Detectable civilizations in our galaxy 4 | Cosmology & Astronomy | Khan Academy
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Taking a shot at estimating the number of detectable civilizations. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/cosmology-and-astronomy/life-earth-universe/life-in-universe-topic/v/detectable-civilizations-in-our-galaxy-5?utm_source=YT&utm_medium=Desc&utm_campaign=cosmologystronomy Missed the previous lesson? https://www.khanacademy.org/science/cosmology-and-astronomy/life-earth-universe/life-in-universe-topic/v/detectable-civilizations-in-our-galaxy-3?utm_source=YT&utm_medium=Desc&utm_campaign=cosmologystronomy Cosmology & Astronomy on Khan Academy: The Earth is huge, but it is tiny compared to the Sun (which is super huge). But the Sun is tiny compared to the solar system which is tiny compared to the distance to the next star. Oh, did we mention that there are over 100 billion stars in our galaxy (which is about 100,000 light years in diameter) which is one of hundreds of billions of galaxies in just the observable universe (which might be infinite for all we know). Don't feel small. We find it liberating. Your everyday human stresses are nothing compared to this enormity that we are a part of. Enjoy the fact that we get to be part of this vastness! About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. For free. For everyone. Forever. #YouCanLearnAnything Subscribe to Khan Academy’s Cosmology & Astronomy channel: https://www.youtube.com/channel/UChNPnEkW8LYZ5Rwi8_A2-DA?sub_confirmation=1 Subscribe to Khan Academy: https://www.youtube.com/subscription_center?add_user=khanacademy
Comments
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Another thing to consider: If some remote civilisation were to listen to the radio and TV signals we humans have been sending out in the recent 100 years, how likely is it that they can be picked up from 30,000 light years away (when they eventually reach there in 30,000 years)? It seems to me like there should be some max radius from which it is possible to fetch signals at all. The size of the whole galaxy just seems unrealistic.
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I fail to see anything in the equation that takes into account how old a star must be before its planets can even have a civilisation. If you go back 10B years with your estimate of stars, then the ones that are less than 4B years old should most likely be left out (as it took 4½B years for humans to evolve on Earth), so I would set the number of stars to 6/10 of the number you are using.
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i agree with u ..
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That's correct. But other civilizations don't really have to wait to send their signals into space before they hear from us of course :-) Just like we are sending random signals, others will probably do the same. So civilizations who broadcasted 100,000 years ago, those signals should already have reached us even from the other side of our galaxy.
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If we are talking about "intelligent" life here, we are talking about life that realizes it exists, life that can think about the universe, ... So a dog is not "intelligent" in that way. (No offence towards dogs, they are great animals!)
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I'm right. An intelligent species would build a civilization.
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*face palm
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No. Dogs are not considered intelligent lifeforms.
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Or maybe these 12.5 civilizations are too busy burning heretics than trying to invent quantum physics.
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12 ???? I feel lonely ....
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I always thought "intelligent" life meant things like animals. Now itseems it must mean human-like. So a dog would NOT be considered intelligent life?!!
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@mogghee We are getting very close to FTL CERN has confirmed FTL Particles and Fermi will begin their tests in 6 months sigh the USA is failing behind we used to be the scientific powerhouse then we let all the MBAs and lawyers and shareholders take a hold of our country.
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Personally i think the "10000 years" of electromagnetic communication is way off. Just looking at our own species, we started transmitting signals about 80 years ago, and we're at the point where we have so much destructive technology, so much violence, and so much disregard for our planet that we may kill ourselves in the near future. Any other civilization would have to evolve, and would presumably have the same tribalistic problems we do when it comes to getting along peacefully.
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My guess would end up in 0.00012 detectable civilizations
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Sadly, SETI has been shut down. Donate to the SETI Institute!
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what if a civilization discovers how to use gravity to bend the universe and bypass the light year variable or populate another planet? wouldn't the equasion be incorrect? well saying that i suppose there are trillions of variables to take into account and this does narrow it down to the core basics.
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well, pretty obvious actually. the diameter of the milky way is about 100.000 ly so even the first television broadcast, which was about 80 years ago, did not pass even a 1/1000th of the galaxy yet. even if the other civilization is only 1000 ly away, it would still take another 920 years to reach them ;-)
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Wow, nice vid.
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@stuffedk It's not really silly, it's meant to be hugely speculative. It's a thought experiment - one which Khan didn't even pioneer. Check out Carl Sagan doing the Drake equation also. Also take notice next time to the fact that they mention over and over that it's hugely speculative.
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WTF WTF! I just got censored off the the Khan Academy website! All I wrote was that this equation is über silly since there are so many assumptions. Change the assumptions just a tiny bit and you would get 1 or 1000. I have been watching so many videos and was and kind of still am really big fan, so I feel very disappointed.
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