Astrobiology is a branch of biology that studies life on Earth and beyond. It focuses on the origin and evolution of life in the universe, including the possibility of alien life in outer space.

Space is a frontier that humans have been exploring since before we put a man on the moon. We've searched for other planets, other stars, and even for other sentient lifeforms. There has always been interest to know if life exists outside of Earth, and if so, are these aliens our friends or our foes.

The fascination with alien life has been around for centuries, perhaps. In earlier days these aliens were seen as menacing beings sent here to abduct and study humans. The abductions were portrayed in books and movies as being a terrifying experience. Reports of UFO sightings have been around for many decades.

In the late 1960s the TV show Star Trek showed a hypothetical future where mankind had made first contact with a menagerie of alien life. The show portrayed us even living in harmony with some of them. This improbable reality is the dream of many. Others fear that aliens will enslave us. Why would they do that? Because we are probably much lower in our evolution and technology processes than they are.

There is also the fear that alien lifeforms will want to clone humans to have control over them. Some of these ideas are a little far-fetched and tend to focus on installing a dread of aliens. A healthy cautiousness is perhaps a better way to think about alien life.

The search for extraterrestrial intelligence, or SETI, began around the 1900s and has expanded in various ways. Scientists have tried to find ways to send messages to outer space in the hopes of making first contact with aliens. First contact refers to the first meeting or contact made between two communities that have never met before. In the world of sci-fi it refers to the first meeting between humans and extraterrestrials. This has yet to happen, as far as we're aware.

It may be that aliens have visited Earth, but we were unaware of them observing us. Have you ever looked up at the night sky and seen an unidentified flying object? Do you think it was terrestrial or alien? Often these UFOs are military crafts completing training exercises or running tests. Perhaps one day you may spot a genuine UFO from an alien world.

One group of people searching for alien life is the SETI Institute. It was founded in 1984 and is dedicated to searching for alien life outside our planet. The SETI project began at NASA with just two employees and is now an institution with about 100 scientists. They have several projects trying to find the answers to life outside of Earth.

Some of these answers we've already found, such as the data sent back from Mars telling us it once had water. Thanks to our findings about Mars we know that it was once a planet that had all the elements to sustain life. It's entirely possible that life exists in the subsurface of Mars, but we haven't found it yet. Scientists theorize that if life began on Earth, why can't it exist elsewhere?

If life exists outside of our little bubble here on Earth how are we likely to find them? Can we send a beacon to let other lifeforms know where we are? If so, what kind of beacon should we send? A long-distance radio signal? A giant mirror bouncing a laser? All are potential ways to contact alien life but some scientists think we should listen first.

In 1974 the Arecibo message was beamed to Messier 13 (M13). M13 is a cluster of about 300,000 stars that is 22,180 light years from Earth. The message was a simple image depicting elements of humans, Earth, and our solar system. Due to the distance of M13 we will need to wait a lengthy time to receive our reply.

Our search for alien life has yet to yield answers, but we continue to search. Do you believe that life may exist or may have existed on other planets?