Saturday, 5 September 2009
Earth Is Just The Right Size For Life
New Scientist reports that Earth is just the right size for sustaining life. Image courtesy of Wikipedia.
The discovery of huge exoplanets has given rise to the hope that they might harbour life. However, recently New Scientist suggested that this might well be wishful thinking.
Super earths or large rocky planets with a mass five to ten times that of Earth might simply be too huge to sustain life.
On 15 September, Vlada Stamenkovic of the German Aerospace Center (Deutschen Zentrums für Luft- und Raumfahrt) and colleagues will present a paper at the European Planetary Science Congress in Potsdam, Germany, in which they will describe the results of their research on the basic prerequisites for sustaining life.
They discovered that rocky planets should approximately be the size of Earth in order to support plate tectonics and have a magnetic field.
According to Stamenkovic, plate tectonics will probably not work on too huge planets such as super earths. What is needed for supporting plate tectonics is a planet with a mass of approximately 0.5 to 2.5 times that of Earth. And a magnetic field is needed for shielding the planet from cosmic radiation.
This has led Stamenkovic to believe that Earth is special.
Not all astrobiologists will agree with him. Some still hope that life is lurking somewhere in outer space.
The research of Stamenkovic and colleagues nevertheless supports that what Bible-believing scientists have known for a long time: Earth is a privileged planet, designed for sustaining life. As the Apollo 8 astronauts put it in their 1968 Christmas message: “In the beginning God created the heaven and the earth.”
Shiga, David. 2009. Earth-sized planets are just right for life. New Scientist 2724 (2 September). http://www.newscientist.com/article/mg20327243.600-earthsized-planets-are-just-right-for-life.html