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  • richardmitnick 9:10 am on December 31, 2019 Permalink | Reply
    Tags: "An Australian Crater Could Force Us to Rethink How We Judge a Planet's Age", , , , , Curiosity, , ,   

    From Curiosity: “An Australian Crater Could Force Us to Rethink How We Judge a Planet’s Age” 

    Curiosity Makes You Smarter

    From From Curiosity

    December 20, 2019
    Elizabeth Howell

    1
    Wolfe Creek Crater: the second largest meteor impact site in the world. Dainis Dravins – Lund Observatory, Sweden.

    A rock the size of a semitrailer that smacked Australia more than 100,000 years ago could help us better understand the universe. Astronomers just recalculated the age of an ancient desert crater [Meteoritics & Planetary Science] and discovered that it’s much younger than previously thought. By studying craters on Earth, we can better estimate how often comets and meteorites smacked into worlds around our solar system, thereby calculating their ages — and based on this work, we may have to rethink everything we know.

    Younger Than It Looks

    The scar of that ancient collision in Australia is called Wolfe Creek Crater, and it’s rather large, having been formed by a meteorite that was likely 50 feet (15 meters) in diameter. The object slammed into the desert and created a divot that’s been deemed the second largest crater on Earth from which fragments of the meteorite were recovered. Craters often disappear underwater or via geologic activity, so we’re lucky to have this find available to us.

    Scientists initially pegged the crater as 300,000 years old, putting it at about the same age as the human species. But the new estimate suggests it’s actually quite a bit younger, at only 120,000 years old, dating back to a warmer period on Earth known as the Eemian interglacial period. (On a side note, the Eemian is interesting to scientists studying climate change today, as some studies suggest our Earth nowadays is as warm as it was way back then.)

    How did this new age estimate arise? It was probably in part due to the fact that we have better scientific equipment than we did before. Also, researchers used two independent dating techniques: exposure dating, which estimates how long the sediment has been exposed to cosmic rays on the Earth’s surface, and optically stimulated luminescence, which measures how long ago sediment — in this case, sand buried after the impact — was last exposed to sunlight.

    “Results from the two dating techniques mutually support each other within the same age range,” said lead author Tim Barrows in a statement.

    Counting Craters

    Re-dating the crater in Australia has implications that could rock our solar system. There are planets and moons and tiny worlds with rocky surfaces all over our planetary neighborhood, some of the more famous being Mercury, the Moon, and Pluto. Astronomers estimate the age of their surfaces by using a technique called crater counting, which is exactly what it sounds like: They count the number of craters in an area and compare that number with an estimate of how often a small world smacks into the surface.

    Simply put, if scientists find a crater that’s younger than expected, that might mean that the rate of objects hitting Earth (and other worlds) slightly increases. With this new measurement, the research team estimates that large objects smack into our planet about once every 180 years or so. In roughly the last century, we know of two such events: an object that flattened 800 square miles (2,000 square kilometers) of forest in Tunguska, Siberia in 1908, and another that shattered glass and injured people when it broke up over the Russian town Chelyabinsk in 2013.

    NASA is, of course, on the case with a fleet of telescopes scanning the sky for any possible threats to Earth. Fortunately, they’ve found nothing pressing that could flatten a city, although they continue the search just in case — and they’re also aware that smaller objects (like Chelyabinsk) can still sneak through since they’re below the detection threshold of some telescopes. However, don’t lose any sleep yet. The agency will let us know if they find something worrying.

    In the meantime, the larger implication to take from this study is that the ages of craters all over the solar system may have to be reconsidered. The famous Meteor Crater in Arizona, for example, got a similar treatment from these researchers. They calculated that it’s likely to be 61,000 years old, which is about 10,000 years younger than previously estimated. So it will be interesting to see how this changes our understanding of ancient climates and life on our own planet — and on other worlds

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 9:10 am on December 30, 2019 Permalink | Reply
    Tags: , , , , , Curiosity, , ,   

    From Curiosity: “How Big (or Small) Can a Black Hole Get?” 

    Curiosity Makes You Smarter

    From From Curiosity

    December 21, 2019
    Matthew R. Francis

    The biggest astronomy story of 2019 arguably was the first-ever image of a black hole, captured by a world-spanning observatory, the Event Horizon Telescope.

    Event Horizon Telescope Array

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)


    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    Future Array/Telescopes

    IRAM NOEMA in the French Alps on the wide and isolated Plateau de Bure at an elevation of 2550 meters, the telescope currently consists of ten antennas, each 15 meters in diameter.interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

    NSF CfA Greenland telescope


    Greenland Telescope

    ARO 12m Radio Telescope, Kitt Peak National Observatory, Arizona, USA, Altitude 1,914 m (6,280 ft)


    ARO 12m Radio Telescope

    Caltech Owens Valley Radio Observatory, located near Big Pine, California (US) in Owens Valley, Altitude1,222 m (4,009 ft)

    The first image of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via JPL/ Event Horizon Telescope Collaboration.

