The axion is a very good dark matter candidate. We think it may exist because of how physics works inside nuclei. It’s different from the WIMP in that it’s extremely light and you look for it by coupling to photons or, say a radio frequency kind of energy. I got involved in this because I was looking at dark matter and saw that there are a lot of people looking for WIMPs and not many people looking for axions. It’s difficult to look for, but there have been some technical breakthroughs that help. For example, just about everyone has cell phones now and so a lot of work has been done at those frequencies — which just happen to be the right frequencies to use when looking for axions. Meanwhile, there’s a lot of work on quantum computers, which means that there’s also a lot of really nice low temperature radio frequency amplification. That too helps with these experiments. So the time is right be looking for axions.

    TKF: Besides the WIMP and the axion, there are a lot of other theorized particles out there. One of our viewers wrote in and would like to know how likely is it that dark matter is in fact neither of the particles that your experiments look for but rather is composed of super heavy particles called WIMPzillas.

    H.N.: The WIMPzilla has WIMP in its name, so that means it’s weakly interacting, and the zilla part is that it’s just as massive as Godzilla. The way it works is that all of our astrophysical measurements tell us how much mass there is per unit volume – essentially, the cumulative total mass per unit volume of dark matter. But these measurements don’t tell us how to apportion that mass. Are there a great many light particles or just a few really heavy particles? We can’t tell from astrophysical data. So it could be that the dark matter consists of just a few super duper heavy things, like WIMPzillas. But because there wouldn’t be many of them out there, to detect them you’d have to build it a gigantic detector. What we run into there is that nobody wants to give us billions of dollars to build that gigantic detector. It’s just too much money. I think that’s what keeps us from making progress on the idea of the WIMPzilla.

    LUX Dark matter
    The LUX detector before its large tank was filled with more than 70,000 gallons of ultra-pure water. The water shields the detector from background radiation.
    Credit: Matt Kapust, Sanford Underground Research Facility

    E.F.F.: There are many theoretical dark matter particles. We have to pick a combination of what we can look for with the experiments that we can build and what theory and our current understanding suggests are the best places to look. Now, not all of the theories have as good a foundation as others. Some would work but have different types of assumptions built into them and so we need to make a value judgment as experimentalists. We go to the “theory café” and choose which are the best courses on the menu, then we trim the list down to those that are the most feasible to detect, and then we look at which of those we can afford. That convolution of parameters is what prompts us to look for particular candidates. And if we don’t find dark matter in those places, we will look for them elsewhere. And of course there’s no reason why dark matter has to be one thing; it might be composed of several different particles. We might find WIMPs and axions and other things we don’t know of yet.

    TKF: One of our viewers points us to a press release issued last week by Case Western University that describes a theory in which dark matter is made up of macroscopic objects. This viewer would like to know whether there’s any reason why dark matter would be more likely to be made up of the individual exotic particles that you look for than it is to be made up of macroscopic particles.

    H.N.: Papers like that are one of the reasons this field is so exciting. There are just so many different ideas out there and there’s this big discussion going on all the time. New ideas come in, we discuss them and think about them, and sometimes the new idea is inconsistent but other times people say, “Wow we have no idea that could be great.”

    This concept that the dark matter might consist of particles that coalesce into solid or massive objects has been around for a long time. In fact, there was a search 20 or so years ago where they looked for large objects in our galaxy that were creating gravitational lensing. When you look at stars out in our galaxy, if they suddenly become brighter that’s evidence of a massive object moving in front of them. You might wonder how an object moving in front of something would give it more light, but that’s the beauty of gravitational lensing — the light focuses around the object. So this idea has been out there, and this paper looks to be a very careful reanalysis.

    Another example is an idea that’s been around for a long time that maybe there is a different kind of nuclear matter out there. Our nuclear matter is made of up and down quarks and maybe there’s another type of nuclear matter that involves the strange quark. People have been searching for that for 30 or 40 years, but we’ve never been able to find it. Maybe it exists and maybe it’s the dark matter we’re searching for. I would say that in some estimate of probabilities it’s less likely, but we could be wrong. What’s great is to have the scientific discussion always going because the probabilities get reassessed all the time.

    G.R.: These massive objects have a very amusing acronym. They’re massive compact halo objects, MACHOs. So for a while it was MACHOs versus WIMPs.

    E.F.F.: One thing that I would add is that this paper and this whole idea of the variety of models really highlights how diverse the possibilities for looking for dark matter are. In that paper, they looked into mica samples that had been buried for many, many years, looking for tracks. When you have a candidate, the theoretical community starts scanning every possibility of a signal that might have been left — not just in our detectors, but also in the atmosphere, in meteorites, in stars and in the structure that we see in the universe. There are other detectors out there that are more indirect than the ones we’ve specifically designed for dark matter. That’s one of the things that makes it exciting: maybe we find dark matter in our detectors and we might also find traces of it in other things that we haven’t even thought about yet.

    TKF: In the history of particle physics, there have been a number of particles that we knew existed long before we were able to detect them — and in a lot of cases, we knew a lot about these particles’ characteristics before we found them. This seems very different from where we are now with dark matter. Why is that? What is fundamentally different here?

    G.R.: We know about dark matter from gravitational interactions, and we have a hard time fitting gravity in with the fundamental particles to begin with. I think that’s a big part of it. Would you all agree?

    H.N.: There are some analogues, but you have to go back in time quite a bit. One of the famous analogues is the discovery of the neutron. The proton was discovered in a fantastic series of experiments during World War I by [Ernest] Rutherford, but he had good intuition and thought there should be another particle that’s like the proton that is neutral, which they called the neutron. Even though they had a pretty good idea what it should be like, it took 12 or 15 years for them to detect one because it was just difficult. Then there was an experiment done by Frederic and Irene Joliot-Curie and their group in France and they interpreted the results in a very strange way. But a guy named James Chadwick looked at their data and said, “My God that’s it!” He repeated the experiment and proved the existence of the neutron.

    That story is so important because the neutron is the key to most uses of nuclear energy. I suspect with dark matter we’ll have some sort of rerun of that. We’re all looking and somewhere, maybe even now, there’s a little bit of data that will cause someone to have an “Ah ha!” moment.

    E.F.F.: We also have this nice framework of the Standard Model, but right now we don’t really have one single theory of what should come after it. The most popular possibility is supersymmetry, which is one of the things that a large number of physicists at the Large Hadron Collider are trying to find. But it’s not at all clear that this is the solution of what lies beyond the Standard Model. That ambiguity leads to a plethora of dark matter models because dark matter lies outside of the framework of the Standard Model and we don’t know in which direction this model will grow or how it will change. Physicists are looking at all the possibilities, many of which have good dark matter candidates. There’s this chasm between where we are now and where the light of understanding is, and we don’t yet know which direction to go to find it. So people are looking in all possible directions generating a lot of great ideas.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    TKF: It seems that the results of your experiments will direct the search in one way or another. One of our viewers would like to know a little bit more about how you go about detecting dark matter in your experiments. Since dark matter really doesn’t interact with us very much, how do you go about seeing it?

    G.R.: Our experiments use very different techniques. My experiment looks for axions that every once in a while couple to photons. They do so in a way that the photons produced are of microwave frequencies. This is quite literally the frequency used by your cell phone or in your microwave oven. So we look for a very occasional transmutation of an axion from the dark matter around us into a microwave photon. We also help this process along using a strong magnetic field. Because the frequency of the photon coming from the axion is very specific, this ends up being a scanning experiment. It’s almost like tuning an AM radio; you know there’s a signal out there at a certain frequency, but you don’t know what the frequency is so you tune around, listening to hear a station. Only we’re looking for a signal that’s coming from dark matter turning into photons.

