Exoplanets everywhere, so, are we alone?
One of the advantages of experiencing a sky show under the vast outback Australia sky is the sense of perspective that is gained.
Size and space is everything. In our place on Earth in Broken Hill we can see from horizon to horizon with very little obstruction. No tall buildings, no high vegetation, no polluting bright lights.
We are immersed in the immensity of space – on Earth and overhead! As we enter a new year and anticipate new astronomical knowledge, our sense of perspective is being quickly nudged along with the emerging proposition that there are probably more planets in our galaxy than there are stars.
Of course, we may not see too far into space with our Earth-based naked eyes. However, NASA’s Kepler mission is looking for us – looking far away in the same spot in space so that we can find Earth-like worlds. We call these new places exoplanets because they are outside of our solar system.
We are learning, from Kepler’s data, http://kepler.nasa.gov/Mission/discoveries/, that the number of planets is generous, and that the likelihood of finding Earth-like planets within habitable zones is very high. Recently, NASA announced it had verified the 1000th plant outside our solar system from among 4000 candidates identified so far.
Just this week NASA announced two newly verified planets are likely to be made of rock, like Earth, and that they orbit their parent stars in the habitable zones. This is the distance from the parent star where liquid water could exist on the surface as the temperature would allow this.
The two new planets are also about the same size as Earth, but too far away for a really good look with our current space-time challenges! One is at 475 light years and the other at 1,100 light years. They also have very short “years”. One orbits its parent star every 35 days and the other every 112 days.
You’d grow old quickly if you applied our Earth-based concepts of time and birthdays.
However, they do propose interesting prospects for future generations of scientists. There’s the idea of travel to these new worlds. It simply cannot occur even in a lifetime over such long distances with current technology. And there’s the answer we are looking for to that most famous question we continue to ask: “Are we alone?” Late in 2015, for Southern Hemisphere sky watchers, when Cygnus and Lyra return to our northern sky, we can gaze in the direction of these two new planets.
By this time, Kepler will have done much more observing and Earth-based scientists will have confirmed many more planets. We’ll review this situation again at that time, and ask the same questions again.