Posted on by Jon Voisey

First Super-Earth Atmosphere Observed

Artist’s impression of GJ 1214b
Artist’s impression of GJ 1214b

[/caption]

With the recent milestone of the discovery of the 500th extra solar planet the future of planetary astronomy is promising. As the number of known planets increases so does our knowledge. With the addition of observations of atmospheres of transiting planets, astronomers are gaining a fuller picture of how planets form and live.

Thus far, the observations of atmospheres have been limited to the “Hot-Jupiter” type of planets which often puff up, extending their atmospheres and making them easier to observe. However, a recent set of observations, to be published in the December 2nd issue of Nature, have pushed the lower limit and extended observations of exoplanetary atmospheres to a super-Earth.

The planet in question, GJ 1214b passes in front of its parent star when viewed from Earth allowing for minor eclipses which help astronomers determine features of the system such as its radius and also its density. Earlier work, published in the Astrophysical Journal in August of this year, noted that the planet had an unusually low density (1.87 g/cm3). This ruled out an entirely rocky or iron based planet as well as even a giant snowball composed entirely of water ice. The conclusion was that the planet was surrounded by a thick gaseous atmosphere and the three possible atmospheres were proposed that could satisfy the observations.

The first was that the atmosphere was accreted directly from the protoplanetary nebula during formation. In this instance, the atmosphere would likely retain much of the primordial composition of hydrogen and helium since the mass would be sufficient to keep it from escaping readily. The second was that the planet itself is composed mostly of ices of water, carbon dioxide, carbon monoxide and other compounds. If such a planet formed, sublimation could result in the formation of an atmosphere that would be unable to escape. Lastly, if a strong component of rocky material formed the planet, outgassings could produce an atmosphere of water steam from geysers, as well as carbon monoxide and carbon dioxide and other gasses.

The challenge for following astronomers would be to match the spectra of the atmosphere to one of these models, or possibly a new one. The new team is composed of Jacob Bean, Eliza Kempton, and Derek Homeier, working from the University of Göttingen and the University of California, Santa Cruz. Their spectra of the planet’s atmosphere was largely featureless, showing no strong absorption lines. This largely rules out the first of the cases in which the atmosphere is mostly hydrogen unless there is a thick layer of clouds obscuring the signal from it. However, the team notes that this finding is consistent with an atmosphere composed largely of vapors from ices. The authors are careful to note that “the planet would not harbor any liquid water due to the high temperatures present throughout its atmosphere.”

These findings don’t conclusively demonstrate that nature of the atmosphere, but narrow down the degeneracy to either a steam filled atmosphere or one with thick clouds and haze. Despite not completely narrowing down the possibilities, Bean notes that the application of transit spectroscopy to a super-Earth has “reached a real milestone on the road toward characterizing these worlds.” For further study, Bean suggests that “[f]ollow-up observations in longer wavelength infrared light are now needed to determine which of these atmospheres exists on GJ 1214b.”

Posted on by Mark Thompson

Red Dwarf Discovery Changes Everything!

Artists Impression of a Red Dwarf (courtesy NASA)

[/caption]

Its often said that the number of grains of sand on Earth equals the number of stars in the Universe. Well it looks like a recent study by astronomers working at the Keck Observatory in Hawaii have found that its more like three times the number of grains of sand on Earth! Working with some of the most sophisticated equipment available, astronomers from Yale University have been counting the number of dim red dwarf stars in nearby galaxies which has led to a dramatic rethink of the number of stars in the Universe.

Red dwarfs are small, faint stars compared to most others and until now, have not been detected in nearby galaxies. Pieter van Dokkum and his team from Yale University studied eight massive elliptical galaxies between 50 and 300 million lights years from us and discovered that these tiny stars are much more bountiful than first thought. “No one knew how many of these stars there were,” said Van Dokkum. “Different theoretical models predicted a wide range of possibilities, so this answers a long standing question about just how abundant these stars are.”

