Category Archives: Asteroids & Comets

Asteroids & Comets, Astronomy, Events

The ISON story continues

The latest on comet ISON:

NASA Investigating the Life of Comet ISON

After several days of continued observations, scientists continue to work to determine and to understand the fate of Comet ISON: There’s no doubt that the comet shrank in size considerably as it rounded the sun and there’s no doubt that something made it out on the other side to shoot back into space. The question remains as to whether the bright spot seen moving away from the sun was simply debris, or whether a small nucleus of the original ball of ice was still there. Regardless, it is likely that it is now only dust.

Comet ISON comes in from the bottom right and moves out toward the upper right, getting fainter and fainter.
Comet ISON comes in from the bottom right and moves out toward the upper right, getting fainter and fainter, in this time-lapse image from the ESA/NASA Solar and Heliospheric Observatory. The image of the sun at the center is from NASA’s Solar Dynamics Observatory. Image Credit: ESA/NASA/SOHO/SDO/GSFC

Comet ISON, which began its journey from the Oort Cloud some 3 million years ago, made its closest approach to the sun on Nov. 28, 2013. The comet was visible in instruments on NASA’s Solar Terrestrial Relations Observatory, or STEREO, and the joint European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, via images called coronagraphs. Coronagraphs block out the sun and a considerable distance around it, in order to better observe the dim structures in the sun’s atmosphere, the corona. As such, there was a period of several hours when the comet was obscured in these images, blocked from view along with the sun. During this period of time, NASA’s Solar Dynamics Observatory could not see the comet, leading many scientists to surmise that the comet had disintegrated completely. However, something did reappear in SOHO and STEREO coronagraphs some time later – though it was significantly less bright.

http://youtu.be/kcROVqmF9SY
Comet ISON is shown approaching the sun and curving away from it in this movie containing imagery from both NASA’s Solar Terrestrial Relations Observatory and the joint ESA/NASA Solar and Heliospheric Observatory from November 2013. ISON dims dramatically as it streams away from the sun.
Image Credit: ESA/NASA/SOHO/STEREO/GSFC

Whether that spot of light was merely a cloud of dust that once was a comet, or if it still had a nucleus – a small ball of its original, icy material – intact, is still unclear. It seems likely that as of Dec. 1, there was no nucleus left. By monitoring its changes in brightness over time, scientists can estimate whether there’s a nucleus or not, but our best chance at knowing for sure will be if the Hubble Space Telescope makes observations later in December 2013.

Regardless of its fate, Comet ISON did not disappoint researchers. Over the last year, observatories around the world and in space gathered one of the largest sets of comet observations of all time, which should provide fodder for study for years to come. The number of space-based, ground-based, and amateur observations were unprecedented, with twelve NASA space-based assets observing over the past year.

Related Links:

For more information on Comet ISON: www.nasa.gov/ison

To download recent ISON imagery: http://svs.gsfc.nasa.gov/Gallery/CometISON.html

Asteroids & Comets, Astronomy, Education

Video: NOVA’s “Asteroid: Doomsday or Payday” + Background on the Chelyabinsk research

Sandia National Laboratories released this item about work done by one of its researchers on the Chelyabinsk meteor fireball. His work was included in a recent NOVA episode Asteroid: Doomsday or Payday.

Physicist’s journey reveals smaller asteroids could cause bigger problems

ALBUQUERQUE, N.M. — Once in a lifetime, a physicist may get a chance to test his theories and simulations in a real-life event that changes the course of his scientific life. But rarely does that opportunity literally fall from the sky.

Chelyabinsk sky rendering

The asteroid that fell to earth near Chelyabinsk, Russia, 
gave scientists new insights into the risks of  smaller
asteroid impacts. (Simulation by Mark Boslough;
rendering by Brad Carvey.) 

That’s the impact of the Feb. 15 asteroid that burst over the Russian city of Chelyabinsk on Sandia physicist Mark Boslough, subject of a TV documentary that airs tonight and co-author of a recent cover story in Nature about the asteroid fireball that injured about 1,500 people and damaged more than 7,000 buildings, collapsing roofs and breaking thousands of windows.

Boslough’s journey to Russia shortly after the impact is chronicled in the NOVA episode “Asteroid: Doomsday or Payday,” which will air on Public Broadcasting Service stations [on Nov. 20, 2013].

The complete NOVA program Asteroid; Doomsday or Payday.

The show focuses on the destructive potential of asteroids, chronicling how Boslough and his colleagues learn that small asteroids can do far more damage than previously thought. The Nature paper also suggests that there may be more small asteroids than formerly thought.

The day the asteroid hit, Boslough learned of the event via Facebook from posts of Russian news stories and YouTube videos showing an object that exploded in the Russian sky.

“I saw it on Facebook long before the sound wave had even arrived in this part of the world,” Boslough said, estimating the transglobal sound wave took more than seven hours to reach New Mexico. “I really didn’t expect to experience this in my lifetime.”

As one of the first scientists to visit Chelyabinsk after the asteroid struck, Boslough set out to discover where the object came from. Because it came down near a populated area, he and his colleagues were able to collect videos from people who caught the asteroid on film and video, especially the ubiquitous Russian dashboard cameras, a staple in establishing blame in traffic mishaps.

“This event was certainly one of the best-documented asteroid events ever,” said Boslough.

Boslough’s goal was to perform stellar calculations of the asteroid’s trajectory by visiting — at night when the stars shone — the exact spots where the footage was recorded.

