Tagged: Astronomy Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 11:51 pm on November 27, 2014 Permalink | Reply
    Tags: Astronomy, , , , GNN,   

    From CERN Courier: “The Global Neutrino Network takes off” 

    CERN Courier

    Nov 27, 2014
    GNN Global Neutrino Network

    On 20–12 September, CERN hosted the fifth annual Mediterranean-Antarctic Neutrino Telescope Symposium (MANTS) . For the first time, the meeting was organized under the GNN umbrella.

    The idea to link more closely the various neutrino telescope projects under both water and ice has been a topic for discussion in the international community of high-energy neutrino astrophysicists for several years. On 15 October 2013, representatives of the ANTARES, BAIKAL, IceCube and KM3NeT collaborations signed a memorandum of understanding for co-operation within a Global Neutrino Network (GNN). GNN aims for extended inter-collaboration exchanges, more coherent strategy planning and exploitation of the resulting synergistic effects.

    No doubt, the evidence for extraterrestrial neutrinos recently reported by IceCube at the South Pole (“Cosmic neutrinos and more: IceCube’s first three years”) has given wings to GNN, and is encouraging the KM3NeT (in the Mediterranean Sea) and GVD (Lake Baikal) collaborations in their efforts to achieve appropriate funding to build northern-hemisphere cubic-kilometre detectors. IceCube is also working towards an extension of its present configuration.

    One focus of the MANTS meeting was, naturally, on the most recent results from IceCube and ANTARES, and their relevance for future projects. The initial configurations of KM3NeT (with three to four times the sensitivity of ANTARES) and GVD (with sensitivity similar to ANTARES) could provide additional information on the characteristics of the IceCube signals, first because they look at a complementary part of the sky, and second because water has optical properties that are different from ice. Cross-checks with different systematics are of the highest importance for these detectors in natural media. As an example, KM3NeT will measure down-going muons from cosmic-ray interactions in the atmosphere with superb precision. This could help in determining more precisely the flux of atmospheric neutrinos co-generated with those muons, in particular those from the decay of charmed mesons, which are expected to have particularly high energies and therefore could mimic an extraterrestrial signal.

    A large part of the meeting was devoted to finding the best “figures of merit” characterizing the physics capabilities of the detectors. These not only allow comparison of the different projects, but also provide an important tool to optimize future detector configurations. The latter also concerns the two sub-projects that aim to determine the neutrino mass hierarchy using atmospheric neutrinos. These are both small, high-density versions of the huge kilometre-scale arrays: PINGU at the South Pole and ORCA in the Mediterranean Sea. In this effort a particularly close co-operation has emerged during the past year, down to technical details.

    Combining data from different detectors is another aspect of GNN. A recent common analysis of IceCube and ANTARES sky maps has provided the best sensitivity ever for point sources in certain regions of the sky, and will be published soon. Further goals of GNN include the co-ordination of alert and multimessenger policies, exchange and mutual checks of software, creation of a common software pool, development of standards for data representation, cross-checks of results with different systematics, and the organization of schools and other forums for exchanging expertise and experts. Mutual representation in the experiments’ science advisory committees is another way to promote close contact and mutual understanding.

    Contingent upon availability of funding, the mid 2020s could see one Global Neutrino Observatory, with instrumented volumes of 5–8 km3 in each hemisphere. This would, finally, fully raise the curtain just lifted by IceCube, and provide a rich view on the high-energy neutrino sky.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

  • richardmitnick 10:46 pm on November 27, 2014 Permalink | Reply
    Tags: Astronomy, , , , , ,   

    From SPACE.com: “Found! First Earth-Size Planet That Could Support Life” 

    space-dot-com logo


    For the first time, scientists have discovered an Earth-size alien planet in the habitable zone of its host star, an “Earth cousin” that just might have liquid water and the right conditions for life.This artist illustration shows what it might be like to stand on the surface of the planet Kepler-186f, the first-ever Earth-size planet to be found in the habitable zone of its star.
    Credit: Danielle Futselaar

    The newfound planet, called Kepler-186f, was first spotted by NASA’s Kepler space telescope and circles a dim red dwarf star about 490 light-years from Earth. While the host star is dimmer than Earth’s sun and the planet is slightly bigger than Earth, the positioning of the alien world coupled with its size suggests that Kepler-186f could have water on its surface, scientists say.

    Comparison of best-fit size of the exoplanet Kepler-186 f with the Solar System planet Earth, as reported in the Open Exoplanet Catalogueas of 2014-04-20.

    NASA Kepler Telescope

    “One of the things we’ve been looking for is maybe an Earth twin, which is an Earth-size planet in the habitable zone of a sunlike star,” Tom Barclay, Kepler scientist and co-author of the new exoplanet research, told Space.com. “This [Kepler-186f] is an Earth-size planet in the habitable zone of a cooler star. So, while it’s not an Earth twin, it is perhaps an Earth cousin. It has similar characteristics, but a different parent.”

    This artist illustration shows the planet Kepler-186f, the first Earth-size alien planet discovered in the habitable zone of its star.
    Credit: NASA Ames/SETI Institute/JPL-CalTech

    Potentially habitable planet

    Scientists think that Kepler-186f — the outermost of five planets found to be orbiting the star Kepler-186 — orbits at a distance of 32.5 million miles (52.4 million kilometers), theoretically within the habitable zone for a red dwarf.

    Earth orbits the sun from an average distance of about 93 million miles (150 million km), but the sun is larger and brighter than the Kepler-186 star, meaning that the sun’s habitable zone begins farther out from the star by comparison to Kepler-186.