For years astronomers have assumed that the number of red dwarfs in any galaxy was in the same proportion that we find here in the Milky Way but surprisingly the study revealed there are about 20 times more in the target galaxies. According to Charlie Conroy of the Harvard-Smithsonian Center who also worked on the project, “not only does this affect our understanding of the number of stars in the Universe but the discovery could have a major impact on our understanding of galaxy formation and evolution.” Knowing that there are now more stars than previously thought, this lowers the amount of dark matter (a mysterious substance that cannot be directly observed but its presence inferred from its gravitational influence) needed to explain the observed gravitational influence on surrounding space.

Not only has the discovery affected the amount of dark matter we expect to find but it also changes the quantity of planets that may exist in the Universe. Planets have recently been discovered orbiting around other red dwarf stars such as the system orbiting around Gliese 581, one which may harbour life. Now that we know there are a significantly higher number of red dwarfs in the Universe, the potential number of planets in the Universe has increased too. Van Dookum explains “There are possibly trillions of Earth’s orbiting these stars, since the red dwarfs they have discovered are typically more than 10 billion years old, so have been around long enough for complex life to evolve, its one reason why people are interested in this type of star.”

It seems then that this discovery, which on the face of it seems quite humdrum, actually has far reaching consequences that not only affect our view of the number of stars in the Universe but has dramatically changed our understanding of the distribution of matter in the Universe and the number of planets that may harbour intelligent life.

The new findings appear in the Dec. 1st online issue of the journal Nature.

Source: from the Harvard Smithsonian Center for Astrophysics.

Mark Thompson is a writer and the astronomy presenter on the BBC One Show. See his website, The People’s Astronomer, and you can follow him on Twitter, @PeoplesAstro

Posted on by Jon Voisey

ε Eridani’s Dust Disc

This artist's conception shows the closest known planetary system to our own, called Epsilon Eridani. Credit: NASA/JPL/Caltech

[/caption]

Many stars have been discovered to have narrow discs of warm dust surrounding them. Since dynamical effects with the star’s solar winds should clear these out over long timescales, it’s presumed that these must be recently formed, likely through collisions of small rocky bodies in an asteroid or Kuiper belt. Such a disc has been detected around the nearby star ε Eridani. However, ε Eridani is also known to harbor one planet at a distance of 3.4 AU, and a second one at 40 AU is suspected. Because of this inner planet, any asteroid belt that close would be dynamically unstable as well and should have been cleared out long ago rendering the system incapable of producing dust in this region. So where did ε Eridani get this dust? A new study investigates this.

The inner dust ring was first discovered by a team of astronomers working with the Spitzer Space Telescope last year. In addition to this mysterious inner ring, the system also contains an outer, cold ring of dust at distances greater than 65 AU with a more clumpy nature, possibly shepherded by the outer planet.

The authors of the new paper, led by Martin Reidemeister at Friedrich-Schiller University in Germany, propose that the inner dust ring wasn’t originally formed there. Instead, they propose it was created via collisions in the outer Kuiper belt with the outer ring, but migrated inwards due to an effect known as Poynting-Robertson drag. This effect is created when outflows from the star interact with small objects. While the outflows will ultimately be streaming perpendicular to the orbit, the motion of the orbiting particles will make them plow through this, making them appear to have a component of motion towards the particle in the particle’s reference frame. This is the same effect that makes rain seem as if it’s falling towards you as you’re driving and causes it to pile up on your windshield. Since this added component of motion is opposed to the motion of the particle, it robs the particle of angular momentum, causing it to spiral inwards. Given that ε Eridani is known to have strong winds, this effect seems primed to be an explanation.

To test this hypothesis, the team modeled the system, varying the eccentricity of the inner planet between two possible orbits for the inner planet, both with and without the outer planet, and varying compositions for the outer dust ring (more or less silicates vs. ice). The team found that they could reasonably reproduce the observed system if the dust started as a mixture of ices and silicates in which the ices underwent sublimation as they moved inwards, past the snow line. Additionally, the orbit of the inner planet, though strikingly different for the two proposed orbits, did not have a large effect on the overall distribution of dust.

In the near future, ε Eridani is slated to be the subject of further publications probing its dust discs. The author notes that other teams have already conducted observations using the James Clerk Maxwell Telescope as well as others and that, ε Eridani will likely be a prime target for the James Webb Space Telescope upon launch.

