life_in_universe.pdf

We are not special (probably) The Milky Way is a typical galaxy – not too large, not too small, not merging The Sun is a very typical star – average size, temperature, middle-aged. Is our Solar System typical? We don’t yet know the answer. Exoplanets: planets around other stars We have measured the...

We are not special (probably) The Milky Way is a typical galaxy – not too large, not too small, not merging The Sun is a very typical star – average size, temperature, middle-aged. Is our Solar System typical? We don’t yet know the answer. Exoplanets: planets around other stars We have measured the existence of about 5,566 exoplanets! And more are discovered every day. BUT – we know very little about these planets. Usually just a size or mass and an orbit. We know nothing about temperatures, atmospheres, water, or surface composition The exoplanets we have measured are plagued by observation biases – some orbits and sizes are much easier to find. This makes it hard to know how typical or special our own planetary system is. Habitable planets might be common...but there are a lot of complications to this simple model. So we don’t really know how common habitable planets are yet. Life might be common (maybe) Life on Earth arose very early – basically as soon as conditions made it possible for life to survive. Does that mean life arises easily? We only have one known planet with life, so this might be a bad assumption. Life in the Universe Traditional knowledge Native Skywatchers Many cultures have deep connections to the stars. Ideas that we come from the stars and will return there when we die, and a common belief that other people/beings live among the stars. Where to look for life? Follow the water Where is there water in our solar system? C. Belcourt How do we find water? Distances within the Solar System are huge: how do we look for water on other bodies in the Solar System? Distances to exoplanet are (literally) astronomical: how do we look for water on exoplanets outside our Solar System?