Protoplanets and life...

Why start a blog on the small fry of the solar system? Well they have a lot teach us, and are in many ways a lot more accessible than many of the main planets (except earth obviously). Since the thing most people think about when they think of space is aliens I'm going to start with how the little guys of the solar system have advanced our understanding of life in the cosmos, and how they can teach us more.

First, a bit of background:
According to our best theories, and the evidence we've collected, the solar system formed about 4.5 billion years ago from a cloud of dust and gas. This cloud didn't build itself into the solar system we know overnight. For about 100 million years there were hundreds of small worlds in place of the nine big ones that we have today, called protoplanets. What we know about them comes mainly from meteorites. These, with a few exceptions, are believed to be fragments blasted off their surfaces by asteroid impacts, and collisions with each other. We also know a bit from observing the dwarf planets and asteroids, objects which are thought to be survivors from that time.

So what do we know about them (and what does this have to do with life)?
We know that many of them were big enough to have gravity that could pull them into a sphere, and warm enough, thanks to accretion heat (heat from stuff falling onto the surface) and radioactive elements, for their interiors to melt.
This led amongst other things to differentiation of their interiors, where the heavy elements sank towards the middle, and the lighter ones floated towards the surface. This has given us some of the different types of meteorites we find today, different types from different parts of the protoplanets. Recently meteorites were found that show some of these little worlds developed crusts similar to Earth. We know from observeing Ceres (a dwarf planet) and Vesta (about as big as rock can get without being a dwarf planet) that proto worlds could have very different characters: Certes is loaded with water ice, and might hold an ocean beneath its crust even today. Vesta shows signs of being a volcano world, a bit like asmaller version of Io, and seems to have been disfigured by a titanic smash with another space rock.

No really, what has this got to do with alien life?
What I'm leading up to with this; Some of these protoplanets had conditions that led to the creation of the building blocks of life. That basically means carbon chemistry, and liquid water. A fairly rare class of meteorite, calld carbanceous chondrites, have carbon buried in their interiors, and show signs of being in contact with liquid water. This has caused amino acids, the building blocks for protiens, and nucleobases, the building blocks of DNA to form inside them. Could any of this have got as far as simple life?
We don't know. It's quite likely that most of these worlds were destroyed, or froze solid before things could get that far, but at the very least some of the chemistry that eventually led to life on earth began out there. And when we've only begun to learn about these little worlds, and the conditions that have led to life, who can say for sure what was there?

If any of these ramblings have given you some curiosity aboutthe little worlds out there, here are some links you might find interesting:

Dawn: A space mission to Ceres and Vesta.

Hayabusa: A space mission to one of the solarsystems many asteroids.

Meteorite news:News all about meteorites.

Space weather: Follows the storms from the sun and general astronomical events.

I'd also recommend any of the following forums: BAUT forum, Unmannedspaceflight, habitable zone for anyone with a generall interest in space.

Thats all for now, I'm going to aim for one post a week, so have a good week one and all!