    “This is the first definitive Earth-sized planet found in the habitable zone around another star,” Elisa Quintana, of the SETI Institute and NASA’s Ames Research Center and the lead author of a new study detailing the findings, said in a statement.

    Other planets of various sizes have been found in the habitable zones of their stars. However, Kepler-186f is the first alien planet this close to Earth in size found orbiting in that potentially life-supporting area of an extrasolar system, according to exoplanet scientists.

    An historic discovery

    “This is an historic discovery of the first truly Earth-size planet found in the habitable zone around its star,” Geoff Marcy, an astronomer at the University of California, Berkeley, who is unaffiliated with the research, told Space.com via email. “This is the best case for a habitable planet yet found. The results are absolutely rock-solid. The planet itself may not be, but I’d bet my house on it. In any case, it’s a gem.”

    The newly discovered planet measures about 1.1 Earth radii, making it slightly larger than Earth, but researchers still think the alien world may be rocky like Earth. Researchers still aren’t sure what Kepler-186f’s atmosphere is made of, a key element that could help scientists understand if the planet is hospitable to life.

    “What we’ve learned, just over the past few years, is that there is a definite transition which occurs around about 1.5 Earth radii,” Quintana said in a statement. “What happens there is that for radii between 1.5 and 2 Earth radii, the planet becomes massive enough that it starts to accumulate a very thick hydrogen and helium atmosphere, so it starts to resemble the gas giants of our solar system rather than anything else that we see as terrestrial.”

    This diagram shows the position of Kepler-186f in relation to Earth.
    Credit: NASA Ames/SETI Institute/JPL-CalTech

    The edge of habitability

    Kepler-186f actually lies at the edge of the Kepler-186 star’s habitable zone, meaning that liquid water on the planet’s surface could freeze, according to study co-author Stephen Kane of San Francisco State University.

    Because of its position in the outer part of the habitable zone, the planet’s larger size could actually help keep its water liquid, Kane said in a statement. Since it is slightly bigger than Earth, Kepler-186f could have a thicker atmosphere, which would insulate the planet and potentially keep its water in liquid form, Kane added.

    “It [Kepler-186f] goes around its star over 130 days, but because its star is a lower mass than our sun, the planet orbits slightly inner of where Mercury orbits in our own solar system,” Barclay said. “It’s on the cooler edge of the habitable zone. It’s still well within it, but it receives less energy than Earth receives. So, if you’re on this planet [Kepler-186f], the star would appear dimmer.”

    Exoplanet hunting in the future

    Kepler-186f could be too dim for follow-up studies that would probe the planet’s atmosphere. NASA’s James Webb Space Telescope Hubble’s successor, expected to launch to space in 2018 — is designed to image planets around relatively nearby stars; however, the Kepler-186 system might be too far off for the powerful telescope to investigate, Barclay said.

    NASA Webb Telescope

    NASA Hubble Telescope

    Scientists using the Kepler telescope discovered Kepler-186f using the transit method: When the planet moved across the face of its star from the telescope’s perspective, Kepler recorded a slight dip in the star’s brightness, allowing researchers to learn more about the planet itself. Kepler suffered a major malfunction last year and is no longer working in the same fashion, but scientists are still going through the spacecraft’s trove of data searching for new alien worlds.

    “I find it simply awesome that we live in a time when finding potentially habitable planets is common, and the method to find them is standardized,” MIT exoplanet hunter and astrophysicist Sara Seager, who is unaffiliated with the research, told Space.com via email.

    The new research was published online today (April 17) in the journal Science.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

  • richardmitnick 1:38 pm on November 27, 2014 Permalink | Reply
    Tags: , Astronomy, , , , JAXA, SEN   

    From SEN: “Japan’s Hayabusa 2 mission to an asteroid is set to launch” 


    27 November 2014
    Paul Sutherland

    As the world celebrates the success of Europe’s Rosetta, Japanese space scientists are preparing to launch the latest mission to explore one of the minor bodies of the Solar System.

    Hayabasu spacecraft
    Hayabusa 2

    Their Hayabusa 2 spacecraft is due to blast off at 1:24:48 p.m. Japanese time (04:24:48 UTC) on Sunday 30 November from the Tanegashima Space Center.

    Its mission will be to rendezvous with an asteroid, land a small probe on its surface, and then return samples to Earth. It follows an earlier Japanese Hayabusa mission to an asteroid named Itokawa.


    Asteroids generally differ from comets, such as 67P/Churyumov-Gerasimenko. which Rosetta is circling, because they don’t fizz with gas and dust. They seem to be chunks of material from the formation of the Solar System which never collected together to form planets.


    ESA Rosetta spacecraft

    Hayabusa 2’s target is a 1km-wide asteroid labelled 1999 JU3, after the year when it was discovered. It is a C-type asteroid, thought to contain more organic material than other asteroids, and so might again help scientists understand how the Solar System evolved.

    The Japanese space agency JAXA intend for Hayabusa 2 to catch up with asteroid 1999 JU3 in 2018. It will land a small cube-shaped probe called MASCOT (Mobile Asteroid Surface Scout) developed by the German Space Agency (DLR) together with French space partners the Centre National d’Etudes Spatiales (CNES).

    The lander is able to move its centre of gravity so that it can tip itself over in order to move across the asteroid’s surface.

