Life in the Universe #3: The Great Filter

Doing some tweeting here: @DeepAstronomy
Whew! This was the hardest video for me (by far) to make. I started this script on August 21, 2009 and I'm finally finishing this up almost a year later. I would encourage anyone who has any questions to make comments, I'll by happy to try to help because I think this is a very important, albeit very difficult concept to understand.

The format is a little different, I used a green screen for the first time, please let me know what you think.

Thanks for your patience!

All music used was used with permission and under the Creative Commons License.

[deepastronomy]

@maastona The amount of matter is fixed, however in an expanding universe, energy is not conserved. Before you jump all over that, what I mean is that when the space through which particles move is changing (expanding universe), the TOTAL energy is not conserved: there's energy in vacuum of space (dark energy) -> more vacuum (expansion of universe) -> total energy in the universe goes up.

[deepastronomy]

@dragonfirefoxx No, but it sounds like all the people at the cool lunch table are there.

[deepastronomy]

@1RadicalOne I hope I don't come across as trying to make ANY conclusive case. Nothing about this subject is conclusive, and I assure you, I'm by no means trying to prove a negative. Almost everything about this subject is conjecture and hypothesis (recreational thinking) because we have no evidence whatsoever that's speaks to how common or rare life in the universe should be.

These ideas are not by any means meant to argue ANYTHING conclusively because it can't be done with what we know now.

[deepastronomy]

@AleximusMaximus Keep up the good fight! You'll be glad you did.

[AlvinHDavernport]

You're an enlightening man, Mr. (Dr.?) Darnell. You're the one subscription I have that I'm always paying attention to, and even if I've already watched all your videos, I keep watching them whenever I can. Thanks for this amazing piece of work, I thoroughly enjoyed it.

[deepastronomy]

@DigitizedSelf That was a limitation of iMovie, I think it looks bad too. Unfortunately, in order to have the white out transition, I had to sacrifice the timing. It's a limitation of the software, I don't have Final Cut Pro.

[deepastronomy]

@SeltsamerAttraktor I'm afraid you won't. Whats on wikipedia is all there is....

[deepastronomy]

@SeltsamerAttraktor That's right, and I covered that in Life in the Universe #1. If we can find one microbe that we KNOW is not from Earth and is from extraterrestrial origin, then it's everywhere...

[deepastronomy]

@1RadicalOne That's not my reasoning. My reasoning goes, 'if an event turns out to be relatively common - such as simple life forming on a planet, then that is probably not a filter.' Finding life within our solar system lends STRONG credence to the idea that simple life is a common occurrence and would probably not constitute Great Filter.

Of course there may be other reasons life may not evolve an intelligence, the term Great Filter is given to those possible explanations of why it may not.

[leahcim]

Great job, Tony, elucidating and contrasting the various possibilities....

[deepastronomy]

@ogurth Yes, I have - and I know, that's cool. That's one of the great things about working where I work, I've actually seen the data! I plan to do some vids on it...

[deepastronomy]

@djthumbpro Yes, there can be any number of filters that prevent intelligence from developing. But what are the BIG ones? The most likely ones? If they occur late in the development of a species (after technology), then there's probably been all sorts of civs that have begun and died already in our galaxy. That's bad news for us because we may be approaching it ourselves. If they occur early, like starting at all, then we may be ok since we've probably passed that point.

[deepastronomy]

@njimko23 All of them, I've excluded those that couldn't harbor life. That number includes the stars that could have habitable planets orbiting them

[deepastronomy]

@AugustusAurelianus1 Of course one could conjecture in this way, but since the probability of ANY form of life (outside of Earth) is in question, and we know of only one true success story, it makes a lot of sense to start with conditions we know work, namely, those that brought us about. That doesn't preclude other scenarios (like those you point out), but if we have to start somewhere, it should be from a place where a known success story exists.

[AggravatedAstronomer]

Glad to see you are still going TD :) I would miss your uploads very much! Got to keep myself inspired as I struggle through my astrophysics course! :)

[deepastronomy]

@djthumbpro Excellent question, I responded to your comment above.

[deepastronomy]

@FmMan33 I guess I think of intelligent life as being able to start a civilization of SOME kind, I know that's simplistic, but I like to keep these speculations as simple as possible since we really don't have any information.

[stanwilder]

Great food for thought!
thanks for this Mr. Darnell

[deepastronomy]

@Salmo77 Well, we have to start somewhere, don't we? There are probably more ways to do it than we can possibly imagine, but it makes sense to start with those cases we KNOW work: those like ours....

[Enots]

I love your videos, they always get me thinking. Please keep them coming.