Posted on by Nancy Atkinson

Secret Mini Space Shuttle Could Land on Friday

The X-37B spaceplane sits on a runway at Vandenberg Air Force Base during prelaunch taxi tests. Credit: U.S. Air Force

[/caption]

The US Air Force announced that the X-37B Orbital Test Vehicle, a miniature, unmanned space shuttle could return to Earth as soon as this Friday, December 3. It has been in Earth orbit for about nine months on a classified mission for the military. It will land at Vandenberg Air Force Base in Los Angeles sometime between Friday and Monday, Air Force officials said in a statement. The exact time of touchdown will depend on weather conditions and technical factors.

Preparations for the landing began on Tuesday, the Air Force Space Command said. The backup landing site would be Edwards Air Force Base.

The X-37B launched from Cape Canaveral, Florida on April 22. It was built by Boeing, and the vehicle looks like a space shuttle orbiter, but is much smaller: at 9 meters long and 4.5 meter wide (29 X 15 ft), with a payload bay that is 2.1 by 1.2 meters (7 by 4 feet) the X-37B is about 1/4th the size of a shuttle.

Launch of the X37-B. Credit: Alan Walters (awaltersphoto.com) for Universe Today

The X-37B uses solar arrays and lithium ion batteries to generate power instead of fuel cells like the space shuttle, a major reason why it can stay on orbit for much longer.

Originally the vehicle was scheduled for launch in from the payload bay of the Space Shuttle, but that plan was axed following the Columbia accident.

The X-37B’s mission is to “demonstrate a reliable, reusable, unmanned space test platform for the United States Air Force,” according to a fact sheet put out by the military. “Objectives of the OTV program include space experimentation, risk reduction and concept of operations development for reusable space vehicle technologies.”

It will be interesting to see if the military will share any of the on-orbit activities of the space plane and what capabilities and uses this vehicle might have in the future.

See our previous article “What is the Air Force’s Secret X-37B Space Plane Doing in Orbit?” for more information.

Source: Air Force Space Command

Posted on by Jason Rhian

Falcon 9 Ready for Second Flight – Dragon for First

SpaceX's Dragon spacecraft is set to launch from Cape Canaveral on Dec. 7. Image Credit: SpaceX

[/caption]

Space Exploration Technologies (SpaceX) is preparing to conduct the first demonstration launch for NASA’s Commercial Orbital Transportation Services (COTS) program, utilizing its Falcon 9 rocket. This first test flight appears to be holding solid for its targeted liftoff on Tuesday, Dec. 7. Launch will take place from the company’s launch site at Launch Complex 40 located at Cape Canaveral Air Force Station in Florida.

The launch window for this first demo flight extends from 9:03 a.m. to 12:22 p.m. EST. If it is required, launch opportunities are also open on Dec. 8 and Dec. 9 during the same general time frame. NASA TV will have coverage — you can watch it online at this link, or if you have it through your satellite or cable provider.

COTS 1, as this first flight has been dubbed, will be the first launch of the Dragon spacecraft, this will also mark the first commercial attempt to have their spacecraft reenter Earth’s atmosphere. The planned Dec. 7 flight is the first of three test launches currently envisioned in the Falcon 9 test flight series. This first flight is planned to check out important characteristics of both the Dragon spacecraft as well as the Falcon 9 launch vehicle. Some of these include orbital operations, launch elements of the combined Dragon/Falcon 9 vehicle, descent, re-entry and splashdown (which will occur in the Pacific Ocean).

NASA established the COTS program to obtain commercial launch services to jump start the commercial space industry. Under the Obama administration’s plans for the space agency, NASA will utilize these private space firms to send cargo to the International Space Station (ISS). More to the point, it is hoped that these commercial space companies can reduce the hefty price tag associated with sending something into orbit.

There will be a press conference held before the launch, it is currently planned to be held on Monday, Dec. 6, at 1:30 p.m. The conference will be held at NASA’s Kennedy Space Center press site, and will also be on NASA TV. Speakers during the press conference will include, Phil McAlister, acting director, Commercial Space Flight Development, Alan Lindenmoyer, manager, Commercial Crew and Cargo Program, Gwynne Shotwell, president of SpaceX and Mike McAleenan, Falcon 9 Launch Weather Officer 45th Weather Squadron.