    One big reason this achievement was so astounding is because black holes are relatively tiny compared to their mass: this black hole is 6.5 billion times the mass of our sun, but in overall size, it’s comparable to the size of the solar system. So what sets the size of a black hole, and how big — or small — can they get? And what does the size of a black hole even mean?

    Beyond the Blue Event Horizon

    Black holes are objects of pure gravity: they don’t have chemical composition or any of the defining characteristics of stars, planets, and other more ordinary inhabitants of the universe. That means they don’t have a surface, atmosphere, or any of the usual things that indicate size.

    Instead, a black hole’s size is defined by its event horizon, which is the boundary past which nothing can escape the gravitational pull, not even light. So even though no material is actually at the horizon, it’s what matters. We literally can’t study what’s inside it.

    Unlike stars, which change size a lot over their lifetimes, a black hole’s size is entirely determined by two factors: its mass and how fast it spins. (Technically it could also carry an electric charge, but realistic black holes probably don’t have enough charge buildup to make a measurable difference.) If it’s not spinning, the diameter of a black hole is approximately 6 kilometers (3.7 miles) for each solar mass — the mass of one sun — it packs in. In other words, a one-solar-mass black hole would be 6 kilometers across, while a 10 solar mass black hole is 60 kilometers (37.3 miles) across. To be very clear, that’s very tiny compared to its mass: the sun is 1.4 million kilometers (865,000 miles) in diameter, while a black hole of equivalent mass has a diameter less than many foot races.

    Realistic black holes spin, though, based on astronomical observations. This rotation shrinks the event horizon diameter by as much as half, making realistic black holes even tinier in comparison to their masses. The rapidly-spinning 6.5 billion solar mass black hole in M87 is the size of a solar system, but 6.5 billion stars are enough for a small galaxy.

    Absolute Units

    Even M87’s black hole isn’t as massive as they get. The record-holder is a 40 billion solar mass giant in the galaxy Holm 15A, and it’s possible even bigger black holes lurk elsewhere. That’s because the only upper limit on a black hole’s size is a practical one.

    In fact, how supermassive black holes get that big is still mysterious. They seem to have formed to be that massive, based on observations of galaxies from early times. However, they can also get bigger by eating matter — though like Cookie Monster, they’re messy eaters — and by merging with other black holes. We haven’t seen that happen for supermassive black holes yet, so between that and the messiness of black hole eating habits, it’s unlikely black holes can get too much bulkier than Holm 15A over the 13.8 billion year history of the universe so far.

    How Low Can You Go?

    Supermassive black holes are outnumbered by their “stellar mass” cousins, which are no bigger than a few dozen solar masses. These are formed from the supernova explosions of very massive stars, which sets a lower limit on stellar-mass black holes: they can’t be any smaller than three solar masses (give or take) because smaller stars leave behind neutron stars or white dwarfs rather than black holes.

    Since stars only grow so large before they’re too unstable, scientists predict the maximum is about 20 solar masses. However, the gravitational wave observatories LIGO and Virgo have identified multiple stellar-mass black holes bigger than that, and astronomers detected what might be a 70-solar-mass black hole in the Milky Way, so we still have some mysteries to solve.

    MIT /Caltech Advanced aLigo


    VIRGO Gravitational Wave interferometer, near Pisa, Italy

    Milky Way Credits: NASA/JPL-Caltech /ESO R. Hurt. The bar is visible in this image

    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    SgrA* NASA/Chandra supermassive black hole at the center of the Milky Way, X-ray image of the center of our galaxy, where the supermassive black hole Sagittarius A* resides. Image via X-ray: NASA/UMass/D.Wang et al., IR: NASA/STScI.

    Sgr A* from ESO VLT

    Star S0-2 Andrea Ghez Keck/UCLA Galactic Center Group at SGR A*, the supermassive black hole at the center of the milky way

    Some theories also predict smaller black holes that formed in the very early universe. These primordial black holes could range in size from smaller than atoms to very large, with the smaller variety being more likely. However, we’ve never convincingly seen primordial black holes, and various studies have limited how many of them there might be in the universe. Rare or common, truly tiny black holes weighing in at less than a gram would be very difficult to detect, since the way we find their astronomical relatives is by their influence on nearby stars or gas.

