New Scientist magazine recently had an interesting article on how our study of exoplanets has raised questions about the beginnings of our own solar system. In the piece,
Mercury May Be the Sole Survivor of a Planetary Pile-up, the author notes that a number of planetary systems being seen elsewhere in the galaxy have small, rocky planets in an orbit closer to their suns than Mercury is to our sun. The speculation now is that this may be the normal order of things in younger solar systems and over time the collision of these smaller planets may create one larger survivor such as Mercury. Of course, these rocky planets could also pulverize one another into dust unless they are made of stronger stuff, which may explain why Mercury survived given its considerable iron core.
This is another fascination off-shoot of our search for other planets and potential life in our galaxy. While we are looking at the present situation in our neighborhood, we may learn quite a bit about our past as well. And we are in the very early stages of our search.
Image Credit: NASA Discovery Program. Shows the process of collision and accretion created the four
rocky, or terrestrial, planets of our inner solar system — Mercury, Venus,
Earth, and Mars.
