Featured Research

from universities, journals, and other organizations

Scientists Gaining Clearer Picture Of Comet Makeup And Origin

Date:
July 25, 2006
Source:
Johns Hopkins University Applied Physics Laboratory
Summary:
Scientists are getting their best understanding yet of the makeup of comets -- not only of the materials inside these planetary building blocks, but also of the way they could have formed around the Sun in the solar system's earliest years.

Comet Tempel 1, 67 seconds after impact, taken by the high-resolution camera on the Deep Impact's flyby craft.
Credit: NASA/JPL-Caltech/Deep Impact Imaging Team

Scientists are getting their best understanding yet of the makeup of comets -- not only of the materials inside these planetary building blocks, but also of the way they could have formed around the Sun in the solar system's earliest years.

When NASA's Deep Impact spacecraft slammed into comet Tempel 1 on July 4, 2005, the collision sent tons of pristine materials into space and gave astronomers from around the world, using ground- and space-based telescopes, the first look "inside" a comet. From that sample, over the past several months, scientists who used the imaging spectrometer on NASA's Spitzer Space Telescope have refined their models of what a comet is made of and how it comes together.

The Spitzer observation team, led by Dr. Carey Lisse of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., writes about its findings this week on the Science Express Web site.

"Spitzer's spectral observations of the impact at Tempel 1 not only gave us a much better understanding of a comet's makeup, but we now know more about the environment in the solar system at the time this comet was formed," Lisse says.

From its orbit in space, Spitzer's infrared spectrograph closely observed the materials ejected from Tempel 1 when Deep Impact's probe dove into the comet's surface. Astronomers spotted the signatures of solid chemicals never seen before in comets, such as carbonates (chalk) and smectite (clay), metal sulfides (like Fool's Gold), and carbon-containing molecules called polycyclic aromatic hydrocarbons, found in barbecue grills or automobile exhaust on Earth.

Lisse says the clay and carbonates were surprises because they typically require liquid water to make -- and liquid water isn't found in the regions of deep space where comets form. Also surprising was the superabundance of crystalline silicates, material formed only at red-hot temperatures found inside the orbit of Mercury.

"In the same body, you have material formed in the inner solar system, where water can be liquid, and frozen material from out by Uranus and Neptune," Lisse says. "Except for the lightest elements, the total abundances of atoms in the comet are practically the same as makes up the Sun. It implies there was a great deal of churning in the primordial solar system, with high- and low-temperature materials mixing over great distances."

Planets, comets and asteroids were all born out of a thick and dusty mix of chemicals that surrounded the young Sun. Because comets formed in the outer, colder regions of our solar system, some of this early planetary material remains frozen inside them. By refining their list of comet ingredients, theoreticians can begin testing models of planet formation.

More than 80 telescopes on and above Earth observed Deep Impact's rendezvous with Tempel 1, and their findings are shedding light on the comet's broader history in the solar system. Lisse's team is also comparing Spitzer's discoveries with those from NASA's Stardust mission, which last January returned particles from the coma (or atmosphere) of comet Wild 2 back to Earth.

"We can compare the inferred composition of Tempel 1 to the Stardust sample returns and obtain a 'ground truth,' " Lisse says. "From this we can create a Rosetta stone, which we'll use to better understand the materials seen in our own solar system as well as around other stars."

Twelve of the 14 species found by Spitzer match up with preliminary Stardust analyses, Lisse says, but several mysteries remain. For example, the Stardust samples do not yet include definitive evidence of the carbonate and clay minerals found in Tempel 1.

"There's no reason to think Tempel 1 represents all comets," he says. "Deep Impact only hit and excavated Tempel 1 in one precise location, and Stardust only sampled the surface of one comet at one point in its orbit. We'll need additional missions to comets -- such as robotic landing spacecraft or sample-return probes -- to help us complete the picture."

NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. Spitzer's infrared array camera was built by NASA's Goddard Space Flight Center, Greenbelt, Md.

The University of Maryland, College Park, conducted the overall mission management for Deep Impact, a Discovery class NASA program. JPL handled project management for the Deep Impact mission. The spacecraft was built for NASA by Ball Aerospace & Technologies Corporation, Boulder, Colo.


Story Source:

The above story is based on materials provided by Johns Hopkins University Applied Physics Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins University Applied Physics Laboratory. "Scientists Gaining Clearer Picture Of Comet Makeup And Origin." ScienceDaily. ScienceDaily, 25 July 2006. <www.sciencedaily.com/releases/2006/07/060724110458.htm>.
Johns Hopkins University Applied Physics Laboratory. (2006, July 25). Scientists Gaining Clearer Picture Of Comet Makeup And Origin. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2006/07/060724110458.htm
Johns Hopkins University Applied Physics Laboratory. "Scientists Gaining Clearer Picture Of Comet Makeup And Origin." ScienceDaily. www.sciencedaily.com/releases/2006/07/060724110458.htm (accessed August 23, 2014).

Share This




More Space & Time News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Did Russia Really Find Plankton On The ISS? NASA Not So Sure

Newsy (Aug. 21, 2014) Russian cosmonauts say they've found evidence of sea plankton on the International Space Station's windows. NASA is a little more skeptical. Video provided by Newsy
Powered by NewsLook.com
Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com
Tiny Satellites, Like The One Tossed From ISS, On The Rise

Tiny Satellites, Like The One Tossed From ISS, On The Rise

Newsy (Aug. 18, 2014) The Chasqui I, hand-delivered into orbit by a Russian cosmonaut, is one of hundreds of small satellites set to go up in the next few years. Video provided by Newsy
Powered by NewsLook.com
This Week @ NASA, August 15, 2014

This Week @ NASA, August 15, 2014

NASA (Aug. 15, 2014) Carbon Observatory’s First Data, ATV-5 Delivers Cargo, Cygnus Departs Station and more... Video provided by NASA
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins