Universe Today

January 14, 2013April 13, 2022 by Ken Kremer

Rover Team Chooses 1st Rock Drilling Target for Curiosity

Image caption: Time lapse mosaic shows Curiosity rover’s arm movement from raised position to surface deployment on Sol 149 (Jan. 5) for contact science near the lower point of the slithery chain of narrow protruding rocks known as ‘Snake River’ – located inside the basin called “Yellowknife Bay’. The rover team will soon conduct historic first rock drilling in these surroindings. Curiosity has now driven to the larger, broken rock just above, right of the sinuous ‘Snake River’ rock formation. Photomosaic was stitched from Navcam raw images and is colorized with patches of sky added to fill in image gaps. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo

A team of Mars scientists and engineers have chosen the 1st rock drilling target for NASA’s Curiosity rover after carefully considering a range of options over the past several weeks at the robots current location inside a shallow depression known as ‘Yellowknife Bay’, which is replete with light toned rocks.

An official NASA announcement with further information is forthcoming on Tuesday this week, according to a source for this report.

Curiosity is now conducting a detailed science evaluation of the vicinity around a slithery chain of rocks called ‘Snake River’, jutting up from the sandy, rock strewn Martian floor – see our illustrative photo mosaics above & below and earlier story here.

Drilling goes to the heart of the mission and will mark a historic feat in planetary exploration – as the first time that an indigenous sample has been cored from the interior of a rock on another planet and subsequently analyzed by chemical spectrometers to determine its elemental composition and determine if organic molecules are present.

The first report of the drill target selection came just a day ago from Craig Covault at NASA Watch/Spaceref in an article, here – featuring our ‘Snake River’ time lapse mosaic (by Ken Kremer and Marco Di Lorenzo). The mosaic shows the arm in action deploying its science instruments and rotating to capture pictures with the MAHLI microscopic imager and contact science with the APXS mineral spectrometer.

The exact drilling spot has not been divulged but is likely near ‘Snake River’ and visible in our mosaics from Sol 149 and earlier Sols inside the ‘Yellowknife Bay’ basin – which exhibits cross bedding and is reminiscent of a dried up shoreline. Curiosity has now driven to the larger, broken rock just above, right of the sinuous ‘Snake River’ rock formation for up-close contact science investigations.

Image Caption: Before and after comparison of images of 1st ever rock brush off by Curiosity’s Dust Removal Tool (DRT) on Sol 150 (Jan 6, 2013), nearby to Snake River. Images taken by the high resolution Mastcam 100 camera, contrast enhanced. The brushed patch of rock target called “Ekwir_1” ‘is about 1.85 inches by 2.44 inches (47 millimeters by 62 millimeters). Credit: NASA/JPL-Caltech/MSSS/Ken Kremer

The Mars Science Lab (MSL) team is coordinating with top JPL & NASA management to get approval for the drilling location chosen or select another rock.

The high powered hammering drill is located on the tool turret at the end of the car-sized robots 7 foot (2.1 meter) long mechanical arm.

The percussive drill is the last component of Curiosity’s ten state-of-the-art science instruments that remains to be checked out and put into action.

Rock samples collected from the first test bore holes will be pulverized and the powdery mix will initially be used to rinse the interior chambers of the drill mechanisms and cleanse out residual earthly contaminants – and then dumped. The same procedure was carried out at the windblown ‘Rocknest’ ripple with the initial scoops of soil to cleanse the CHIMRA sample processing systems.

So it’s likely to take several weeks and possible a month or more until sieved samples are finally delivered to the CheMin and SAM analytical chemistry labs on the rover deck for analysis of their inorganic and organic chemical composition.

Image caption: Photo mosaic shows NASA’s Curiosity Mars rover reaching out to investigate rocks at a spot inside Yellowknife Bay on Sol 132, Dec 19, 2012. In search of first drilling target the rover drove to a spot at the right edge of this mosaic called Snake River rock. Curiosity’s navigation camera captured the scene surrounding the rover with the arm deployed and the APXS and MAHLI science instruments on tool turret collecting imaging and X-ray spectroscopic data. Base of Mount Sharp visible at right. The mosaic is colorized with patches of sky added to fill in gaps. Click to enlarge. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo

As a prelude on Sol 150 (Jan 6.), the rover successfully brushed off one of the flat rocks around Snake River for the first time by using the motorized, wire-bristle brush on the Dust Removal Tool (DRT), built by Honeybee Robotics of NYC.

