Aliens Are Real: Part 3
He was looking for anomalous radio signals that could have been sent by intelligent life. Eventually, his idea turned into Seti standing for Search for Extra Terrestrial Intelligence , which used the downtime on radar telescopes around the world to scour the sky for any signals.
Alien 3 - Wikipedia
For 50 years, however, the sky has been silent. There are lots of practical problems involved in hunting for aliens, of course, chief among them being distance. If our nearest neighbours were life-forms on the fictional forest moon of Endor, 1, light years away, it would take a millennium for us to receive any message they might send. If the Endorians were watching us, the light reaching them from Earth at this very moment would show them our planet as it was 1, years ago; in Europe that means lots of fighting between knights around castles and, in north America, small bands of natives living on the great plains.
Where are the aliens?
It is not a timescale that allows for quick banter — and, anyway, they might not be communicating in our direction. The lack of a signal from ET has not, however, prevented astronomers and biologists not to mention film-makers coming up with a whole range of ideas about what aliens might be like. In the early days of Seti, astronomers focused on the search for planets like ours — the idea being that, since the only biology we know about is our own, we might as well assume aliens are going to be something like us.
But there's no reason why that should be true. You don't even need to step off the Earth to find life that is radically different from our common experience of it.
Are Aliens Real? Is There Life on Other Planets?
These single-celled creatures have been found in boiling hot vents of water thrusting through the ocean floor, or at temperatures well below the freezing point of water. The front ends of some creatures that live near deep-sea vents are C warmer than their back ends. We're at least as extreme compared to them as they are compared to us. On Earth, life exists in water and on land but, on a giant gas planet, for example, it might exist high in the atmosphere, trapping nutrients from the air swirling around it.
And given that aliens may be so out of our experience, guessing motives and intentions if they ever got in touch seems beyond the realm's even of Hawking's mind. Paul Davies, an astrophysicist at Arizona State University and chair of Seti's post-detection taskforce, argues that alien brains, with their different architecture, would interpret information very differently from ours.
What we think of as beautiful or friendly might come across as violent to them, or vice versa.
I don't think you can put human views on to them; that's a dangerous way of thinking. If they exist at all, we cannot assume they're like us. Answers to some of these conundrums will begin to emerge in the next few decades. The researchers at the forefront of the work are astrobiologists, working in an area that has steadily marched in from the fringes of science thanks to the improvements in technology available to explore space. Scientists discovered the first few extrasolar planets in the early s and, ever since, the numbers have shot up.
Today, scientists know of planets orbiting around more than stars. Most are gas giants in the mould of Jupiter, the smallest being Gliese , which has a mass of 1. In , Nasa launched the Kepler satellite, a probe specifically designed to look for Earth-like planets. Future generations of ground-based telescopes, such as the proposed European Extremely Large Telescope with a 30m main mirror , could be operational by , and would be powerful enough to image the atmospheres of faraway planets, looking for chemical signatures that could indicate life.
The Seti Institute also, finally, has a serious piece of kit under construction: In all the years that Seti has been running, it has managed to look carefully at less than 1, star systems. Japan promises to stop using nuclear power.
And, as the interactive above demonstrates, the world is likely to find alien life. It could happen even sooner, depending how many civilizations are out there to be found.
Reasons to Believe
To understand why this is, it helps to know about someone name Frank Drake. Drake is the least lonely man on Earth—if not in the entire galaxy. Start with the number of stars in our galaxy, which is conservatively estimated at billion, though is often cited as three times that.
Not all of those exoplanets would be capable of sustaining Earth-like life, so the equation assumes from 1 to 5 in any system could. The mere existence of intelligent life forms tells us nothing, however, unless they have the ability to make themselves known—which means to manipulate radio waves and other forms of electromagnetic signaling. Finally, and perhaps most anthropocentrically, the equation considers how long any one of those semaphoring civilizations would be around to blink their signals our way. A sun like ours survives for about 10 billion years; life on Earth has been around for only about 3.
If we destroy ourselves in an environmental or nuclear holocaust tomorrow, our signal will go dark then.
The aliens are hiding in underground oceans.
If we survive for tens of thousands of years, we will be announcing our presence to the cosmos for far longer—and the same is true of all of the other civilizations that live in the Milky Way. Factor all of this together and stir in a little statistical seasoning concerning our increasing ability to study other star systems for signals, and, as the above interactive shows—the results can vary wildly. If you play the game conservatively—lowballing all of the variables—you might get about 1, detectable civilizations out there at any given time.