Wednesday, July 17, 2013

Super Earths, Gravity and the Possibility of Life On Other Planets

I was happy to come across this article while I was trolling the internet one evening, which states that scientists have found 3 Super Earths orbiting star Gliese 667C in the star's habitable zone. That's the zone where the possibility of liquid water exists and with the possibility of liquid water comes the possibility of life.

Now, the planets orbit closer to the star than we do to ours because the star is cooler. It's a Red Dwarf star estimated to be at least 2 billion years old. The fact that it took twice that for bi-pedal humanoid life to appear on this planet leads me to believe that the possibility of intelligent life on these planets is slim to none BUT there's still the possibility that life of some kind may exist on these planets!

There's also the possibility that these planets, because they orbit so close to the star, are tidally locked. That means that one side of the planet always faces toward the star and the other side away. If this is the case then the probability of any life dips way down but, again, this is all theory and because the Universe is full of impossibilities then without concrete proof (like, actually seeing the planet) we have no idea what's going on there.

I started thinking about the gravity of Super Earths and realized that I didn't really know how to determine the gravity of a planet. Was it just the mass? I came across this helpful article which explained that it wasn't just a planets mass but also its radius which determined the planet's gravity. There's a chart on the page which includes the planet Gliese 667Cc, which is the Super-Earth closest to the star in its habitable zone and it's also the largest. That planet has a gravity of 1.36 compared to Earth's 1 so, yeah, the gravity is slightly heavier there but not crushingly so. I would be more interested in knowing the gravity of Gliese 667Cf, which is smaller than 'c' but sits more firmly in the habitable zone.

Ideally, scientists would like to find a planet around the same type of star as our sun ('G' type), in its habitable zone and roughly around the same age. If it's a Super-Earth then its got to have a mass/radius ratio that puts it as close to 1g as possible. That's as close to comparing apples to apples as you're going to get and just because we haven't found it yet doesn't mean that it doesn't exist.

The Universe is chock full of pretty weird stuff. Just look at us!