    E.F.F.: Both Harry and I look for similar particles, these WIMPs. My experiment is particularly good at looking for WIMPs that are about the mass of a proton or a couple times heavier than that, while Harry’s experiment is better at looking for particles that are maybe a hundred to several hundred times heavier than the proton. But the idea is the same. As Harry mentioned before, we know the density of dark matter particles in our region of space in the galaxy, so we can calculate how many of these dark matter particles should be going through me, through you, through your room right now.

    If you stick out your hand and you assume that WIMPs are maybe sixty times the mass of the proton — I’m just picking a number here — you calculate that there should be about 20 million WIMPs going through your hand every second. Now these dark matter particles go straight through your hand and straight through the Earth, but perhaps very occasionally they interact with one of the atoms in the matter that the Earth is made of. So we build detectors that hope to catch some of those very, very rare interactions.

    My experiment uses a crystal made out of germanium or silicon that we cool down to milli-kelvin temperatures: almost at absolute zero. If you remember your high school physics, atoms stop vibrating when they get very, very cold. So the atoms in this crystal are not vibrating much at all. If a dark matter particle interacts with one of the atoms in the crystal, the whole crystal starts vibrating and those vibrations are sensed by little microphones that we call phonon sensors. They also release charge and we measure that charge as well. Both of those help us to determine not only the energy that was imparted to the target but what type of interaction it was: Was it an interaction like the one you would expect from a photon or an electron, or was it an interaction you would expect from a WIMP or perhaps a neutron? That helps us to distinguish a dark matter signal from backgrounds coming from radioactivity in our environment. That’s very important when you’re looking for a very elusive signal.

    TKF: In fact you even go to the extent of working far underground to reduce this background noise, is that right?

    E.F.F.: That’s right. And I’ll actually let Harry take it from here.

    H.N.: Our experiments are going to be in two different mines. Ours is about a mile underground in western South Dakota in the Black Hills — the same black hills mentioned in the Beatles song Rocky Raccoon. Meanwhile, Enectali is up in Sudbury, Ontario, where there’s a heavy metal mine.

    One analogy I wanted to bring up is that what Enectali and I do is a microscopic version of billiards. The targets — in my case are xenon and in his case germanium and silicon — are like the colored balls on a pool table, and what we’re trying to detect is the cue ball — the dark matter particle we can’t see. But if the cue ball collides with the colored balls, they suddenly move. That’s what we detect.

    As Enectali said, the reason we go deep in a mine and the reason we build elaborate shields around these things is so that we aren’t fooled by radioactivity or neutrons or neutrinos moving the billiard balls. And there are a lot fewer of these fakes when we go deep. Plus, it’s an awful lot of fun to go in these mines. I’ve been working in them for ten or fifteen years now and it’s great to go a mile underground.

    TKF: If one of your experiments is successful in seeing dark matter, Enectali you said in a previous conversation that the next steps would be to study the dark matter particle’s characteristics and use that knowledge to better understand the particle’s role in the universe. I’m hoping you can explain that last bit a little bit further. Just how far-reaching would such a discovery be?

    E.F.F.: We’re very lucky in that we get to ask these really big questions about what the universe is made of. We know that dark matter makes up about 25 or 26 percent of the universe, and through direct detection we’re trying to figure out what that is exactly.

    But even once we know the mass of the dark matter particle, we still need to understand a lot of other things: whether it has spin, whether it is its own anti-particle, all kinds of properties of the particle itself. But that’s not all that there is to it. This particle was produced some time ago. We want to know how it was produced, when it was produced, what did that do to the universe and to the formation of the universe. There’s a very complicated history of what happened in the universe between the Big Bang and today, and dark matter has a big role to play.

    Dark matter is the glue that holds all the galaxies, all the clusters of galaxies and all the super clusters together. So without dark matter, the universe would not look like it does today. The type of dark matter could change the way that structure formed. So that’s one very important thing that we would like to understand. Another thing is that we don’t really know how dark matter behaves here in our galaxy today. We know its density, but we don’t really know how it’s moving. We have some assumptions, but it will be very interesting to really understand the motion of dark matter – whether it’s clumpy, whether it has structures or streams, whether some of it is in a flat disk. The answers to these questions will have implications for the stars in our galaxy and beyond. All those things will be the next step in what we would love to be doing, which is dark matter astronomy.

    TKF: We have one last question from a viewer who identifies herself as “an interested artist.” Her question is: If you find dark matter, what are you going to call it? It won’t be dark anymore.

    G.R.: I can start with a bad idea. It was called dark matter originally because when you look up at the sky, there are things that produce light — like stars — and there are things that we know are out there because they interact gravitationally but they’re not producing light. They’re dark. But that name kind of implies that they absorb or block light, when in fact dark matter doesn’t. Light goes right through it. So you can call it clear matter, but dark matter at least sounds mysterious. Clear matter sounds rather boring.

    H.N.: I hope you get people better at language than physicists to answer this! If it’s physicists who name it, we’ll end up with a name like gluon. I’d prefer to have a better name than that. Since this viewer is an artist, I’ll point out a sculpture at the Tate in London by Cornelia Parker called Cold Dark Matter: An Exploded View. This idea that there’s something out there that we can’t sense yet is one of those things that sends chills down my spine. I think that scientists share that feeling of wonderment with artists.

    E.F.F.: I’d love to have a naming contest for this 20-some-odd percent of the universe. I think it would produce much better names than we would come up with on our own.

    See the full article here.

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  • richardmitnick 12:15 pm on December 13, 2014 Permalink | Reply
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    From SPACE.com: ” Religion & Astronomy: From Galileo to Aliens” 2011 but very interesting 

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    SPACE.com

    Jan 13, 2011
    Leslie Mullen

    Part 1

    Our Sun is just one small point of light in the swirl of suns that shape the disc of the Milky Way. The galaxy’s hundreds of billions of stars are strewn so widely apart, it would take a spaceship traveling at the speed of light one hundred thousand years to travel the distance. The starry wheel of the galaxy turns around a massive black hole, a point of infinite density with gravity so complete that not even light can escape.

    The structure and scale of our galaxy is astonishing. But ours is just one among hundreds of billions of galaxies in the universe.

    1
    Is this what our own Milky Way Galaxy looks like from far away? Similar in size and design to our home galaxy, spiral galaxy NGC 3370 is about 100 million light-years away, toward the constellation Leo. Image credit: NASA, ESA, Hubble Heritage (STScI/AURA)

    Little wonder, then, that the contemplation of the cosmos can evoke the same emotions as religious awe and reverence. According to Father Paul Pavel Gabor, an astronomer for the Vatican Observatory, this is not always a positive experience. Just as some may experience fear and trembling when contemplating God and Heaven, there are those who become similarly overwhelmed when confronted with the astronomical proportions of the heavens.

    “They find it quite awe-inspiring, but in the wrong way,” Gabor notes. “When I show people pictures of the local cluster of galaxies, just to give them a sense of the scale of things, the reaction quite often is, “Oh dear. I’m completely insignificant, and I’m uncomfortable about this whole universe thing.”

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    Local Group

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    Science, and particularly geometry and astronomy/astrology, was linked directly to the divine for most medieval scholars. The compass in this 13th century manuscript is a symbol of God’s act of creation. God has created the universe after geometric and harmonic principles, to seek these principles was therefore to seek and worship God. Image credit: Österreichische Nationalbibliothek

    In Gabor’s view, one way to counter this despair is to have faith in a higher power, to believe in a God that created the universe as a gesture of love.

