Earth's Moon a rare species
2007 11 27
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
Exponential growth of Ashkenazi Jews following a Medieval population bottleneck
2014 09 17
A recent paper by Marta Costa et al. found that around 80% of Ashkenazi mitochondrial DNA had a prehistoric European origin (and ruled out the Khazar hypothesis). Combined with previous Y chromosome studies indicating that the male line is Middle Eastern, the results suggested a scenario in which Jewish males married European females after traveling to Europe.
Now another paper, ...
Bankers Rule: City of London vs. Scottish Independence
2014 09 17
Now that the independence referendum is too close to call, the bankers express their worry. The media blitz ramps up to tip the outcome. Scottish independence has finally rattled the City of London has the usual banksters forecasting the dislocations from a currency panic.
Scotland has a long and noteworthy history of banking. Money, savings and investing is entrenched in the ...
French separatists want Scots to say "yes"
2014 09 17
Separatist leaders in Brittany, Corsica and the French Basque Country will watch with interest as Scotland votes on independence next week, but they don’t expect France to follow the UK’s lead any time soon.
Pro-independence activists point to the fact they have their own languages and cultural identities. France, however, remains a deeply centralized country and any talk of a negotiated ...
Devil’s Deal: US-Backed Syrian Rebels Already Signed Pact with ISIS Prior to Haines Beheading
2014 09 17
While Washington considers appropriating half a billion in funds to the Syrian rebels, we now learn that opposition groups the Free Syrian Army (FSA) and al Qaeda affiliate ‘al Nusra Front’, have officially aligned themselves with ISIS…
Despite grand words by US President Obama and British PM David Cameron, here’s what’s really behind their plan to bomb ISIS in Syria…
In a ...
World War III for Dummies
2014 09 16
A Step-by-Step Guide to Understanding the Present World Situation.
1998 - 2000
Powerful elites and influential think tanks forecast a coming period of American aggression. Zbigniew Brzezinski speaks for the Globalist faction of the western PRC (Predatory Ruling Class) in ’The Grand Chessboard’, a book in which he openly advocates for bolder American action in dominating the Eurasian land mass.
During this ...
|More News » |