Featured Research

from universities, journals, and other organizations

Shock Waves Through The Solar Nebula Could Explain Water-Rich Rocks

Date:
January 29, 2003
Source:
University Of Arizona
Summary:
Shock waves through icy parts of the solar nebula could well be the mechanism that enriched meteorites with water -- water that some believe provided an otherwise dry Earth with oceans, according to a new study published in the current issue of Science (Jan. 24).

Shock waves through icy parts of the solar nebula could well be the mechanism that enriched meteorites with water -- water that some believe provided an otherwise dry Earth with oceans, according to a new study published in the current issue of Science (Jan. 24).

Scientists have long debated how "chondrules" might have formed. Chondrules are millimeter-sized blobs of once-melted minerals found within chondritic meteorites, which are thought to be the oldest objects in the solar system.

In some of these meteorites, chondrules are rimmed by fine silicate dust particles that have reacted with water.

Researchers at first speculated that chondrules and their water-rich rims formed when water molecules in the solar nebula collided with dust. But a 1987 study dispelled that idea, because the time it would take for the minerals to form in this manner would be longer than the lifetime of the solar nebula.

Planetary scientists at the University of Arizona and University of Hawaii now report that chondrule-forming shock waves in icy regions of the nebula could have produced conditions that allowed rapid mineral hydration. Fred J. Ciesla, Dante S. Lauretta and Lon L. Hood of the UA and Barbara Cohen of the UH collaborated in the study.

Lauretta and Cohen speculated years ago that a big energetic event, like a shock wave, might produce enough energy to vaporize ice particles and briefly create conditions that made such quick hydration reactions possible.

Ciesla modeled the scenario of what happened to particles of silicate and ice during a shock wave event.

"And what happens is, the ice particles vaporize in this very energetic event, producing high water vapor pressure. During this brief period of increased water pressure, the hydration reaction occurs much faster than previously predicted," Ciesla said. "During this brief period, the chondrules melt and the rims form in the same event."

Gas slows as it passes through a shock front, increasing in temperature and density. But solid particles entrained in the gas continue through the shock wave at high velocity. "The solid particles heat up because they are speeding through the slower-moving gas. And just as a meteor is heated up and burns when it enters Earth's atmosphere, particles are heated when they collide with the gas molecules. Gas both heats and slows the chondrules, so they melt and begin to cool. The water vapor then reacts with the dust to form these hydrated silicates, and the chondrules accrete these silicates to form their rims."

"An interesting characteristic of these particular meteorites is that they contain a lot of water, and the deuterium-to-hydrogen ratios in that water matches the ratios we find in Earth's water," Ciesla noted.

Why Earth has water is a mystery, for "especially early on in the solar nebula, the area where the Earth formed was too hot for water to incorporate into a solid body," Ciesla said. Meteorites may have delivered at least part of Earth's water, although that remains open to debate, he added.

The scenario also suggests how so much organic material has survived in the carbonaceous chondrite meteorites. If water reacted with the fine dust in the solar nebula as the new research suggests, temperatures in the meteorites would have remained low enough for organic molecules to survive and be delivered, along with water, to Earth.

Although the idea that shock waves formed the hydrated rock and chondrules found in the most primitive meteorites stands up to quantitative analysis, scientists are still speculating about where the shock waves come from, and it's a topic Ciesla hopes to address in this doctoral thesis.

UA planetary scientist Lon Hood, one of the authors on the Science paper, originally theorized that as Jupiter was forming, it excited the orbits of the many "planetismals," or planet building-blocks, in the region that became the present day asteroid belt so that they were propelled through the gas in the solar nebula at speeds greater than the speed of sound, creating shock waves. Ciesla has begun testing that idea.

Other ideas on the origin of shock waves also involve Jupiter is some way, he said.


Story Source:

The above story is based on materials provided by University Of Arizona. Note: Materials may be edited for content and length.


Cite This Page:

University Of Arizona. "Shock Waves Through The Solar Nebula Could Explain Water-Rich Rocks." ScienceDaily. ScienceDaily, 29 January 2003. <www.sciencedaily.com/releases/2003/01/030129081126.htm>.
University Of Arizona. (2003, January 29). Shock Waves Through The Solar Nebula Could Explain Water-Rich Rocks. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/2003/01/030129081126.htm
University Of Arizona. "Shock Waves Through The Solar Nebula Could Explain Water-Rich Rocks." ScienceDaily. www.sciencedaily.com/releases/2003/01/030129081126.htm (accessed August 30, 2014).

Share This




More Space & Time News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Experiment Tests Whether Universe Is Actually A Hologram

Experiment Tests Whether Universe Is Actually A Hologram

Newsy (Aug. 27, 2014) Researchers at Fermilab are using a device called "The Holometer" to test whether our universe is actually a 2-D hologram that just seems 3-D. Video provided by Newsy
Powered by NewsLook.com
SpaceX’s Falcon 9 Rocket Explodes After Liftoff

SpaceX’s Falcon 9 Rocket Explodes After Liftoff

Newsy (Aug. 23, 2014) The private spaceflight company says it is preparing a thorough investigation into Friday's mishap. Video provided by Newsy
Powered by NewsLook.com
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

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