In our defense, it was very late last night and I didn't feel like looking it up when he was so blatantly wrong about breaking the light barrier being the only way it would happen.

Side note: I can't believe I forgot about cryostasis. It was the way HAL killed everyone except Dave and Frank.

Just coming back to the Great Filter theory for a moment...it starts like so many theories about alien life on a complete misunderstand of probability. It assume that as there are a 10 to 200 sextillion stars in the universe that 1 of them must have a planet circling it that has the capacity to sustain life. This is incorrect.

In simple terms suppose I open a new pack of cards and shuffle it blind. I now ask you to draw a card. What are the chances of you drawing the 43 of Helmets? It doesn't matter if we now extend the pack of cards to every card in the shop, or every card ever made since the dawn of time. The 43 of helmets either exists as a card - or it doesn't. If it existed as a one of promotional card back in 1923 and we shuffled a billion, billion cards then the probability of us drawing that card would be 1 in a billion, billion. If the card never existed then the probability of drawing the card would be zero, regardless of the number of cards we shuffle.

I find it odd that people would believe in aliens just because there are so many stars. Do any of you think a grain of sand here on earth could talk?

No, but if we had even a single example of a process that led to a talking grain of sand, there might be a different calculus.

Fair comment FineRedmist - I'll rephrase the question. Does anyone think that a fish here on earth can speak English?

The card, as you put it, exists at least once in the form of the human race. We already know of a number of planets within the right distance of their respective start to have water present in liquid form. There is absolutely no reason to believe the "card" is in the enormously large deck twice. And that does not even include the possibility of intelligent life so different, we wouldn't even know what to look for.

I've seen nothing to lead me to believe that any fish on Earth could talk. But ask me whether there might be a chimp signing somewhere, maybe. I wouldn't discount the possibility.

@ILN ... both Jamiet and I did and I think Chairman did too.

@Maniac ... many living creatures on Earth have shown the ability to communicate and speak. Animals of all kinds have shown to have much more intelligence than people would have thought in the past. If we ever figure out how to "translate" fish communications, maybe we'll find that we can work with them too. We can communicate pretty accurately with things like dolphins and some whales, but dolphins and whales are mammals, so it depends on your definition of "fish" (i.e. the biological definition or the "it swims" definition).

Maniac, Great! So you believe that there is a great filter. If there isn't any other living organisms, or intelligent organisms in the world, there has to be something unique about mankind that we are living and intelligent. Therefore if out of trillions of stars there is no intelligent life then there is something that prevents the development of life in all cases except ours, the great filter (in your case it would be a planet capable of sustaining life).

There are a wide variety of living organisms outside of humans, and they can exist in all sorts of conditions (at the bottom of the ocean, near insanely hot volcanic vents, in the coldest reaches of the arctic). The variety of life on Earth is exactly what sets the certain probability of there being life elsewhere.

If you narrow it to intelligent life, humans are unique in their certain capacity, whatever it is, but we're increasingly discovering that elements once thought unique to humans are not so. Self-awareness, problem solving, reasoning, communication, and empathy are all elements were discovering in different species of animals today like elephants, crows, dolphins, etc. It's likely a combination of biological factors (body and mind; the ability to problem solve and imagine/forsee along with the opposable thumb and upright gait) which gave rise to dominant humans and less the singular aspect of intelligence.

Who cares about intelligent life? Intelligence is not adaptive, it's actually a tremendous energy burden, so we're not likely to find it.

I care

So do i.

How is it an energy burden?

If i understood correctly, i think he's referring to our intelligence causing us to live a lifestyle that's energy demanding.

But dw, he talking shiet.

Also, what do you mean by intelligence not being adaptive? lol

A few responses to comments on this thread.

1) There was great agreement in the early pages that there must surely be intelligent alien life out in space, because there are billions of stars. This is, as Maniac pointed out, false. The oft-cited (and almost always misused) Drake equation has many factors in it which are completely unknown and possibly inscrutable to us, and only by unjustifiably assuming some or another value could one reach such conclusions. For example, the probability of life arising on an earthlike planet might (for all we know) be so small as to be, for all practical purposes, indistinguishable from zero.

2) bo is correct that we don't need to send a manned spaceship somewhere in order to find life. We don't necessarily even have to get super close, depending how similar the putative civilization was to ours. There would be spectral and radio signatures visible from the low tens of light years away, most likely.

