Earth's Moon a rare species
Moons like the Earth's - which are formed in catastrophic collisions - are extremely rare in the universe, a study by U.S. astronomers suggests.
Cosmic collisions: Artist's impression of bodies as big as mountain ranges smashing together. Such collisions form the basis of the planet-building process. An even bigger collision between Earth and a body the size of Mars is thought to have created our moon. Image: NASA/JPL/Caltech
Billions of years ago, an object the size of Mars crashed into the Earth, hurling dust and debris into orbit. Some of this material eventually coalesced to form our Moon.
Now a new study in The Astrophysical Journal reports that only five to 10 per cent of planetary systems in the universe have moons created this way.
"When a moon forms from a violent collision, dust should be blasted everywhere," said lead author Nadya Gorlova of the University of Florida, Gainesville. "If there were lots of moons forming, we would have seen dust around lots of stars - but we didn't."
A trail of dust
Using NASA's Spitzer Space Telescope, Gorlova and colleagues looked for the dusty signs of similar collisions. They examined 400 stars that are all about 30 million years old - roughly the age of our Sun when Earth's moon formed.
They found only one out of the 400 stars immersed in the telltale dust. Taking into account the amount of time the dust should stick around, and the age range at which moon-forming collisions can occur, the researchers calculated the probability of a solar system making a moon like Earth's to be at most five to 10 per cent.
Rocky planet window
Like our moon, rocky planets are built up through messy collisions that scatter dust and debris around. Current thinking holds that this process lasts from about 10 to 50 million years after a star forms.
But the fact that Gorlova and her team found only one star out of 400 with collision-generated dust, suggests that the 30-million-year-old stars in the study have, for the most part, finished making their planets.
"We don't know that the collision we witnessed around the one star is definitely going to produce a moon, so moon-forming events could be much less frequent than our calculation suggests," said George Rieke of the University of Arizona, Tucson, a co-author of the study.
But for moon lovers, the news isn't all bad. For one thing, moons can form in different ways: the other moons in our solar system either formed simultaneously with their planet or were captured by their planet's gravity.
And even though the majority of rocky planets in the universe might not have moons like Earth's, there are billions of rocky planets out there, so five to 10 percent is a lot of moons.
Article from: http://www.cosmosmagazine.com/node/1720
Our Enigmatic Moon
Were we on the Moon in 2309 B.C.?
The Moon - What Is It And Who Made It?
Mysterious Moonbase Message
Red Ice Creations Radio - Ted Twietmeyer - What NASA isn't Telling you about Mars
Red Ice Creations Radio - Ted Twietmeyer - The Moon & Sun, Time & UFO's (Subscription)
'Lunar Ark' Proposed in Case of Deadly Impact on Earth
Red Ice Creations Radio - Joseph P Farrell - Cosmic War, Interplanetary Warfare & Mesopotamian Mythology
Red Ice Creations Radio - Joseph P Farrell - Interplanetary Warfare, Mythology & Nazi Occultism (Subscription)
Red Ice Creations Radio - Michael Tsarion - Lucifer & The Dark Side of the Sun
Ancient Moon 'computer' revisited
Velikovsky's Ghost Returns
Giant impact added to Earth's core
Latest News from our Front Page
School Textbook: “There’s No Such Thing as Reverse Racism” Only White People can be Racist
Only white people can be racist.
A school textbook teaches students that “there is no such thing as reverse racism” and that women can never be as sexist as men.
The passage, which appears to be taken from a “multicultural education series” book entitled Is Everyone Equal, states, “STOP: There is no such thing as reverse racism or reverse sexism (or the ...
Americans to Receive Full Biometric Treatment for all Forms of European Travel
Travel becomes truly ominous...
In a trend that isn't wholly surprising, EU Observer reports:
US citizens and other non-EU nationals who enter Europe will be asked to have their faces image-captured and fingerprints scanned upon arrival at a half-dozen major airports. [emphasis added]
This "biometric dragnet" is the pilot test for the EU's new "smart borders" packages. The test ...
Breaking: Google gives new meaning to “Orwellian”
Becomes Ministry of Truth
“…if all records told the same tale — then the lie passed into history and became truth.” (1984, George Orwell)
The New Scientist has the stunning story (2/28/15, “Google wants to rank websites based on facts not links,” by Hal Hodson):
“THE internet is stuffed with garbage. Anti-vaccination websites make the front page of Google, and fact-free ‘news’ stories ...
Boris Nemtsov, Putin Foe, Is Shot Dead in Shadow of Kremlin - A Staged Shooting?
NY Times: Boris Nemtsov, Putin Foe, Is Shot Dead in Shadow of Kremlin
Mr. Nemtsov, a former first deputy prime minister of Russia, was killed in central Moscow in the highest-profile assassination in Russia during the tenure of President Vladimir V. Putin.
A Staged Shooting?
Why does the dead body of fitness enthusiast Boris Nemtsov have a pot belly?
The Anti-New York Times doesn't ...
Spielberg's Hoax - The Last Days of The Big Lie
Editor's Note: This is an absolutely SHOCKING video. How this has gone largely unchallenged for such a long time, is a remarkable testimony to the trustworthiness of gullible but good-hearted people. Watch it all the way to the end and learn something new about the remarkable lies and falsehood in our world.
If the video is blocked in your country, see ...
|More News » |