    Hayabusa 2 will also carry an impactor to blast a 2-metre-wide crater in the asteroid’s surface, which will allow the spacecraft to collect fragments and bring them home for study in the laboratory.

    Germany’s MASCOT lander is fitted to the Hayabusa 2 spacecraft. Image credit: DLR

    The first Hayabusa kept space enthusiasts and scientists on the edge of their seats with its performance. Launched in May 2003, it reached the 500-metre long Itokawa in September 2005, then twice brushed its surface, allowing some surface grains to lodge in its collector. But a bid to blast out samples from the asteroid and to land a mini-probe called Minerva both failed.

    Then fuel and power failures led scientists to fear that they had lost Hayabusa. But amazingly, they managed to regain control over the following months, and against all the odds, the probe was able to fire its capsule of precious asteroid dirt to a safe landing in the Australian Outback in June 2010.

    Hayabusa 2 is the size of a small van, measuring 1.0 metres x 1.6 metres x 1.2 metres, and has two solar panels to provide power. In space it will be driven by an ion engine using xenon propellant

    The asteroid selected by JAXA is a “perfect specimen” according to Professor Humberto Campins, an international expert on asteroids and comets, at the University of Central Florida. He has said: “Based on our analysis, it should be rich in primitive materials, specifically organic molecules and hydrated minerals from the early days of our Solar System. If successful it could give us clues about the birth of water and life in our world.”

    Scientists believe that learning more about objects such as 1999 JU3 will also help develop methods to deal with any cosmic debris, such as Near Earth Asteroids, that might be found on course to impact the Earth.

    A number of other spacecraft have visited asteroids, including Rosetta which flew past 2867 Steins in 2008 and 21 Lutetia in 2010, en route to Comet 67P/Churyumov-Gerasimenko, and NASA’s Dawn mission which is currently heading for Ceres after orbiting Vesta for a year.

    A video shows how the MASCOT lander will hit the asteroid and explore its surface. Credit: DLR

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The vision of Sen—space exploration network—is to create a global space content network. Sen provides space news and information on the science, economics and government of space and in so doing aims to:
    —promote interest in space;
    —raise awareness of the reality of humankind and Earth in the Universe, providing a different perspective to life on this planet;
    —educate and encourage consideration of the physics, economics and government of space;
    —create a community in which people can learn, debate and share information about space;
    —further the exploration of space;
    —film the universe forever building an electronic version of the universe, a never ending work of art, creating Sen Universe – a computerised to scale 3D universe, starting with the Solar System. Sen Universe will replace computer imagery with real film and imagery as our exploration of the universe continues, forever building an electronic version of the universe, a never ending work of art and science.
    —Ultimately, in achieving the above, Sen aims to be a business without boundary in space and time.

    Space is everything, it affects everything – it defines our environment, the government of mankind, relations, the future. By promoting interest and awareness of space a different perspective of our conduct and government of life on the planet can be obtained in the hope of creating a united planet.

    Sen will aim to be an enterprise that represents the best human effort at creating an enterprise without boundary in space and time.

  • richardmitnick 1:00 pm on November 27, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From Ethan Siegel: “The Most Precise Signal in the Universe” 

    Starts with a bang
    Starts with a Bang

    Nov 26, 2014
    Ethan Siegel

    And how, if we manage to harness it on Earth, it could be the most accurate probe in all of scientific history.

    “We… are what happens when a primordial mixture of hydrogen and helium evolves for so long that it begins to ask where it came from.” -Jill Tarter

    And if we look out into the Universe, it begins to provide us with some tantalizing hints. From right here in our own cosmic playground on Earth to signals from beyond our own Solar System and even our galaxy, there’s no shortage of information to be gathered from the Universe itself.

    Image credit: Martin Šrubař © 2006, via http://fusion.srubar.net/principles-of-nuclear-fusion.html.

    Most of our information comes from a very fundamental type of interaction: a transition from one energy state to another. In the center of a star, for example, two subatomic particles — protons, neutrons or complex nuclei — can fuse together, transitioning into a lower-energy state and emitting energy in the process.

    The emitted energy, after literally trillions of interactions, eventually makes its way to the surface of that star, where it eventually exits into the Universe as starlight.

    Image credit: NASA / New Horizons.

    But there are plenty of other transitions as well that emit light of all sorts of wavelengths. Perhaps most familiar to us are the atomic transitions, where electrons bound to nuclei can either absorb a photon and jump up to a higher energy state, or emit a photon as they jump down to a lower energy state.

    Image credit: Mike’s Physics Wiki, via http://simmonds.wikidot.com/image:absorption-jpg.

    Each and every element has their own, unique energy levels that electrons can transition between, corresponding to quantum properties unique to each and every atom.

    These transitions also correspond to spectral lines, where — if you shine a light on ground-state atoms — they’ll absorb light of a very particular frequency, or — if you energize atoms to an excited state — they’ll spontaneously emit light of a very particular frequency.

    Image credit: initial source unknown, retrieved from http://www.riverdell.org/Page/550.

    The thing that you might not realize is this: the emitted or absorbed light isn’t of one exact frequency, but rather spans a range of frequencies centered on a particular value. There are three reasons for this:

    1.) There’s an inherent width to any line, which is determined by the speed of the transition and the frequency of the light. Transitions that occur quickly have broader lines, while those that occur more slowly have narrower ones. Also, very low frequencies have broader widths, while higher frequencies have narrower ones.
    Image credit: Nigel Sharp, National Optical Astronomical Observatories/National Solar Observatory at Kitt Peak/Association of Universities for Research in Astronomy, and the National Science Foundation.

