MessageToEagle.com

Puzzle Of The Moon's Origin:
Giant Collision May Not Have Formed Moon

31 March, 2012

MessageToEagle.com - Science has yet to provide a satisfactory explanation of the origin of our closest neighbor - the Moon.

There are so many questions regarding the Moon, but perhaps two of them are most important:
Where did the moon come from, and how did it get there?

A new research based on lunar material collected by Apollo astronauts in the 1970s does not support the widely held theory that a giant collision between Earth and a Mars-sized object gave birth to the moon 4.5 billion years ago.

In the giant-collision scenario, computer simulations suggest that the moon had two parents: Earth and a hypothetical planetary body that scientists call “Theia.

” But a comparative analysis of titanium from the moon, Earth and meteorites, published by Junjun Zhang, graduate student in geophysical sciences at the University of Chicago, and four co-authors indicates the moon’s material came from Earth alone.

If two objects had given rise to the moon, “Just like in humans, the moon would have inherited some of the material from the Earth and some of the material from the impactor, approximately half and half,” said Nicolas Dauphas, associate professor in geophysical sciences at UChicago, and co-author of the study, which appears in the March 25 edition of Nature Geoscience.

“What we found is that the child does not look any different compared to the Earth,” Dauphas said.

“It’s a child with only one parent, as far as we can tell.”



Formation of the Moon.
Five hours after collision. Painting by William K. Hartmann based on computer simulation.


The researchers selected titanium for their study because the element is highly refractory and titanium isotopes — forms of titanium that contain only slight subatomic variations.

This means that titanium tends to remain in a solid or molten state rather than becoming a gas when exposed to tremendous heat. The resistance of titanium isotopes to vaporization makes it less likely that they would become incorporated by the Earth and the developing moon in equal amounts.

Titanium also contains different isotopic signatures forged in countless stellar explosions that occurred before the sun’s birth. These explosions flung subtly different titanium isotopes into interstellar space.

Different objects in the newly forming solar system gobbled up those isotopes in different ways through collisions, leaving clues that let scientists infer where the solar materials including the moon came from.



Credits: William K. Hartmann


“When we look at different bodies, different asteroids, there are different isotopic signatures. It’s like their different DNAs,” Dauphas said.

However, oxygen isotopic compositions have been found to be identical between terrestrial and lunar samples, which is inconsistent with numerical models estimating that more than 40% of the Moon-forming disk material was derived from Theia.

Solving the conundrum of the moon’s origin probably will prove challenging because all of the alternative scenarios for the moon’s formation have drawbacks.

An old idea, long abandoned, is that the moon arose via fission from a molten, rapidly rotating Earth following a giant impact. This idea explains the similarity between Earth and moon, but how such a large, concentrated mass could spin fast enough to split in two remains problematical.

Another scenario suggests that Earth collided with an icy body lacking entirely in titanium. There are no bodies made purely of ice in the solar system, however.

“They would always have a significant fraction of solid material, so you would still expect the object to deliver some titanium,” Dauphas said.

It’s also possible that Theia had the same composition as Earth. This is unlikely, however, because of the widely accepted view that the Earth incorporated material over tens of millions of years in collisions with smaller bodies that flew in from different regions of the developing solar system.

“We thought we knew what the moon was made of and how it formed, but even 40 years after Apollo, there is still a lot of science to do with those samples that are in curatorial facilities at NASA,” Dauphas said.

MessageToEagle.com via UChicago.

See also:
Moon's Abnormal Magnetic Anomalies Linked To Asteroid Collision

Follow MessageToEagle.com for the latest news on Facebook and Twitter !

Don't Miss Our Stories! Get Our Daily Email Newsletter

Enter your email address:


Once you have confirmed your email address, you will be subscribed to the newsletter.

Recommend this article:

Why Do We See The Man In The Moon?

Doesn't Secret Dark Matter Exist?

Black Gaps In The Sky Puzzle Astronomers

Never Ending Winter In Our Solar System

Mysterious Dark Matter

Mysterious Flares Emitting From Sagittarius A

Subscribe To Our Space, Astronomy, Astrophysics, Earth and Xenology News!