If everything goes off without a hitch, a press conference will be held about an hour after splashdown takes place. If this mission is a success it will go along way to reinforcing the success of the first launch of the Falcon 9, held this past June. More importantly it will prove the viability of the Dragon spacecraft.

Posted on by Nicholos Wethington

Calm Down: NASA Hasn’t Found any Aliens

No, NASA is probably not announcing extraterrestrial life. And though this stock image shows a water bear, these cool little creatures come from right here on Earth (and have nothing to do with the announcement, but are scary looking when magnified). Image Credit: NASA

[/caption]

You may have heard in your wanderings through the blogosphere and in the internet today that NASA will be holding a press conference on December 2nd in which they will make an announcement regarding information the search for extraterrestrial life. And that this announcement involves astrobiology, the study of life outside what we know about here on Earth. While true, it is nothing to get worked up about.

Speculation abounds that this is, “the big one,” and that an announcement will be made that extraterrestrial life has been discovered. You can find this speculation at Kottke.org, io9, Gawker, and a lot of other places.

To be clear, there is almost no chance that the press release will be announcing little green men or little brown bacteria anywhere. Follow along for the long explanation below the fold.

Here’s what the press release is titled: “NASA Sets News Conference on Astrobiology Discovery: Science Journal Has Embargoed Details Until 2 p.m. EST On Dec. 2”. All this means is that Science Journal will be publishing some results related to astrobiology that are under embargo until that time. The embargo system is a basically a way of allowing journalists to see scientific results and get interviews and do research on an article before it’s published, but only if they promise to publish their information after the original publication does so. It makes sense, and it works most of the time to the benefit of almost everyone.

NASA regularly – like every day – announces upcoming press conferences and releases, and embargoed press releases float around to science writers like those of us here at Universe Today. This in itself is nothing out of the ordinary, and anyone with an email address can sign up to have these announcements delivered to their inbox or view them on NASA’s website. These emails are meant mainly to notify members of the press that there is something coming up worthy of being a phone-in listener of, the details of which require you to have press credentials.

The press release goes on to say,

“NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life. Astrobiology is the study of the origin, evolution, distribution and future of life in the universe.
The news conference will be held at the NASA Headquarters auditorium at 300 E St. SW, in Washington. It will be broadcast live on NASA Television and streamed on the agency’s website at http://www.nasa.gov.
Participants are:
– Mary Voytek, director, Astrobiology Program, NASA Headquarters, Washington
– Felisa Wolfe-Simon, NASA astrobiology research fellow, U.S. Geological Survey, Menlo Park, Calif.
– Pamela Conrad, astrobiologist, NASA’s Goddard Space Flight Center, Greenbelt, Md.
– Steven Benner, distinguished fellow, Foundation for Applied Molecular Evolution, Gainesville, Fla.
– James Elser, professor, Arizona State University, Tempe”

And that’s about it. My first reaction to this was that they had potentially made the discovery of exotic, new organic molecules in an exoplanetary atmosphere, or that some chemical conducive to the existence of life as we know it was possibly found on some body in the Solar System. Announcements like this come out of NASA all of the time.

Just because some of the participants do work in fields that are related to oceanography or ecology or biology, does not mean that their services are required here to help make an announcement that life other than that on Earth has been discovered, as other speculative bloggers might think.

As Nancy wrote in a post earlier today, extraterrestrial life is very much of interest to Universe Today readers. Which is why she’ll be listening in on that news conference Thursday, and reporting what findings are released.

Extraterrestrial life is very much of interest to probably most of the population of our planet, too, and the fact that we have the tools necessary to potentially make this discovery within the next few hundred years (or sooner), is really, really exciting.

But just because it’s exciting doesn’t mean we have to jump all over a NASA press release that includes the words “extraterrestrial life” or “precursor to life on Mars” and make wild speculations. When that announcement is made (or if, depending on how you choose to solve the Drake Equation), you can be sure that it will be very closely guarded until being made public, and after that the President will likely have some things to say.

