In “Life on Earth: Is our planet special?” (BBC News , 9 December 2011), Howard Falcon-Lang tells us,
Far from being unique, many now regard Earth as an ordinary lump of space rock and believe that life “out there” is almost inevitable. But could the truth be somewhat more complex?
On Friday, top scientists are meeting at the Geological Society in London to debate this very issue, posing the question: “Is the Earth special?”. What emerges is that aspects of our planet and its evolution are remarkably strange.
Prof Monica Grady is a meteorite expert at the Open University. She explained in what sense the Earth could be considered special.
“Well, there are several unusual aspects of our planet,” she said. “First is our strong magnetic field. No one is exactly sure how it works, but it’s something to do with the turbulent motion that occurs in the Earth’s liquid outer core. Without it, we would be bombarded by harmful radiation from the Sun.”
It gets better.
A key barrier to determining the odds of the habitability of other planets has been the need to minimize the ways in which Earth is special. “Special” doesn’t mean that no other planets could be like Earth, but that we need to assess our chances rationally.
As opposed to pointless speculation like “Could exoplanets support life that has a different chemical composition?” Absent the proposed composition, who knows?