3) Finally, a small, interesting point. If a ship could travel fast enough, it would not have to be a "generational ship" in order to travel hundreds of light years. That's because, although its journey as measured at earth (or at its destination) would be hundreds of years (and so, in particular, we wouldn't learn what it found for that long), its journey as measured by its travelers could be just a few years. To turn 100 years into 30 years, for example, the ship would have to go about 95.4% of the speed of light. (Admittedly, this might be harder than just building a generational ship. But it's interesting. And it might not be, given the psychological and medical unknowns of the latter.).

"If i understood correctly, i think he's referring to our intelligence causing us to live a lifestyle that's energy demanding."

It requires a huge amount of caloric intake to develop intelligent brains. The amount of caloric intake pregnant mothers require is astounding, comparatively speaking. The fact that even after birth, babies have still only developed their brain to a small extent (about 30% I think) compared to how it will be when fully developed speaks to the amount of energy required. Humans produce comparatively few babies because of the energy requirements.

It is not adaptive for the reasons I listed above. It does not aid survival. Humans have to defend and provide food for their young for a much longer time period than other organisms. And other comparatively intelligent organisms have not fared well because it takes so much energy to reproduce young.

Can you expand on your third point, semck? It sounds interesting but I never took a physics class and whatever justification you used to get there goes right over my head.

Sure, bo. The effect is called time dilation. It is a consequence of Einstein's special theory of relativity. It means that if somebody is moving, relative to you, then their clocks are moving slower than yours, in the sense that the time you measure between any two events on their path (e.g., their leaving earth and their arriving at a distant star) is longer than the time they measure.

This leads to a bit of an apparent paradox -- which isn't an actual paradox -- because you're also moving relative to them (from their point of view), which means that, for them, YOUR clocks are moving slower than THEIR clocks, for events that happen to you. A complementary principle that helps this all work out is that you also measure distances differently: distances along their pathway will be shorter to them than they will be to you (and vice versa). So suppose somebody is travelling at 95.4% of the speed of light, from earth to a planet 100 light years away. From their perspective, the star is 30 light years away, and will take them 30 years to reach. From your perspective, it's 100 light years away, and will take them 100 years to reach. Neither is wrong -- it's just that, according to relativity, time and space are different in different inertial reference frames (i.e., reference frames that are moving at a constant speed with respect to each other).

The actual factor, by the way, is sqrt(1 - v^2 / c^2), where v is the relative velocity, and c is the speed of light.

Here is a nice page on the effect, located in a longer series about relativity.

http://www.pa.msu.edu/courses/2000fall/phy232/lectures/relativity/dilation.html

Read: "The Forever Wars" by Joe Haldeman.

Makes a little bit of sense, I think...

Semck:

Two points:
1. I do believe that they have used expirements to actually verify time dilation, by synching two clocks, putting one into orbit (that means, it flew really fast..) and when it cam back the clocks were no longer in synch - something to that effect.

2. Modern FTL theory does utilize a "warp bubble" - basiclaly space is compressed and expanded in front and back of the ship to propel the vessel, but the ship within the bubble can be effectively motionless. So, do you know if under this warp bubble theory if time dilation would still occur? Or because the ship is really not traveling within normal space at all that FTL speeds could occur in "normal time"?

(Yes...NASA scientists are working on this, convinced it is doable...with the right power source...which we are nowhere close to having, of course...)

I hadn't thought about time dilation. That combined with cryostasis could make those very distant stars that we know have planets circling them at the right distances very reachable.

Some varieties of crows can make and use tools and are good problem solvers. The same with some cephalopods. Both are a long, long away on our family tree. If life is not rare elsewhere, I don't think intelligence would be that rare either. Technology is another question, but intelligence? Sure.

Considering that the earliest forms of life may have derived from comets hitting the earth, life shouldn't be too rare. If comets are common here, to presume that they are rare elsewhere, like life and intelligence, is a little egocentric.

Sea otters use rocks to crack open shellfish.

https://www.youtube.com/watch?v=1DoWdHOtlrk

@krellin,

1) You are correct. It has also been verified in many particle-lifetime experiments, although these are perhaps intuitively less convincing, at least to many.

2) That's an interesting question. I'm familiar with the drives in question, which employ *general* relativity, but haven't thought about their implication for time dilation (or vice versa). I'm going to try to think that through and get back to you, but GR is notoriously tricky, so I won't hazard a response until I do get a chance to analyze carefully.

It would be pretty freaking sweet if we could do FTL without time dilation, and Star Trek got it totally right. lol Of course, w would first need to pretty much harness the power of a tiny black hole to do such a thing, I believe...

Well, the idea behind Trek is creating a warp bubble in space so the ship itself doesn't travel as much as the bubble does. Lind of slipping into hyperspace. But I always liked folding space so that departure and destination meet at a point and you travel instantaneously.