The brushing was completed on a rock target called ‘Ekwir_1’ – see our mosaic showing a before and after comparison of rock surface images snapped by the Mastcam-100 high resolution color camera.

Brushing is a key step prior to rock drilling and allows the team to much more easily gain insight into the rocks composition with the science instruments compared to the obscured view of a dust blanketed rock. Spirit & Opportunity also have Honeybee Robotics built brushes that have still endured throughout their years’ long miraculous lifetimes.

The team then commanded the rover to bump a bit closer to “slightly younger rocks in front of the rover,” says MSL team member Ken Herkenhoff.

“The contact science activities in the current location went well, including the first brushing of the surface. In order to characterize the geology and chemistry of the rocks at the edge of Yellowknife Bay, we intend to repeat the set of brushing, APXS, MAHLI, ChemCam and Mastcam activities at the new location starting on Sol 152.”

“We are studying chemical and textural differences in the rocks near Snake River,” says Herkenhoff.

On Sol 152 (Jan. 8), Curiosity drove 2.5 meters closer to the area surrounding ‘Snake River’ and began snapping high resolution color imagery.

“It’s one piece of the puzzle,” says John Grotzinger, the mission’s chief scientist of the California Institute of Technology. “It has a crosscutting relationship to the surrounding rock and appears to have formed after the deposition of the layer that it transects.”

Grotzinger and the team are excited because Curiosity is a sort of time machine providing a glimpse into the Red Planets ancient history when the environment was warmer and wetter billions of years ago and much more conducive to the origin of life.

Ken Kremer

Image caption: Diagram shows all instruments on Tool turret on robotic arm. Credit: NASA

January 13, 2013December 23, 2015 by Ken Kremer

Private Test Pilots to Fly 1st Commercial Crewed Space Flights for NASA

Dream Chaser from Sierra Nevada docks at ISS

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Image Caption: Dream Chaser commercial crew vehicle built by Sierra Nevada Corp docks at ISS

Commercial test pilots, not NASA astronauts, will fly the first crewed missions that NASA hopes will at last restore America’s capability to blast humans to Earth orbit from American soil – perhaps as early as 2015 – which was totally lost following the forced shuttle shutdown.

At a news briefing this week, NASA managers at the Kennedy Space Center (KSC) said the agency is implementing a new way of doing business in human spaceflight and purposely wants private companies to assume the flight risk first with their crews before exposing NASA crews as a revolutionary new flight requirement. Both NASA and the companies strongly emphasized that there will be no shortcuts to flying safe.

A trio of American aerospace firms – Boeing, SpaceX and Sierra Nevada Corp – are leading the charge to develop and launch the new commercially built human-rated spacecraft that will launch Americans to LEO atop American rockets from American bases.

The goal is to ensure the nation has safe, reliable and affordable crew transportation systems for low-Earth orbit (LEO) and International Space Station (ISS) missions around the middle of this decade.

The test launch schedule hinges completely on scarce Federal dollars from NASA for which there is no guarantee in the current tough fiscal environment.

The three companies are working with NASA in a public-private partnership using a combination of NASA seed money and company funds. Each company was awarded contracts under NASA’s Commercial Crew Integrated Capability Initiative, or CCiCap, program, the third in a series of contracts aimed at kick starting the development of the so-called private sector ‘space taxis’ to fly astronauts to and from the ISS.

Caption: Boeing CST-100 crew vehicle docks at the ISS

The combined value of NASA’s Phase 1 CCiCap contracts is about $1.1 Billion and runs through March 2014 said Ed Mango, NASA’s Commercial Crew Program manager. Phase 2 contract awards will follow and eventually lead to the actual flight units after a down selection to one or more of the companies, depending on NASA’s approved budget.

Since the premature retirement of NASA’s shuttle fleet in 2011, US astronauts have been 100% reliant on the Russians to hitch a ride to the ISS – at a price tag of over $60 Million per seat. This is taking place while American aerospace workers sit on the unemployment line and American expertise and billions of dollars of hi-tech space hardware rots away or sits idly by with each passing day.

Boeing, SpaceX and Sierra Nevada Corp seek to go where no private company has gone before – to low Earth orbit with their private sector manned spacecraft. And representatives from all three told reporters they are all eager to move forward.

