The space news this week was of the discovery of a very earth like planet around a very earth-like star. The planet is named Kepler 452b, because the star the planet orbits a star named Kepler 452. The star being the 452nd previously unnamed star investigated by the Kepler mission telescope. The Kepler mission is to search for habitable planets and this is not actually the most habitable planet found so far, but the first ‘very habitable’ planet around a star like our own star, the sun.
What makes this special?
So the sixth most habitable planet makes news while not even being the most habitable found so far, because it reminds us of home as it orbits a star like our own sun? Or is it the suggestion that by being not just habitable but like earth in other ways, we might find a planet that could no only sustain life, but actually have given rise to native life of its own!
The three Searches.
I would suggest there are really three searches going on:
- the search for advanced alien civilisation (The Seti Institute)
- the search for hospitable planets, and ideally moons(The NASA Kepler mission)
- the search for planets (and/or moons) with their own alien life
Is there someone like us out there? (Seti)
This search should be able to look faster and further. This should be the easiest.
The search for advanced alien civilisations generally focuses that is such a civilisation is all like ours, then all we have to is look for the same type of signals as those our civilisation is broadcasting from earth as a by-product of our hi-tech way of life. If they live in any similar to the way we live we should be able to detect their existence with radio telescopes. Seti has already searched most likely every single target for the Kepler mission and found no evidence of civilisations like ours. The universe does seem to be very empty of civilisations like ours, what do not yet know is just how empty.
The Search for hospitable planets and/or moons. (Kepler Mission)
Read the brief from the NASA website, and would assume we are looking for planets just like earth. Places perhaps where, at some future time, we could land and establish colonies? The catch is that no planet like the earth we live on can exist without already having life. We live on planet that has been totally changed by the life on our planet. Early Earth had an atmosphere poisonous to modern humans with no oxygen to breath nor an ozone layer block life destroying radiation before plants and other life completely changed the atmosphere. In fact free oxygen never exists naturally anywhere in the universe without plants to separate that oxygen from compounds with other chemical elements.
No plants can ever at all like the earth we live on without being changed by plants over billions of years.So the search for a true hospitable planet, means the search for a planet that actually has already been transformed by living organisms.
The search for a planet with life. (Kepler?)
The reality is that to find a planet actually like the earth as we know it, we need to find a planet with life. If we could detect oxygen molecules in a planet’s atmosphere then we could detect life. Free oxygen, as opposed to oxygen as a compound like water or iron oxide etc, would only be present of life of some type has separated that oxygen. So oxygen would mean life, but we have no way of detecting oxygen in the atmosphere of a planet orbiting a distant star.
So how can we find life? Reality is that all we can do is try and somewhere which mimics as closely as possible the only place where we know life does exist: earth.
The excitement of Kepler 452b: maybe there is life!
452b is a planet not just in the ‘goldilocks zone’ where the temperature is right and of around the right size, but it is also circling a star similar to our own sun and as been circling that star for even longer than we have been circling our sun.
That is the excitement. Perhaps more ingredients creating the environment for life than anywhere else discovered so far. But is it enough? That will be a future post.