    “Faith tells you that the universe is not something to intimidate you, but it is something given to you as a gift, by somebody who wants to give you something nice, something pretty,” he says. “So looking at those astronomy pictures, you can either feel that the glass is half full, and believe that you’re really being given something here, or you can feel the glass is half empty and this is just frightening and you want to hide in your little rabbit hole somewhere.”

    Whether you are terrified or thrilled by the grandeur of the universe, there is no disputing its elemental nature: it is the source of us all. As Carl Sagan once said, “We are made of star stuff.” The chemical elements that shape the breadth of creation also form our galaxy, our planet and even the cells of our bodies. Exploring the cosmos therefore is one way to get close to a “grand creator.” This notion is reflected in the final lines of John Gillespie Magee Jr.’s poem “High Flight”, which President Reagan read at the memorial service for the Challenger astronauts:

    with silent, lifting mind I’ve trod
    The high untrespassed sanctity of space,

    Put out my hand, and touched the face of God.

    The Great Architect

    The term “cosmos” means “ordered world”. For most of recorded history, humans have believed that God created the ordered universe out of chaos. This belief is still shared by a majority of people around the world today, but aspects of that faith have changed as our scientific knowledge of the cosmos has grown. For instance, Gabor’s colleague, Vatican astronomer Brother Guy Consolmagno, says that while many people believe God created the universe, they think its very enormity makes it impossible for God to take any personal note of us. This mote of dust we call planet Earth is insignificantly tiny in comparison to the smallest of stars, and each of our lives lasts for the briefest of cosmic moments.
    Timeline of events that followed the Big Bang. Rather than matter and energy erupting into a pre-existing space, modern Big Bang theory holds that space and time came into being simultaneously with matter and energy. Recent observations, including those by NASA’s WMAP orbiting observatory, favor specific inflation scenarios over other long held ideas. Credit: NASA

    “Some people will refuse to believe because they still haven’t grasped what kind of God we’re talking about, a God that is so “other” that it is possible,” says Consolmagno.

    2
    Timeline of events that followed the Big Bang. Rather than matter and energy erupting into a pre-existing space, modern Big Bang theory holds that space and time came into being simultaneously with matter and energy. Recent observations, including those by NASA’s WMAP orbiting observatory, favor specific inflation scenarios over other long held ideas. Credit: NASA

    This philosophical notion of a God for whom all things are possible, and who is beyond our basic human capacity of understanding, finds an echo in the still mysterious nature of the universe. For instance, most of the universe is currently attributed to the obscure categories “dark energy” and “dark matter”. Writing in Scientific American, the astrophysicist David Cline noted those terms are really just expressions of our ignorance.

    Another area of scientific ignorance is the time before the Big Bang. What, if anything, happened before the universe began its current outward expansion? The Roman Catholic priest Georges Lemaître originally proposed the idea that the universe expanded from an initial point (which he called ‘the primeval atom’), and the Catholic Church supported the Big Bang theory even before most cosmologists did. This “day without yesterday” was seen as being consistent with the creation ex nihilo (out of nothing) as described in the Book of Genesis.

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    Brother Guy Consolmagno wears a T-shirt that brings together Maxwell’s equations with God’s line from the Old Testament, “Let There Be Light.” Image credit: Institute of Physics/ James Dacey

    According to a recent Reuter’s news report, Pope Benedict XVI said that “God’s mind was behind complex scientific theories such as the Big Bang”. The Pope did not cite the Big Bang specifically, but spoke more generally about the creation of the universe:

    “The universe is not the result of chance, as some would like to believe. In contemplating it, we are invited to read for ourselves something quite profound: the wisdom of the Creator, the inexhaustible imagination of God, his infinite love for us. We should not let ourselves be limited by the concept of theories that only arrive at a certain point and which — if you look closely — are not set up as rivals of faith, but don’t manage to explain the ultimate sense of reality. In the beauty of the world, in its mystery, in its grandness and in its rationality how can we not read the eternal rationality, and how can we do nothing less than to be taken by hand as it leads us to the ultimate unique God, creator of heaven and earth.”

    In another talk given at a different time, Pope Benedict said that one way we could try to understand the universe better is through mathematics:

    “[Galileo] was convinced that God has given us two books, the book of Sacred Scripture and the book of Nature. And the language of Nature — this was his conviction — was mathematics, so it is the language of God, a language of the Creator. The surprising thing is that this invention of our human intellect is truly key to understanding Nature, that Nature is truly structured in a mathematical way, and that our mathematics, invented by our human mind, is truly the instrument for working with Nature, to put it at our service, to use it through technology.”

    n
    The Hubble Ultra-Deep Field is an image of a small region of space in the constellation Fornax, composited from Hubble Space Telescope data accumulated over a period from September 3, 2003 through January 16, 2004. The patch of sky, chosen because it had a low density of bright stars in the near-field, is filled with galaxies. Image credit: NASA/ESA

    Consolmagno says that some wonder whether mathematics was invented by man to describe Nature, or whether we discovered the mathematical properties that were built into Nature by a higher power.

    “Maybe it’s a little bit of both,” he says. “The thing that always astonishes me, beyond the fact that the universe is mathematical, the universe makes sense. The mathematics is beautiful. When a student grasps what Maxwell’s equations tell them, there’s this leap of joy that’s as great as looking at the sunset that Maxwell’s equations can explain. Why it should work at all is something no philosopher has been able to figure out.”

    Part 2

    January 21, 2011

    One of the most famous examples of the clash between religion and science is the trial of Galileo Galilei. Galileo supported Copernicus’ view that the Earth orbited the sun, a “heliocentric” theory which the church declared contrary to Scripture. Galileo was warned to abandon his support for this theory and instead embrace the traditional “geocentric” notion that the Earth was an unmovable point around which the universe revolved.

    gg
    Galileo explaining lunar topography to two cardinals. Painting by Jean Leon Huens.

    Instead, in 1632 Galileo published Dialogue Concerning the Two Chief World Systems. The book was structured as a conversation between Salviati, a heliocentric philosopher, Simplicio, a geocentric philosopher, and Sagredo, a neutral layman. Pope Urban VIII had actually given Galileo permission to write the book as long as he didn’t promote one viewpoint over the other. However, Salviati forcefully argued Galileo’s beliefs, while Simplicio was often ridiculed as a fool.

    An often-repeated view about the furor which followed the publication of Galileo’s book is that the pope was insulted by having his words expressed by Simplicio. Not only was the character made to look ridiculous, but the name itself likely was a double entendre for “simple-minded” (simplice in Italian). However, Vatican astronomer Brother Guy Consolmagno disputes this analysis.

    “First, ‘Simplicio’ was a well-established name in philosophical discourses, not something invented by Galileo, to represent a person who was able to see through the fog generated by the more clever and learned philosophers who invent elaborate theories and lose sight of simple obvious truths, like the innocent child who can recognize that the emperor has no clothes,” said Consolmagno. “In this context, its use could be seen as a compliment. Second, this kind of punning is quite common in English but my impression is that it is not really done all that much, or in the same way, in Italian; I do not know if anyone at that time and place would have interpreted it the way we English speakers do. And finally, the book was originally approved by the Pope’s censors before being published; if he were going to be insulted by the name, he’d have noticed it long before it was ever printed.”

