Are we alone in the universe? And being the social creatures we are, it's natural to wonder: Is there another planet with an atmosphere similar to ours, with fresh drinking water, flora, and fauna to support life?
Scientists are still asking these questions, but now, they finally have the technology that might provide the answers. The great quest for life-bearing planets is in high gear as astronomers watch the skies using cutting-edge telescopes.
Housed in giant observatories, these precision instruments can now view planets in other solar systems across the galaxy. The widening scope of man's abilities to observe and investigate the vastness of space has significant implications.
In ancient Greece, philosopher Aristotle believed that the Earth sat in the middle of a small, orderly universe and that we were utterly alone. Epicurus of Samos, on the other hand, believed that there was an infinite number of worlds out in the galaxy thanks to constant change and evolution. His viewpoint matches what we know is true today. There are numerous planets out there that there is sure to be a similar one somewhere.
But Aristotle himself might have been on to something. All biological life exists today thanks to a specific and orderly set of conditions that an exact duplicate or similar might not exist. So, beyond finding another planet out there, we need to ask the question: Is biology the happy result of cosmic evolution, or is it a one-off, a unique gem in a galaxy borne out of chaos?
And we have numerous examples of "similar to Earth but not quite" planets to illustrate why some believe we are a rare and unique phenomenon in the vast universe.
Kepler-452b, for example, has an orbit size similar to ours and a nearby star just like the sun. However, upon closer look, it is five times the size of the Earth with a cloudy, Venus-like atmosphere.
There is also the dwarf star Trappist-1 with seven planets in orbit; the fourth one, in particular, has potential. It is slightly smaller than the Earth, with signs of water on its surface.
With all this technology, scientists have compiled a list of 24 (tentative) super-habitable planets that have the potential to support life. Each has water, a magnetic field generated by its orbit, a hospitable atmosphere that deflects solar radiation, and fertile landforms. The next step is to find out if there is life on these candidate planets though we have to wait for newer technologies to do so.
Future space telescopes might soon include instruments that can detect oxygen, methane and other signs of biological life. And with the success of the Mars rovers, soon, we might be able to take actual pictures of planetary surfaces so we can see the terrain and experience the weather "first hand."
Though we may not be sure of the existence of other planets similar to ours, we are confident that Earth is unique and one of a kind. Only time and technological advances can tell if another Earth exists.
Directed by: David Sky Brody