Gaia Mission Passes Vital Tests

Caption: Fully integrated Gaia payload module with nearly all of the multilayer insulation fabric installed. Credit: Astrium SAS

Earlier this month ESA’s Gaia mission passed vital tests to ensure it can withstand the extreme temperatures of space. This week in the Astrium cleanroom at Intespace in Toulouse, France, had it’s payload module integrated, ready for further testing before it finally launches next year. This is a good opportunity to get to know the nuts and bolts of this exciting mission that will survey a billion stars in the Milky Way and create a 3D map to reveal its composition, formation and evolution.

Gaia will be operating at a distance of 1.5 million km from Earth (at L2 Lagrangian point, which keeps pace with Earth as we orbit the Sun) and at a temperature of -110°C. It will monitor each of its target stars about 70 times over a five-year period, repeatedly measuring the positions, to an accuracy of 24 microarcseconds, of all objects down to magnitude 20 (about 400,000 times fainter than can be seen with the naked eye) This will provide detailed maps of each star’s motion, to reveal their origins and evolution, as well as the physical properties of each star, including luminosity, temperature, gravity and composition.

The service module houses the electronics for the science instruments and the spacecraft resources, such as thermal control, propulsion, communication, and attitude and orbit control. During the 19-day tests earlier this month, Gaia endured the thermal balance and thermal-vacuum cycle tests, held under vacuum conditions and subjected to a range of temperatures. Temperatures inside Gaia during the test period were recorded between -20°C and +70°C.

“The thermal tests went very well; all measurements were close to predictions and the spacecraft proved to be robust with stable behavior,” reports Gaia Project Manager Giuseppe Sarri.

For the next two months the same thermal tests will be carried out on Gaia’s payload module, which contains the scientific instruments. The module is covered in multilayer insulation fabric to protect the spacecraft’s optics and mirrors from the cold of space, called the ‘thermal tent.’

Gaia contains two optical telescopes that can precisely determine the location of stars and analyze their spectra. The largest mirror in each telescope is 1.45 m by 0.5 m. The Focal Plane Assembly features three different zones associated with the science instruments: Astro, the astrometric instrument that detects and pinpoints celestial objects; the Blue and Red Photometers (BP/RP), that determines stellar properties like temperature, mass, age, elemental composition; and the Radial-Velocity Spectrometer (RVS),that measures the velocity of celestial objects along the line of sight.

The focal plane array will also carry the largest digital camera ever built with, the most sensitive set of light detectors ever assembled for a space mission, using 106 CCDs with nearly 1 billion pixels covering an area of 2.8 square metres

After launch, Gaia will always point away from the Sun. L2 offers a stable thermal environment, a clear view of the Universe as the Sun, Earth and Moon are always outside the instruments’ fields of view, and a moderate radiation environment. However Gaia must still be shielded from the heat of the Sun by a giant shade to keep its instruments in permanent shadow. A ‘skirt’ will unfold consisting of a dozen separate panels. These will deploy to form a circular disc about 10 m across. This acts as both a sunshade, to keep the telescopes stable at below –100°C, and its surface will be partially covered with solar panels to generate electricity.

Once testing is completed the payload module will be mated to the service module at the beginning of next year and Gaia will be launched from Europe’s Spaceport in French Guiana at the end of 2013.

Find out more about the mission here

The Universe Shines for Astronomy Photographer of the Year Winners

The overall winner in the Royal Observatory Greenwich’s annual Astronomy Photographer of the Year competition, M51 by Martin Pugh.

Want to see some absolutely gorgeous images of our Universe, all taken by amateur astrophotographers? Look no farther than the winners of the 4th annual Astronomy Photographer of the Year competition, held by the Royal Observatory Greenwich and Sky at Night Magazine. The winners were announced last night at the Royal Observatory, with a record number of entries received in 2012 from photographers from around the world.

“Many of the pictures have been taken with equipment that was out of the range of the amateur many years ago,” said Sir Patrick Moore, from the BBC’s Sky at Night, who is a judge in the competition. “I also like the choice of subjects: photographing people and the night skies is very difficult. The entrants have done very well indeed.”

The overall winner was from Australian Martin Pugh with his beautiful and crisp shot of M51, the Whirlpool Galaxy.

