For as long as humans have been around, we have wondered if we are alone in the universe. Is there life on other planets? What does it take for life to exist? Let’s examine these questions a little more.
Life out there
Most likely if there is life near us, it won’t look anything like we imagined. Our bodies are incredibly complex and took millions of years to become the way they are today. If we find alien life it is likely it will be in the form of tiny microscopic organisms, not little green men.
Astronaut John Grunsfeld believes that if there is intelligent life out there, it will soon be able to find us. He thinks that with our modern machines and satellites we have made so many changes to the way the Earth looks, that someone looking from the outside would easily be able to tell there is intelligent life living on the surface.
What does a planet need for life?
For life that we recognize to exist, it needs two things- liquid water and some kind of energy source.
On Earth, we have an abundance of water and organisms that evolved to use incoming sunlight or chemicals present in their environment as energy. There are a lot of planets in the universe, but not many have any water, much less water that isn’t frozen. Also, a planet would have to be close enough to the star that it orbits to receive enough sunlight to be used as energy. The area a planet falls in that would give enough energy from its star is called the “habitable zone”.
What are we looking for?
What we really want to find is biosignatures. A biosignature is a sign of life- a chemical, a life source, or an event that we know wouldn’t be caused naturally.
We are using specialized telescopes like the Kepler Space Telescope and satellites like the Transiting Exoplanet Surveying Satellite, but we don’t have anything yet that can measure far enough. There could be all kinds of things just beyond where we can see- for now. NASA is confident that within 20 or 30 years technology will have advanced enough to find some of these far planets.
Where is it?
There might be life in our own universe! Recently NASA found signs of liquid water on Mars, and suspect there might even be oceans on some of the moons of Saturn and Jupiter hidden under layers of ice! There also might be hundreds of earth-like planets orbiting stars all over the universe, many of which haven’t even formed yet.
Want to know more about alien life? Come check out our show, The Search For Life, narrated by Academy Award nominated actor Harrison Ford, every Saturday this november at 2 p.m.