    Still, the political fallout eventually led the church to withdraw its permission to publish the book. Galileo faced a specially convened panel of ten judges, who found him guilty of suspicion of heresy. By abjuring – saying that he never believed in the heliocentric point of view expressed in the book – Galileo’s sentence was reduced to house arrest.

    “He served (his sentence) first as the honored guest of the bishop of Siena before returning to his own villa, where he lived for another decade, had a regular string of visitors, and wrote another book,” said Consolmagno. “I don’t want to whitewash the mistakes the church made in the Galileo affair, but…it certainly was not a simple knee-jerk reaction against science.”

    Consolmagno said that to truly understand what happened, we need to take into account the philosophical thinking of the time and the events that were taking place both within the Church and in the larger society. This context can be glimpsed in the original documents from the trial, which have been translated into English in various publications, such as Maurice Finocchiaro’s The Galileo Affair (University of California Press, 1989).

    “They got Galileo on a technicality, and he was guilty of that technicality; but why they decided to go after him, in that way, at that time, is an open question,” said Consolmagno. “We can see today that he should never have been brought to trial in the first place.”

    By 1992, Pope John Paul II issued a declaration acknowledging errors in Galileo’s trial. No such apologetic statement has been made for Giordano Bruno, whom the Church burned at the stake in 1600.

    Bruno not only supported the heliocentric view, he also claimed there are multiple worlds beyond Earth, each orbiting their own sun. Consolmagno and his colleague, Vatican astronomer Father Paul Pavel Gabor, say Bruno’s death sentence was not due to him advancing these notions.

    “The old joke is that if he was burned for anything back then, it was for plagiarism,” said Consolmagno. “Nicholas of Cusa published those same ideas 200 years earlier, and he was a Cardinal.”

    Nicholas of Cusa’s book, On Learned Ignorance, in which he discussed the possibility of multiple worlds, was published in 1440. He also wrote that aliens could exist on the moon and the sun.

    “He was made a cardinal in 1448, so it’s quite obvious that it didn’t damage his career,” noted Gabor.

    Consolmagno said the most probable reason for the church’s enmity was that Bruno denied the divinity of Christ, as well as some other fundamental doctrines of Christianity.

    k
    Bronze statue of Giordano Bruno by Ettore Ferrari , Campo de’ Fiori, Rome

    “I think the real problem with Bruno was he was accused of being an English spy,” added Gabor. He said that Bruno was imprisoned in various places throughout Europe before landing in jail in Venice, which then led to his death in Rome. Gabor said that the file on last 7 years of his trial is gone, because Napoleon looted the Vatican for paper.

    “Everybody who keeps writing about it as if they knew what happened is actually just fantasizing,” said Gabor.

    Both Consolmagno and Gabor stress that the idea of aliens and multiple worlds is not a new idea for the church, and doesn’t challenge or threaten the central beliefs of their religion. The Vatican even sponsored an astrobiology workshop in 2009. According to Consolmagno, the church did so in order to create a forum for top scientists in the field to have a conversation.

    “It was not the way it was reported on CNN, where the Catholic church was worried about aliens,” he said.

    They say there was no religious discussion during this workshop; instead the focus was purely on the science of astrobiology. The philosophical crossover between religion and science was only discussed informally, during coffee breaks and other social gatherings.

    Philosophers have been grappling with the implications of alien life for hundreds of years, if not longer. But until aliens are found, said Consolmagno, these issues will remain in the realm of science fiction instead of religion or science.

    “I think that’s a very important role that science fiction has to play, because at this point we’re just playing with ideas,” said Consolmagno. “We’re just exploring the space where the ideas could be. We don’t know – we don’t have the answers. That’s why it’s so much fun!”

    See the full article here.

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  • richardmitnick 3:47 pm on December 12, 2014 Permalink | Reply
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    From SPACE.com: “Cosmic Mystery Solved? Possible Dark Matter Signal Spotted” 

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    SPACE.com

    December 11, 2014
    Mike Wall

    Astronomers may finally have detected a signal of dark matter, the mysterious and elusive stuff thought to make up most of the material universe.

    While poring over data collected by the European Space Agency’s XMM-Newton spacecraft, a team of researchers spotted an odd spike in X-ray emissions coming from two different celestial objects — the Andromeda galaxy and the Perseus galaxy cluster.

    A
    Andromeda galaxy

    p
    Perseus galaxy cluster

    ESA XMM Newton
    ESA/XMM-Newton

    The signal corresponds to no known particle or atom and thus may have been produced by dark matter, researchers said.

    “The signal’s distribution within the galaxy corresponds exactly to what we were expecting with dark matter — that is, concentrated and intense in the center of objects and weaker and diffuse on the edges,” study co-author Oleg Ruchayskiy, of the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, said in a statement.

    “With the goal of verifying our findings, we then looked at data from our own galaxy, the Milky Way, and made the same observations,” added lead author Alexey Boyarsky, of EPFL and Leiden University in the Netherlands.

    Dark matter is so named because it neither absorbs nor emits light and therefore cannot be directly observed. But astronomers know dark matter exists because it interacts gravitationally with the “normal” matter we can see and touch.

    And there is apparently a lot of dark matter out there: Observations of star motion and galaxy dynamics suggest that about 80 percent of all matter in the universe is “dark,” exerting a gravitational force but not interacting with light.

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    The Bullet Cluster
    Hot gas in this collision of galaxy clusters is seen as two pink clumps that contain most of the normal matter. The bullet-shaped clump on the right is hot gas from one cluster, which passed through the hot gas from the other larger cluster. Other telescopes were used to detect the bulk of the matter in the clusters, which turns out to be dark matter (highlighted in blue)
    Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.

    v
    Hubble Reveals Ghostly Ring of Dark Matter
    Credit: NASA/ESA Hubble
    A ghostly ring of dark matter floating in the galaxy cluster ZwCl0024+1652, one of the strongest pieces of evidence to date for the existence of dark matter. Astronomers think the dark-matter ring was produced from a collision between two gigantic clusters.
    Hot gas in this collision of galaxy clusters is seen as two pink clumps that contain most of the normal matter. The bullet-shaped clump on the right is hot gas from one cluster, which passed through the hot gas from the other larger cluster. Other telescopes were used to detect the bulk of the matter in the clusters, which turns out to be dark matter (highlighted in blue).

    3
    Dark Matter’s Link to Brilliant Galaxies Confirmed
    Credit: Paul Bode and Yue Shen, Princeton University
    The illustration shows the distribution of dark matter, massive halos, and luminous quasars in a simulation of the early universe, shown 1.6 billion years after the Big Bang. Gray-colored filamentary structure shows the distribution of dark matter; small white circles mark concentrated “halos” of dark matter more massive than 3 trillion times the mass of the sun; larger, blue circles mark the most massive halos, more than 7 trillion times of the sun, which host the most luminous quasars. The strong clustering of the quasars in the SDSS sample demonstrates that they reside in these rare, very massive halos. The box shown is 360 million light years across.

    Researchers have proposed a number of different exotic particles as the constituents of dark matter, including weakly interacting massive particles (WIMPs), axions and sterile neutrinos, hypothetical cousins of “ordinary” neutrinos (confirmed particles that resemble electrons but lack an electrical charge).

    The decay of sterile neutrinos is thought to produce X-rays, so the research team suspects these may be the dark matter particles responsible for the mysterious signal coming from Andromeda and the Perseus cluster.

    If the results — which will be published next week in the journal Physical Review Letters — hold up, they could usher in a new era in astronomy, study team members said.

    “Confirmation of this discovery may lead to construction of new telescopes specially designed for studying the signals from dark matter particles,” Boyarsky said. “We will know where to look in order to trace dark structures in space and will be able to reconstruct how the universe has formed.”