“The photographer has made the most of exceptionally good atmospheric conditions to capture an astonishing range of detail in his image of this iconic galaxy,” said Dr. Marek Kukula, the Royal Observatory Public Astronomer and a judge in the competition. “The beautiful spiral structure, dark lanes of dust, and the way the pink clouds of hydrogen really stand out – it’s a remarkable achievement by an amateur astronomer; one of the best images of M51 that I’ve seen.”

Here are more of the winning shots (and you can click on any of these images for the larger versions on Flickr or the ROG site):

The “People and Space” winner was Laurent Laveder from France, with “Facing Venus-Jupiter Close Conjunction.”

The “Our Solar System” category winner was Transit of Venus 2012 in Hydrogen-Alpha, by Chris Warren of the UK.

One of the year’s biggest astronomical events, the last transit of Venus for 105 years, was featured in numerous entries to the 2012 competition. The Our Solar System category was won by Chris Warren, for his fleeting image of the transit taken through a thin patch of cloud at Blackheath in London. F

Earth and Space category winner, “Orion, Taurus and the Pleiades” by Masahiro Miyasaka from Japan.

The winner of the Earth and Space category was Japan’s Masahiro Miyasaka for his image of Orion, Taurus and the Pleiades forming a dramatic backdrop above an eerie frozen landscape in Nagano.

“Young Astronomy Photographer of the Year” category winner was Jacob von Chorus from Canada

Young Astronomy Photographer of the Year accolade was won by 15 year old Jacob von Chorus from Canada, who impressed the judges with his beautiful shot of the Pleiades, showing many of the hot young stars which make up the cluster and the swirling wisps of blue-hued gas.

See more images of the winning and runner-up “Highly Commended” for each category at the ROG’s website.

See here for information about how you can participate in next year’s competition. Congrats to this year’s winners!

Astrophoto: A Well-Rounded Glow

The bubble nebula Abell 39. Credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona

In theory, planetary nebulae should be simple and spherical, like the soap bubbles you made as a child. But only a rare few actually are! Here’s an example of one of the almost perfectly round planetary nebulae.

“Abell 39 is the quintessential bubble nebula with spherical form,” writes Adam Block, who is an avid astrophotographer, as well as the Public Observing Programs Coordinator at the Mount Lemmon Sky Center in Tucson, Arizona. “As this is a ‘true color”‘(broadband) image, it is difficult to show the limb brightening and the variations in the transparent shell like narrowband images do. I am glad to finally have this one in the collection of recent work.”

See more information about this image at the Mount Lemmon Sky Center’s website

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Fires in the Sky: Aurorae and Meteor Photo by Ole Salomonsen

A bright fireball slashes through curtains of aurorae shimmering above the mountains of northern Norway, captured on camera by Ole C. Salomonsen in the early hours of September 20.

Salomonsen, a master at photographing the Northern Lights, says this was the biggest fireball he’s ever caught on camera.

“The fireball lasted for about 6-7 seconds until it vanished behind the mountain,” Ole recalls. “By the way, this mountain is over 1350 meters (4440 feet) high, and I am standing only 600 meters from the foot of it, so do not be fooled by the 14mm wide angle lens! There was some very distinguished blue colors surrounding the fireballs edges. Never ever seen anything big like this!”

The mountain at right is called “Otertinden”, and is about a 90 minute drive north of Tromsø, Norway — a hot spot for stunning auroral displays.

And if you’re wondering if the aurorae and the meteor are really in the same region of the atmosphere, well, they likely are. Incoming meteoroids begin to glow at around 70 to 100 km up, which is also about the same altitude that aurorae are visible.

Although Ole stated that this wasn’t the best aurora photo from the shoot, the fireball and its reflection in the still river made him feel this one “deserved to go first.”

The photo was taken with a Canon EOS 1D-X and a Nikon 14-24mm lens.

See more of Ole’s work on his website,, and you can like his page on Facebook here. (Also he’s got a couple of great time-lapse videos too!)

Image © Ole C. Salomonsen. All rights reserved. Used with permission.

Early Galaxy Found from the Cosmic ‘Dark Ages’

In the big image at left, the many galaxies of a massive cluster called MACS J1149+2223 dominate the scene. Gravitational lensing by the giant cluster brightened the light from the newfound galaxy, known as MACS 1149-JD, some 15 times. At upper right, a partial zoom-in shows MACS 1149-JD in more detail, and a deeper zoom appears to the lower right. Image credit: NASA/ESA/STScI/JHU

Take a close look at the pixelated red spot on the lower right portion of the image above, as it might be the oldest thing humanity has ever seen. This is a galaxy from the very early days of the Universe, and the light from the primordial galaxy traveled approximately 13.2 billion light-years before reaching the Spitzer and Hubble space telescopes. The telescopes — and the astronomers using them — had a little help from a gravitational lens effect to be able to see such a faint and distant object, which was shining way back when our Universe was just 500 million years old.

