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
Do Many Neocons Just Hate All Europeans?
Marxis Neocon Charles Krauthammer
A few months ago I encountered at a conference an eminent Straussian scholar who teaches at an Ivy League institution, and he almost immediately launched into a tirade against “the Europeans,” who are at the point of “finishing Hitler’s work.” The only exception that my interlocutor would concede to this sweeping statement was for the English “who ...
Swedish Feminists Drink Blood
Swedish Feminists drink menstrual blood to fight the Patriarchy!
Here is the story from alltomstockholm.se as translated by Google (English not 100% correct)
A feast to celebrate the woman - and your period
Menstruation - and this year's celebration.
Theatre Bristol salute month's bloodiest weeks and cause menstrual celebration of International Women's Day.
- We will offer menstrual drinks, says Daniela Kullman.
On International Women's Day ...
'What do we need this war for?' Ukrainians flee from 100k army draft
With the heavy fighting taking its toll on the Ukrainian army, another military draft is underway - the fourth within less than a year. It's the largest one to date - set to get 100k people into the military. This includes everyone up to the age of 60, with a voluntary mobilization for women. Fleeing the draft some are getting ...
Gunman Storms Dutch TV Station Demanding Airtime
Dutch authorities have released few details about the bizarre case of 19-year-old Tarik Zahzah’s attack on the main news studio of television station NOS on Thursday. To get the obvious question out of the way first, the police say there is no evidence that Zahzah, who is half-Egyptian, acted on behalf of organized terrorism.
The authorities always say that on the ...
How Alan Dershowitz bullied rape victims to protect a serial child molester
Harvard law professor Alan Dershowitz always felt children were fair game for Israeli missiles. Now the question is whether he thinks they are fair game for the sexual exploits of his powerful associates and himself.
Dershowitz and the UK’s Prince Andrew were accused in a recent court filing of raping a teenage girl who was forced into sexual slavery by ...
|More News » |