Actually, they probably don’t either. Or, more accurately, if they do know they probably can’t get to us.

Ever since humankind has figured out what the heavens are,  there have been those who have looked up at the sky and wondered if we are alone. The truth is, not too long ago the idea that our Solar System was inhabited not only by life, but by intelligent civilizations. was not ridiculous fantasy, but the object of speculation. This idea was perpetuated by science fiction, most notably H.G. Wells and his famous book turned radio play War of the Worlds. Through little advertising and a convincing, news cast approach to the story, H.G. Wells was able to, accidentally, convince thousands of people that the earth was under attack from a hyper-intelligent martians, leading to a considerable amount of panic. Since the 1970’s however, specifically the Viking missions, we have known that Mars is actually quite lifeless and barren. This of course, did not quench our thirst for knowledge, did it damage the egos of those who continued to look for life.

According the Kepler Space telescope, the premier planet telescope, 1 in 5 stars in the universe are orbited by a potentially habitable, earth size planet. What does this mean for chances of life outside our precious solar system. It means that it’s not only very likely, but would be almost impossible to have not occurred  already. It is estimated that amount of stars in the universe are on the order of 10^24, which is a 1 with 24 zeros following. If 1 and 5 of these has a potentially habitable planet, the idea that we are the only planet similar to ours that could harbor self replicating matter is not only ridiculous, but frankly insulting to someones intelligence. We cannot say with certain, of course, what the probability of life existing around a habitable planet is, because we have never found it, but most would agree that this fact is a limitation of current technology, and does not speak to the abundance of life in the universe.

The first exoplanet was discovered in 1994, which means that I am older than the simple fact that planets exist outside of our solar system. Since then, many milestones in exoplanet research have been achieved. Initially, we could only detect planets much larger Jupiter, which is over 300 more times as massive then the earth. It wasn’t until 2010 that we were able to directly image an exoplanet, and these are still the kind of planets that make Jupiter look like a shrimp. Couple this with the fact that the Kepler Space Telescope looks at only a tiny portion of the sky and you realize how incredibly hard it is to detect life.

Finally, we can only look up at the observable universe. This may seem initially quite obvious, but think of this: We see only the light from stars, planets and gas that are close enough to us that light has reached us since the beginning of the universe. The further we look away, the further back in time we peer, and the less like the current universe that part of the universe appears. The truth is, there is another universe out there, unobservable or much more evolved than we see it, each galaxy containing billions of stars, approximately 1/5 of which has a planet similar to ours. Chances are, there are millions, if not billions of alien civilizations looking up at their own sky, with their unique constellations and their owns moons and suns, wondering where we are. But the truth is, they are quite far away, and even if they could find us, they probably won’t be able to get to us.

Does this mean that we should stop looking? Absolutely not. The thing about human curiosity is that it has no bounds. And the search for earth-like planets, like many other searches, yields results other than its primary objective. From combing the data of Kepler we know have thousands of confirmed planets, and even more planet candidates. Each of these has it’s own data regarding its mass, orbit, potential composition and its stars mass. All of this data means we are now able to say things about planets that we were never to be able to say before, and ultimately that’s what its all about. The whole point of this thing called life, wherever it resides in the universe, is the pursuit of the knowledge. So the next time someone asks you what we are spending all this money on, tell them knowledge, and walk away.

Links: http://www.space.com/8680-direct-photo-alien-planet-finally-confirmed.html

http://planetquest.jpl.nasa.gov/page/history

http://home.web.cern.ch/about/updates/2014/04/cern-switch-comic-sans

The power of stars and constellations to capture the human imagination has persisted throughout history. While our means of deciphering the celestial sphere has changed, the sensation of staring into the night sky and pondering our existence among the vastness of the universe has been shared across time and culture. Nowadays, it is essentially effortless to download an app to learn the constellations or use computer software to pinpoint the next eclipse. However, before the advent of such technology as Newtonian physics and the telescope, detailed records of the heavenly bodies were much harder to procure. Remarkably, despite the obstacles to compiling these records, many ancient civilizations made precise astronomy a priority.

El Castillo at Chichen Itza – Image Source: http://www.world-mysteries.com/chichen_kukulcan.htm

The development of the field of archaeoastronomy has rapidly advanced since the 1960s, when Stonehenge was proposed as a monument to astronomical alignment. The number of studies on sites across the world exploded, with many researchers publishing positive results. It is now clear that civilizations on every continent across centuries of human history maintained rigorous observation of stars and planets. The evidence was left primarily in architecture, which unmistakably honors their discoveries.

Newgrange Tomb, Ireland – Image Source: Steve Emerson

Maybe the most impressive aspect of the archaeoastronomical discoveries is the fact that today the stars are not necessarily observed in the same position as they were when these monuments were built. Due to the proper motion of stars and the precession of Earth’s axis. Archaeoastronomers have to account for this and calculate those positions retroactively.

Personally, the most fascinating realization about this field is that these civilizations had no known communication with each other. Independently, indigenous peoples arrived at the conclusion that their position in the universe was of utmost importance, and worth devoting unmatched time and resources to. That is a noble pursuit that continues to this day.

Sources and Further Reading:

http://en.wikipedia.org/wiki/Archaeoastronomy

http://www.archaeoastronomy.com/