Earth's Moon a rare species
2007 11 27

From: cosmosmagazine.com


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
Moons like the Earth's - which are formed in catastrophic collisions - are extremely rare in the universe, a study by U.S. astronomers suggests.

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



Related Articles
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

Norway Joins the Race to Develop Killer Robots
2014 10 24
Norway is a large exporter of weapons, which makes the resolution of the debate about creating killer robots an important issue for everyone.  One could debate the overall merits or failings of robotic systems, but an area that clearly has become a point for concern on all sides is the emergence of "killer robots." According to robotics pioneer, David Hanson, ...
Gene That Once Aided Survival in the Arctic Found to Have Negative Impact on Health Today
2014 10 23
In individuals living in the Arctic, researchers have discovered a gene variant that arose thousands of years ago and most likely provided an evolutionary advantage for processing high-fat diets or for surviving in a cold environment; however, the variant also seems to increase the risk of hypoglycemia, or low blood sugar, and infant mortality in today’s northern populations. {snip} “Our work ...
The Ebola hoax: questions, answers, and the false belief in the “One It”
2014 10 23
“The Reality Manufacturing Company doesn’t just sell ‘fake paintings’ that are easy to spot. No. They also sell images that are geared to mesh with people’s deeply held instincts and thereby produce rigid false beliefs. People are sure that if they gave up such beliefs, their world would fall apart and blow away in the wind.” ...
New Controversial Theory Suggests "Hobbits" Were Not Human - Who Were These Mysterious Beings?
2014 10 23
The origin of the Hobbit species remains a challenging subject to scientists. The Hobbit’s discovery confirmed the view that the Earth was once populated by many species of human, but new research the Hobbit’s were not human at all! So, who were these mysterious beings? Where did they come from? The idea that our species, Homo sapiens, was the only species of human on ...
Right into enemy hands? ISIS shows off new weapons allegedly airdropped by US (VIDEO)
2014 10 23
Islamic State has published a new video in which a jihadist shows off brand-new American hardware, which was purportedly intended for the Kurds they are fighting in the Syrian border town of Kobani. The undated video, posted by the unofficial IS mouthpiece “a3maq news”, sees a jihadist showing several boxes of munitions with English-language markings, with a parachute spread out on ...
More News »