In the past the search for other intelligent life in the universe was a more passive pursuit. Scientists were forced to sit back and simply wait for an alien signal to make its way into one of the SETI antennas. These days, humanity’s taking a more proactive approach by using modern optic technology in the Kepler Space Telescope to actually look out into the galaxy and search for other planets around other stars which are similar enough to ours that they might support life.
In essence scientists are looking for a twin of good old planet Earth. In the past that’s been difficult, because while we have been able to spot other planets in orbit around other suns, we haven’t had the technology to actually see planets as small as our little blue and green Earth.
That changed this week when scientists at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. have announced the first ever discovery of planets the size of Earth. They’ve found two of them, the smallest extra-solar (that means outside our solar system) planets discovered so far.
Both planets, found in orbit around a G-type star (our sun is also a G-type star) called Kepler-20, are at the wrong distance from their sun to have an Earth-like climate. Their orbit is more like that of Mercury, making them both very very hot and making life as we known it unlikely to exist there. Temperatures are estimated to range between 800 and 1,400 degrees Fahrenheit. Even liquid water is out of the question at those temperatures.
The critical thing here is that scientists have now proven that it’s actually possible to spot planets the size of our Earth. The next step is to find one that’s not only the same size, but the same distance from its star as our planet is from the sun.