Extraterrestrial life

[Alg]

What are these "chances" that I keep reading about? >.> I had no idea that this was all random <.<

 

This isn't a debate, at least I think. As far as I know, we're all just throwing around random speculations and gazing outside our windows in wonder. :)

If it wasn't for urban light pollution that would be a lot more fun. There's a lot of cool stuff in space, whether or not life is among those isn't important. Or at least until not we find it. Even more considering we're just orbiting a smallish star near the edge of the galaxy and most of what we see in space is the past. Who knows what could be there now.

[Zilla]

Slightly Off-Topic, but I thought of something; Perhaps are Universe that we know is actually just a simple area of space of a much larger Universe. (Lets call it the Omniverse.) Our area of space could appear to be what we know so far, but perhaps the gaps to another "Universe" is so large, even light decays while traveling through it, essentially making it impossible to see other spaces in the Omniverse.

 

If that case is true, that could mean there is actually trillions of galaxies, not just billions, and lets just say what I said earlier that on average each galaxy has 200 billion stars, which in turn have 5 planets each and so on.

[SeanyTheSailor]

The Universe is infinite in both time and space, in my opinion.

 

Easy to say, hard to think about.

 

It's not hard to think about at all, because it's wrong, and the proof is staring right back at us every living moment of every day (and on page 1 of this topic).

 

This isn't a debate, at least I think. As far as I know, we're all just throwing around random speculations and gazing outside our windows in wonder.

actually, I was hoping that the otherwise science proficient community would consider scienfitic astrophysics points that they didn't neccessarily know before reading the topic, and realize that some things are very certain, and not speculations at all. Some of the things thrown out are proven to be wrong, so this topic may broaden horizons for many.

I'll make a deal with you I will believe its wrong when you prove you were there at this beginning and thus that there ever was one. It's easy to say there had to be a beginning and dismiss the other side as being wrong. Just because it surpasses our current understanding doesnt mean its wrong.

[armourdilo]

Aliens definitely exist or have existed. In an infinite amount of space, with a very very large (infinite?) amount of matter and with about a window of the last 2 billion years where the conditions in the universe have been just right for life, and for the fact that we're here, it's less likely that sentient life doesn't exist somewhere else. Of course, I doubt we'll ever meet. They're probably millions if not billions of light years away from us. They'll never reach us in their time, neither us them. As for observing aliens with telescopes, well, it won't be the same as seeing them, the light we see will be millions of years old, their species may have gone extinct by then. I hope I'm wrong though.

[Aliath]

Maybe someday two sentient species from two different planets will meet.

 

I hope we encounter wookies. Seriously. That would be awesome.

[Youmu]

Although I don't believe in extraterrestrial life, there has to be something out there.

 

It kinda feels lonely knowing that we're the only ones out there... hopefully one day some others out there will reach us.

[Zilla]

Aliens definitely exist or have existed. In an infinite amount of space, with a very very large (infinite?) amount of matter and with about a window of the last 2 billion years where the conditions in the universe have been just right for life, and for the fact that we're here, it's less likely that sentient life doesn't exist somewhere else. Of course, I doubt we'll ever meet. They're probably millions if not billions of light years away from us. They'll never reach us in their time, neither us them. As for observing aliens with telescopes, well, it won't be the same as seeing them, the light we see will be millions of years old, their species may have gone extinct by then. I hope I'm wrong though.

 

Perhaps the last two billion years for familiar Chordates on this planet perhaps, during the last 10 billion years after a majority of the Universe has cooled slightly, life could have formed.

__________

 

I would also like to note; consider the Homo genus has been around for 2.4 million years, and recently Humankind seems to be going through an apparent technology acceleration stage, the chances for advanced life that is much more advanced than us has a fairly good chance to exist considering the size of the Universe, even if one out of one-billion planets have life more advanced then us, it would still leave around 1,500 space-faring species, In our galaxy alone.

[meol]

I refuse to believe we are the best the Universe has came up with in 14 000 000 000 years. It's hard pressing enough to think there isn't at least some basic life somewhere in the Milky Way.

 

Little green men in Roswell? That's ridiculous.

[Nadril]

I have a feeling we aren't the only ones in this universe.

 

I do wonder though how life would develop on another planet. I mean it's no guarantee that they would look anything like us or even be based off of carbon (or whatever) like we are. Hell, for all we know aliens have been here before but we simply don't have the means to see them, haha.