    2.) Thermal effects. When a gas (or any material) is heated, the profile of either emission or absorption lines broadens. This is why, for example, when we look at the spectrum of a hot thing (like the Sun), its spectral lines are significantly broader than you’d find if you took those same lines in a laboratory on Earth.

    3.) And finally, there are kinetic effects. If atoms are completely stationary, you’ll get a very narrow line, but if atoms move back-and-forth rapidly — at hundreds of kilometers per second, for example — the line will broaden because of the Doppler shift: some atoms moving towards you, resulting in a blueshift, and others moving away from you, giving a redshift. This occurs frequently in astrophysical sources of gas, like galaxies.

    Image credit: Charles R. Evans of University of North Carolina, via http://user.physics.unc.edu/~evans/.

    But these lines are also incredibly interesting, because they’re so well-understood! Even though quantum mechanics is confusing and open to interpretation in a lot of ways, its predictions for phenomena like this are precise and concrete.

    This understanding also gives us an opportunity — particularly if we can control for thermal and kinetic effects — to understand the inherent widths of these lines, and to look for exotic effects that could cause an additional broadening of these lines.

    Image credit: © Swinburne University of Technology, via http://astronomy.swin.edu.au/cosmos/t/thermal+doppler+broadening.

    Most lines are too broad, inherently, to find any effects other than thermal or kinetic ones, because they’re created on extremely short timescales. (Most atomic transitions, for example, take place on the order of a single nanosecond, or 10^-9 seconds!) But there’s one line that could provide a remarkable opportunity for this: the 21-cm line of hydrogen!

    Image credit: S. Stanko, B. Klein and J. Kerp, A&A 2005, via http://www.aanda.org/articles/aa/full/2005/22/aa2227-04/aa2227-04.html.

    You see, when hydrogen atoms are formed, they’re among the simplest systems in the Universe, consisting solely of an electron and a proton. Very quickly, in the absence of everything else, they’ll move into the ground state, where the electron orbits the proton in its lowest-energy shell: the 1s state.

    Image credit: Paul Nylander, via http://nylander.wordpress.com/2003/04/30/hydrogen-electron-orbital-probability-distribution-cross-sections/.

    But it might not be perfectly in the ground state. You see, electrons and protons both have spins, and these spins can be either aligned, as in they can both be spin up or spin down, or they can be anti-aligned, where one is spin up and one is spin down.

    Image credit: Pearson Education / Addison-Wesley, retrieved from Jim Brau at http://pages.uoregon.edu/jimbrau/.

    The energy difference between these two states is minuscule: at 5.9 micro-electron-Volts, it’s one of the smallest energy transitions known. This corresponds to photons of extremely low energies, and with wavelengths that are whoppingly macroscopic: of 21 centimeters in wavelength! It’s also forbidden quantum mechanically, so that the only way to move from the “excited” state to the ground state is through quantum tunneling, an exponentially suppressed process.

    Images credit: R Nave of Hyperphysics from Georgia State University.

    Nonetheless, it does happen, albeit on timescales of around ten million years on average. In both principle and in practice, we can use this for a number of scientific purposes, including for probing the Universe before any stars or luminous sources had formed. But if we wanted to get really ambitious — if we wanted to dream big — we could take advantage of the extremely small natural line width of this configuration,

    Image credit: equation 8 from Siegel and Fry, 2005, via http://arxiv.org/pdf/astro-ph/0503162v2.pdf.

    to search for what has previously been unthinkable.

    Image credit: Lionel BRET/EUROLIOS.

    All objects in the Universe that gravitationally interact with one another affect not only spacetime, causing its curvature through their matter and energy, but are themselves affected by the curvature of spacetime. If you have multiple objects moving through it at once, they’ll cause the emission of gravitational waves as they interact, which itself will have specific frequencies. Gravitational waves are also generated by transient astrophysical phenomena like supernovae, by orbiting black holes, and during inflation as well.

    Image credit: Henze, NASA, of gravitational waves produced by two orbiting black holes. Via http://www.ligo.org/science/GW-Sources.php.

    Now, here’s the kicker: gravitational waves can broaden any emission line, and since this one is already inherently narrow to a width of ~10^-24, we can simply cool down a collection of hydrogen atoms to remove thermal and kinetic effects, and measure the width to arbitrary accuracy. If we get the exact prediction from quantum mechanics, there are no gravitational waves. But if we get a measurement of a width that fluctuates to be ever-so-slightly larger, we will have detected them!

    Image credit: spectral line broadening via BotRejectsInc at http://cronodon.com/SpaceTech/CVAccretionDisc.html.

    Other phenomena that could be responsible for such a non-transient feature, or one that’s always present, would be a gravitational wave signal due to extra dimensions, a Universe that never had an inflationary phase or a time-varying gravitational constant. It’s an incredibly ambitious, far-fetched idea, as it requires cooling to temperatures on the order of picoKelvin just to measure the inherent width, and even lower than that (down to attoKelvin scales) if you want to measure realistic gravitational waves. Nevertheless, it’s a fantastic theoretical possibility, and one that could shed light on an otherwise invisible, undetectable phenomenon permeating our Universe!

    The rest is left as an exercise for the experimentalists.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible.

  • richardmitnick 11:12 am on November 27, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From ESA: “Venus Express will raise orbit and keep going” 

    European Space Agency

    26 November 2014

    Between 23 and 30 November the operations team at ESOC will conduct manoeuvres to raise the pericentre of the Venus Express (VEX) orbit again, in an effort to keep the spacecraft in productive orbit around Venus.