    You can read the paper at the online preprint site arXiv: http://arxiv.org/pdf/1402.4119v1.pdf

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  • richardmitnick 5:17 am on December 11, 2014 Permalink | Reply
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    From SPACE.com: “Potentially Dangerous Asteroids (Images)” 

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    SPACE.com

    April 10, 2013
    Mike Wall

    m
    This NASA graphic shows the orbits of all the known Potentially Hazardous Asteroids (PHAs), numbering over 1,400 as of early 2013. Shown here is a close-up of the orbits overlaid on the orbits of Earth and other inner planets.

    If you’ve seen films like “Armageddon,” you know the potential threat asteroids can be for Earth. To meet that threat, NASA has built a map like no other: a plot of every dangerous asteroid that could potentially endanger our planet … at least the ones we know about.

    NASA released the new map of “potentially hazardous asteroids” on Aug. 2 in a post to its online Planetary Photojournal overseen by the agency’s Jet Propulsion Laboratory in Pasadena, Calif. The map shows the orbital paths of more than 1,400 asteroids known creep too close to Earth for comfort. None of the asteroids mapped pose an impact threat to Earth within the next 100 years, agency officials said.

    “These are the asteroids considered hazardous because they are fairly large (at least 460 feet or 140 meters in size), and because they follow orbits that pass close to the Earth’s orbit (within 4.7 million miles or 7.5 million kilometers),” NASA officials explained in the image description.

    2
    This diagram illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid, or PHA (orange). PHAs have the closest orbits to Earth’s orbit, coming within 5 million miles (about 8 million kilometers), and they are large enough to survive passage through Earth’s atmosphere and cause significant damage.

    3
    This chart illustrates how infrared is used to more accurately determine an asteroid’s size.

    4
    This radar image of asteroid 2005 YU55 was obtained on Nov. 7, 2011, at 11:45 a.m. PST (2:45 p.m. EST/1945 UTC), when the space rock was at 3.6 lunar distances, which is about 860,000 miles, or 1.38 million kilometers, from Earth

    5
    This still from a NASA animation by Jon Giorgini of the Jet Propulsion Laboratory shows the trajectory of asteroid 2005 YU55 as it passes between Earth and the moon on Nov. 8, 2011.

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    This radar image of potentially hazardous asteroid 1999 RQ36 — the target of NASA’s Osiris-Rex sample-return mission — was obtained by NASA’s Deep Space Network antenna in Goldstone, Calif. on Sept 23, 1999.

    NASA Osiris-REx
    NASA’s Osiris-Rex spacecraft

    NASA Deep Space Network antenna
    >NASA’s Deep Space Network antenna

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    ESA’s Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on January, 5-6, 2013. This image shows the asteroid in Herschel’s three PACS wavelengths: 70, 100 and 160 microns.

    ESA Herschel
    ESA Herschel schematic
    ESA/Herschel

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    The orbit of asteroid 2011 AG5 carries it beyond the orbit of Mars and as close to the sun as halfway between Earth and Venus.

    1
    NEOWISE survey has found that more potentially hazardous asteroids, or PHAs, are closely aligned with the plane of our solar system than previous models suggested. PHAs are the subset of near-Earth asteroids (NEAs) with the closest orbits to Earth’s orbit, coming within 5 million miles (about 8 million kilometers).

    NASA Wise Telescope
    NASA/WISE

    2
    NASA’s NEOWISE asteroid survey indicates that there are at least 40 percent fewer near-Earth asteroids in total that are larger than 330 feet, or 100 meters. NASA used its WISE infrared space telescope to make the find.

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    The asteroid 2012 KP24 flew past Earth on May 28, 2012. While the space rock passed within the moon’s orbit, it did not pose any danger to the planet.

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    This NASA diagram shows the orbit of newfound asteroid 2011 SM173, which flew within 180,000 miles of Earth on Sept. 30, 2011. The asteroid was discovered a day earlier on Sept. 29.

    6
    An object entered the atmosphere over the Urals early in the morning of Feb. 15, 2013. The fireball exploded above Chelyabinsk city, and the resulting overpressure caused damage to buildings and injuries to hundreds of people. This photo was taken by Alex Alishevskikh from about a minute after noticing the blast.

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    The Tunguska explosion flattened some 500,000 acres of Siberian forest on June 30, 1908. This image is from the Leonid Kulik expedition in 1927.

    9
    A 130-foot-meteor created the mile-wide Meteor Crater in Arizona. The comet proposed to have impacted life in North America was significantly larger, but no crater indicating its collision has been found.

    6
    Astronaut Clayton C. Anderson tweeted this picture from space, a view of Aorounga Impact Crater, southeast of of Emi Koussi volcano in Chad.

    9
    Landsat image (color composite) of the newfound Kebira Crater in the Western Desert of Egypt at the border with Libya. The outer rim of the crater is about 19 miles (31 km) in diameter. Image courtesy of Boston University Center for Remote Sensing

    See the full article here.

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  • richardmitnick 12:01 pm on December 10, 2014 Permalink | Reply
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    From SPACE.com: “Space Diamonds in Gold Country: California Meteorite’s Secrets Revealed” 

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    SPACE.com

    December 10, 2014
    Elizabeth Howell

    A meteorite that crashed down in California’s gold country is showing off treasures of a different sort: small diamonds that could tell scientists more about the insides of asteroids.

    The Sutter’s Mill meteorite smashed into the ground on April 22, 2012, after a fiery entry that caught the attention of professional and amateur observers alike. A scientific team raced against rain to pick up meteorite fragments before water polluted the samples. Their efforts helped to produce a cosmic jackpot.

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    NASA Ames and SETI Institute meteor astronomer Peter Jenniskens collected fragments of the Sutter’s Mill meteorite fall on April 24, 2012, two days following the fall, the second recovered find.
    Credit: NASA Ames/Eric James

    Embedded in part of the meteorite were 10-micron diamond grains — much smaller than what is used in diamond rings. But their diminutive size is still bigger than what is usually found in meteorites. The finding hints at what could have existed in the parent cosmic body that eventually broke apart and produced the Sutter’s Mill meteoroid before the fragment slammed into Earth’s atmosphere.

    “Sutter’s Mill gives us a glimpse of what future NASA spacecraft may find when they bring back samples from a primitive asteroid,” lead researcher Peter Jenniskens, who holds dual affiliations at the SETI Institute and at NASA’s Ames Research Center, said in a statement. “From what falls naturally to the ground, much does not survive the violent collision with Earth’s atmosphere.”

    m
    Sutter’s Mill Meteorite Composite Image
    A composite image showing how the Sutter’s Mill meteorite fell in California in April 2012.
    Credit: L. Warren; composite by P. Jenniskens/NASA Ames/SETI

    Diamonds weren’t all that researchers found. More fragments revealed isotopes of an element called chromium. The different types of chromium reveal that at least five stars sent material to the young solar system about 4.5 billion years ago, with some of the materials still sticking around in the meteorite, scientists found.

    “The formation of the solar system did not fully erase and homogenize these signatures, and Sutter’s Mill provides the clearest record yet,” Qing-Zhu Yin, the Sutter’s Mill Meteorite Consortium lead in isotope and trace element geochemistry, said in the same statement.

    dc
    Diamond Crystals in Sutter’s Mill Meteorite
    A secondary electron image revealing diamond crystals inside a fragment of a meteorite that fell in Sutter’s Mill, California.
    Credit: NASA Johnson/M. Zolensky

    The small body had a complicated history after that, with liquid water permeating some fragments (producing minerals such as calcium and magnesium carbonate). This could have been an indication of radiation in the meteorite’s parent body, which heated ice beyond the melting point.

