First Possible Extra-Terrestrial Biosphere (so-called “Earth-like” planet) Found!!!
You’d think it wouldn’t have been a story so ried in the news in a way….but there it was; perhaps the ninth or even tenth story cited on this evening’s "National" news (see http://www.cbc.ca/national). Why they keep trying to call these new theoretical worlds they’re looking for (and now may have found) "Earth-like" baffles me completely. No world; with or without phenomena that could be described as ‘life’ on its surface is likely to resemble Earth in any way. But that isn’t to say today’s discovery doesn’t deserve one getting pretty excited over the latest extra-solar planet discovered by astronomers. It would well be that our species has found a planet, Earth-sized, and with its very own biosphere – unbelievably close to Earth (in astronomical terms).
They keep finding smaller and smaller planets using the method used to detect planets around other stars: the so-called "gravity-wobble" which causes fluctuations in the stellar glare from planets orbiting their parent stars. This new planet, named "Gliese 581 c", is 1.5 Earth’s mass and – this is the big kicker – a planetary mean temperature between 0 and 40°C! Earth’s planet-wide mean temperature is closing on 7°C (normally 5; but thanks to global warming not anymore). That means that we’re looking at a world with a dim, red-dwarf star (later in its life span than ours, if memory serves) and an extremely good candidate for holding onto an atmsophere comprised of compounds like nitrogen, argon and, most important, oxygen. Water wouldn’t be a big surprise if those elements were about either since hydrogen is the most common element of all and, combined with oxygen, wel…you get the idea.
The parent star, Gleise 581, is about 20 light-years (ly) from earth. The next-nearest star system to ours is the binary star-system commonly referred to as Alpha Centauri at just 4.3 ly. Within 20 ly, there are less than a couple dozen star systems; so should this prove to be a life-bearing world, we’re also likely to find a galaxy teeming with life….perhaps as common as at least one stable biosphere for every 15 or 16 stellar systems!
And if life is that common, intelligent life – that answer to the final question: "are we alone" has a much greater likelikhood of being answered the way the vast majority of us hope (and in our hearts already can feel): "most definitely not!"