All three commercial vehicles – the Boeing CST-100; SpaceX Dragon and Sierra Nevada Dream Chaser – are designed to carry a crew of up to 7 astronauts and remain docked at the ISS for more than 6 months.

“For well over a year now, since Atlantis [flew the last space shuttle mission], the United States of America no longer has the capability to launch people into space. And that’s something that we are not happy about,” said Garrett Reisman, a former space shuttle astronaut who is now the SpaceX Commercial Crew project manager leading their development effort. “We’re very proud to be part of the group that’s going to do something about that and get Americans back into space.”

Caption: Blastoff of SpaceX Cargo Dragon atop Falcon 9 from Cape Canaveral, Florida on May, 22, 2012, bound for the ISS. Credit: Ken Kremer

“We are the emotional successors to the shuttle,” said Mark Sirangelo, Sierra Nevada Corp. vice president and SNC Space Systems chairman. “Our target was to repatriate that industry back to the United States, and that’s what we’re doing.”

Sierra Nevada is developing the winged Dream Chaser, a mini-shuttle that launches atop an Atlas V rocket and lands on a runway like the shuttle. Boeing and SpaceX are building capsules that will launch atop Atlas V and Falcon 9 rockets, respectively, and then land by parachute like the Russian Soyuz capsule.

SpaceX appears to be leading the pack using a man-rated version of their Dragon capsule which has already docked twice to the ISS on critical cargo delivery missions during 2012. From the start, the SpaceX Dragon was built to meet the specification ratings requirements for a human crew.

Caption: Dragon spacecraft approaches the International Space Station on May 25, 2012 for grapple and berthing . Photo: NASA

Reisman said the first manned Dragon test flight with SpaceX test pilots could be launched in mid 2015. A flight to the ISS could take place by late 2015. Leading up to that in April 2014, SpaceX is planning to carry out an unmanned in-flight abort test to simulate and test a worst case scenario “at the worst possible moment.”

Boeing is aiming for an initial three day orbital test flight of their CST-100 capsule during 2016, said John Mulholland, the Boeing Commercial Programs Space Exploration vice president and program manager. Mulholland added that Chris Ferguson, the commander of the final shuttle flight by Atlantis, is leading the flight test effort.

Boeing has leased one of NASA’s Orbiter Processing Facility hangers (OPF-3) at KSC. Mulholland told me that Boeing will ‘cut metal’ soon. “Our first piece of flight design hardware will be delivered to KSC and OPF-3 within 5 months.”

Caption: Boeing CST-100 capsule mock-up, interior view. Credit: Ken Kremer

Sierra Nevada plans to start atmospheric drop tests of an engineering test article of the Dream Chaser from a carrier aircraft in the next few months in an autonomous mode. The test article is a full sized vehicle.

“It’s not outfitted for orbital flight; it is outfitted for atmospheric flight tests,” Sirangelo told me. “The best analogy is it’s very similar to what NASA did in the shuttle program with the Enterprise, creating a vehicle that would allow it to do significant flights whose design then would filter into the final vehicle for orbital flight.”

Now to the issue of using commercial space test pilots in place of NASA astronauts on the initial test flights.

At the briefing, Reisman stated, “We were told that because this would be part of the development and prior to final certification that we were not allowed, legally, to use NASA astronauts to be part of that test pilot crew.”

So I asked NASA’s Ed Mango, “Why are NASA astronauts not allowed on the initial commercial test flights?”

Mango replied that NASA wants to implement the model adopted by the military wherein the commercial company assumes the initial risk before handing the airplanes to the government.

“We would like them to get to a point where they’re ready to put their crew on their vehicle at their risk,” said Mango. “And so it changes the dynamic a little bit. Normally under a contract, the contractor comes forward and says he’s ready to go fly but it’s a NASA individual that’s going to sit on the rocket, so it becomes a NASA risk.

“What we did is we flipped it around under iCAP. It’s not what we’re going to do long term under phase two, but we flipped it around under iCAP and said we want to know when you’re ready to fly your crew and put your people at risk. And that then becomes something that we’re able to evaluate.”