    ESA Venus Express
    ESA/Venus Express

    Visualisation of Venus Express during the aerobraking manoeuvre, which will see the spacecraft orbiting Venus at an altitude of around 130 km from 18 June to 11 July. In the month before, the altitude will gradually be reduced from around 200 km to 130 km. If the spacecraft survives and fuel permits, the elevation of the orbit will be raised back up to approximately 450 km, allowing operations to continue for a further few months. Eventually, however, the spacecraft will plunge back into the atmosphere and the mission will end. ESA–C. Carreau

    These manoeuvres could be the last for VEX due to low propellant levels, but all being well, VEX will continue its valuable scientific observations into 2015. The question is: how much longer can the spacecraft operate?

    Venus Express has been in a reduced science phase since its orbit was changed following the hugely successful aerobraking campaign during the summer of 2014. The mission, originally planned for two-plus-two (two years nominal operation with a two-year extension) years, has been successfully collecting critical science data from the ‘Morning Star’ for over eight years now.

    “This has been a fantastic mission and a great achievement for science over the last eight years and Venus Express continues to return excellent scientific data,” states Håkan Svedhem, Venus Express Project Scientist.

    “The spacecraft remains healthy after this year’s demanding aerobraking campaign and return to scientific productivity, and we’re looking forward to getting as much science as possible while the fuel lasts.”

    Lifting the orbit

    Due to a combination of effects from the gravity of Venus and our Sun, VEX’s closest point of approach, the pericentre, is constantly descending closer to Venus. This ‘decay’ of the pericentre altitude would eventually damage the spacecraft (due to drag) if it is not raised away from the atmosphere.

    The OCMs taking place now are using the spacecraft’s thrusters to lift the satellite at controlled increments back to a safer orbit. Without them, the pericentre altitude falls around 3 to 5 km per day.

    As a result of the successful aerobraking manoeuvres earlier this year, the nominal 24-hr orbital period has been reduced to just over 22 hrs. Given that the routine flight control procedures followed for the last eight years – science planning, observations, ground station passes, reaction wheel offloading – were designed for a 24-hr orbit, the change of orbital period by nearly two hours has affected many aspects of planning and operations for the flight control team.

    “It’s increasingly demanding to fly the spacecraft during this reduced science phase due to the changed orbit,” says Adam Williams, acting Spacecraft Operations Manager of Venus Express at ESOC.

    “For most of our mission, we had a very regular 24-hour orbit. Now, we’re in a 22-hour orbit and this results in varying periods for science and ground station passes, so our operations tempo is much more irregular and very demanding.”

    Correcting orbital decay

    The OCMs scheduled for this month will correct the natural decay that has occurred since the PRM (pericentre raising manoeuvres) conducted in July, after the aerobraking activity.

    “Aerobraking was very successful in July. It’s a credit to the designers that we have such a robust spacecraft capable of these demanding manoeuvres, and to the operators that they have kept it working so well. The mission has continued for much longer than its planned nominal lifetime and will likely continue even further,” explains Patrick Martin, Venus Express Mission Manager.

    Adding to the challenge, the team won’t know if each manoeuvre has been successful until the following day’s communications pass. In one case, they will have to wait two days for their telemetry to return due to ground station availability constraints.

    How much fuel do we have?

    Everything now hangs on the amount of fuel and oxidiser on board the spacecraft.

    It is calculated that there is around 3 kg of fuel and 5 kg of oxidiser remaining, although some of this may not be usable due to movement of propellant in the tanks. Estimates indicate around 1.4 kg of fuel and 2 kg of oxidiser are needed for the manoeuvres.

    However, it’s impossible to be certain just how much propellant is actually available and the mission’s continuation into 2015 has been approved on the assumption that propellant remains available.

    Whatever happens, once the fuel is exhausted, this hugely successful mission will come to a natural end.

    A monumental mission

    The Venus Express mission has observed Venus for over eight years and returned startling and amazing data from Earth’s nearest planetary neighbour. Observations have focused on the structure, dynamics, composition and chemistry of the dense atmosphere and overlying clouds. VEX also investigated the swirling vortex at the planet’s south pole.

    VEX discovered Venus’ surprisingly cold region high in the planet’s atmosphere, and the high-altitude ozone layer. The mission confirmed that Venus is losing water from its upper atmosphere and that it may have been much more humid and Earth-like.

    Andrea Accomazzo, 3rd from right, Venus Express Spacecraft Operations Manager, and members of the Venus Express mission control team anxiously await confirmation of orbit entry in ESOC’s Main Control Room, 11 April 2006. Credit: ESA/J. Mai

    Some observations of the surface terrain were possible with the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS). The data provide the best evidence to date that Venus has been volcanically active in recent geological times. In the upper atmosphere, large variations of sulphur dioxide have been discovered.

    Access more information on the discoveries of the mission here.

    Toward the end of an era

    VEX continues going strong, generating valuable scientific data, and is expected to continue to do so in robust health into 2015. The satellite itself is in excellent condition, as are all its functional instruments.

    “It is a bit sad to know that sooner or later the spacecraft will run out of propellant,” says ESA’s Andrea Accomazzo, Head of the Solar and Planetary Missions Division at ESOC and the first Venus Express Spacecraft Operations Manager.