    Other unusual elements — such as a calcium sulfide called oldhamite — also indicate heating in the parent body, as well as in areas that were not heated at all. Heating also came when the fragment was sailing on its own. Sometime in the past 100,000 years, the meteoroid was heated up to at least 572 degrees Fahrenheit (300 degrees Celsius). This heating could have happened during the entry into Earth’s atmosphere, the researchers said.

    “I don’t know of any similar meteorites that contain both heated and unheated materials,” said team member Mike Zolensky, a space scientist at NASA’s Johnson Space Center in Houston.

    The heated portions caused other changes inside the meteorite’s interior, such as the removal of volatile organic compounds. Scientists also managed to track down amino acids (protein building blocks) inside the meteorite.

    Thirteen papers based on the findings were recently published in the journal Meteoritics and Planetary Science.

    See the full article here.

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  • richardmitnick 5:30 pm on December 8, 2014 Permalink | Reply
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    From SPACE.com: “Did Deadly Gamma-Ray Burst Cause a Mass Extinction on Earth?” 

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    December 08, 2014
    Charles Q. Choi

    A gamma-ray burst, the most powerful kind of explosion known in the universe, may have triggered a mass extinction on Earth within the past billion years, researchers say.

    grb
    In this illustration, a jet is produced by an unusually bright gamma-ray burst.
    Credit: NASA/Swift/Cruz deWilde

    These deadly outbursts could help explain the so-called Fermi paradox, the seeming contradiction between the high chance of alien life and the lack of evidence for it, scientists added.

    Gamma-ray bursts are brief, intense explosions of high-frequency electromagnetic radiation. These outbursts give off as much energy as the sun during its entire 10-billion-year lifetime in anywhere from milliseconds to minutes. Scientists think gamma-ray bursts may be caused by giant exploding stars known as hypernovas, or by collisions between pairs of dead stars known as neutron stars.

    ns
    The pulsar PSR B1509-58, a rapidly spinning neutron star (X-rays from Chandra are gold; Infrared from WISE in red, green and blue/max)
    When an image from NASA’s Chandra X-ray Observatory of PSR B1509-58 — a spinning neutron star surrounded by a cloud of energetic particles –was released in 2009, it quickly gained attention because many saw a hand-like structure in the X-ray emission. In a new image of the system, X-rays from Chandra in gold are seen along with infrared data from NASA’s Wide-field Infrared Survey Explorer (WISE) telescope in red, green and blue. Pareidolia may strike again as some people report seeing a shape of a face.
    NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, also took a picture of the neutron star nebula in 2014, using higher-energy X-rays than Chandra.

    NASA Chandra Telescope
    NASA/Chandra

    NASA Wise Telescope
    NASA/WISE

    NASA NuSTAR
    NASA/NuSTAR

    PSR B1509-58 is about 17,000 light-years from Earth.

    JPL, a division of the California Institute of Technology in Pasadena, manages the WISE mission for NASA. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

    If a gamma-ray burst exploded within the Milky Way, it could wreak extraordinary havoc if it were pointed directly at Earth, even from thousands of light-years away. Although gamma rays would not penetrate Earth’s atmosphere well enough to burn the ground, they would chemically damage the atmosphere, depleting the ozone layer that protects the planet from damaging ultraviolet rays that could trigger mass extinctions. It’s also possible that gamma-ray bursts may spew out cosmic rays, which are high-energy particles that may create an experience similar to a nuclear explosion for those on the side of the Earth facing the explosion, causing radiation sickness.

    To see how great a threat gamma-ray bursts might pose to Earth, researchers investigated how likely it was that such an explosion could have inflicted damage on the planet in the past.

    Gamma-ray bursts are traditionally divided into two groups — long and short — depending on whether they last more or less than 2 seconds. Long gamma-ray bursts are associated with the deaths of massive stars, while short gamma-ray bursts are most likely caused by the mergers of neutron stars.

    For the most part, long gamma-ray bursts happen in galaxies very different from the Milky Way — dwarf galaxies low in any element heavier than hydrogen and helium. Any long gamma-ray bursts in the Milky Way will likely be confined in regions of the galaxy that are similarly low in any element heavier than hydrogen and helium, the researchers said.

    The scientists discovered the chance that a long gamma-ray burst could trigger mass extinctions on Earth was 50 percent in the past 500 million years, 60 percent in the past 1 billion years, and more than 90 percent in the past 5 billion years. For comparison, the solar system is about 4.6 billion years old.

    Short gamma-ray bursts happen about five times more often than long ones. However, since these shorter bursts are weaker, the researchers found they had negligible life-threatening effects on Earth. They also calculated that gamma-ray bursts from galaxies outside the Milky Way probably pose no threat to Earth.

    These findings suggest that a nearby gamma-ray burst may have caused one of the five greatest mass extinctions on Earth, such as the Ordovician extinction that occurred 440 million years ago. The Ordovician extinction was the earliest of the so-called Big Five extinction events, and is thought by many to be the second largest.

    The scientists also investigated the danger that gamma-ray bursts may pose for life elsewhere in the Milky Way. Stars are packed more densely together toward the center of the galaxy, meaning worlds there face a greater danger of gamma-ray bursts. Worlds in the region about 6,500 light-years around the Milky Way’s core, where 25 percent of the galaxy’s stars reside, faced more than a 95 percent chance of a lethal gamma-ray burst within the past billion years. The researchers suggest that life as it is known on Earth could survive with certainty only in the outskirts of the Milky Way, more than 32,600 light-years from the galactic core.

    The researchers also explored the danger gamma-ray bursts could pose for the universe as a whole. They suggest that because of gamma-ray bursts, life as it is known on Earth might safely develop in only 10 percent of galaxies. They also suggest that such life could only have developed in the past 5 billion years. Before then, galaxies were smaller in size, and gamma-ray bursts were therefore always close enough to cause mass extinctions to any potentially life-harboring planets.

    “This may be an explanation, or at least a partial one, to what is called the Fermi paradox or the ‘Big Silence,'” said lead study author Tsvi Piran, a physicist at the Hebrew University in Jerusalem. “Why we haven’t encountered advanced civilizations so far? The Milky Way galaxy is much older than the solar system and there was ample time and ample space — the number of planetary systems with conditions similar to Earth is huge — for life to develop elsewhere in the galaxy. So why we haven’t encountered advanced civilizations so far?”

    The answer to Fermi’s paradox may be that gamma-ray bursts have struck many life-harboring planets. The most severe criticism of these estimates “is that we address life as we know it on Earth,” Piran told Live Science. “One can imagine very different forms of life that are resilient to the relevant radiation.”

    Piran and his colleague, Raul Jimenez, detailed their findings online today (Dec. 5) in the journal Physical Review Letters.

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  • richardmitnick 5:37 pm on December 7, 2014 Permalink | Reply
    Tags: , , China, Space Exploration, space.com   

    From SPACE.com: “China Has Big Plans to Explore the Moon and Mars” 

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    SPACE.com

    December 03, 2014
    Leonard David

    China continues to ramp up its space activities, which include a new launch complex, more powerful boosters and the construction of a large space station, as well as plans for complex robotic missions to the moon and Mars.

    For example, China’s “little fly” spacecraft looped around the moon and returned to Earth Nov. 1 (Beijing time) after eight days of flight, parachuting safely down in northern China’s Inner Mongolia.