“In the end all our partners want to fly safe. They’re not going to take any shortcuts on flying safe,” he elaborated. “All of us have the same initiative and it doesn’t matter who’s sitting on top of the vehicle. It’s a person, and that person needs to fly safely and get back home to their families. That’s the mission of all our folks and our partners – to go back home and see their family.”

Given the nations fiscal difficulties and lack of bipartisan cooperation there is no guarantee that NASA will receive the budget it needs to keep the commercial crew program on track.

Indeed, the Obama Administrations budget request for commercial crew has been repeatedly slashed by the US Congress to only half the request in the past two years. These huge funding cuts have already forced a multi-year delay in the inaugural test flights and increased the time span that the US has no choice but to pay Russia to launch US astronauts to the ISS.

“The budget is going to be an extremely challenging topic, not only for this program but for all NASA programs,” said Phil McAlister, NASA Commercial Spaceflight Development director.

NASA is pursuing a dual track approach in reviving NASA’s human spaceflight program. The much larger Orion crew capsule is simultaneously being developed to launch atop the new SLS super rocket and carry astronauts back to the Moon by 2021 and then farther into deep space to Asteroids and one day hopefully Mars.

Ken Kremer

Caption: Dream Chaser awaits launch atop Atlas V rocket

January 11, 2013December 23, 2015 by Jason Major

AR1654 is a Monster Sunspot. (And It’s Aiming Our Way.)

Active Region 1654 on the Sun’s western limb, seen by SDO on Jan. 11 (NASA/SDO/HMI team. Diagram by J. Major.)

Like an enormous cannon that is slowly turning its barrel toward us, the latest giant sunspot region AR1654 is steadily moving into position to face Earth, loaded with plenty of magnetic energy to create M-class flares — moderate-sized outbursts of solar energy that have the potential to cause brief radio blackouts on Earth and, at the very least, spark bright aurorae around the upper latitudes.

According to SpaceWeather.com, AR1654 “could be the sunspot that breaks the recent lengthy spell of calm space weather around our planet.”

The image above, captured by NASA’s Solar Dynamics Observatory earlier today, shows the structure of AR1654 upon the Sun’s photosphere — its light-emitting “surface” layer. Stretching many tens of thousands of miles, this magnetic solar blemish easily dwarfs our entire planet. And it’s not just a prediction that this sunspot will unleash a flare — it already has.

AR1654 came around the limb of the sun crackling with activity. Shortly after the probability of AR1654 releasing a flare was raised to 50% it did just that, letting loose with a burst of magnetic energy that was observed by SDO’s multi-channel cameras. Watch the video below:

Peaking at 9:11 UTC, this M1-class flare won’t have much more effect on Earth than perhaps some radio and GPS interference and maybe increased auroral activity. But AR1654 is still evolving and growing… and moving to face us.

In the meantime, solar astronomers and observatories like SDO are keeping an ever-watchful eye on this magnetic monster.

Keep up with the latest news here on Universe Today, on the SDO mission site and on spaceweather.com.

UPDATE 1/12: According to the NOAA, AR1654 has a 5% chance of producing an X-class flare, based on its current magnetic activity and alignment.

A sunspot is a magnetically active region on the sun that appears dark because it’s relatively cooler than the surrounding area—6,000ºF (3,300ºC) versus 10,000ºF (5,500º C). Sunspots are where solar flares are most likely to occur since the magnetic fields in these active regions can build up enough energy to break, releasing bursts of intense radiation into the solar system.

January 11, 2013April 26, 2016 by Nancy Atkinson

Bigelow Inflatable Module Will be Added to Space Station

NASA Deputy Administrator Lori Garver is given a tour of the Bigelow Aerospace facilities in 2011 by the company’s President Robert Bigelow. Photo: NASA/Bill Ingalls

The next addition to the International Space Station will likely be an inflatable module from Bigelow Aerospace. NASA announced today they have awarded a $17.8 million contract to Bigelow to provide a new module for the ISS. “The Bigelow Expandable Activity Module will demonstrate the benefits of this space habitat technology for future exploration and commercial space endeavors,” NASA said in a press release. This would be the first privately built module to be added to the space station.

“The International Space Station is a unique laboratory that enables important discoveries that benefit humanity and vastly increase understanding of how humans can live and work in space for long periods,” NASA Deputy Administrator Lori Garver said. “This partnership agreement for the use of expandable habitats represents a step forward in cutting-edge technology that can allow humans to thrive in space safely and affordably, and heralds important progress in U.S. commercial space innovation.”

