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ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest.

Yes it does.
http://en.wikipedia.org/wiki/Newton's_law_of_universal_gravitation
If there were infite planets they would exert infinite gravitational pull.

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

Kinda does make sense. If the universe is infinitely large, and as such has infinite matter, then there would be an infinity large gravitational force pulling in all directions.

Newton's laws are a little outdated in the modern parlance. The outward expansion of the big bang cancels out the gravitational force, and as the universe expands further it gets weaker. There are some other proposed theories to explain why the universe hadn't collapsed in on itself.

While it is unlikely in the current framework that the universe is infinite, it is not impossible that it is. It's hard to state much in this sort of cosmology with any kind of certainty.

Shrike325 wrote:

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

Kinda does make sense. If the universe is infinitely large, and as such has infinite matter, then there would be an infinity large gravitational force pulling in all directions.

But it doesn't make sense that that would prevent an infinite universe or a universe with infinite matter (those are two very different things). Gravity also attenuates at an exponential curve so gravity doesn't gather like a giant tidal wave to rip us all apart. It just stops doing anything past a certain distance.

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak? Do you have any sort of formal astrophysics education?

The chances of intelligent life is a lot lower, but I don't think it's unreasonable to imagine that it might exist.

Given that it exists in the only observed location of biological life it doesn't seem incredibly unreasonable. The time scales throw it off a lot though.

Good tv show about this on the ol' Beeb. There is some evidence that life has evolved numerous times just on earth. As for intelligent life, the corvid family, philosophically speaking, has all the traits associated with intelligence, self awareness, perception of others, reasoning, language, use of tools etc. The only behaviour they currently lack is the desire to create artwork. Some scientists even going as far as saying they are on the cusp of where we were 100,000 years ago.

Shrike325 wrote:

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

Kinda does make sense. If the universe is infinitely large, and as such has infinite matter, then there would be an infinity large gravitational force pulling in all directions.

But that field would be dispersed across infinite space, cancelling it out.

Rented Tritium wrote:

Shrike325 wrote:

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

Kinda does make sense. If the universe is infinitely large, and as such has infinite matter, then there would be an infinity large gravitational force pulling in all directions.

But that field would be dispersed across infinite space, cancelling it out.

But the distance between the observer and the observed is not infinite.

ShumaGorath wrote:

Shrike325 wrote:

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

Kinda does make sense. If the universe is infinitely large, and as such has infinite matter, then there would be an infinity large gravitational force pulling in all directions.

But it doesn't make sense that that would prevent an infinite universe or a universe with infinite matter (those are two very different things). Gravity also attenuates at an exponential curve so gravity doesn't gather like a giant tidal wave to rip us all apart. It just stops doing anything past a certain distance.

You are arguing for an infinite number of planets because the universe is infinitely large. Unless those planets are massless, then you are arguing for a universe with infinite mass. If there is infinite mass, then there is an infinitely large gravitational force. If there is an infinitely large gravitational force pulling in all directions, molecular bonds could not form. If molecular bods could not form (as they would be pulled apart), then life could not exist at all. I exist. Therefore there is a finite amount of mass, therefore there are a finite number of planets, this does not necessarily preclude an infinitely large universe, as it is quite possible that the universe is infinitely large, but at some point, becomes empty.

Joey, as much as I like your Avatar, I sometimes think you deliberately choose to be argumentative.

Joey wrote:No.
The universe is a finite place and the maths says it's pretty unlikely.
You may as well say "well there's all these grains of sand, one of them must be a completely accurate map of Chipping Norton".

Looking at the evolution of life on earth, the same patterns have come to form over an over again. The same structures have shown themselves in entirely separate evolutionary paths.
Our understanding of how life has formed on earth can lend itself to its formation on other planets, there is understanding enough that we can draw upon certain norms. i.e. the need for water for the creation of life.
The maths actually say the opposite of what you say is true - we know complex life has come into being at least once, and the almost incomprehensible number of stars and galaxies within the universe means that claiming we are the only ones is egotistical to the extreme.

Really the greater barrier is time and space - the universe is simply so old, and so massive, that the difficulty might be instead being in the right place and time to encounter them.

You could also point out Greg Bear's (the SF writers) slightly pessimistic theory - that the nature of life is struggle, and any complex and intelligent forms of life that have come into being (and unable to separate themselves from that fundamental character) have ultimately destroyed themselves when they have eventually created weapons capable of doing so. Perhaps there are a million burning balls in the galaxy, life blasted or poisoned out of existence.

