Intelligent Life in Our Universe

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  • 0:02 Intelligent Life in…
  • 1:13 Traveling Between Stars
  • 2:51 Communicating With ET
  • 6:14 The Chances of…
  • 8:12 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will explore the possibility of finding intelligent life beyond Earth by traveling to it or by detecting its signals, as well as the chances that such life exists in the first place.

Intelligent Life in the Universe

Professional scientists would love nothing more than to have evidence for the existence of intelligent life elsewhere in the universe. It would truly make them giddy, but such scientists must also be realistic and factual when it comes to analyzing evidence of potential intelligent life on other planets, or perhaps, intelligent life that has visited Earth from elsewhere.

While the news and TV programs love to gain ratings by sensationalizing reports of UFOs visiting Earth, it is with deep regret that I have to tell you that there is absolutely no credible evidence that a visitation by an intelligent alien life form has ever occurred. Such reports are either complete fabrications, honest mistakes, or can be explained by natural phenomenon or man-made objects.

So instead of sensationalizing this lesson about the possibilities of intelligent life on other planets, we'll take a more rational and objective approach to figuring out if such life is possible and whether or not we'll ever find it.

Traveling Between Stars

First, let us consider that instead of waiting for a civilization to visit Earth, we want to go out and explore ourselves to try and find one. For all we know, the nearest civilization may not be capable of spaceflight just yet, so we'll have to come to them. So, get your wrenches, rocket fuel, metal, and space food and start building a spaceship!

Given our current technology and the fastest space probe ever launched, how long do you think it will take for us to reach the nearest star, which is relatively a paltry 4 light-years away? It would take 90,000 years. Even if you had some magical ability to all of a sudden travel at even half the speed of light to the nearest star, reaching it in 8 years, you'd need 400 times as much energy as the entire U.S. consumes in a single year to power a 100-ton spaceship. I think we can realistically put the construction of that spaceship of ours on hold for now, don't you? But you can eat the astronaut food if you want.

Since we assume that the laws of physics and composition of the universe is the same throughout the universe, we can equally realistically say that the chance that some distant civilization has visited Earth is equally improbable because nothing can travel faster than the speed of light. And the faster you travel, the more energy you need -- energy other civilizations (and our own) may simply not have.

Communicating With E.T.

Since meeting an alien and shaking their hand, foot, or whatever they greet us with is unlikely, we have to turn to other forms by which we can communicate with them. So, now take your wrench, metal, and screws, and let's start building radio telescopes instead.

Since electromagnetic waves cannot travel faster than the speed of light, you have to realize that whatever message you send out will take a long time to be received at great distances from us. It will take just as long for us to hear a reply.

In 1974, astronomers sent out an anticoded message, which is a message that can be easily understood by extraterrestrial intelligent life forms about which we know nothing about. This message was pointed at a globular cluster called M13, which is 26,000 light-years away. If any intelligent life receives this message, it will look like a picture to them. So, what's the problem here? It will take 26,000 years for any life form to receive it and another 26,000 years for us to get a reply back -- talk about a communication delay! At least it's better than traveling 90,000 years to the nearest star!

Now, although the anticoded message was a purposeful message sent to E.T., we have been somewhat accidentally sending out signals into space for over 60 years by way of radio shows, daytime TV, and what not. Thus, if there is an alien civilization within 60 light-years of us, and they are advanced enough, they will be able to detect our presence as a result of your grandma's favorite TV program. Similarly, we can monitor for alien civilizations for their daytime TV and radio shows! One famous project called SETI, search for extra-terrestrial intelligence, has tried to do so but hasn't been successful yet.

The problem with any attempt at listening to alien communication is that there is a huge array of radio frequency bands to monitor. Astronomers cannot monitor all of them efficiently. Therefore, the search has focused on something known as the water hole, a window in the radio spectrum, with low background interference, which lies between the 21 cm line of neutral hydrogen (H) and the 18 cm line of hydroxide (OH). H + OH = H20, which equals water, thus the name 'water hole.' We can only hope that an advanced civilization will appreciate the significance of the water hole and use it to communicate with us as well.

The other problem with a communication strategy is the fact that there is a constant noise of electromagnetic waves being emitted by our technology on Earth, which is drowning out an astronomer's ability to catch any potential noise coming from E.T.! As you can tell, like the idea of traveling to meet E.T. or having them travel to us, the idea of finding a signal from E.T. is daunting in its scope and fraught with its own pitfalls and problems.

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