NASA will release more information about the agreement and the module next week, but previous reports have indicated the inflatable module would be used for adding additional storage and workspace, and the module would be certified to remain on-orbit for two years.
NASA has been in discussions with Bigelow for several years about using their inflatable technology.

In 2006 Bigelow launched their Genesis I inflatable test module into orbit and according to their website, it is still functioning and “continuing to produce invaluable images, videos and data for Bigelow Aerospace. It is now demonstrating the long-term viability of expandable habitat technology in an actual orbital environment.”

A second Genesis module was launched in 2007 and it, too, is still functioning in orbit.
Bigelow has said that even though the outer shell of their module is soft, as opposed to the rigid outer shell of current modules at the ISS, Bigelow’s inflatable modules are more resistant to micrometeoroid or orbital debris strikes. Bigelow uses multiple layers of Vectran, a material which is twice as strong as Kevlar. In ground tests, according to NASASpacefight.com, objects that would penetrate ISS modules only penetrated half-way through the skin of Bigelow’s modules.

January 11, 2013April 26, 2016 by Fraser Cain

Watch this Solar Prominence Blast Off the Surface of the Sun

“I may not get a lot done today with the Sun putting on this sort of show”, announced amateur astrophotographer Paul Stewart from his upside down observatory in New Zealand yesterday. No kidding Paul, I can’t imagine anything else that you should be doing with your day other than recording this amazing animation of a massive prominence blasting off the surface of the Sun.

The animation you’re seeing attached to this article was captured by Paul on January 10th, 2013 and consists of 28 separate images of the Sun. But each of these images is actually a composite of about 1000 frames of video; only the best 30% of the frames were kept, and the rest were discarded. Paul stacked up each individual frame using AutoStakkert with Registax, and then manually lined them up in Photoshop. Finally, the whole thing was animated in Virtualdub.

Wondering about the gear Paul used? He was equipped with a Lunt Solar Systems 80mm H-Alpha Pressure Tuned Telescope (that’s it over on the right), using a DMK21AU618AS camera. “It was the first light with this camera, I think it has passed the test.” Indeed it has.

Known as the Upside Down Astronomer, Paul recently got his new website operating, with amazing photographs, detailed info on his gear, and an ongoing blog of updates. Check out the detailed construction images of his green dome.

A single frame of the animation, showing the power of the prominence on the Sun.

So what are we looking at here; what are these solar prominences? With all its twisting swirling gas, the Sun is surrounded by powerful magnetic fields which are constantly shifting, combining and snapping apart. Hot plasma (charged hydrogen and helium atoms) in the Sun’s atmosphere flows along the tangled structure of the magnetic fields. When these magnetic fields shift and snap, a tremendous amount of energy is released, and the plasma is blasted off into space. When these prominences are directed towards Earth, the stream of particles interacts with the Earth’s magnetic field to produce the beautiful auroras we see in the Northern and Southern latitudes.

January 11, 2013December 23, 2015 by Fraser Cain

Virtual Star Party – Jan. 6, 2013: The One Year Anniversary Edition

The Virtual Star Party is one year old. Well, not the Virtual Star Party itself, but our efforts to broadcast a live view from telescopes into a Google+ hangout. Thanks to everyone who has supported us and watched our efforts evolve from those first tentative steps to our comprehensive coverage now.

Astronomers: Mike Phillips, Stuart Forman and Mark Behrendt

Commentary: Dr. Phil Plait and Ray Sanders.

Host: Fraser Cain.

Here are some pictures from the event:

Blue Snowball Nebula by Stuart Forman

M33 Andromeda Nebula by Stuart Forman

Jupiter by Mike Phillips

We run the Virtual Star Party every Sunday night as a live Google+ Hangout. Want to find when it’s happening next? Just circle the Virtual Star Party page on Google+. Visit the Universe Today YouTube channel to see an archive of all our past events.

January 11, 2013December 23, 2015 by Nancy Atkinson

Astrophoto: A Man-Made Sunspot

The International Space Station Transiting across the disc of the Sun on January 9, 2013. Credit: Efrain Morales

The Sun has been active recently along with showing several sunspots. But astrophotogher Efrain Morales captured an additional ‘man-made’ sunspot as the International Space Station transited across the face of the solar disk.