“This galaxy is the most distant object we have ever observed with high confidence,” said Wei Zheng, a principal research scientist in the department of physics and astronomy at Johns Hopkins University in Baltimore who is lead author of a new paper appearing in Nature. “Future work involving this galaxy, as well as others like it that we hope to find, will allow us to study the universe’s earliest objects and how the dark ages ended.”

This ancient and distant galaxy comes from an important time in the Universe’s history — one which astronomers know little about – the early part of the epoch of reionization, when the Universe began to move from the so-called cosmic dark ages. During this period, the Universe went from a dark, starless expanse to a recognizable cosmos full of galaxies. The discovery of the faint, small galaxy opens a window onto the deepest, most remote epochs of cosmic history.

“In essence, during the epoch of reionization, the lights came on in the universe,” said paper co-author Leonidas Moustakas, from JPL.

Because both the Hubble and Spitzer telescopes were used in this observation, this newfound galaxy, named MACS 1149-JD, was imaged in five different wavebands. As part of the Cluster Lensing And Supernova Survey with Hubble Program, the Hubble Space Telescope registered the newly described, far-flung galaxy in four visible and infrared wavelength bands. Spitzer measured it in a fifth, longer-wavelength infrared band, placing the discovery on firmer ground.

Objects at these extreme distances are mostly beyond the detection sensitivity of today’s largest telescopes. To catch sight of these early, distant galaxies, astronomers rely on gravitational lensing, where the gravity of foreground objects warps and magnifies the light from background objects. A massive galaxy cluster situated between our galaxy and MACS 1149-JD magnified the newfound galaxy’s light, brightening the remote object some 15 times and bringing it into view.

Astronomers use redshift to describe cosmic distances, and the ancient but newly-found galaxy has a redshift, of 9.6. The term redshift refers to how much an object’s light has shifted into longer wavelengths as a result of the expansion of the universe.

Based on the Hubble and Spitzer observations, astronomers think the distant galaxy was less than 200 million years old when it was viewed. It also is small and compact, containing only about 1 percent of the Milky Way’s mass. According to leading cosmological theories, the first galaxies indeed should have started out tiny. They then progressively merged, eventually accumulating into the sizable galaxies of the more modern universe.

The epoch of reionization refers to the period in the history of the Universe during which the predominantly neutral intergalactic medium was ionized by the emergence of the first luminous sources, and these first galaxies likely played the dominant role in lighting up the Universe. By studying reionization, astronomers can learn about the process of structure formation in the Universe, and find the evolutionary links between the smooth matter distribution at early times revealed by cosmic microwave background studies, and the highly structured Universe of galaxies and clusters of galaxies at redshifts of 6 and below.

This epoch began about 400,000 years after the Big Bang when neutral hydrogen gas formed from cooling particles. The first luminous stars and their host galaxies emerged a few hundred million years later. The energy released by these earliest galaxies is thought to have caused the neutral hydrogen strewn throughout the Universe to ionize, or lose an electron, a state that the gas has remained in since that time.

The paper is available here (pdf document).

Source: JPL

Did a Killer Asteroid Drive the Planet Into An Ice Age?

A simulation of the Eltanin strike

A simulation of the Eltanin meteor strike

When a mountain-sized asteroid struck the deep ocean off the coast of Antarctica 2.5 million years ago, it set off an apocalyptic chain of events: a devastating rain of molten rock and then a deadly tsunami that inundated the coastlines of the Pacific Ocean. But according to a team of Australian researchers, this was just the beginning. Then came a protracted ice age that killed off many of the Earth’s large mammals.

The Eltanin meteor, named after the USNS Eltanin which surveyed the area in 1964, is the only impact that has ever been discovered in a deep-ocean basin. These deep water impacts must be more common – so much of the planet is ocean – but they’re tricky to find because of the inaccessible depths of the impact craters. Researchers examining sediments in the area discovered tiny grains of impact melt and debris from meteorite fragments. Something big smashed this spot.

An asteroid strike on land is devastating, but an asteroid strike in the deep ocean is even worse. On both land and ocean, you get the plume of water vapor, sulfur, and dust blasted into the high atmosphere, raining molten rock down across a wide area. But for asteroid strikes in the ocean, this is followed by a devastating tsunami that inundates coastlines around the world. There are waves hundreds of meters high at the crash site, and they travel deep inland on every coastline. A local event becomes a global event.

But with the Eltanin meteor, this was followed by a prolonged ice age.

Professor James Goff and his colleagues from the University of New South Wales in Australia have been researching the Eltanin meteor and its after-effects. The timing of the impact seems to line up with geologic deposits in Chile, Australia and Antarctica. Geologists traditionally connected these deposits with slower geological processes, like glaciation. But Goff and his team think these deposits might have been dropped all at once by the devastating tsunami from Eltanin.

Here’s a video that shows how the impact and subsequent tsunami might have played out.

Although the Earth was already thought to be cooling in the mid to late Pliocene, the material kicked into the high atmosphere by Eltanin could have pushed the planet’s climate past the tipping point:

“There’s no doubt the world was already cooling through the mid and late Pliocene,” says co-author Professor Mike Archer. “What we’re suggesting is that the Eltanin impact may have rammed this slow-moving change forward in an instant – hurtling the world into the cycle of glaciations that characterized the next 2.5 million years and triggered our own evolution as a species.”

It was this time of a global ice age that transitioned the planet from the Pliocene to the Pleistocene. It was a bad time to be a Chalicothere or Anthracotheriidae, but a good time to be a hominid. So… thanks Eltanin.

View Larger Map

The location of the Elatin meteor crater

Original Source: Journal of Quaternary Science

SETI Astronomer Jill Tarter Recalls ‘Contact,’ 15 Years On

SETI's Jill Tarter. Credit: SETI


In 1985, famed astronomer, author and TV host Carl Sagan invited Jill Tarter to dinner at his house near Cornell University. Tarter, heavily involved with the Search for Extra-Terrestrial Intelligence, gladly accepted the chance to speak with Sagan, a member of SETI’s board of trustees.

Seated with Sagan and his wife, Ann Druyan, Tarter learned that Sagan had a fiction book on the go.

“Annie said, ‘You may recognize someone in the book, but I think you’ll like her,'” Tarter recalled in an interview with Universe Today.

Suspecting the character was based on herself, Tarter’s response to Druyan was: “‘Just make sure she doesn’t eat ice cones so much.’ It was something I was teased about.”

Female, in a male-dominated field

It was 15 years ago this month that the movie Contact, based on Sagan’s book of the same title, expanded to a run in international theatres after a successful summer in North America. The movie explores the implication of aliens making contact with Earth, but does it from more of a scientific perspective than most films.

While Contact, the movie did not talk about the pi sequences or advanced mathematical discussions in Contact, the book, it did bring concepts such as prime numbers, interference with radio telescopes, and the religion vs. science debate to theatres in 1997.

Tarter, who has just retired as the long-time director of the SETI Institute, said she was stunned by the parallels between her own life and that of Ellie Arroway, the character based on her in Contact. Both lost parents at an early age. Both also had to make their way in a field aggressively dominated by males.

Tarter recalls a meeting with fellow female scientists of her generation some years ago.

“A huge percentage of us had been, in high school, either cheerleaders or drum majorettes. This is so counterintuitive, right? Because we’re the nerds, we’re the brainy ones … (it was because) we were all competitors, and there weren’t any (female) sports to compete at. These sports were open, and we competed, and we generally won.”

Working on set

Tarter cautions the parallels did not totally match. The hopes and aspirations of Ellie in the book, and also the movie, were products of Sagan’s imagination. But the producers and actors of the film did want to get a close sense of what it was like to work with SETI.

After Jodie Foster was cast as Ellie, there were multiple phone calls between the actress and Tarter to discuss SETI.

“From her point of view, she was clear she wasn’t going to teach anyone astronomy. She was interested, in a personal way, about what the scientists were like,” Tarter said.

When the crew was filming at the Arecibo Observatory in Puerto Rico, Tarter flew there to observe the work, meet with Foster and also show the actress around. Tarter recalls bringing Foster up in a cabin that had a perfect view of the telescope, some 500 feet above the dish.

Microphones and walkie-talkies

Filming was an interesting process for Tarter, as well. There were the microphones, and the tools the crew used to check continuity. Most amusingly for Tarter, she observed Foster (reported height 5 feet, 2 inches) needing to stand on a box for most of the close-up shots with actor Matthew McConaughey (reported as 6 feet tall).