As for aliens having the technology to travel the gulf between stars, and then messing up so they make some farmer in Kansas aware of their presence? I would say that such a thing would be extremely unlikely.

I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Shrike325 wrote:

ShumaGorath wrote:

Shrike325 wrote:

ShumaGorath wrote:

Joey wrote:

ShumaGorath wrote:

No...there is an actual number of planets in the universe.
If there is life in the universe then it would have to be related to us, the chance of complicated biological information evolving twice, independently, is negligible.

Where are you getting this gak?

Logic.
If the universe had an infinite number of planets their gravitational pull would be infinite, therefore we must assume it is finite.

That doesn't make sense in the slightest. That concept does not mesh with any common understanding of gravity or the dispersion of matter in the universe.

Kinda does make sense. If the universe is infinitely large, and as such has infinite matter, then there would be an infinity large gravitational force pulling in all directions.

But it doesn't make sense that that would prevent an infinite universe or a universe with infinite matter (those are two very different things). Gravity also attenuates at an exponential curve so gravity doesn't gather like a giant tidal wave to rip us all apart. It just stops doing anything past a certain distance.

You are arguing for an infinite number of planets because the universe is infinitely large. Unless those planets are massless, then you are arguing for a universe with infinite mass. If there is infinite mass, then there is an infinitely large gravitational force. If there is an infinitely large gravitational force pulling in all directions, molecular bonds could not form. If molecular bods could not form (as they would be pulled apart), then life could not exist at all. I exist. Therefore there is a finite amount of mass, therefore there are a finite number of planets, this does not necessarily preclude an infinitely large universe, as it is quite possible that the universe is infinitely large, but at some point, becomes empty.

Thats not how gravity works. Two equal gravitational pulls on both sides of you pull equally. You aren't ripped apart, it just cancels out. Gravity also attenuates rapidly, meaning that infinite gravitational force over an infinite area doesn't imply infinite pull from the point of the observer. It actually implies that there would be no gravity at all. There are pockets of gravity in the universe that correspond to concentrations of matter and energy, but they are fairly evenly distributed which prevents some sort of ridiculous collapse scenario. Theres already enough energy in the observable universe to do that according to this view of gravity which pretty intensely implies that it's wrong.

Yeah, we can just drop the infinite argument and say that it's finite, but mind bogglingly huge and still come to more or less the same conclusions.

kronk wrote:I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Because with an infinite universe, there are infinitely many alien civilizations. With infinitely many alien civilizations, there are infinitely many that have the ability to travel to Earth, and with infinitely many having the ability to travel to earth, there are infinitely many that ARE visiting Earth.

@ShumaGorath:
Please elaborate.

From my understanding F(gravity) = G * ((m(1) * m(2)) / r^2).
If there is infinite mass, than from any point, F(gravity) goes to infinity in all directions.

Pacific wrote:Joey, as much as I like your Avatar, I sometimes think you deliberately choose to be argumentative.

Joey wrote:No.
The universe is a finite place and the maths says it's pretty unlikely.
You may as well say "well there's all these grains of sand, one of them must be a completely accurate map of Chipping Norton".

Looking at the evolution of life on earth, the same patterns have come to form over an over again. The same structures have shown themselves in entirely separate evolutionary paths.
Our understanding of how life has formed on earth can lend itself to its formation on other planets, there is understanding enough that we can draw upon certain norms. i.e. the need for water for the creation of life.
The maths actually say the opposite of what you say is true - we know complex life has come into being at least once, and the almost incomprehensible number of stars and galaxies within the universe means that claiming we are the only ones is egotistical to the extreme.

Really the greater barrier is time and space - the universe is simply so old, and so massive, that the difficulty might be instead being in the right place and time to encounter them.

You could also point out Greg Bear's (the SF writers) slightly pessimistic theory - that the nature of life is struggle, and any complex and intelligent forms of life that have come into being (and unable to separate themselves from that fundamental character) have ultimately destroyed themselves when they have eventually created weapons capable of doing so. Perhaps there are a million burning balls in the galaxy, life blasted or poisoned out of existence.

As for aliens having the technology to travel the gulf between stars, and then messing up so they make some farmer in Kansas aware of their presence? I would say that such a thing would be extremely unlikely.

Once you have DNA, the rest of life is pretty easy.
Question is, how do you form DNA, or any biological code, at random?
No one knows the answr to that so no one actually knows how likely alien life is.


Automatically Appended Next Post:

Shrike325 wrote:
@ShumaGorath:
Please elaborate.