    The capsule used seven kinds of thermal protection materials, returning data that will be applied to China’s Chang’e 5 robotic lunar sample return mission, which is slated to launch in 2017 from the new Wenchang Satellite Launch Center.

    In the human spaceflight arena, China’s manned space agency is readying the Wenchang Satellite Launch Center for liftoff around 2016, which will be followed by the crewed Shenzhou 11 spacecraft and a Tianzhou cargo vessel that will rendezvous with the lab.

    Chinese officials expect that the core space station module will be launched around 2018, and the orbiting facility is slated to be completed by about 2022.

    All of these plans form a comphrehensive space exploration agenda for the coming years.

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    China’s new Wenchang Satellite Launch Center on Hainan island is reportedly completed and will handle an array of Earth-orbiting and deep-space missions. Credit: CMSE

    Incremental steps

    The Lunar Exploration Analysis Group (LEAG), an assembly of experts convened by NASA to assist in planning the scientific exploration of the moon, is eyeing China’s growing lunar exploration capacity.

    “China has had a well developed, focused plan, and they are using incremental steps to lunar exploration,” said Jeffrey Plescia, chairman of LEAG. “Each mission has achieved the primary goal — orbiters, landing, rovers — leading up to sample return and then on to humans.”

    The objective of the recent test of the lunar sample return capsule was to demonstrate gear that can return from the moon and land safely.

    “I would guess that, given the pieces they have tested, that they have a high probability of success on the sample return,” Plescia told Space.com. “My personal guess, though, is that their lunar exploration, while trying to do some science, is more focused on the geopolitical theater. They are demonstrating that they have the technical capability of doing the most sophisticated deep-space activities. They have a program, and they can keep to the schedule and accomplish mission goals on time.”

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    China made history on Dec. 14, 2013 with the successful landing of its Chang’e 3 lander carrying the Yutu rover. The mission is the first soft-landing on the moon since 1976 and made China only the third country ever perform the lunar feat.
    Above: China’s lunar rover Yutu (“Jade Rabbit”) is seen by a camera on the country’s Chang’e 3 lander after both successfully landed on the moon together on Dec. 14, 2013

    In comparison, Plescia said, “the United States has been floundering around for decades, trying to figure out what to do.”

    In the meantime, the U.S. has de-emphasized manned missions into space, instead focusing on a robotic science program that is “myopic at best,” as it’s narrowly focused on Mars, Plesica said. However, he added that the U.S.’ Mars missions have provided a lot of surface detail and made a number of impressive discoveries.

    “The real problem [in the U.S.] is the lack of direction and commitment,” Plescia said. “I think, like others, that the moon is key to understanding how to live and work in space and explore the solar system.”

    Expanded access to space

    China’s space program has been extremely active recently, said Dean Cheng, a research fellow on Chinese political and security affairs at the Heritage Foundation in Washington, D.C.

    Several Shijian and Yaogan satellites — two series of spacecraft that are believed to have military functions — have been launched in 2014. The “little fly” probe circumnavigated the moon, performing a vital precursor of any human lunar missions, he said. Also, the Chinese recently displayed a Mars rover at a popular air show, and there are reports that the country could dispatch a robotic Red Planet mission by the end of the decade.

    In the interim, Chinese officials have discussed the possibility of even more powerful rockets than the still-under-development Long March 5 booster, Cheng said. In addition, the new Wenchang launch site on Hainan is apparently ready for a public unveiling, he said.

    “This new facility will be China’s southernmost launch site, with obvious benefits in terms of payload. It will also be China’s first launch facility that is located on the coast,” Cheng said. “Larger Chinese launch vehicles will now be possible, since they can be shipped to the new launch facility by sea, rather than [be] limited by Chinese railway tunnel widths and track curvature.”

    “When the Wenchang satellite launch center is officially opened, it will mark a further step in China’s efforts to expand its access to space,” with the ability to hurl heavier payloads into space, Cheng told Space.com. “These are expected to include a Chinese space station, lunar sample retrieval mission and a Mars rover.”

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    China’s Automated Re-Entry Capsule
    A recent ceremony in China showcased the automated re-entry capsule that flew a circumlunar trajectory and returned to Earth under parachute. The capsule housed various items, including the Chinese flag. Credit: CASC

    Long-term commitment

    China also established new space ties with 4M (the Manfred Memorial Moon Mission), the first private mission to the moon, suggesting an interesting link between China and private space entrepreneurs, Cheng said. There are also reports of cooperation between China and Russia, and one or more joint space ventures may be announced in 2015, he said.

    “All of this is a reminder that China’s space development efforts are likely to continue sustained interest under the new Chinese leader, Xi Jinping, as it did under his predecessors Hu Jintao, Jiang Zemin and Deng Xiaoping,” Cheng said.

    “Despite reports of a slowing economy, at this point, there does not seem to be much evidence that the space development effort is suffering any budgetary cutbacks,” he added.

    Indeed, China’s long-term commitment to space development is one of that nation’s great strengths, Cheng said, “as it supports sustained development of program[s], rather than a ‘feast or famine’ approach.”

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    China is readying the Tiangong 2 space lab for liftoff around 2016. Once in orbit, it would be followed by the piloted Shenzhou 11 spacecraft and a Tianzhou cargo vessel that will rendezvous with the lab. Credit: CCTV

    Investment in space

    “China is continuing to pursue a number of goals it decided upon decades ago,” said Gregory Kulacki, senior analyst and China project manager for the Global Security Program at the Union of Concerned Scientists (UCS), based in Cambridge, Mass.

    Like Cheng, Kulacki believes the launch facility on the island of Hainan is a key new capability.

    “It has been on the drawing board for quite a long time, and has experienced numerous delays, but is now prepared to serve as the home space port for China’s new generation of wider-bodied launch vehicles that can carry larger payloads,” Kulacki told Space.com. “These new vehicles have also experienced some delays, but China has no fixed deadlines to meet.”

    “As these major new pieces of China’s space infrastructure come online, including new satellite manufacturing facilities in Tianjin, the pace and scale of its activities in space will continue to grow,” Kulacki said. “China already has considerable space assets on orbit, and its investment in space will continue to increase significantly over the next several decades.”

    People who claim China is pursuing an asymmetric space warfare strategy misread the nation’s intentions, Kulacki said. Rather, “the strategic objective of Chinese space policy is not to exploit asymmetry between China and the United States, but to end it,” he said.

    See the full article here.

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  • richardmitnick 6:13 pm on December 6, 2014 Permalink | Reply
    Tags: , , , , Dwarf Planet Pluto, space.com   

    From SPACE.com- “Dwarf Planet Pluto: Facts About the Icy Former Planet” 

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    SPACE.com

    November 03, 2014
    Charles Q. Choi

    Pluto is the only dwarf planet to once have been considered a major planet. Once thought of as the ninth planet and the one most distant from the sun, Pluto is now seen as one of the largest known members of the Kuiper Belt, a shadowy disk-like zone beyond the orbit of Neptune populated by a trillion or more comets.

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    Known objects in the Kuiper belt, derived from data from the Minor Planet Center. Objects in the main belt are colored green, whereas scattered objects are colored orange. The four outer planets are blue. Neptune’s few known trojans are yellow, whereas Jupiter’s are pink. The scattered objects between Jupiter’s orbit and the Kuiper belt are known as centaurs. The scale is in astronomical units. The pronounced gap at the bottom is due to difficulties in detection against the background of the plane of the Milky Way.

