Thread: Our Galaxy May Have 50 Billion Exoplanets–and It’s Still Making More

Originally Posted by kalesh

I cant put links right now (seven day rule) I will edit when I can.

Ok so the general gist of my response is that I'm an asshole that jumped the gun. I do want to take issue with two points though:

1) Your use of the word "scientists" rather than the phrase "some scientists". Scientists accept evolution. Scientists do not think that we're the only intelligent species. It seems common to say that "scientists say this" or "scientists say that" when there is really no consensus. Until there is a consensus, scientists (as a whole) say nothing. I recognize that this is just pedantry on my part though.

That argument wont work on someone who couldn't care less about the bible. Look at the ancient religions. check out Ramayana, Mahabharat, etc, look at the text version, not half assed films and you will find references to flying machines, spacecraft, ET and so on. Hell we even had intelligent and technologically advanced monkeys, (as advanced as humans of the time).

The only species of technologically advanced monkey's that I'm aware of is humans and to call us monkeys I have to go with the view that's still the in minority and define monkeys as a monophyletic group so that it includes the apes. It's usual to prefer monophyletic groupings these days but there seems to be some hesitancy to calling ourselves monkeys. At least we're finally willing to call ourselves apes.

Do you have any evidence of this other than people writing it down? Because there seems to be a willingness to believe that people make shit up today but somehow didn't make shit up thousands of years ago.

Originally Posted by Xei

Um well, it's not particularly obvious (it's also wrong). The first guy is actually talking about the galaxy, although he is talking about intelligent life and not life in general. There is a relatively good argument for this, which is that intelligent life could have evolved at any time within the last few billion years, yet it'd only take a time period of the order of a hundred thousand years or so to send messages to the whole galaxy if it were technologically advanced.

My problems with this are that it's equating "intelligent" with "technologically advanced" and that it's assuming that they would want to make contact. As for saying that they don't want to make contact but that their technology would still leak radiation, it's perfectly possible that they developed a technology that doesn't use electro-magnetism. So you're assuming that too. That is a fairly solid assumption but is still just that.
It has to be taken as possible that a different development of physics, asking different questions, would lead to a different technology or that they passed through an electromagnetic phase, discovered something more advanced and the waves passed us before we could detect them.

It's also possible that they're intelligent but haven't yet discovered electromagnatism. It's also possible that electro-magnetic waves seriously disrupt they're biology and so they don't use it or shield it.

There are just so many believable ways for this argument to fail.

Originally Posted by Xei

Bearing in mind we're talking about a very large number of potential worlds though. Is it really an almost certainty that every life form is stupid enough to destroy itself? Seems extremely anthropocentric.

I don't think that it's too antrhopocentric. Any organism that could become technologically advanced would have evolved from a non-technologically advanced organism. We are only colossally stupid in "advanced" societies where instincts and impulses that make perfect sense in an ancestral environment fail completely here. We're quite "intelligent" as hunter gatherers when we're living as natural selection "designed" us to. That is, no tribe of hunter-gatherers is ever going to drive the entire species extinct and will behave in a way that is well adapted to their environment. Why would evolution ever equip an organism to deal with an environment that's radically different than any it's been exposed to? It's a little anthropocentric but I believe not enough to discount entirely.

What if we never discover life on other planets? Would your perspective of our world change?

Originally Posted by Aquanina

What if we never discover life on other planets? Would your perspective of our world change?

That's a tricky question. I'll take it to mean not that we never discover life on other planets (because that wouldn't constitute proof against it and I expect to be dead by the time that we'd looked at enough planets for it to begin to constitute an approximation of proof) but rather that, right now, I was to come definitively into the knowledge that life on other planets didn't exist.

That would leave me in one of two spots as far as I can tell.

• Believe in a creator god that created life here on earth and then let evolution occur.
• Believe that something is special about the chemical makeup of earth that allowed abiogenesis to occur here but no where else.

My taste runs more towards the latter. Attempting find out what distinguishes earth from all of the other planets could move us forward towards an answer. Believing in a god would not.

Originally Posted by Xei

Bearing in mind we're talking about a very large number of potential worlds though. Is it really an almost certainty that every life form is stupid enough to destroy itself? Seems extremely anthropocentric.

Not necessarily destroy itself (as in nuclear holocaust or whatever), just be destroyed. It could be from natural disasters, or maybe civilizations consume all their planet's resources before they gain the capability to colonize other worlds. It wouldn't take much in the way of natural catastrophes or overexploitation within the next century to fatally harm the human race, and we are in no position to salvage it on another planet.

Also, if an intelligent race has survived for millions of years (which as you have indicated is insignificant compared to the age of the galaxy), one would expect it to have evolved enough to spread across the galaxy and create something like a type 3 civilization on the Kardeshev scale. And since we don't see blazing radio (or other) signals like any star system within 50 light-years of us would see, it doesn't seem that we are surrounded by a galaxy-wide intelligent race (or group of races). That being said, there might be something that prevents civilizations from growing much larger than the interstellar stage. Possibly the inability to communicate faster than light-speed would make maintaining such a civilization impossible.

Originally Posted by kalesh

And scientists still stay we are the only intelligent species in the universe. Yeah right.

Really? What scientists? The same ones who claim global warming is a myth? It's the scientific consensus that intelligent life is not only possible, but that's it's likely abundant. The Drake Equation puts the number of current advanced civilization in our galaxy alone between 10 and 20000. Any scientist that believes we are alone in the universe is a quack. It's scientifically possible that we are alone, but the odds of that are astronomically minute.

...we really don't know that. Where did you get those numbers for the Drake equation?

It's important to remember that probabilities work multiplicatively, not additively. So, although there are 10^22 stars in the observable universe and that seems like a hell of a lot, that actually means that if a condition necessary for life on a planet arises with probability 1/10 (for example, correct temperature, presence of water, etcetera), then you only need 22 such conditions before it looks like there might only be 1 life sustaining planet in the universe.

Thats only if those 22 such conditions are mutually exclusive. I got the numbers from the Drake equation from the internet, same as anyone gets any info

Well we really don't know enough about abiogenesis to assign many of the constants in the equation anything but a very large range (getting a maximum variation of 2*10^3 in all of the factors added together is just silly).

And yes of course, if they're mutually exclusive, but really I was only illustrating a point in simple terms, that point being that very large numbers of planets could still possibly be overwhelmed by the logarithmic nature of probability.

Even with the logarithmic nature of probability, it is still significantly more probable that intelliginet life exists.

Based on what?

I do agree with you, but I realise that I don't actually have much in the way of evidence, and as I've said there are some negative signs.

Originally Posted by Xei

Based on what?

What's the alternative? Must we believe that our solar system is "special" compared to the rest of the universe?

How is that an argument?

If by chance it is... then yes?