From my understanding F(gravity) = G * ((m(1) * m(2)) / r^2).
If there is infinite mass, than from any point, F(gravity) goes to infinity in all directions.

That is correct, but if people want to drop the infite argument then let them.

Considering the size of the universe, I think it is all but guaranteed that there are other planets with life on them out there, and a fairly good chance that some of it is intelligent life.

However, I'm quite confident that absolutely none of it has ever come to earth.

Shrike325 wrote:

kronk wrote:I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Because with an infinite universe, there are infinitely many alien civilizations. With infinitely many alien civilizations, there are infinitely many that have the ability to travel to Earth, and with infinitely many having the ability to travel to earth, there are infinitely many that ARE visiting Earth.

@ShumaGorath:
Please elaborate.

From my understanding F(gravity) = G * ((m(1) * m(2)) / r^2).
If there is infinite mass, than from any point, F(gravity) goes to infinity in all directions.

At which point its important to understand how gravity interacts with energy, time, space and matter.


Automatically Appended Next Post:

kronk wrote:I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Infinite implies certainty. If it's infinite then there is an occurrence of every possibility an infinite number of times. It's a pretty big difference.

Shrike325 wrote:

kronk wrote:I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Because with an infinite universe, there are infinitely many alien civilizations. With infinitely many alien civilizations, there are infinitely many that have the ability to travel to Earth, and with infinitely many having the ability to travel to earth, there are infinitely many that ARE visiting Earth.

@ShumaGorath:
Please elaborate.

From my understanding F(gravity) = G * ((m(1) * m(2)) / r^2).
If there is infinite mass, than from any point, F(gravity) goes to infinity in all directions.

Gravity is infinite but also incredibly weak, it is in fact the weakest of the four fundamental forces to the point that a simple bar magnet can overpower the attraction of the entire earth and lift a nail with ease. Besides equal pulls in opposite directions cancel out so if the universe is equal then there is infinite force in every direction and thus no net force in any particular direction (barring anomalies caused by local masses).

There is also the inflation caused by dark energy and the wonderful world of quantum mechanics to account for that suggest a force countering gravity and the certainty of every possible action respectively.

reds8n wrote:

ShumaGorath wrote:*Ancient Aliens Meme*

Whilst I'm sure we all chuckle at this, can we please make this the last appearence of this particular meme in this thread, thanks in advance.

I want to believe that'll happen... oh wait... no I don't...

corpsesarefun wrote:

Shrike325 wrote:

kronk wrote:I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Because with an infinite universe, there are infinitely many alien civilizations. With infinitely many alien civilizations, there are infinitely many that have the ability to travel to Earth, and with infinitely many having the ability to travel to earth, there are infinitely many that ARE visiting Earth.

@ShumaGorath:
Please elaborate.

From my understanding F(gravity) = G * ((m(1) * m(2)) / r^2).
If there is infinite mass, than from any point, F(gravity) goes to infinity in all directions.

Gravity is infinite but also incredibly weak,

Impossible. It is either infinite, or it is finite and weak.

Shrike325 wrote:

corpsesarefun wrote:

Shrike325 wrote:

kronk wrote:I'm not sure why people are getting hung up on infinite. It doesn't have anything to do with anything.

There is a metric gak-ton of Galaxies, Stars, Solar Systems, and, therefore, planets in the universe. To say that there's not at least 1 other planet with intelligent life on it is not a concept I can agree with, but I'll respect your opinion.

Because with an infinite universe, there are infinitely many alien civilizations. With infinitely many alien civilizations, there are infinitely many that have the ability to travel to Earth, and with infinitely many having the ability to travel to earth, there are infinitely many that ARE visiting Earth.

@ShumaGorath:
Please elaborate.

From my understanding F(gravity) = G * ((m(1) * m(2)) / r^2).
If there is infinite mass, than from any point, F(gravity) goes to infinity in all directions.

Gravity is infinite but also incredibly weak,

Impossible. It is either infinite, or it is finite and weak.

Infinite in occurance and infinite in strength are not the same. Two infinite amounts are not inherently equal. Set size, base number, granularity, and numerous other things are exceptionally important in calculating things with infinite values.

What?

It has infinite range as it has force determined by an inverse square of it's distance yet is relatively ineffectual when compared to the other four forces, how is that impossible?

Right, with infinite mass in the universe you have an infinitely strong gravitational force, I suppose I should have been more specific.