    Pluto was reclassified as a dwarf planet in 2006, a change widely thought of as a demotion that has attracted controversy and debate that has continued in scientific communities for the last eight years.

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    A best-fit color image/map of Pluto generated with the Hubble Space Telescope and advanced computers. It is unknown if the brightness differences are mountains, craters, or polar caps.
    4 February 2010
    Source http://hubblesite.org/newscenter/archive/releases/2010/06/image/d/
    NASA, ESA, and Marc W. Buie (Southwest Research Institute)

    American astronomer Percival Lowell first caught hints of Pluto’s existence in 1905 from odd deviations he observed in the orbits of Neptune and Uranus, suggesting that another world’s gravity was tugging at them from beyond. He predicted its location in 1915, but died without finding it. Its discovery came in 1930 from Clyde Tombaugh at the Lowell Observatory, based on predictions from Lowell and other astronomers.

    Pluto is the only world named by an 11-year-old girl, Venetia Burney of Oxford, England, who suggested to her grandfather that it get its name from the Roman god of the underworld. Her grandfather then passed the name on to Lowell Observatory. The name also honors Percival Lowell, whose initials are the first two letters of Pluto.
    Physical characteristics

    Since Pluto is so far from Earth, little is known about the planet’s size or surface conditions. Pluto has an estimated diameter less than one-fifth that of Earth or only about two-thirds as wide as Earth’s moon. The planets’ surface conditions probably consist of a rocky core surrounded by a mantle of water ice, with more exotic ices such as methane and nitrogen frost coating its surface. NASA’s Hubble Space Telescope also revealed evidence that Pluto’s crust could contain complex organic molecules. Chemicals such as nitrogen and methane may lay frozen beneath the icy crust.

    Pluto’s orbit is highly eccentric, or far from circular, which means its distance from the sun can vary considerably and at times, Pluto’s orbit will take it within the orbit of the planet Neptune. When Pluto is closer to the sun, its surface ices thaw and temporarily form a thin atmosphere, mostly of nitrogen, with some methane. Pluto’s low gravity, which is a little more than one-twentieth that of Earth’s, causes this atmosphere to extend much higher in altitude than Earth’s. When traveling farther away from the sun, most of Pluto’s atmosphere is thought to freeze and all but disappear. Still, in the time that it does have an atmosphere, Pluto can apparently experience strong winds.

    Pluto’s surface is one of the coldest places in the solar system at roughly minus 375 degrees F (minus 225 degrees C). For a long time, astronomers knew little about its surface because of its distance from Earth, but more is coming, bit by bit, with the Hubble Space Telescope returning images of a planet that appears reddish, yellowish and grayish in places, with a curious bright spot near the equator that might be rich in carbon monoxide frost. When compared with past images, the Hubble pictures revealed that Pluto had apparently grown redder over time, apparently due to seasonal changes.

    NASA Hubble Telescope
    NASA/ESA Hubble

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    This is the most detailed view to date of the entire surface of the dwarf planet Pluto, as constructed from multiple NASA Hubble Space Telescope photographs taken from 2002 to 2003.
    Credit: NASA, ESA, and M. Buie (Southwest Research Institute)
    View full size image

    Orbital characteristics

    Pluto’s highly elliptical orbit can take it more than 49 times as far out from the sun as Earth. It actually gets closer to the sun than Neptune for 20 years out of Pluto’s 248-Earth-years-long orbit, providing astronomers a rare chance to study this small, cold, distant world. So after 20 years as the eighth planet (in order going out from the sun), in 1999, Pluto crossed Neptune’s orbit to become the farthest planet from the sun (until it was demoted to the status of dwarf planet).

    Composition & structure

    Atmospheric composition: Methane, nitrogen

    Magnetic field: It remains unknown whether Pluto has a magnetic field, but its small size and slow rotation suggest it has little to none.

    Chemical composition: Probably a mixture of 70 percent rock and 30 percent water ice.

    Internal structure: Probably a rocky core surrounded by a mantle of water ice, with more exotic ices such as methane and nitrogen frost coating its surface.

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    Dwarf planet Pluto was discovered in 1930 and was once considered to be the ninth planet from the sun in Earth’s solar system.
    Credit: Karl Tate, SPACE.com

    Orbit & rotation

    Average distance from the sun: 3,670,050,000 miles (5,906,380,000 km) — 39.482 times that of Earth

    Perihelion (closest approach to the sun): 2,756,902,000 miles (4,436,820,000 km) — 30.171 times that of Earth

    Aphelion (farthest distance from the sun): 4,583,190,000 miles (7,375,930,000 km) — 48.481 times that of Earth
    Pluto’s moons

    In 1978, astronomers discovered Pluto had a very large moon nearly half its size, dubbed Charon, named for the mythological demon who ferried souls to the underworld in Greek mythology. The huge size of Charon sometimes leads scientists to refer to Pluto and Charon as a double dwarf planet or binary system.

    Pluto and Charon are just 12,200 miles (19,640 km) apart, less than the distance by flight between London and Sydney. Charon’s orbit around Pluto takes 6.4 Earth days, and one Pluto rotation — a Pluto day — also takes 6.4 Earth days. This is because Charon hovers over the same spot on Pluto’s surface, and the same side of Charon always faces Pluto, a phenomenon known as tidal locking.

    While Pluto appears reddish, Charon seems grayish. Scientists suggest Pluto is covered with nitrogen and methane while Charon is covered with ordinary water ice. In its early days, the moon may have contained a subsurface ocean, though it probably can’t support one today.

    Compared with most of solar system’s planets and moons, the Pluto-Charon system is tipped on its side in relation to the sun. Also, Pluto’s rotation is retrograde compared to the other worlds — it spins backward, from east to west.

    In 2005, as scientists photographed Pluto with the Hubble Space Telescope in preparation for the New Horizons mission — the first spacecraft to visit Pluto and the Kuiper Belt — they discovered two other tiny moons of Pluto, now dubbed Nix and Hydra. These are two to three times farther away from Pluto than Charon, and they are thought to be just 31 to 62 miles (50 to 100 km) wide.

    NASA New Horizons spacecraft
    NASA/New Horizons

    Scientists using Hubble discovered a fourth moon, Kerberos, in 2011. This moon is estimated to be 8 to 21 miles (13 to 34 km) in diameter. P4’s orbit is between the orbits of Nix and Hydra. On July 11, 2012, a fifth moon Styx, was discovered, fueling the debate about Pluto’s status as a planet.

    The four newly spotted moons may have formed from the collision that created Charon, hurled away from Pluto by the gravity of the massive moon.

    Research & exploration

    Pluto’s distance from Earth has made it hard to see with telescopes and a daunting challenge to explore with spacecraft — NASA’s New Horizons mission will be the first probe to study Pluto, its moons, and other worlds within the Kuiper Belt. It was launched on January 2006, making its closest approach to Pluto on July 2015, and carries some of the ashes of Pluto’s discoverer, Clyde Tombaugh.

    The limited knowledge of Pluto creates unprecedented dangers for the exploration. Prior to the mission’s launch, scientists only knew about the existence of three moons. The discovery of Keberos and Styx during the spacecraft’s journey fueled the idea that more satellites could orbit the dwarf planet, unseen from Earth. Not only the moons, but the debris fields they may have created, could prove hazardous to New Horizons.
    Pluto’s formation & origins

    The leading theory for the formation of Pluto and Charon is that a nascent Pluto was struck with a glancing blow by another Pluto-sized object. Most of the combined matter became Pluto, while the rest spun off to become Charon.

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    See the full article, with video, here
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