“If the stars show up on the digital camera, we can get those angles and then calibrate that image that was taken from the dash cam, and know exactly the angles to the trajectory of the fireball,” he said in the documentary. “We’ll have a very precise trajectory as it streaked through the atmosphere, so we can backtrack that to get the orbit, the pre-impact orbit.”

The program also discusses how asteroids can contain rare and valuable elements, leading researchers to seriously evaluate the benefit of harvesting them for their rare elements.

But Boslough also wants the research community to pay more attention to the potential risk that asteroids present.

“If something like the Tunguska event of 1908 happened now, it could kill hundreds of thousands or even a million people, if it happened right over a big city,” he said in the documentary. “An asteroid has more damage potential on the ground than a nuclear bomb of the same energy.”

Boslough was part of a team of 33 researchers who completed the study featured in Nature. “A 500-kiloton airburst over Chelyabinsk and an enhanced hazard from small impactors” examines the characteristics of the fireball. Boslough and his colleagues also used the simulations to help design the journal’s cover.

You also can see an animated simulation of the airburst produced by Boslough, as well as scientific animations and images by Sandia contractor and visual effect expert Brad Carvey and visual effect expert Andrea Carvey. Sandia’s Laboratory Directed Research & Development program funded the simulations.

Using data collected from his visit shortly after the asteroid struck, along with data from an international team, Boslough developed several additional simulations that he and other researchers have used to model the explosion and estimate the force of the blast.

The paper’s authors performed a global survey of airbursts of a kiloton or more and found that the number of building-sized objects may be 10 times greater than estimates based on other methods.

The authors, led by Peter Brown of the University of Western Ontario, estimated the Chelyabinsk event was equivalent to an explosion of about 500 kilotons of TNT. At its peak, the airburst appeared to be 30 times brighter than the sun.

“Because the frequency of a strike of an asteroid of this size has exceeded expectations, with three such strikes in just over a century (Chelyabinsk, Tunguska and a large airburst in the South Atlantic in 1963 detected by infrasound), the number of similar-sized asteroids capable of causing damage may be greater than suspected,” Boslough said.

Dick Spalding of Sandia’s Nonproliferation Technologies Research and Development Department also co-authored the paper.

The authors also showed that previous models for estimating airburst damage do not match the observations.

An earlier paper by Boslough highlights the conclusion that most airbursts are more damaging than previously thought.

“We really have to rethink the risk from airbursts. Chelyabinsk was unusual due to the a low inclination at which it entered the atmosphere, but 90 percent of objects enter the atmosphere at a steeper angle and cause more damage on the surface,” Boslough said. That paper, which he wrote two years ago, was recently published online in Acta Astronautica.

The Chelyabinsk fireball is something those who saw it will never forget, and neither will Boslough.

“What’s amazing to me though, when you think about it, this is part of an asteroid that had been, floating through space, orbiting the sun for billions of years” he said for the documentary in a late February interview. “And two weeks ago, it exploded in the atmosphere, dropped to the ground, and here I am holding it in my hand! That’s amazing.”

View two airburst simulations or see photos at Sandia’s asteroid airburst Flickr set.

Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies and economic competitiveness.

Asteroids & Comets, Space participation

Planetary Resources and NASA partnering to crowdsource asteroid detection

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Planetary Resources “The Asteroid Mining Company” has announced a partnership with NASA

 to design and implement crowdsourcing algorithm challenges in the effort to detect, track and characterize near-Earth objects (NEOs).  All data compiled and used for these challenges will be open-sourced and publicly available.

Last summer PRI raised over $1.5M in a Kickstarter campaign to fund outreach programs, including a collaboration with the Zooniverse citizen science organization to create Asteroid Zoo. In Asteroid Zoo, volunteers via the web will scan a data set of over 3 million images obtained with the  Catalina Sky Survey to find and characterize near-earth objects.

The NASA partnership will build on this work:

Lindley Johnson, Program Executive of NASA’s near Earth object observation program, said, “This partnership uses NASA resources in innovative ways and takes advantage of public expertise to improve identification of potential threats to our planet.  This opportunity is one of many efforts we’re undertaking as part of our asteroid initiative.”

Today, there are approximately 620,000 asteroids that are tracked in our Solar System.  This number represents less than one percent of the estimated objects that orbit the Sun.  “While improving the algorithms to detect NEOs helps gain more data, additional surveys, telescopes and capability put to the search will also assist in completing the task of compiling a comprehensive open-sourced catalog,” continued Lewicki.

Asteroids & Comets, Space Science, Space Systems

Video: Asteroid Initiative Workshop – Grand Challenge Panel Part 1

Here’s another video of presentations at the recent NASA workshop on proposals for asteroid missions:

NASA TV coverage of the Grand Challenge panel session of the NASA-hosted public workshop at the Lunar and Planetary Institute in Houston to examine 96 of the ideas submitted to the recent Request For Information on ways to accomplish the agency’s asteroid initiative.

Asteroids & Comets, Space Policy, Space Systems

Video: NASA workshop on proposals for asteroid program

Here is the initial session of a recent workshop on proposals submitted for NASA’s asteroid initiative:

NASA TV coverage of the plenary session of the NASA-hosted public workshop at the Lunar and Planetary Institute in Houston to examine 96 of the ideas submitted to the recent Request For Information on ways to accomplish the agency’s asteroid initiative