Stephen Hawking on Life in the Universe

[Skami Pilno]

Many of you may have already read this article, but I thought I would share this thought provoking lecture by Stephen Hawking. Life in the Universe.
Just the intro:

Spoiler

In this talk, I would like to speculate a little, on the development of life in the universe, and in particular, the development of intelligent life. I shall take this to include the human race, even though much of its behaviour through out history, has been pretty stupid, and not calculated to aid the survival of the species. Two questions I shall discuss are, 'What is the probability of life existing else where in the universe?' and, 'How may life develop in the future?'

It is a matter of common experience, that things get more disordered and chaotic with time. This observation can be elevated to the status of a law, the so-called Second Law of Thermodynamics. This says that the total amount of disorder, or entropy, in the universe, always increases with time. However, the Law refers only to the total amount of disorder. The order in one body can increase, provided that the amount of disorder in its surroundings increases by a greater amount. This is what happens in a living being. One can define Life to be an ordered system that can sustain itself against the tendency to disorder, and can reproduce itself. That is, it can make similar, but independent, ordered systems. To do these things, the system must convert energy in some ordered form, like food, sunlight, or electric power, into disordered energy, in the form of heat. In this way, the system can satisfy the requirement that the total amount of disorder increases, while, at the same time, increasing the order in itself and its offspring. A living being usually has two elements: a set of instructions that tell the system how to sustain and reproduce itself, and a mechanism to carry out the instructions. In biology, these two parts are called genes and metabolism. But it is worth emphasising that there need be nothing biological about them. For example, a computer virus is a program that will make copies of itself in the memory of a computer, and will transfer itself to other computers. Thus it fits the definition of a living system, that I have given. Like a biological virus, it is a rather degenerate form, because it contains only instructions or genes, and doesn't have any metabolism of its own. Instead, it reprograms the metabolism of the host computer, or cell. Some people have questioned whether viruses should count as life, because they are parasites, and can not exist independently of their hosts. But then most forms of life, ourselves included, are parasites, in that they feed off and depend for their survival on other forms of life. I think computer viruses should count as life. Maybe it says something about human nature, that the only form of life we have created so far is purely destructive. Talk about creating life in our own image. I shall return to electronic forms of life later on.

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Personally, I found it to be quite profound, at times funny, at other times disturbing, but well reasoned throughout. After reading this, I am much more interested in reading his books.

Any thoughts on life in the universe, hunamity's future, or even the article?

[Armin]

Originally Posted by Skami Pilno

Many of you may have already read this article, but I thought I would share this thought provoking lecture by Stephen Hawking. Life in the Universe.
Just the intro:

--------------------------
Personally, I found it to be quite profound, at times funny, at other times disturbing, but well reasoned throughout. After reading this, I am much more interested in reading his books.

Any thoughts on life in the universe, hunamity's future, or even the article?

It's a shame I can't even discuss this based on the rules of the Forum.

[SaintRidley]

Life in the universe? Douglas Adams had something to say about that:

It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.

[Wardog]

Originally Posted by Armin

It's a shame I can't even discuss this based on the rules of the Forum.

I know religions will have their own perspectives on this subject, but it isn't religious per se.

As long as you don't say anything about any given religion's views on the subject, or use a religious argument for/against anything, I'm sure it should be fine.

(Also, no arguing about the composition of the Galactic Senate, or offering legal advice regarding conpensation for alien abductions).

[warty goblin]

I revisit this question in my head every now and again. Since we only have one data point about life in the universe (and seriously incomplete information about that point), inference on the frequency with which it appears or gains intelligence strikes me as more or less without basis. All we can say it it isn't impossible. Everything else is pure speculation.

That said, my personal speculation is that the question itself is pretty close to irrelevant. Insofar as I can reason, the universe is too big, and movement in it too hard. Even if there is life out there, the odds are extremely good we will never encounter them. It seems fairly unlikely that we'll never establish anything like a self-sufficient outpost elsewhere in the solar system. The chances of us actually colonizing another planet seem pretty close to zero.

Life elsewhere strikes me as useful as a philosophical exercise or narrative tool. It's actual existence or lack thereof probably doesn't matter.

[noparlpf]

Seems to me like the main reason we have no evidence of life in the universe is we never had a war over eugenics in the '90s. If we had, we'd have been in space by now, and Vulcans and whatnot would be all over the place.
My logic is flawless, what are you talking about.

[JoshL]

Five years ago, we thought that planets around other stars might be kinda rare. Two years ago we thought that planets in Earthlike orbits (the "Goldilocks Zone") were very, very rare. These views are no longer held to be true, thanks to advances in tech. Some of the exoplanet surveys that came out last year are astounding. Doubly so when you think of how small of a fraction of a single galaxy in the universe we can observe.

Little bit of scale for a moment. Last year we observed the first (of many) exoplanets, Kepler-22b. It is 600 light years away. Our galaxy is estimated between 100,000 and 120,000 light years across, and the disc is 1,000 light years thick. Put another way: picture a 12" pizza that is 1/10th of an inch thick (crappy floppy new york style). This planet is closer to us than the pizza is thick. Oh, and there are more pizzas on the tables nearby...

A couple months after that news hit, astronomers found three possible exoplanets in the Goldilocks Zone of star GJ-667C. It's 22 light years away. Using that same Galactic Pizza, that system is 0.0022 inches away (the average thickness of 20# copy paper is around 0.0038). Not long after that, another paper was published (I think by the Kepler study that found the first one; I can't recall, but it was March or April of this year) showing just how common those planets really are.

These are all planets, by the way, that could potentially support life as WE know it. Us, with appropriate terraforming, and provided we can get there. Which is the big problem. Currently our speed record is the Galileo probe (which studied, then crashed into Jupiter at about 106,900 mph, or 0.00016 the speed of light). The fastest we've managed to get something to travel, and we did that by crashing it. To get to GJ-667C, an object going that fast would take around 137,500 years, if my math is right.

So then, the odds that there are other lifeforms in the galaxy? Pretty good, actually. The odds that we will ever see them? Next to nothing.

More Douglas Adams quotes: Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space...

(as you might have guessed, I love thinking about this stuff!)

[Scowling Dragon]

One other piece of info I learned was even if we meet other life, its unlikely we will ever be EVER close on the same level of Social and Technological development.

[Ravens_cry]

There are just so many unknowns, it is literally impossible to say, and even if there is some form of intelligent life in every solar system, (a number which seems rather optimistic given that for over 99.9% of its history intelligent life didn't exist on Earth) they are still hopelessly out of reach, and likely to remain so for quite some time, if not forever.

[Traab]

As far as I can think, there almost has to be life of some form somewhere in the virtually infinite vastness of space. The odds that random chance only allowed the existence of life on one planet out of trillions, (im sure its probably higher than that) must be, heh, astronomical. If you also include planets were life might have existed at one point, I just cant believe that it isnt as close to a fact as can exist without physical proof. There are estimated to be 4,674,712,500 planets in the milky way alone that have all the major necessary conditions that would allow abiogenesis to occur. Think about it, in the milky way galaxy alone, over 4 and a half BILLION worlds are capable of having earth style life exist on them. (Thats honestly the best way I can phrase it, im sure it was awkward but you get the point.)

[Ravens_cry]

Perhaps, but since we have never encountered any life elsewhere yet, we don't even have an inkling of the true odds. All something like the Drake equation is good for is telling us what we need to know in order to know. Unfortunately, we know next to nothing of the numbers required to fill said equation.
Let's say you had a gold ring and were surrounded by people who you don't know whether or not they got a gold ring except those that are very, very, close to you, and those specific ones don't.
Just what are the odds of someone else having a gold ring?

[Frozen_Feet]

I'm pretty convinced there is life besides that found on earth out there. I even hold it's possible that a star, or something akin to star, could be a cognizant being.

The joke here is that 99% of the life out there likely exists on such principles that we will not even realize they are alive, even if we can observe them, which is not given. Alien life is, in all likelihood, alien.