William Atkins
Friday, 06 February 2009 23:21
Science -
Space
Page 1 of 4
According to a new theory (which some are calling 'radical') by U.S. astronomer Brad Hansen, the two larger inner planets of our Solar System (Earth and Venus) formed first and the leftover materials came together to form the two smaller inner planets (Mercury and Mars).
The four inner rocky planets of the
Solar System, centered about the Sun, are thought by astronomers to have formed about 4.5 billion years ago. They formed from the gases and dust spewed off from the Sun in its early development.
Theoretical astrophysicist
Brad Hansen, from the Department of Physics and Astronomy at the University of California at Los Angeles (UCLA), however, used a different assumption than what is normally used by astronomers when simulating the formation of these planets.
Hansen stated,
“In this picture, Mars and Mercury are essentially byproducts" of Earth and Venus.” [National Geographic Society: “
Mars and Mercury Formed From Planetary Scraps.”]
He made his comments at the
213th meeting of the American Astronomical Society (
AAS) held in Long Beach, California, U.S.A., between January 4 and 8, 2009.
Hansen added that these materials slowly formed into larger and larger objects, eventually developing into what astronomers call planetesimals, or small rocky astronomical objects that orbited about the Sun early in its development, and eventually coalesced and formed into planets.
Dr. Hansen ran computer simulations of this process that eventually formed the planets of Mercury, Venus, Earth, and Mars. He made a different assumption than is normally used in the early stage of planet formation. Usually scientists have dust particles forming randomly from a homogenous debris disk.
What do scientists usually see happen to planet formation when this traditional assumption is used? Check out page two for this and other information.