    “When we launched Venus Express, nobody thought it would last this long. This spacecraft has been operating in a very demanding environment for many years; with this mission we could capitalise and consolidate our early experiences with Rosetta and Mars Express. This all contributed to the now very well established capability at ESA to conceive and operate interplanetary missions.”

    ESA Rosetta spacecraft

    ESA Mars Express Orbiter
    ESA/Mars Express

    “Venus Express is, after Rosetta and Mars Express, the most recently launched of ESA’s interplanetary jewels. It was supposed to be a short mission, but the robustness of the spacecraft and the skills of our operations and flight dynamics teams have made it a much longer lasting, incredibly successful mission,” says Paolo Ferri, Head of Mission Operations.

    “Its mission at Venus has been not only a major scientific achievement, but also very important for our teams to gain experience in operating a probe so close to the Sun. This will be extremely useful also for the preparation of the upcoming BepiColombo mission to Mercury.”

    ESA Bepi Columbo
    ESA/ BepiColumbo

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

    ESA50 Logo large

  • richardmitnick 8:06 pm on November 26, 2014 Permalink | Reply
    Tags: , Astronomy, , , ,   

    From ESO: “ESOcast 69: Revolutionary ALMA Image Reveals Planetary Genesis “ 

    European Southern Observatory

    ESOcast 69 presents the result of the latest ALMA observations, which reveal extraordinarily fine detail that has never been seen before in the planet-forming disc around the young star HL Tauri.

    This revolutionary image is the result of the first observations that have used ALMA with its antennas at close to the widest configuration possible. As a result, it is the sharpest picture ever made at submillimetre wavelengths.

    Watch, enjoy, learn.

    See the full article here.

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-




    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.

  • richardmitnick 5:45 pm on November 26, 2014 Permalink | Reply
    Tags: Astronomy, , , , ESA European Service Module,   

    From ESA: “European Service Module gets real” 

    European Space Agency

    26 Nov 2014

    On 17 November, ESA signed a contract in Berlin with the Airbus Defence and Space division to develop and build the European Service Module for Orion, NASA’s new crewed spacecraft. It is the first time that Europe will provide system-critical elements for an American space transportation vehicle.

    Credits: NASA

    NASA Orion Spacecraft
    NASA Orion spacecraft

    NASA intends to use this service module for the 2017 unmanned flight of Orion. The vehicle will perform a high-altitude orbital mission around the Moon. This flight will be a precursor for future Orion human space exploration missions beyond low-Earth orbit.

    The official name of Orion is ‘Multi-Purpose Crew Vehicle’, because the spacecraft can be used to conduct different missions. Eventually, NASA will use Orion to send astronauts to Mars.

    The design of the European Service Module (ESM) is based on the Automated Transfer Vehicle (ATV), the European supply craft for the International Space Station. It is a major achievement, as this is the first European development of a human spacecraft operating beyond Earth orbit.

    ESA Automated Transfer Vehicle

    “Being selected by NASA to develop critical elements for the Orion project – currently their most important exploration project – is a clear recognition of Europe’s performance in the frame of the ATV programme,” says Nico Dettmann, Head of ESA’s Space Transportation Department.

    “Cooperation with NASA is going well. It is fruitful and is happening with the same good spirit as with the International Space Station partnership,” he adds.

    The ESM is a cylindrical module with a diameter of 4.5 metres and a total length – main engine excluded – of 2.7 metres. It is fitted with four solar array ‘wings’ with a span of 18.8 metres. Its dry mass is 3.5 metric tons and it can carry 8.6 tons of propellant. Besides propulsion and power, ESM carries consumables.

    The Critical Design Review (CDR) is planned for 2015.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

    ESA50 Logo large

  • richardmitnick 5:29 pm on November 26, 2014 Permalink | Reply
    Tags: Astronomy, , , , Magnetosphere,   

    From NASA/Goddard: “NASA’s Van Allen Probes Spot an Impenetrable Barrier in Space” 

    NASA Goddard Banner

    November 26, 2014

    Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Two donuts of seething radiation that surround Earth, called the Van Allen radiation belts, have been found to contain a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.

    NASA Van Allen Probes
    A NASA Van Allen probe

    A cloud of cold, charged gas around Earth, called the plasmasphere and seen here in purple, interacts with the particles in Earth’s radiation belts — shown in grey— to create an impenetrable barrier that blocks the fastest electrons from moving in closer to our planet.
    Image Credit: NASA/Goddard

    The Van Allen belts are a collection of charged particles, gathered in place by Earth’s magnetic field. They can wax and wane in response to incoming energy from the sun, sometimes swelling up enough to expose satellites in low-Earth orbit to damaging radiation. The discovery of the drain that acts as a barrier within the belts was made using NASA’s Van Allen Probes, launched in August 2012 to study the region. A paper on these results appeared in the Nov. 27, 2014, issue of Nature magazine.

    “This barrier for the ultra-fast electrons is a remarkable feature of the belts,” said Dan Baker, a space scientist at the University of Colorado in Boulder and first author of the paper. “We’re able to study it for the first time, because we never had such accurate measurements of these high-energy electrons before.”

    Understanding what gives the radiation belts their shape and what can affect the way they swell or shrink helps scientists predict the onset of those changes. Such predictions can help scientists protect satellites in the area from the radiation.

    The Van Allen belts were the first discovery of the space age, measured with the launch of a US satellite, Explorer 1, in 1958. In the decades since, scientists have learned that the size of the two belts can change – or merge, or even separate into three belts occasionally. But generally the inner belt stretches from 400 to 6,000 miles above Earth’s surface and the outer belt stretches from 8,400 to 36,000 miles above Earth’s surface.

