New Theories Arise to Explain Creation of the Moon
October 20, 2012 11:03 AM
comment(s) - last by
The Giant Impact Theory
Two new studies attempt to prove the Giant Impact Theory in different ways
Two different studies say they've found evidence supporting the theory that
was created from a collision between Earth and a Mars-sized body.
The Giant Impact Theory, which was proposed back in 1975, suggests that the early Earth and a Mars-sized planet called Theia collided with one another. This completely obliterated Theia, and its composition created a ring around Earth and eventually came together to create the moon.
While scientists have been able to explain how this event occurred, one major thing didn't add up: the composition of the moon.
Scientists long believed that for this theory to be true, the moon would have to be composed mainly of Theia's elements. Moon rocks from that were brought to Earth were studied, and surprisingly, they had the same types and amounts of elements that the Earth had, including titanium, silicon and oxygen. This didn't make sense, and has left the theory wide open for the last 30+ years.
However, scientists from Washington University in St. Louis managed to measure a small excess of a heavier variant of zinc in moon rocks from that were brought to Earth in the 1970s. They believe the excess is due to
heavier zinc atoms
condensing out of the collision's cloud faster than the lighter zinc atoms, and the vapor that remained escaped before it condensed.
This bit of sorting by mass is called isotopic fractionation, and it's what scientists have been looking for all along. This shows that the moon rocks were depleted of easily evaporated elements called volatiles, and a large collision could explain this depletion while other theories can't.
"The magnitude of the fractionation we measured in lunar rocks is 10 times larger than what we see in terrestrial and Martian rocks," said Frédéric Moynier, PhD, from Washington University in St. Louis. "So it's an important difference."
But the Washington University team isn't the only one to bring new evidence to the table. Robin Canup, a planetary scientist from the Southwest Research Institute Colorado, used Harvard scientists' findings to create a theory of her own related to the collision.
According to the Harvard team, which used computer simulations to create its theory, ancient Earth had to have been spinning too fast for today's 24-hour rotation. They suggested that early Earth and a body half the size of Mars could have collided where both were obliterated and combined elements to create both
the moon and Earth's
heavy iron core/lighter rock layers.
At a later point, Earth's rotation could have slowed due to the moon and sun aligning in a way that changed Earth's orbit.
Canup used the idea that Earth's rotation was slowed and came up with the theory that two bodies similar in size collided at a slow speed, and their materials merged to create the Earth and moon.
This article is over a month old, voting and posting comments is disabled
10/20/2012 2:15:52 PM
From better quality reporting I saw a week ago; what's new is that researchers have found an additional mechanism to drain angular momentum from the Earth-Moon system. As a result the proto-Earth could have been spinning faster when it was hit than previously believed. One of recent paper used the higher initial spin rate to get a more thorough mixing of the protoplanets mantles needed in order for the Earth-Moon isotope ratios to match as closely as they do. A second paper by a different group accomplished the same by colliding two protoplanets of approximately equal sizes.
I don't recall where I first read it. Space.com lists the names of the authors and the Journals they were published in so you (or anyone else was access) could read the actual papers being mangled here; and its article mentions everything I did except the additional spindown mechanism.
10/22/2012 7:35:14 AM
Thanks. This makes more sense.
"A lot of people pay zero for the cellphone ... That's what it's worth." -- Apple Chief Operating Officer Timothy Cook
New "Polaris" Robot Prototype Will Drill Moon for Lunar Ice
October 10, 2012, 9:01 PM
Researchers Show Off Transparent Zinc Tin Oxide Memristors
September 17, 2012, 10:57 PM
NASA Preparing to Explore Earth-Moon Libration Point 2
February 13, 2012, 12:35 PM
Quick Note: Drone Loses Fight to the Death With Kangaroo
December 23, 2014, 3:28 PM
Campbell's Monkeys Found to Use Different Dialects to Describe Local Threats
December 22, 2014, 3:52 PM
Scientist Confirm Men are More Likely to Die in "Idiotic" Ways
December 17, 2014, 1:07 PM
Shoppers Surprised to Find Cards Against Humanity's Bullsh*t is Real Feces
December 16, 2014, 11:14 PM
Air Force Worries Hot Fuel Could Harm F-35, "Proactively" Paints Trucks Shiny
December 11, 2014, 9:06 AM
McDonald's is Testing Tablet-Based Burger Customization at 30 Franchises
December 10, 2014, 11:30 AM
Most Popular Articles
Miyamoto: Nintendo is Prepping Successor to Troubled Wii U
December 22, 2014, 6:28 PM
Amazon's Kindle Fire HDX 8.9 Drops to $299 (30 Percent Off) for a Day
December 22, 2014, 10:57 AM
Airbus A350 XWB Passenger Jet Takes Off, First Unit Delivered to Qatar Airlines
December 22, 2014, 1:22 PM
Microsoft, Google Back The Interview, North Korea Vows Attacks on America
December 24, 2014, 4:25 PM
Nokia's Sweet $250 Android Lollipop N1 Tablet is Rumored for Jan. 7 China Launch
December 24, 2014, 1:45 PM
Latest Blog Posts
Sceptre Airs 27", 120 Hz. 1080p Monitor/HDTV w/ 5 ms Response Time for $220
Dec 3, 2014, 10:32 PM
Costco Gives Employees Thanksgiving Off; Wal-Mart Leads "Black Thursday" Charge
Oct 29, 2014, 9:57 PM
"Bear Selfies" Fad Could Turn Deadly, Warn Nevada Wildlife Officials
Oct 28, 2014, 12:00 PM
The Surface Mini That Was Never Released Gets "Hands On" Treatment
Sep 26, 2014, 8:22 AM
ISIS Imposes Ban on Teaching Evolution in Iraq
Sep 17, 2014, 5:22 PM
More Blog Posts
Copyright 2014 DailyTech LLC. -
Terms, Conditions & Privacy Information