For some more level-headed analysis, Keith Cowing at Nasa Watch has some much more reasonable speculation that the announcement involves arsenic biochemistry. The Bad Astronomer, Phil Plait, also has a good debunking of the rampant speculation, and makes some good points about how NASA can create press releases in the future that have better-worded announcements.

So calm down – but don’t stop looking up! Keep being excited about all of the genuinely cool and exciting developments we’re currently making with regards to space.

Source: NASA press release

Posted on by Nancy Atkinson

The Moon Helps Radio Astronomers Search for Neutrinos

Radio astronomers get an assist from the Moon. Credit: Ted Jaeger, University of Iowa, NRAO/AUI/NSF

[/caption]

From an NRAO press release:

Seeking to detect mysterious, ultra-high-energy neutrinos from distant regions of space, a team of astronomers used the Moon as part of an innovative telescope system for the search. Their work gave new insight on the possible origin of the elusive subatomic particles and points the way to opening a new view of the Universe in the future.

The team used special-purpose electronic equipment brought to the National Science Foundation’s Very Large Array (VLA) radio telescope, and took advantage of new, more-sensitive radio receivers installed as part of the Expanded VLA (EVLA) project. Prior to their observations, they tested their system by flying a small, specialized transmitter over the VLA in a helium balloon.

In 200 hours of observations, Ted Jaeger of the University of Iowa and the Naval Research Laboratory, and Robert Mutel and Kenneth Gayley of the University of Iowa did not detect any of the ultra-high-energy neutrinos they sought. This lack of detection placed a new limit on the amount of such particles arriving from space, and cast doubt on some theoretical models for how those neutrinos are produced.

Neutrinos are fast-moving subatomic particles with no electrical charge that readily pass unimpeded through ordinary matter. Though plentiful in the Universe, they are notoriously difficult to detect. Experiments to detect neutrinos from the Sun and supernova explosions have used large volumes of material such as water or chlorine to capture the rare interactions of the particles with ordinary matter.

The ultra-high-energy neutrinos the astronomers sought are postulated to be produced by the energetic, black-hole-powered cores of distant galaxies; massive stellar explosions; annihilation of dark matter; cosmic-ray particles interacting with photons of the Cosmic Microwave Background; tears in the fabric of space-time; and collisions of the ultra-high-energy neutrinos with lower-energy neutrinos left over from the Big Bang.

Radio telescopes can’t detect neutrinos, but the scientists pointed sets of VLA antennas around the edge of the Moon in hopes of seeing brief bursts of radio waves emitted when the neutrinos they sought passed through the Moon and interacted with lunar material. Such interactions, they calculated, should send the radio bursts toward Earth. This technique was first used in 1995 and has been used several times since then, with no detections recorded. The latest VLA observations have been the most sensitive yet done.

“Our observations have set a new upper limit — the lowest yet — for the amount of the type of neutrinos we sought,” Mutel said. “This limit eliminates some models that proposed bursts of these neutrinos coming from the halo of the Milky Way Galaxy,” he added. To test other models, the scientists said, will require observations with more sensitivity.

“Some of the techniques we developed for these observations can be adapted to the next generation of radio telescopes and assist in more-sensitive searches later,” Mutel said. “When we develop the ability to detect these particles, we will open a new window for observing the Universe and advancing our understanding of basic astrophysics,” he said.

The scientists reported their work in the December edition of the journal Astroparticle Physics.

Source: NRAO

Posted on by Nancy Atkinson

Enceladus Fissures Keep Getting Warmer and More Complex

Small water ice particles fly from fissures in the south polar region of Saturn's moon Enceladus in this image taken during the Aug. 13, 2010, flyby of the moon by NASA's Cassini spacecraft. Image credit: NASA/JPL/SSI

[/caption]

As Cassini scientists await the data from today’s flyby of Enceladus, images and data from August of this year have provided more insight into the active fissures on the icy moon’s south polar region. These geyser-spewing fractures are warmer and more complicated than previously thought.