“It was a challenge as the Sun was low on the horizon at 19.5 deg. elevation, just above the canopy of the forest,” Efrain said via email, “along with and the ISS being over 250 miles distant from my location passing over Haiti at the time. His home base is the Jaicoa Observatory in Puerto Rico.

Equipment: SolarMax40, P/B CGE mount, Flea3 Ccd.

Below, see an animation of the ISS transit:

Animation of the International Space Station Transiting across the disc of the Sun on January 9th at about 20:32 UTC. Credit: Efrain Morales.

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.

January 11, 2013April 26, 2016 by Jason Major

So. Many. Stars…

Infrared image of globular cluster 47 Tucanae (NGC 104) captured by ESO’s VISTA telescope.

“My god, it’s full of stars!” said Dave Bowman in the movie 2010 as he entered the monolith, and one could imagine that the breathtaking view before him looked something like this.

Except this isn’t science fiction, it’s reality — this is an image of globular cluster 47 Tucanae taken by the European Southern Observatory’s VISTA telescope at the Paranal Observatory in Chile. It reveals in stunning detail a brilliant collection of literally millions of stars, orbiting our Milky Way galaxy at a distance of 15,000 light-years.

The full image can be seen below.

47 Tucanae (also known as NGC 104) is located in the southern constellation Tucana. It’s bright enough to be seen without a telescope and, even though it’s very far away for a naked-eye object, covers an area about the size of the full Moon.

In reality the cluster is 124 light-years across.

Although globular clusters like 47 Tucanae are chock-full of stars — many of them very old, even as stars go — they are noticeably lacking in clouds of gas and dust. It’s thought that all the gaseous material has long since condensed to form stars, or else has been blown away by radiation and outbursts from the cluster’s exotic inhabitants.

At the heart of 47 Tucanae lie many curious objects like powerful x-ray sources, rapidly-spinning pulsars, “vampire” stars that feed on their neighbors, and strange blue stragglers — old stars that somehow manage to stay looking young. (You could say that a globular cluster is the cosmic version of a trashy reality show set in Beverly Hills.)

Red giants can be seen surrounding the central part of the cluster, old bloated stars that are running out of fuel, their outer layers expanding.

The background stars in the image are part of the Small Magellanic Cloud, which was in the distance behind 47 Tucanae when this image was taken.

VISTA is the world’s largest telescope dedicated to mapping the sky in near-infrared wavelengths. Located at ESO’s Paranal Observatory in Chile, VISTA is revealing new views of the southern sky. Read more about the VISTA survey here.

Image credit: ESO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit

January 11, 2013December 23, 2015 by Nancy Atkinson

Asteroid Apophis: Bigger, Darker But Not a Threat in 2036

Asteroid Apophis was discovered on June 19, 2004. Image credit: UH/IA

During its close approach this week, observatories from ESA and NASA have made some updates on their assessment of asteroid Apophis and its future encounters with Earth. While the Herschel Space Telescope observations indicates the asteroid is bigger and less reflective than first estimated, scientists at the Jet Propulsion Laboratory have effectively ruled out the possibility that this asteroid will impact Earth during a close flyby in 2036.

Repeat after me: Asteroid Apophis is not a threat to Earth in 2029 or 2036. Got that doomsday prognosticators?

Discovered in 2004, Apophis garnered lots of attention when initial calculations of its orbit indicated a 2.7 percent possibility of an Earth impact during a close flyby in 2029. Data discovered during a search of old astronomical images provided the additional information required to rule out the 2029 impact scenario, but a remote possibility of one in 2036 remained – until now.

ESA’s Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on 5/6 January 2013. This image shows the asteroid in Herschel’s three PACS wavelengths: 70, 100 and 160 microns, respectively. Credit: ESA/Herschel/PACS/MACH-11/MPE/B.Altieri (ESAC) and C. Kiss (Konkoly Observatory)

Herschel provided the first thermal infrared observations of Apophis at different wavelengths, which together with optical measurements helped refine estimates of the asteroid’s properties. Previous estimates bracketed the asteroid’s average diameter at 270 ± 60 m; the new Herschel observations returned a more precise diameter of 325 ± 15 m.

“The 20% increase in diameter, from 270 to 325 m, translates into a 75% increase in our estimates of the asteroid’s volume or mass,” says Thomas Müller of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who is leading the analysis of the new data.