    As a result, the universe could conceivably contain really low-mass black holes and we’d never know it without a lucky break. However, the monsters like that of M87 are the ones that will continue to give us the best shot at seeing the way black holes twist and bend spacetime, as small (relatively) as they are.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 6:00 pm on December 22, 2019 Permalink | Reply
    Tags: Apollo 12 mission, Curiosity,   

    From Curiosity: “The Apollo 12 Mission Had a Curious Claim of Bacterial Life” 

    Curiosity Makes You Smarter

    From From Curiosity

    December 20, 2019
    Elizabeth Howell

    1
    View, during NASA’s Apollo 12 mission, of the ‘Intrepid’ Lunar Module as it descends to the surface of the moon, November 19, 1969.
    Interim Archives—Getty Images

    Pieces of a craft that spent two years on the moon in the 1960s turned out to harbor something unexpected: bacteria. Did microbes successfully stow away for a moon mission and survive their return to Earth, or were they introduced during later testing? That’s one of the mysteries surrounding the Apollo 12 mission, which brought pieces of the Surveyor 3 robot back to Earth 50 years ago. Here are the latest theories about what happened.

    Surviving Space?

    The story begins with Apollo 12 astronaut Pete Conrad making a remarkable pinpoint landing on the Ocean of Storms in November 1969, fulfilling the mission objective to land within walking distance of the Surveyor 3 spacecraft that landed two years beforehand. Engineers were curious about how radiation in space might change a spacecraft over time, which is important if you want to design a durable spacecraft.

    Astronauts Conrad and Alan Bean dutifully returned some pieces of Surveyor 3 back to Earth — the TV camera, some electrical cables, a sample scoop, and two pieces of aluminum tubing, according to NASA. What some scientists found in those samples has been the subject of Internet rumors ever since.

    One research group recovered a little bit of the bacterium Streptococcus mitis, a harmless microorganism that lives in the human nose, throat, and mouth, in some foam within Surveyor 3’s newly returned camera. Surveyor 3 hadn’t been sterilized before going to the moon, and this research group supposed that microbes in the foam had survived the launch, the vacuum of space, and three years on the moon without any source for continuing life, such as water or nutrients. But there’s another explanation that you should consider first.

    2
    NASA

    Earthly Contamination?

    We’ve learned a lot about microbiology and about protecting spacecraft in the last 50 years, and the standards we use today are a lot higher than at the end of the 1960s. For example, the camera came back in a nylon duffel bag that was not airtight, unlike the lunar samples themselves.

    “Some people associated with the curation of the Surveyor 3 materials have suggested that the one positive detection of life may be the result of accidental contamination of the material after it was returned to Earth,” NASA said in a statement on the experiment. And there are other explanations, too, including that perhaps the researchers had a false-positive result — that is, maybe they’d incorrectly detected microbes that weren’t actually there.

    NASA noted another thing that probably would not be done today: “One of the implements being used to scrape samples off the Surveyor parts could have been laid down on a non-sterile laboratory bench, and then was used to collect surface samples for culturing. It is, therefore, quite possible that the microorganisms were transferred to the camera after its return to Earth.”

    3
    NASA

    So what’s the verdict between the microbes surviving space for three years, or transferring through simple contamination? It’s hard to say for sure because we can’t repeat the experiment. However, the scientific community is leaning more towards the contamination hypothesis, according to a 2008 statement from one of NASA’s institutes. This hypothesis was also supported in a 2011 conference presentation with a team that included a NASA scientist. The agency tries to take it as a lesson learned when it prepares for missions to places like Mars. The Mars 2020 rover is being designed to search for signs of ancient life, and NASA needs to take every precaution to ensure any life they find is truly Martian.

    Today, you can see the very camera that harbored these microbes at the Smithsonian Institution — a popular location for many space artifacts. The microbe mystery is a fun history lesson to consider and teaches us the importance of always checking claims carefully before accepting them at face value.

    5
    Surveyor III Television Camera
    The television camera from the Surveyor III spacecraft was removed from Surveyor, about two-and-a-half years after the spacecraft landed, by the crew of Apollo 12 and returned to Earth. Smithsonian Ait and Space Museum

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 11:12 am on December 5, 2019 Permalink | Reply
    Tags: "There's an Easy Trick to Telling Stars and Planets Apart in the Sky", , , , , Curiosity   

    From Curiosity: “There’s an Easy Trick to Telling Stars and Planets Apart in the Sky” 

    Curiosity Makes You Smarter

    From From Curiosity

    January 25, 2018 [Just now in social media]
    Cody Gough

    Look up in the night sky, and you’ll see millions of stars and a handful of planets. How can you tell the difference? Just remember: The classic lullaby doesn’t go “twinkle, twinkle, little planet.” There’s a reason for that.
    Planet Light, Planet Bright, First Planet I See Tonight

    Stars twinkle because of the massive distance between them and Earth. And we mean massive: Our sun’s closest stellar neighbors are more than four light-years away. Because of that great distance, we essentially see each star as a single point of light — a shape with almost zero diameter. Once it hits Earth, that starlight is refracted by the various differences of temperature and density as it makes its way through our atmosphere. The refraction is greater than the star’s tiny diameter, so it’s easy to see — and to us, it looks like twinkling. The scientific term for this is astronomical scintillation.