Two errors still irk Tarter today. There is a scene when Ellie gives a modified version of the Drake Equation, which calculates the odds of intelligent life who are capable of communicating with other life forms, and the calculations are all wrong. “It’s really infuriating,” Tarter said.

The other large mistake is a scene where Ellie gets a potential signal from space, while working at the Karl G. Jansky Very Large Array set of radio telescopes in New Mexico.

“She’s sitting in the middle of the array, in a car, with her laptop, and she gets the signal. And the first thing she does is pick up a walkie-talkie and start broadcasting. That signal is going to wipe out the signal from the sky. You don’t transmit by walkie-talkie.”

But overall, Tarter said the movie did a great job at portraying the feel of SETI. And Foster appreciated Tarter’s help. “She would write me handwritten thank-you notes, which was a kind of manner that most people have lost. A great courtesy.”

Hollywood outreach

Tarter walked the red carpet at the movie premiere and spent most of her time watching the film in tears of happiness. That euphoria evaporated when she saw the SETI Institute was not credited at the end of the film. When she talked to one of the film producers, she said she was informed that lawyers usually draft agreements specifying the length of time the credit appears, and the compensation received for doing so.

“We don’t have a lawyer at the SETI Institute,” she said. “When I write a paper, I acknowledge my collaborators. We got that wrong, so we never got any credit. We might have gotten even more recognition.”

But the professional connection with Foster still remains. Foster happily responded to a request from Tarter to do voice-overs for a video clip used for a SETI high school curriculum for integrated science. She also narrated a show, Life: A Cosmic Story, for the California Academy of Sciences Morrison Planetarium.

Tarter is now shifting into full-time outreach for SETI, saying the budgetary problems that shut down the organization’s Allen Telescope Array for several months last year were a warning call.

One of the organization’s newest initiatives is, which crowdsources analysis of signals from the Kepler Field. SETI solicits the public to take some time looking at the signal patterns, one at a time, in search of extraterrestrial communications.

“SETI is too important to allow it to fail,” Tarter said, adding her focus is finding substantial, stable funding from “that individual or institution that is capable of taking a long view.”

Adrenaline Rush: Standing on the Edge of a Spewing Volcano

This may be the most incredible volcano video ever filmed. Looking like it comes from the latest natural disaster flick, this incredible real footage was captured by Geoff Mackley, Bradley Ambrose, Nathan Berg, who came within 30 meters of the bubbling, spewing lava stream from the mouth the Marum volcano on Ambrym, a volcanic island in the archipelago of Vanuatu, off the east coast of Australia.

“Climbing down to within 30 metres of the lava it was so hot (1150 degrees) that without protection we could stand the heat for 6 seconds before retreating,” writes Mackley on his website. “With a respirator fire and heat resistant suit, [we] could stand on the edge and see the amazing spectacle for over 40 minutes.”

Wow! You can see some incredible images at Mackley’s website.
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NASA’s Tribute to Sally Ride

Sally Ride

NASA officials, fellow astronauts and the family of Sally Ride gathered in Houston at the Johnson Space Center on Sept. 18, 2012. They remembered Ride’s life and the legend she leaves behind. An oak tree — one of most enduring types of trees — was planted and dedicated in Ride’s honor. It sits among 62 other trees dedicated to astronauts and space pioneers in a grove located JSC.

Ride passed away on July 23, 2012 after a courageous 17-month battle with pancreatic cancer. “She lived her life to the fullest, with boundless energy, curiosity, intelligence, passion, commitment, and love. Her integrity was absolute; her spirit was immeasurable; her approach to life was fearless,” wrote the team at Sally Ride Science — the science education company Ride founded — on the day of her death.

Award-Winning Short Film is Set on an Exoplanet

A new short film called “Grounded” portrays an astronaut stranded on another planet. The film combines great storytelling with stunning effects, and the visuals are nothing short of convincingly and stunningly real. But the ethereal, dream-like nature of the film is reminiscent of the ending of the movie “2001,” so, actually understanding the plot is not what the film is about. Instead it invites “unique interpretation and reflection by the viewer,” according to the description of the film. In under 8 minutes, the film explores themes of “aging, inheritance, paternal approval, cyclic trajectories, and behaviors passed on through generations,” which is ambitious for a sci-fi genre short. “Grounded” was written, directed, edited and produced by Kevin Margo. It is perhaps one of the best short films I’ve ever seen.
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