    NASA Explorer 1
    NASA/Explorer 1

    A slot of fairly empty space typically separates the belts. But, what keeps them separate? Why is there a region in between the belts with no electrons?

    Enter the newly discovered barrier. The Van Allen Probes data show that the inner edge of the outer belt is, in fact, highly pronounced. For the fastest, highest-energy electrons, this edge is a sharp boundary that, under normal circumstances, the electrons simply cannot penetrate.

    “When you look at really energetic electrons, they can only come to within a certain distance from Earth,” said Shri Kanekal, the deputy mission scientist for the Van Allen Probes at NASA’s Goddard Space Flight Center in Greenbelt, Maryland and a co-author on the Nature paper. “This is completely new. We certainly didn’t expect that.”

    The team looked at possible causes. They determined that human-generated transmissions were not the cause of the barrier. They also looked at physical causes. Could the very shape of the magnetic field surrounding Earth cause the boundary? Scientists studied but eliminated that possibility. What about the presence of other space particles? This appears to be a more likely cause.

    This [animation] shows how particles move through Earth’s radiation belts, the large donuts around Earth. The sphere in the middle shows a cloud of colder material called the plasmasphere. New research shows that the plasmasphere helps keep fast electrons from the radiation belts away from Earth.
    Image Credit: NASA/Goddard/Scientific Visualization Studio


    The radiation belts are not the only particle structures surrounding Earth. A giant cloud of relatively cool, charged particles called the plasmasphere fills the outermost region of Earth’s atmosphere, beginning at about 600 miles up and extending partially into the outer Van Allen belt. The particles at the outer boundary of the plasmasphere cause particles in the outer radiation belt to scatter, removing them from the belt.

    This scattering effect is fairly weak and might not be enough to keep the electrons at the boundary in place, except for a quirk of geometry: The radiation belt electrons move incredibly quickly, but not toward Earth. Instead, they move in giant loops around Earth. The Van Allen Probes data show that in the direction toward Earth, the most energetic electrons have very little motion at all – just a gentle, slow drift that occurs over the course of months. This is a movement so slow and weak that it can be rebuffed by the scattering caused by the plasmasphere.

    This also helps explain why – under extreme conditions, when an especially strong solar wind or a giant solar eruption such as a coronal mass ejection sends clouds of material into near-Earth space – the electrons from the outer belt can be pushed into the usually-empty slot region between the belts.

    “The scattering due to the plasmapause is strong enough to create a wall at the inner edge of the outer Van Allen Belt,” said Baker. “But a strong solar wind event causes the plasmasphere boundary to move inward.”

    A massive inflow of matter from the sun can erode the outer plasmasphere, moving its boundaries inward and allowing electrons from the radiation belts the room to move further inward too.

    The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the Van Allen Probes for NASA’s Science Mission Directorate. The mission is the second in NASA’s Living With a Star program, managed by Goddard.

    For more information about the Van Allen Probe, visit:


    See the full article here.

    This post is dedicated to A.A., whose posts are filled with great NASA data and graphics.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.


  • richardmitnick 4:19 pm on November 26, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From Keck: “‘Eye of Sauron’ Provides New Way of Measuring Distances to Galaxies” 

    Keck Observatory

    Keck Observatory

    Keck Observatory

    November 26, 2014
    No Writer Credit

    A team of scientists, led by Dr. Sebastian Hoenig from the University of Southampton, has accurately measured the distance to the nearby NGC 4151 galaxy, using the W. M. Keck Observatory Interferometer. The team employed a new technique they developed, which allows them to measure precise distances to galaxies tens of millions of light years away. The research was published today in the journal Nature.

    Keck Interferometer
    Interferometry at Keck

    NGC 4151
    This composite image shows the central region of the spiral galaxy NGC 4151, dubbed the “Eye of Sauron” by astronomers for its similarity to the eye of the malevolent character in The Lord of the Rings. In the “pupil” of the eye, X-rays (blue) from the Chandra X-ray Observatory are combined with optical data (yellow) showing positively charged hydrogen (“H II”) from observations with the 1-meter Jacobus Kapteyn Telescope on La Palma. The red around the pupil shows neutral hydrogen detected by radio observations with the NSF’s Very Large Array. This neutral hydrogen is part of a structure near the center of NGC 4151 that has been distorted by gravitational interactions with the rest of the galaxy, and includes material falling towards the center of the galaxy. The yellow blobs around the red ellipse are regions where star formation has recently occurred.
    Date 27 March 2008
    Source http://www.chandra.harvard.edu/photo/2011/n4151/
    Author X-ray: NASA/CXC/CfA/J.Wang et al.; Optical: Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope, Radio: NSF/NRAO/VLA

    NASA Chandra Telescope
    NASA Chandra schematic

    Isaac Newton Jacobus Kapteyn Telescope Telescope
    Isaac Newton Jacobus Kapteyn Telescope interior
    Isaac Newton Jacobus Kapteyn Telescope


    The new technique is similar to that used by land surveyors on earth, who measure both the physical and angular – or ‘apparent’ – size of a distant object, to calculate its distance from Earth.

    Previous reported distances to NGC 4151, which contains a supermassive black hole, ranged from 4- to 29-megaparsecs, but using this new, more accurate method, the researchers calculated the distance to the supermassive black hole as 19 megaparsecs.