    Our sun and the planets in our solar system are much closer than the rest of the stars in the sky. Earth’s atmosphere refracts light from those, too, but since they’re a lot closer to us, they show up with a larger diameter than those faraway stars. This makes them look more like tiny disks than pinpoints — something you might not notice with the naked eye but that’s easy to see with binoculars or a telescope. The light from one edge of that disk might be forced to “zig” in one direction, but light from the opposite side might “zag” in an opposite direction. Those opposing directions effectively cancel each other out, producing a steady shine that doesn’t twinkle like a little star.

    1

    Lost in Space

    Experienced stargazers can figure out which objects are stars and which are planets just by observing which ones twinkle and which ones don’t. But keep in mind that sometimes planets twinkle, too, if you spot them low in the sky. That’s because when you look toward the horizon, you’re looking through more atmosphere than when you’re looking straight up. This means more light refraction, which means more of that astronomical scintillation — aka twinkling.

    If you ever get a chance to visit outer space, of course, then you can expect to see a distinct lack of twinkling to go along with that distinct lack of atmosphere. The lack of light refraction from the atmosphere is why we put telescopes up in space, helping behemoths like the Hubble Space Telescope produce the brilliant and crisp images of the universe that make it famous. But that’s not the only difference you’ll notice in space.

    NASA astronaut James Reilly told SpaceFlight Insider that once your eyes adjust during a spacewalk, “you can start to notice that some of the stars have colors we don’t see here on the ground.

    So you see these pastel colors — light yellows, light pinks, light oranges, even light red ones and light blues — there’s all kinds of colors that you can see in these stars that you can’t see here because it’s filtered out by the atmosphere.”

    Twinkling Is in the Eye of the Beholder

    One other quirk of stargazing is that bright objects in the sky look different to everyone — even different telescopes. The four points emanating from stars in images from the Hubble Telescope, for example, happen in any telescope that focuses light with a mirror rather than with a lens. The four points are known as diffraction spikes and are caused by the light’s path being diffracted slightly as it passes by the cross-shaped struts that support the telescope’s secondary mirror.

    Distortion isn’t just for telescopes. Remember, the human eye has a lens, too! Those lenses have subtle structural imperfections called suture lines that show up where the lens fibers meet together. These imperfections leave a particular imprint on light as it reaches your eyes, so even though stars actually appear as tiny round dots, our lenses have smeared the light into a star-like shape by the time the light reaches our retinas. Because we’re all different, every eye on Earth will see a slightly different star-like smear depending on the exact nature of its suture lines; even your own left and right eyes will differ. But every eye sees the same shape for every single star. Try closing one eye the next time you’re looking up at the sky and see what happens!

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 9:14 am on December 2, 2019 Permalink | Reply
    Tags: "The Universe's Baby Picture Could Help Us Predict Its Future", , , , , , Curiosity, ,   

    From Curiosity: “The Universe’s Baby Picture Could Help Us Predict Its Future” 

    Curiosity Makes You Smarter

    From From Curiosity

    September 18, 2018 [Just now in social media]
    Elizabeth Howell

    Look up at the sky and you see stars and galaxies and planets. But way in the background lurks an interesting form of radiation known as the Cosmic Microwave Background [CMB]. That’s the universe’s baby picture, and when we study that picture, we don’t only see its past — we also see its future.

    CMB per ESA/Planck

    ESA/Planck 2009 to 2013

    What’s Behind the Baby Face?

    Next time you pull out your baby pictures, take a look at the details: what you looked like, who you were with, what you were doing. Often, we can “see” a bit of ourselves today by looking at what we used to be long ago. Our parents, friends, and activities all shaped us into the person we became.

    This concept not only works for people, but it’s also a useful analogy for science. Even our 13.8-billion-year-old universe was a baby in a time long, long ago – just after the universe was formed in an event known as the Big Bang. Shortly after birth, the universe was so hot and so dense that not even light could penetrate the tiny cocoon. Then space expanded rapidly, allowing light to shine through and molecules to come together.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    The first stars and galaxies turned on, and just after them came the first planets.

    Funny enough, we can still see evidence of all that activity by using microwaves. Light is in a spectrum; we can see some of it with our eyes, but there are other forms of light, like X-rays and microwaves, that we can’t see except with telescopes or other scientific instruments. Microwaves have extremely long wavelengths, and by using them, we can peer all the way back to the universe’s first few thousand years. Scientists call this “baby picture” the Cosmic Microwave Background, or CMB.

    1
    NASA WMAP

    NASA/WMAP 2001 to 2010

    Later this month, NASA will send a balloon with a science experiment — known as the Primordial Inflation Polarization Explorer (PIPER) — to the edge of our atmosphere.

    3

    There, PIPER will take more baby pictures of the universe. But why do we care in the first place? What’s the use of looking at the radiation of the universe from so long ago, at a time long before the Earth formed? What’s the point?

    Well, for one thing, it will help us understand the universe’s ultimate fate. Maybe we’re going to keep expanding forever, or maybe we’re going to collapse into a huge crunch. We can best understand this by mapping what the universe is made of. A past mission called the Wilkinson Microwave Anisotropy Probe (WMAP) helped scientists come up with some estimates.

    It turns out that 5 percent of the matter in the universe is normal matter, the kind that telescopes can see. The rest (95 percent) is made up of dark energy and dark matter that telescopes can’t sense except through their effects on normal matter, such as the way they bend light.

    Dark energy and dark matter are exotic and we know little about them, but they’re still super important. They make up most of the mass of the universe. They alter the paths of light and of other objects. And by studying dark matter and dark energy, we can understand how fast the universe is expanding and whether the universe will expand forever, which most scientists think is likely.

    Dark Energy Survey


    Dark Energy Camera [DECam], built at FNAL


    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    Timeline of the Inflationary Universe WMAP

    The Dark Energy Survey (DES) is an international, collaborative effort to map hundreds of millions of galaxies, detect thousands of supernovae, and find patterns of cosmic structure that will reveal the nature of the mysterious dark energy that is accelerating the expansion of our Universe. DES began searching the Southern skies on August 31, 2013.

    According to Einstein’s theory of General Relativity, gravity should lead to a slowing of the cosmic expansion. Yet, in 1998, two teams of astronomers studying distant supernovae made the remarkable discovery that the expansion of the universe is speeding up. To explain cosmic acceleration, cosmologists are faced with two possibilities: either 70% of the universe exists in an exotic form, now called dark energy, that exhibits a gravitational force opposite to the attractive gravity of ordinary matter, or General Relativity must be replaced by a new theory of gravity on cosmic scales.

    DES is designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision. More than 400 scientists from over 25 institutions in the United States, Spain, the United Kingdom, Brazil, Germany, Switzerland, and Australia are working on the project. The collaboration built and is using an extremely sensitive 570-Megapixel digital camera, DECam, mounted on the Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory, high in the Chilean Andes, to carry out the project.

    Over six years (2013-2019), the DES collaboration used 758 nights of observation to carry out a deep, wide-area survey to record information from 300 million galaxies that are billions of light-years from Earth. The survey imaged 5000 square degrees of the southern sky in five optical filters to obtain detailed information about each galaxy. A fraction of the survey time is used to observe smaller patches of sky roughly once a week to discover and study thousands of supernovae and other astrophysical transients.

    Dark Matter Research

    Fritz Zwicky discovered Dark Matter when observing the movement of the Coma Cluster., Vera Rubin a Woman in STEM denied the Nobel, did most of the work on Dark Matter.

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Coma cluster via NASA/ESA Hubble

    Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science)


    Vera Rubin measuring spectra, worked on Dark Matter (Emilio Segre Visual Archives AIP SPL)


    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    The LSST, or Large Synoptic Survey Telescope is to be named the Vera C. Rubin Observatory by an act of the U.S. Congress.

    LSST telescope, The Vera Rubin Survey Telescope currently under construction on the El Peñón peak at Cerro Pachón Chile, a 2,682-meter-high mountain in Coquimbo Region, in northern Chile, alongside the existing Gemini South and Southern Astrophysical Research Telescopes.

    Universe map Sloan Digital Sky Survey (SDSS) 2dF Galaxy Redshift Survey

    Scientists studying the cosmic microwave background hope to learn about more than just how the universe grew—it could also offer insight into dark matter, dark energy and the mass of the neutrino.

    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    Dark Matter Particle Explorer China

    DEAP Dark Matter detector, The DEAP-3600, suspended in the SNOLAB deep in Sudbury’s Creighton Mine

    LBNL LZ Dark Matter project at SURF, Lead, SD, USA


    Inside the ADMX experiment hall at the University of Washington Credit Mark Stone U. of Washington. Axion Dark Matter Experiment

    There’s a lot more you can see peering at the CMB, and NASA has a whole Tumblr page explaining more about our universe’s history and what the PIPER mission will accomplish. So next time you look up at the sky, remember — our universe had a pretty baby face, and we’re only just getting a clear picture of it.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 11:45 am on November 21, 2019 Permalink | Reply
    Tags: "A Striking New Study Says an Ancient Supernova Is Why Humans Walk Upright", , , , , Curiosity, Galactic Bursts vs. Bipedalism   

    From Curiosity: “A Striking New Study Says an Ancient Supernova Is Why Humans Walk Upright” 

    Curiosity Makes You Smarter

    From From Curiosity

    November 19, 2019
    David Dickinson

    A new study hints at a possible fascinating twist in human evolution. Did a chain of cosmic events triggered by a nearby ancient supernova force humans to walk upright?

    The study, out earlier this year, points to an unlikely source for modern human bipedal locomotion: the effect on our environment of a nearby supernova or series of supernovae. The study, titled “From Cosmic Explosions to Terrestrial Fires?” was published in The Journal of Geology.

    Galactic Bursts vs. Bipedalism

    If the proposed mechanism that takes you from an exploding star to an upright human leaves you scratching your head, you’re not alone. In a nutshell, the idea runs like this: A supernova detonates nearby — say within a 150 to 300 light-year radius of our solar system — showering Earth and the nearby vicinity with energetic cosmic rays.

    Cosmic rays produced by high-energy astrophysics sources (ASPERA collaboration – AStroParticle ERAnet)

    This, in turn, showers Earth’s atmosphere with highly energetic particles, raising the frequency of lightning strikes.

    Now, lightning is the biggest natural ignition source for wildfires. More lightning means more wildfires, accelerating the creation of treeless savanna. If you’re hunting upright on the savanna, you have an advantage of seeing prey at a distance. This new environment would have selected for a random mutation allowing for our ancestors to run down prey. Along with our endurance (our ability to sweat), walking upright allows you to succeed on the savanna.

    There is speculation that a gene mutation on chromosome 17 allows humans to walk upright. Of course, as with many adaptations in evolution, this comes at a cost, including all the maladies and back problems modern humans experience.

    Lightning vs. Cosmic Rays

    The study cites an increase in the number of lightning strikes seen in carbon levels in the geological record, and an increase “(in the) iron-60 (isotope) at Earth, and the existence of the Local Bubble,” researcher Adrian Melott (Department of Physics and Astronomy, University of Kansas) told Universe Today, also citing the Nature 2016 paper, Supernovae in the Neighborhood.

    This enhanced rate of forest fires started in the geological record 7-8 million years ago. Humans were thought to have first walked upright around 6 million years ago. The study also cites an ancient supernova event 2 to 3 million years ago (the half-life of Iron-60 is about 2.6 million years) that could be connected with an uptick in terrestrial wildfires.

    Iron-60 found in deep sea floor deposits is a good indicator of ancient supernovae activity. Other suspect isotopes, such as Beryllium-10 and Plutonium-244, are contaminated by interaction with natural radiation and the Earth’s atmosphere (in the case of Be-10) and 20th-century nuclear weapons testing in the case of Pu-244.

    The Local Bubble is a cavity of local space about 150 light-years in diameter, characterized by a density of neutral hydrogen about one-sixth that of the galactic interstellar medium. The most recent event thought to have ‘scooped out’ this hollow is the ancient supernova that created the pulsar remnant Geminga, roughly 300,000 years ago.

    Is the assertion correct? Certainly, the evidence is intriguing, though the logic needed allows for several steps to reach a conclusion. Cosmic rays are thought to trigger lightning, though this assertion is still debated. Ashley Hammond of the American Museum of Natural History notes in a recent Popular Science interview that there’s evidence that bipedal evolution was already well underway, over four million years ago.

    Supernovae come in two basic flavors: a Type 1 supernova, with two stars in a tight binary pair: a main-sequence star feeding material onto a white dwarf until it reaches a critical mass; and a Type 2 supernova, which caused the collapse of a star 8-50 times as massive as our Sun.

    Though we frequently see supernovae in other galaxies, such as the one we witnessed in the galaxy Messier 82 during the January 2014 Virtual Star Party, a bright naked-eye supernova has yet to occur in our galaxy since the start of the age of telescopic astronomy. Astronomer Johannes Kepler caught the last galactic supernova in the constellation Ophiuchus in 1604.

    You could say we’re due.

    3
    Hubble images the remnant for Kepler’s Supernova. NASA/SAO/CXC/D. Patnaude/DSS

    There’s also good evidence to suppose that nearby supernovae early in the solar system’s youth seeded the early solar nebulae with heavy elements, notably Iron-60 and Nickel-60. Thankfully, there are currently no good supernova candidates in the 25 light-year radius ‘kill zone’ inside the Local Bubble … any good naked-eye supernova will simply put on a good show.

    With any luck, if Betelgeuse ‘pops’ in our lifetime, it won’t go off in June, when it’s on the far side of the Sun!

    The aforementioned Nature study puts the odds of a kill-zone supernova near our solar system at once every 800 million years.

    Will we ever know if we have an ancient supernova to thank for walking upright? Well, a modern galactic supernova could put the idea that it could influence rates of terrestrial lightning to the test.

    “We are working on other effects that may be relevant,” Melott told Universe Today, “but it will be a long time before anyone can sort out what caused what, as is usual in geology.”

    For now, it’s fascinating to think that far-away cosmic processes may well have shaped who we are today.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 11:29 am on September 26, 2019 Permalink | Reply
    Tags: "Billions of Years Ago the Universe May Have Been Teeming With Life", , , , , , , Curiosity, Habitable zone-Not Too Hot; Not Too Cold,   

    From Curiosity: “Billions of Years Ago, the Universe May Have Been Teeming With Life” 

    Curiosity Makes You Smarter

    From From Curiosity

    January 26, 2018 [Just now in social media.]
    Ashley Hamer

    1
    Curiosity

    The universe is a cold, dark place. For a planet to support life, it has to be extremely lucky: close enough to its home star to keep water from freezing, far enough away to keep it from boiling off. We’ve only found a handful of planets that sit in this “habitable zone,” and we don’t know if any contain life. But what if it’s not the place that’s important, but the time?

    Not Too Hot, Not Too Cold

    13.8 billion years ago (sing along if you know the words), the universe started as a singularity that exploded in a trillionth of a trillionth of a second, doubling and re-doubling and re-re-doubling in size at a rate faster than the speed of light.

    Lambda-Cold Dark Matter, Accelerated Expansion of the Universe, Big Bang-Inflation (timeline of the universe) Date 2010 Credit: Alex Mittelmann Cold creation

    Suddenly, instead of an impossibly dense fleck of matter, the universe was a hot, garden-variety-dense soup of particles, all quarks and gluons and photons and electrons. How hot was it? It was so hot that particles couldn’t even coalesce into the building blocks of atoms yet. We’re talking hundreds of times hotter than the sun. It was so hot that we can still see its evidence in what’s known as the cosmic microwave background [CMB].

    CMB per ESA/Planck


    ESA/Planck 2009 to 2013

    But just like a pie fresh from the oven, the universe gradually cooled. Particles turned into atoms and atoms turned into stars, and little by little, everything spread out and cooled off as the universe expanded. But somewhere between being too hot for atoms to form and becoming a cold, dark void, space was, well, kind of warm. It was warm enough for liquid water to exist — not just on planets, but everywhere. Seeing as how liquid water is our telltale sign for life, this is a very big deal.

    Things stayed that way for several million years. That might not be enough for intelligent life to arise (it took humans at least 160 million years to evolve from the first mammals, after all) but it’s certainly enough for some kind of life. Single-celled life, perhaps, but life all the same.

    2
    agsandrew / iStock / Getty Images Plus

    All the Parts in Place

    It wasn’t just the balmy temperature that could have made life possible during this “habitable epoch,” as Avi Loeb, the astronomer behind this theory [International Journal of Astrobiology], calls it. There would be enough energy left from the Big Bang to give the formation of life a leg up. And because stars and rocky planets would be new on the scene, there wouldn’t be as much cosmic radiation and destructive debris whipping around, ready to smash into a new planet.

    But that also poses a problem. A lot of the elements that you require to live were formed in supernovae: the explosive deaths of old stars. Since stars weren’t old enough to die yet, the early universe wouldn’t have even formed carbon, much less heavier elements like iron. If life did exist, it would have looked different than the life we know.

    Loeb’s habitable epoch, if real, does blow one other theory out of the water: the anthropic principle. This principle says that the universe has all the elements to support life simply because if it didn’t, we wouldn’t be here to wonder about it. But if Loeb is right, then during the habitable epoch, a lot of those elements were wildly different, and yet life would have existed. Maybe life doesn’t depend on the rules of the universe as we see them. Maybe instead, life thrived on different rules, and us being here today is a rare exception.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 9:58 am on September 25, 2019 Permalink | Reply
    Tags: Curiosity, ,   

    From Curiosity: “The Many-Worlds Interpretation Says There Are Infinite Timelines and Infinite Yous” 

    Curiosity Makes You Smarter

    From From Curiosity

    April 26, 2017 [Just now in social media]
    Ashley Hamer

    1
    Curiosity

    Quantum physics is mind-bending, counterintuitive, and close to impossible to understand. It’s so complicated that a theory saying our reality is just one of an infinite web of infinite timelines is one that’s actually simpler than what most quantum physicists believe. That neat-and-tidy explanation is known as the many-worlds interpretation, and it has caused plenty of controversy in physics circles.

    Split the Difference

    In the 1950s, a student at Princeton University named Hugh Everett III was studying quantum mechanics. He learned about the Copenhagen interpretation, which says that at the very, very smallest level — what we mean when we say quantum — matter exists not just as a particle and not just as a wave, but in all possible states at once (all of those states together is called its wave function; the phenomenon of existing in all of those states at once is called superposition). It also says that when you observe a quantum object, you break that superposition and it essentially “chooses” one state to be in. He also learned about the Heisenberg Uncertainty Principle, which says that because we affect a quantum object’s behavior through observation, we can never be completely certain where it is or what it’s doing at any given time.

    Everett understood these principles, but he took issue with one part: What if, instead of a quantum object “choosing” a state when you observe it — say, it becomes a particle instead of a wave — there was an actual split in the universe that created separate timelines? According to Everett’s theory, in this timeline, the object is a particle, but there’s another timeline where it’s a wave. Even more baffling, this implies that quantum phenomena aren’t the only things that split the universe into separate timelines. For everything that happens, every action you take or decide not to take, there are infinite other timelines — worlds, if we may — where something else took place. That’s the many-worlds interpretation of quantum physics. It may not seem like it, but it’s actually simpler than the Copenhagen interpretation — it doesn’t strike an arbitrary line between the quantum world and everything else, because everything behaves in the same way. It also removes randomness from the picture, which helps the math work out nicely.

    2
    Curiosity

    Many Worlds Means Big Implications

    Not all physicists subscribe to this theory — a recent poll found that the majority are Copenhagen all the way — but a growing minority do. Sean Carroll, for one. He explains that many objections to the theory arise because people come at it from a classical physics point of view. “In classical mechanics … it’s quite a bit of work to accommodate extra universes, and you better have a good reason to justify putting in that work,” he writes. “That is not what happens in quantum mechanics. The capacity for describing multiple universes is automatically there. We don’t have to add anything.”

    If the many-worlds interpretation is true, what does this say about the nature of reality? It says there are infinite versions of you living in infinite alternate timelines. There’s a version of you that got out of bed on a different side this morning, one that ate a different breakfast, one that has differently colored hair, one that’s a different gender, one that’s a foot taller, one that’s a psychopath, one that — we can hardly stomach it! — didn’t decide to read this article. That might make you feel less than unique. On the contrary, the you that you are right now is the only you there will ever be. The moment you do anything, the universe splits and you’re a you that’s living in a different timeline than the you that didn’t take that action. Wild, isn’t it?

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
  • richardmitnick 10:29 am on September 23, 2019 Permalink | Reply
    Tags: , Curiosity, , ,   

    From Curiosity: “Zealandia Is the Lost, Sunken Continent at the Bottom of the Pacific Ocean” 

    Curiosity Makes You Smarter

    From From Curiosity

    August 14, 2017 [Just popped up in social media]
    Reuben Westmaas

    If there’s one thing that excites us more than the idea of alien planets, it’s the thought of what might be waiting beneath the surface of the ocean. Cthulu? Snorks? The lost continent of Atlantis? Unfortunately, science is a big party-pooper that says that probably none of those are actually real. Except … there really is a lost continent in the Pacific Ocean, and its highest point is the only part that’s breached the surface. You know it as New Zealand, but there’s a whole lot more Zealand where that came from.

    1
    You can see the map of New Zealand in this image.

    Looking for Atlantis

    Sail west from Sydney and you’ll find Zealandia. Sort of. You won’t be able to see it (not most of it, anyway), but deep beneath the ocean is a chunk of land spread out over 4.9 million square kilometers (about 3 million square miles) that broke off from Australia about 75 million years ago. Generally, we don’t think of landmasses as being continents if they’re underwater — actually, we often don’t even consider them to be landmasses. But Zealandia meets pretty much all of the criteria: elevation above the surrounding area, a distinctive geology, a well-defined area, and a crust much thicker than that found on the ocean floor.

    In one of the most intensive explorations of a “lost continent” ever, the Australian National University has launched a drillship to explore Zealandia. The mission of the JOIDES Resolution is to collect sediment from the continental crust beneath the ocean and test our theories about how and when Zealandia formed.

    3
    JOIDES Resolution, Operator:Texas A&M University on behalf of the International Ocean Discovery Program

    Scientists currently believe that it was once a part of Gondwana, the supercontinent that also included Australia, Antarctica, Africa, and South America.

    6
    https://www.geo.fu-berlin.de/en/v/geolearning/gondwana/introduction/index.html

    But it probably broke off about 75 million years ago, and over the course of about 20 million years gradually spread itself so thin that it sank like an Oreo in milk. With core samples and mineral deposits, scientists will be able to strengthen these theories — or throw them out entirely.

    An Army of Atlantises

    We’ve actually had an idea of Zealandia’s existence since about 1919 (when it was known as Tasmantis), but it’s not the only sunken continent on the planet. Another, much smaller, leftover of the great Gondwana break-up was discovered in 2017 and named “Mauritia” after Mauritia, one of its only parts to actually break the surface.

    There are quite a few more of these continental crumbs, in fact, but only Zealandia has been deemed big enough to actually be described as a continent. The others, including Mauritia, Madagascar, and a bunch of tiny underwater islands you’ve probably never heard of, have all been deemed “microcontinents” or “continental fragments.” But we prefer to think of them all as Snork sanctuaries.

    See the full article here .

    See the previous post here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Curiosity Makes You Smarter

    Curiosity is on a mission to make learning easier and more fun than it has ever been. Our goal is to ignite curiosity and inspire people to learn. Each day, we create and curate engaging topics for millions of lifelong learners worldwide.

    Experience Curiosity on our website, through our apps and across social media. We designed Curiosity with your busy life in mind. Our editors find interesting and important topics that you’ll want to know more about, and introduce you to the best ways to keep learning.

    We hope you make Curiosity part of your daily digital diet. Never stop learning!

     
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