Horizon Season 2006 Episode 19 We are the Aliens

We are the Aliens is the 19th episode of the 2006 season of the popular science documentary show Horizon. The episode explores the possibility that life on Earth originated from another planet - making humans, in a sense, extraterrestrial aliens.

The show starts off with a historical account of how this theory first came to be and how it has evolved over time. We are taken back to the ancient Greeks who believed that the seeds of life were carried to Earth by comets. We hear about a famous experiment conducted by Stanley Miller and Harold Urey back in the 1950s, which showed that amino acids could be synthesised from simple chemicals in conditions like those of the early Earth. The experiment offered the first piece of evidence that life could have originated on our planet as a random creation. But could there be a more feasible explanation?

The show takes us on a journey into space to seek out potential evidence of life beyond Earth. We go deep into our Solar System to explore the moons of Jupiter and Saturn, which are known to have conditions that could potentially support life. NASA's Cassini probe, which has been orbiting Saturn for over a decade, has provided us with invaluable insights into the chemical make-up of the planet and its moons - insights that show the presence of complex organic molecules. We are also introduced to the possibility of life existing in the subsurface oceans of these moons - hidden beneath icy crusts that have prevented us from detecting them so far.

The show then delves into the possibility of life beyond our Solar System. We learn about the discovery of exoplanets - planets located beyond our Solar System - and how we have been able to detect them using various methods, including the transit method, which looks at changes in the brightness of a star when a planet passes in front of it. The number of exoplanets discovered to date runs into thousands, with some of them located in the ‘habitable zone’ - the region around a star where the temperature is just right to allow liquid water to exist on a planet's surface. Liquid water, the show tells us, is a key ingredient for life as we know it.

The show also covers different methods used by scientists to search for extraterrestrial intelligence (SETI). We hear about the Arecibo message, which was sent out from a radio telescope in Puerto Rico back in 1974, and which contained information about Earth and our Solar System in an attempt to make contact with any intelligent extraterrestrial life that might be listening. The message couldn't be targeted towards any specific star system and is now believed to have made contact impossible.

The show then moves on to explore the possible implications if we were to discover that life did indeed originate from somewhere else. Would this mean that we are not unique in this Universe? Would it mean that life exists all over the Universe? The show concludes by offering us an important message - that we should remain humble and open to the possibility that we might not be alone in the Universe, and that we should continue to search for answers, but with caution, as we may not be ready to deal with the consequences.

Overall, We are the Aliens offers a fascinating insight into the possibility that we are not alone in the Universe and that life may potentially exist beyond our Solar System. The show presents its evidence in an informative and engaging way, with stunning visuals of our Solar System and beyond. Whether you are a science enthusiast or just someone with a passing interest, this episode of Horizon is well worth a watch.