    The galaxy NGC415 is dubbed the Eye of Sauron by astronomers for the similarity to its namesake in the film trilogy The Lord of the Rings. As in the famous saga, a ring plays a crucial role in this new measurement. All big galaxies in the universe host a supermassive black hole in their center and in about 10 percent of all galaxies, these supermassive black holes are growing by swallowing huge amounts of gas and dust from their surrounding environments. In this process, the material heats up and becomes very bright — becoming the most energetic sources of emission in the universe known as active galactic nuclei (AGN).

    This hot dust forms a ring around the supermassive black hole and emits infrared radiation, which the researchers used as the ruler. However, the apparent size of the Eye of Sauron’s ring is so small, the observations were carried out using the Keck Interferometer, which combines Keck Observatory’s twin 10-meter telescopes — already the largest telescopes on Earth — to achieve the resolving power of an 85m telescope.

    To measure the physical size of the dusty ring, the researchers measured the time delay between the emission of light from close to the black hole and the more distant infrared emission. The distance from the center to the hot dust is simply this delay divided by the speed of light.

    By combining the physical size of the dust ring with the apparent size measured with the Keck Interferometer, the researchers were able to determine a distance to NGC 4151.

    “One of the key findings is that the distance determined in this new fashion is quite precise — with 90 percent accuracy,” Hoenig said. “In fact, this method, based on simple geometrical principles, gives the most precise distances for remote galaxies. Moreover, it can be readily used on many more sources than current methods. Such distances are key in pinning down the cosmological parameters that characterize our universe or in accurately measuring black hole masses. Indeed, NGC 4151 is a key to calibrating various techniques of estimating black hole masses. Our new distance implies that these masses may have been systematically underestimated by 40 percent.”

    Hoenig, together with colleagues in Denmark and Japan, is currently setting up a new program to extend their work to many more AGN. The goal is to establish precise distances to a dozen galaxies using this technique and use them to constrain cosmological parameters to within few per cent. Combined with other measurements, this will provide a better understanding of the history of expansion of our universe.

    The Keck Interferometer began construction in 1997, and finished its mission in 2012. It was funded by NASA and managed by JPL. JPL is managed by Caltech for NASA.

    Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    Keck NASA

    Keck Caltech

  • richardmitnick 9:12 am on November 26, 2014 Permalink | Reply
    Tags: Astronomy, , , ,   

    From ESO: “A Colourful Gathering of Middle-aged Stars” 

    European Southern Observatory

    26 November 2014
    Richard Hook
    ESO, Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    The MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile has captured a richly colourful view of the bright star cluster NGC 3532. Some of the stars still shine with a hot bluish colour, but many of the more massive ones have become red giants and glow with a rich orange hue.


    ESO 2.2 meter telescope
    ESO 2.2 meter telescope interior
    ESO 2.2 Meter Telescope at LaSilla

    ESO LaSilla Long View

    NGC 3532 is a bright open cluster located some 1300 light-years away in the constellation of Carina (The Keel of the ship Argo). It is informally known as the Wishing Well Cluster, as it resembles scattered silver coins which have been dropped into a well. It is also referred to as the Football Cluster, although how appropriate this is depends on which side of the Atlantic you live. It acquired the name because of its oval shape, which citizens of rugby-playing nations might see as resembling a rugby ball.

    This very bright star cluster is easily seen with the naked eye from the southern hemisphere. It was discovered by French astronomer Nicolas Louis de Lacaille whilst observing from South Africa in 1752 and was catalogued three years later in 1755. It is one of the most spectacular open star clusters in the whole sky.

    NGC 3532 covers an area of the sky that is almost twice the size of the full Moon. It was described as a binary-rich cluster by John Herschel who observed “several elegant double stars” here during his stay in southern Africa in the 1830s. Of additional, much more recent, historical relevance, NGC 3532 was the first target to be observed by the NASA/ESA Hubble Space Telescope, on 20 May 1990.

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Hubble

    This grouping of stars is about 300 million years old. This makes it middle-aged by open star cluster standards [1]. The cluster stars that started off with moderate masses are still shining brightly with blue-white colours, but the more massive ones have already exhausted their supplies of hydrogen fuel and have become red giant stars. As a result the cluster appears rich in both blue and orange stars. The most massive stars in the original cluster will have already run through their brief but brilliant lives and exploded as supernovae long ago. There are also numerous less conspicuous fainter stars of lower mass that have longer lives and shine with yellow or red hues. NGC 3532 consists of around 400 stars in total.

    The background sky here in a rich part of the Milky Way is very crowded with stars. Some glowing red gas is also apparent, as well as subtle lanes of dust that block the view of more distant stars. These are probably not connected to the cluster itself, which is old enough to have cleared away any material in its surroundings long ago.

    This image of NGC 3532 was captured by the Wide Field Imager instrument at ESO’s La Silla Observatory in February 2013.

    ESO Wide Field Imager 2.2m LaSilla
    WFI at LaSilla


    [1] Stars with masses many times greater than the Sun have lives of just a few million years, the Sun is expected to live for about ten billion years and low-mass stars have expected lives of hundreds of billions of years — much greater than the current age of the Universe.

    See the full article here.

    Please help promote STEM in your local schools.
    STEM Icon

    Stem Education Coalition
    Visit ESO in Social Media-




    ESO Main

    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.

Compose new post
Next post/Next comment
Previous post/Previous comment
Show/Hide comments
Go to top
Go to login
Show/Hide help
shift + esc

Get every new post delivered to your Inbox.

Join 357 other followers

%d bloggers like this: