Author Topic: NASA Scientists Find Moon and Asteroids Share Cosmic History  (Read 4897 times)

Offline catdlr

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News release: 2013-114                                                                    March. 25, 2013

NASA Scientists Find Moon and Asteroids Share Cosmic History



The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-114&cid=release_2013-114

PASADENA, Calif. - NASA and international researchers have discovered that Earth's moon has more in common than previously thought with large asteroids roaming our solar system.

Scientists from NASA's Lunar Science Institute (NLSI) in Moffett Field, Calif., discovered that the same population of high-speed projectiles that impacted our lunar neighbor four billion years ago, also hit the giant asteroid Vesta and perhaps other large asteroids.

The research unveils an unexpected link between Vesta and the moon, and provides new means for studying the early bombardment history of terrestrial planets. The findings are published in the March issue of Nature Geoscience.

"It's always intriguing when interdisciplinary research changes the way we understand the history of our solar system," said Yvonne Pendleton, NLSI director. "Although the moon is located far from Vesta, which is in the main asteroid belt between the orbits of Mars and Jupiter, they seem to share some of the same bombardment history."

The findings support the theory that the repositioning of gas giant planets like Jupiter and Saturn from their original orbits to their current location destabilized portions of the asteroid belt and triggered a solar system-wide bombardment of asteroids billions of years ago, called the lunar cataclysm.

The research provides new constraints on the start and duration of the lunar cataclysm, and demonstrates that the cataclysm was an event that affected not only the inner solar system planets, but the asteroid belt as well.

The moon rocks brought back by NASA Apollo astronauts have long been used to study the bombardment history of the moon. Now the ages derived from meteorite samples have been used to study the collisional history of main belt asteroids. In particular, howardite and eucrite meteorites, which are common species found on Earth, have been used to study asteroid Vesta, their parent body. With the aid of computer simulations, researchers determined that meteorites from Vesta recorded high-speed impacts which are now long gone.

Researchers have linked these two datasets and found that the same population of projectiles responsible for making craters and basins on the moon were also hitting Vesta at very high velocities, enough to leave behind a number of telltale, impact-related ages.

The team's interpretation of the howardites and eucrites was augmented by recent close-in observations of Vesta's surface by NASA's Dawn spacecraft. In addition, the team used the latest dynamical models of early main belt evolution to discover the likely source of these high velocity impactors. The team determined that the population of projectiles that hit Vesta had orbits that also enabled some objects to strike the moon at high speeds.

"It appears that the asteroidal meteorites show signs of the asteroid belt losing a lot of mass four billion years ago, with the escaped mass beating up on both the surviving main belt asteroids and the moon at high speeds" says lead author Simone Marchi, who has a joint appointment between two of NASA's Lunar Science Institutes, one at the Southwest Research Institute in Boulder, Colo., and another at the Lunar and Planetary Institute in Houston. "Our research not only supports the current theory, but it takes it to the next level of understanding."

The NLSI is headquartered at NASA Ames Research Center, Moffett Field, Calif. The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate, Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala.

To learn more about NLSI, visit: http://lunarscience.nasa.gov .

For more information about the Dawn mission, visit: www.nasa.gov/dawn .

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Karen Jenvey 650-604-4789
Ames Research Center, Moffett Field, Calif.
karen.jenvey@nasa.gov


- end -
« Last Edit: 03/25/2013 11:13 PM by catdlr »
Tony De La Rosa

Offline JohnFornaro

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I had thought they were always more or less in their current orbits.

When did Jujpiter and Saturn relocate their orbits? 

Around 4 billion years ago

Or about 5000 years ago, depending on who ya wanna believe:

http://www.saturniancosmology.org/mech.php
Sometimes I just flat out don't get it.

Offline RigelFive

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How many craters on the moon are from asteroid impacts?  The moon probably isn't really just the moon, it's a composite of all the stuff it collected that was floating around the solar system the past 4.5 billion years.

Offline morganism

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This is a pretty weak justification for a story.

LPI just last year pointed out in a paper last spring, that the Late Heavy was based on 1 rock sample that was mislabled/misidentified, and was actually ejecta from another crater, that was dated to same era.

GRAIL results kind of make a different statement there too.

Just because it is literally impossible for a body to be captured as a "moon" in a circular orbit, without a nearly head on impact, doesn't help make a case for anything about Vesta either.

The chem of the two samples arent even close, and to point out shocks in the GEMS and glasses is pretty weak too...

http://www.psrd.hawaii.edu/

Offline JohnFornaro

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oooh. oooh.

It just dawned on me that the Moon and the asteroids are in the ... Exact.  Same.  Solar. System.
Sometimes I just flat out don't get it.

Offline Robert Thompson

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I'm vaguely invested in any planetary / asteroidal science that can help resolve gas giant migration because that informs the search for Earth 2.0. If these questions become more valuable, and finer and finer chemical/mineralogical distinctions are sought, that spells a growing market for sample return. 20 years.

Offline RigelFive

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Perhaps this finally proves that Carl Sagan was wrong.

Offline JohnFornaro

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Perhaps this finally proves that Carl Sagan was wrong.

Huh?  The Drake equation is made up of whole cloth.  The search for exoplanets is starting to put a number on one of the components of that equation.

So Sagan's not wrong yet, by my take.
Sometimes I just flat out don't get it.

Offline RigelFive

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There is a paradox that I read about a few weeks ago.

Lets say you have 10000 grains of sand that form 'a heap'.  Now take 1 grain of sand away.... with 9999 grains, the pile may still be called 'a heap'.

So if you continue removing grains, at what point does the pile STOP becoming 'a heap'?  Perhaps even the last grain of sand, after all other would be removed would (by legacy) be referred to as 'a heap'.

An object collides & grazes with the moon and ejects an asteroid into orbit. 
Which is it (the new object in orbit around the moon)? Is the new object a moon or asteroid?  Is Pluto an asteroid?

Offline Robert Thompson

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-Solar system formed 4.55 Gya
-Giant impact 4.5 Gya
("Moon" could have formed in as little as 100 years)
-Late Heavy Bombardment 4.1 to 3.8 Gya
(OP: "It appears that the asteroidal meteorites show signs of the asteroid belt losing a lot of mass four billion years ago, with the escaped mass beating up on both the surviving main belt asteroids and the moon at high speeds")
-Late Veneer about 3.85 Gya
(Languishing reference on Late Veneer: http://arxiv.org/pdf/1202.6372v2.pdf)

Offline Robert Thompson

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Offline RigelFive

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http://www.space.com/21061-moon-magnetic-field-mystery.html
Now that is interesting!

Mars lost its magnetic field too, but if I recall from articles correctly... it was 4.1 billion years ago.

Mars is bigger than the moon and would have been bombarded.  Mars would likely have had more inertia.  The Moon perhaps would have cooled quicker than Mars.

Must be a bombardment effect that stops the dynamo.


Offline JohnFornaro

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There is a paradox that I read about a few weeks ago.

Lets say you have 10000 grains of sand that form 'a heap'.  Now take 1 grain of sand away.... with 9999 grains, the pile may still be called 'a heap'.

So if you continue removing grains, at what point does the pile STOP becoming 'a heap'?  Perhaps even the last grain of sand, after all other would be removed would (by legacy) be referred to as 'a heap'.

An object collides & grazes with the moon and ejects an asteroid into orbit. 
Which is it (the new object in orbit around the moon)? Is the new object a moon or asteroid?  Is Pluto an asteroid?

The opposite paradox has to do with straws and the camel's back.
Sometimes I just flat out don't get it.

Tags: Moon  Vesta  asteroids