Grab the latest RSS feeds right to your reader, desktop or mobile phone.

Subscribe to RSS headline updates from:
Powered by FeedBurner

Go to - MAIN PAGE

Copyright @ MessageToEagle.com All rights reserved.
Go to - MAIN PAGE

 Subscribe in a reader

Other Popular Articles

Sagittarius B2(N) Cloud - Precursor To Life In The Universe
A few years ago, astronomers directed their telescopes toward the galactic center and the dust cloud Sagittarius B2, located less than 400 light years from the galactic center and some 25,000 light-years from Earth. "Clouds like this one are the raw material for new stars and planets. We know that complex chemistry builds prebiotic molecules in such clouds long before the stars and planets are formed...."

Black Holes With No 'Table Manners' Eat Two Courses At Once!
It is still unknown how the supermassive black holes (SMBH) in galaxy centres accrete gas and grow. Researchers from the University of Leicester (UK) and Monash University in Australia have investigated how some black holes got so big so fast that they are billions of times heavier than the sun.

Mercury Surprises Scientists
On March 17, MESSENGER (MErcury Surface, Space Environment, GEochemistry, and Ranging) completed its one-year primary mission, orbiting Mercury, capturing nearly 100,000 images, and recording data that reveals new information about the planet's core, topography, and the mysterious radar bright material in the permanently shadowed areas near the poles.

Living Earth Simulator - Supercomputer Predicting The Future
In Douglas Adams book the Hitchhikers Guide to the Galaxy we encounter a machine called Deep Thought. It is the most powerful computer ever built. Deep Thought is capable of answering questions concerning life, the Universe, and simply everything. Now scientists are planning to create a similar machine. It is called the Living Earth Simulator (LES).

Warp-Speed Planets Are Some Of The Fastest Objects In The Milky Way
Warped planets are some of the fastest objects in the Milky Way and they zoom through space near the speed of light. Some years ago astronomers were astonished when they they found the first runaway star flying out of our Galaxy at a speed of 1.5 million miles per hour. The discovery intrigued theorists, who wondered: If a star can get tossed outward at such an extreme velocity, could the same thing happen to planets?

Proof Of How The Universe Is Changing

Though the universe is filled with billions upon billions of stars, the discovery of a single variable star in 1923 altered the course of modern astronomy. And, at least one famous astronomer of the time lamented that the discovery had shattered his world view.

Bright Star In The Constellation Lyra Is Cooler Than The Human Body
The coldest class of stars have temperatures as cool as the human body. Astronomers hunted these dark orbs, termed Y dwarfs, for more than a decade without success. When viewed with a visible-light telescope, they are nearly impossible to see.

Thermonuclear Burning In A Neutron Star Detected For The First Time!
It's a very important discovery! For the first time, an international team of scientists have detected all phases of thermonuclear burning in a neutron star, located close to the center of the galaxy in the globular cluster Terzan 5.

Astronomical Mystery - Tremendous Explosion And Appearance Of Odd Rings
Twenty five years ago, on 1987 February 23, the brightest supernova of modern times was observed in the Large Magellanic Cloud.
The collision occurred at speeds near 60 million kilometers per hour and shock-heats the ring material causing it to glow.
Over time, astronomers have watched and waited for the expanding debris from this tremendous stellar explosion to crash into previously expelled material...

Giant Jupiter - Our "Would-Be" Friend With Secrets From The Past

Mysterious Flares Emitting From Sagittarius A

Stars In The Milky Way Move In Mysterious Ways

The "Cloaked" Star Was Difficult To Find
An object obscured by dust, and buried in a two-star system enshrouded by dense gas, is not easy to find.
A "cloaked" star was discovered after it ate a little of its neighbor. The meal must have given the star a bit of indigestion, because it "burped" with a blast of high-energy radiation, which gave it away.

Powerful Jet Pointing Directly At Earth
They are among the most fascinating cosmic phenomena. Astronomers know them as blazars and each of them harbors a supermassive black hole and jets emanating in opposite directions from near its poles. These sources are unique evidence of the most extreme speeds and energies known in the extreme Universe...

W3Counter