Shrike325 wrote:Right, with infinite mass in the universe you have an infinitely strong gravitational force, I suppose I should have been more specific.

Except you don't. You're mashing all that gravity into one place because the equation gives you a sideways 8, but it's infinitely dispersed. If you have an M&M every square mile infinitely in all directions in infinite space it's an infinite number of M&Ms. Except you don't have an infinite pile of M&Ms, you have one M&M every square mile over infinite space. Still not good enough to see one from the location of another. That even dispersal even means that they won't attract each other since all that infinite gravity cancels itself out.

Think of spacetime as a sheet, if you press down on a sheet at one point but hold it taut with equal force then there will be no net effect.

corpsesarefun wrote:Think of spacetime as a sheet, if you press down on a sheet at one point but hold it taut with equal force then there will be no net effect.

Visually that's probably a bad example since sheets and paper tend to bend due to lever action if an equal force is applied in the middle and at the periphery (they're also elastic).

ShumaGorath wrote:

corpsesarefun wrote:Think of spacetime as a sheet, if you press down on a sheet at one point but hold it taut with equal force then there will be no net effect.

Visually that's probably a bad example since sheets and paper tend to bend.

I'm thinking a taut latex sheet or a bedsheet but to be fair most visual examples fail if you go into any detail.

If the universe is infinite and has an infinite amount of mass, gravity would NOT be infinite, because gravitational waves still only travel at the speed of light. So, we'd only be experiencing gravity from objects within our light cone (13.75 billion light years in radius).

That being said, the most widely accepted (but not entirely agreed upon) theories predict the universe as finite in size (but constantly growing).


As for the aliens question, Fermi's Paradox is a very real issue. It boils down to the following:
If life was even super rare (like 1 in a billion), we'd certainly see a few cases of it in our galaxy as there is billions and billions of planets in our galaxy. And, as the universe is incredibly old and the Earth is relatively young, at least one of those alien life forms would be billions of years ahead of us, developmentally. Even at speeds much slower than the speed of light and pausing for centuries at each new planet, they would have colonized the entire galaxy by the time dinosaurs were first evolving. Since we haven't seen them, it must mean that life is even rarer than that estimate.

So, there's only a few reasonable possibilities (in my ranking of most desirable to least desirable):

1) Our planet exists in the equivalent of a nature preserve. Aliens are well aware of us, but they want to leave us alone so we can develop naturally. (This means it's possible they visit regularly as a form of anthropology.)

2) Life is so incredibly rare that we're the only life in the Milky Way. (This means there's still probably life somewhere else in the Universe, but we'll never ever ever meet it.)

3) Alien life is so incredibly foreign in nature that we simply can't recognize it for what it is. They may be here with us and we don't even notice them, or they may be ignoring us because they don't recognize us as life. (Perhaps they live in sulfuric acid pools on Venus and think water is too poisonous for life.)

4) The Galaxy is, in fact, a really bad place to live. The first (or one of the first) species to start colonizing the Galaxy was incredibly hostile. There's now a near-constant state of all out war among the stars. The surviving species have to devote all of their resources to fighting everyone else to stay alive. If this is the case, the first time humanity makes contact with anyone, they'll most likely immediately wipe us out since we may be a threat to them. (And, we won't be able to defend ourselves, since they're a billion years more advanced in technology than us.)

5) Life is actually somewhat common, but there's a great barrier to actually performing manned space exploration. This causes every (or at least so many that the only survivors are as common as scenario 2) species that encounters it to fail to expand beyond their home planet. Best case scenario is that it's nuclear weapons, and once a species develops nukes, it wipes itself out. If so, we've done a pretty amazing job so far and actually stand a chance at being the first ones to survive it. Worst case scenario, there's some science experiment or other technological advance that's so obvious, every species comes up with it. But, it inevitably leads to their own destruction. (Perhaps it's burning natural resources, and every species before us has caused climate change that killed them all, and we've only got a few years left.)



All the above has been stated by me, a trained physicist (with a BS, no post-graduate degree) with a heavy amateur fascination with advanced physics theory. I'm not a professional, but I like to think of myself as pretty close.

Grakmar wrote:If the universe is infinite and has an infinite amount of mass, gravity would NOT be infinite, because gravitational waves still only travel at the speed of light. So, we'd only be experiencing gravity from objects within our light cone (13.75 billion light years in radius).

That being said, the most widely accepted (but not entirely agreed upon) theories predict the universe as finite in size (but constantly growing).

Not proven, we know next to nothing about gravitational waves and they may well move faster than light.