By analyzing the heat emitted by Apophis, Herschel also provided a new estimate of the asteroid’s albedo – a measure of its reflectivity – of 0.23. This value means that 23% of the sunlight falling onto the asteroid is reflected; the rest is absorbed and heats up the asteroid. The previous albedo estimate for Apophis was 0.33.

Knowing the thermal properties of an asteroid indicates how its orbit might be altered due to subtle heating by the Sun. Known as the Yarkovsky effect, the heating and cooling cycle of a small body as it rotates and as its distance from the Sun changes can instigate long-term changes to the asteroid’s orbit.

Additional data from the Magdalena Ridge Observatory in New Mexico, the Pan-STARRS observatory in Hawaii and the Goldstone Solar System Radar have provided more conclusive evidence when scientists ran the numbers.

“We have effectively ruled out the possibility of an Earth impact by Apophis in 2036,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at JPL. “The impact odds as they stand now are less than one in a million, which makes us comfortable saying we can effectively rule out an Earth impact in 2036. Our interest in asteroid Apophis will essentially be for its scientific interest for the foreseeable future.”

But the flyby on April 13, 2029 will be one for the record books, scientists say. On that date, Apophis will become the closest flyby of an asteroid of its size when it comes no closer than 31,300 kilometers (19,400 miles) above Earth’s surface.

“But much sooner, a closer approach by a lesser-known asteroid is going to occur in the middle of next month when a 40-meter-sized asteroid, 2012 DA14, flies safely past Earth’s surface at about 17,200 miles,” said Yeomans. “With new telescopes coming online, the upgrade of existing telescopes and the continued refinement of our orbital determination process, there’s never a dull moment working on near-Earth objects.”

Goldstone radar observations of Apophis will continue through January 17th, and additional tracking is planned next month with the Arecibo radio dish in Puerto Rico, which should provide even more refinements in Apophis’ orbit.

Sources: ESA, JPL

(99942) Lead video: APOPHIS sur fond d’étoiles au Pic du Midi from Francois Colas on Vimeo.

January 10, 2013December 23, 2015 by Nancy Atkinson

Behold: The Largest Known Spiral Galaxy

his composite of the giant barred spiral galaxy NGC 6872 combines visible light images from the European Southern Observatory's Very Large Telescope with far-ultraviolet (1,528 angstroms) data from NASA's GALEX and 3.6-micron infrared data acquired by NASA's Spitzer Space Telescope. Credit: NASA's Goddard Space Flight Center/ESO/JPL-Caltech/DSS

Astronomers have long known that a spectacular barred spiral galaxy named NGC 6872 is a behemoth, but by compiling data from several space- and ground-based observatories and running a few computer simulations, they have now determined this is the largest spiral galaxy we know of.

Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy.

“Without GALEX’s ability to detect the ultraviolet light of the youngest, hottest stars, we would never have recognized the full extent of this intriguing system,” said lead scientist Rafael Eufrasio, from the Goddard Space Flight Center the Catholic University of America in Washington. He presented the findings Thursday at the American Astronomical Society meeting in Long Beach, California.

But this galaxy didn’t get so gargantuan all on its own. Astronomers think large galaxies, including our own, grew through mergers and acquisitions — assembling over billions of years by absorbing numerous smaller systems.

The galaxy’s unusual size and appearance stem from its interaction with a much smaller disk galaxy named IC 4970, which has only about one-fifth the mass of NGC 6872. The odd couple is located 212 million light-years from Earth in the southern constellation Pavo.
Intriguingly, the gravitational interaction of NGC 6872 and IC 4970 may have done the opposite, spawning what may develop into a new small galaxy.

“The northeastern arm of NGC 6872 is the most disturbed and is rippling with star formation, but at its far end, visible only in the ultraviolet, is an object that appears to be a tidal dwarf galaxy similar to those seen in other interacting systems,” said team member Duilia de Mello, a professor of astronomy at Catholic University.

The researchers used archived data from the Galaxy Evolution Explorer (GALEX) mission, and studied the galaxy across the spectrum using data from the European Southern Observatory’s Very Large Telescope, the Two Micron All Sky Survey, and NASA’s Spitzer Space Telescope.

Read the team’s paper

Source: NASA