“The exquisite resolution obtained on one segment of the Damascus fracture — one of the most active regions within the south polar terrain — has revealed a surface temperature reaching a staggering 190 Kelvin, or 120 degrees below zero Fahrenheit,” said Cassini imaging team lead Carolyn Porco, in an email announcing the new images. “Far from the fractures, the temperature of the south polar terrain dips as low as 52 Kelvin, or 365 degrees below zero Fahrenheit.”

Porco said that what this means is that a phenomenal amount of heat is emerging from the fractures which are “undoubtedly the result of the tidal flexing of Enceladus brought about by its orbital resonance with Dione. However, details of this heating process are still unclear and are being studied at this very moment.”

This image shows a high-resolution heat intensity map of part of the south polar region of Saturn's moon Enceladus, made from data obtained by NASA's Cassini spacecraft. Image credit: NASA/JPL/GSFC/SWRI/SSI

The flyby on August 13, 2010 provided infrared spectroscopy along with high resolution images which have enabled scientists to construct the highest-resolution heat intensity maps yet of the hottest part of a region of long fissures spraying water vapor and icy particles from Enceladus. These fissures — known as “tiger stripes,” appear to be laid on in a complex web, and could be connected underground.

Additional high-resolution spectrometer maps of one end of the tiger stripes Alexandria Sulcus and Cairo Sulcus reveal never-before-seen warm fractures that branch off like split ends from the main tiger stripe trenches. They also show an intriguing warm spot isolated from other active surface fissures.

“The ends of the tiger stripes may be the places where the activity is just getting started, or is winding down, so the complex patterns of heat we see there may give us clues to the life cycle of tiger stripes,” said John Spencer, a Cassini team scientist based at Southwest Research Institute in Boulder, Colo.

The temperature measured in this flyby appears slightly higher than previously measured temperatures at Damascus, which were around 170 Kelvin (minus 150 degrees Fahrenheit).

Spencer said he isn’t sure if this tiger stripe is just more active than it was the last time Cassini’s spectrometer scanned it, in 2008, or if the hottest part of the tiger stripe is so narrow that previous scans averaged its temperature out over a larger area. In any case, the new scan had such good resolution, showing details as small as 800 meters (2,600 feet), that scientists could see for the first time warm material flanking the central trench of Damascus, cooling off quickly away from the trench. The Damascus thermal scan also shows large variations in heat output within a few kilometers along the length of the fracture. This unprecedented resolution will help scientists understand how the tiger stripes deliver heat to the surface of Enceladus.

Cassini acquired the thermal map of Damascus simultaneously with a visible-light image where the tiger stripe is lit by sunlight reflecting off Saturn. The visible-light and thermal data were merged to help scientists understand the relationships between physical heat processes and surface geology.

“Our high-resolution images show that this section of Damascus Sulcus is among the most structurally complex and tectonically dynamic of the tiger stripes,” said imaging science team associate Paul Helfenstein of Cornell University, Ithaca, N.Y. Some details in the appearance of the landforms, such as a peculiar pattern of curving striations along the flanks of Damascus, had not previously been noticed in ordinary sunlit images.

ets of water ice particles spew from Saturn's moon Enceladus in this image obtained by NASA's Cassini spacecraft on Aug. 13, 2010. Image credit: NASA/JPL/SSI

The Aug. 13 flyby of Enceladus is the last one dedicated to thermal mapping until 2015 and also gave Cassini its last look at any part of the active south polar region in sunlight.

The flyby today will aid in understanding the interior of the moon through gravity measurements.

To see more images from the August flyby, see Cassini website, and the CICLOPS imaging site.

Source: JPL, Porco email

Posted on by Nancy Atkinson

Science Sees Farther: Extraterrestrial Life

Are we alone in the universe? Can we save the lives of millions with new vaccines? How can we manage the increasing demands on our planet’s resources? Scientists try to answer these questions and more as part of a celebration of the 350th year of The Royal Society, the UK’s national academy of sciences. The Society has unveiled a new section on their website today, called “Science Sees Farther”, which includes essays, interviews and more on 12 different scientific topics, including extraterrestrial life, aging, health, climate change, and geoengineering, as well as discussions of the always-present uncertainties in science and how the internet has changed the science landscape.
Continue reading “Science Sees Farther: Extraterrestrial Life”