[Will H]

The huge size of the Universe makes it pretty much certain that what caused life here will cause life elsewhere, but the huge size of the Universe makes it pretty much certain that we haven't been in contact with them before and won't for a very long time. I... that is we need to start colonising other planets before that happens.

[Asmodeous4]

The Universe is massive, how can there not be more life out there? The chances are that there isn't any more in our Solar System, our whole galaxy even. But that is one in how many thousands of billions? With that many galaxies, the correct conditions have to have been reproduced somewhere. Also, it would kinda feel lonely if we were the only ones, but I doubt we'll ever "make contact" in our species time.

[DerekZoolandah]

I'd just like to point something out to everyone - the Big Bang theory states that the universe is expanding, but not that new matter is being created. Theoretically, all matter that exists has always been and will always be. In however many trillions of trillions of years, every object will be pulled to such a degree that no carbon-based life will be sustained.

 

Just thought I'd input :)

[dixon3133]

Has to be somewhere..im more interested in how intelligent they are compared to us.

[Lenin64]

I'd just like to point something out to everyone - the Big Bang theory states that the universe is expanding, but not that new matter is being created. Theoretically, all matter that exists has always been and will always be. In however many trillions of trillions of years, every object will be pulled to such a degree that no carbon-based life will be sustained.

 

Just thought I'd input :)

No, because universe expansion just means all the matter is moving outward. Ever been to space? Not really much there. In fact, most of it's vaccuum, completely empty save for those little balls of matter than make up planets, stars, etc. So it's really more like blowing on a group of marbles than stretching silly putty; the marbles will expand outward, but they themselves don't expand, just the area they encompass.

[nerdboyxxx]

I find it hard to believe that there isn't some form of life elsewhere in the universe. In fact, I bet there is sentient life as well.

 

The Universe is infinite. There could be hundreds of billions of other planets just like ours, with humans. I'm not saying they're anywhere close, or that we'll ever even comprehend how far they are from us.

 

The Universe is so freaking infinite that there could be hundreds of billions of planets with giant walking, talking bears. I'm not being sarcastic. Seriously, think about it.

 

Umm, I said that there was life. Reread my post. :???:

 

I'm agreeing with you, and expanding on your point. ;)

If you think about it if it is that infinite someone on an entirely different planet looking exactly the same as you and in the exact same conditions could be doing the exact same thing right now..........

 

Than the fabric of time itself would rip apart and the world would be in utter chaos...

 

Do you people watch Dr. Who? :P.

 

Anyway, yeah the odds that there is life out there is massive, but the number of planets that exist out there must be in the trillions. So yeah, there has to be something out there.

 

Maybe there is a planet filled with pokemon...

[Alg]

Maybe there is a planet filled with pokemon...

This makes space travel and exploration worth ANY investment.

[DerekZoolandah]

I'd just like to point something out to everyone - the Big Bang theory states that the universe is expanding, but not that new matter is being created. Theoretically, all matter that exists has always been and will always be. In however many trillions of trillions of years, every object will be pulled to such a degree that no carbon-based life will be sustained.

 

Just thought I'd input :)

No, because universe expansion just means all the matter is moving outward. Ever been to space? Not really much there. In fact, most of it's vaccuum, completely empty save for those little balls of matter than make up planets, stars, etc. So it's really more like blowing on a group of marbles than stretching silly putty; the marbles will expand outward, but they themselves don't expand, just the area they encompass.

 

The universe isn't completely empty. There isn't a perfect vacuum (again, theoretically) anywhere in the universe.

 

The second point is what I'm saying - the mass that they have isn't getting bigger, just the area it holds.

[assassin_696]

Hehe, a common misconception. I will prove to you that the universe is not infinite by use of Olber's paradox, and Enstein's solution: The sky is dark at night. The universe is not static. The universe has a limited age.

 

explanation: if the universe WAS infinite, the sky would be infinitely light as there are infinitely many stars in any given direction. With this infinity, supernovae would cover the nightsky completely at all times. The sky is dark, so the universe must be finite.

 

You could still have an infinite universe if the boundaries of the universe (whatever that means) were expanding faster than the speed of light so light from those stars could never reach us. Same principle as the horizon problem

 

The universe is not static. An infinite universe could not expand. Due to the redshift observed when examining distant objects in the night sky, we know the universe expands, the universe is therefore not infinite. This relation is quantified by Hubble's law.

 

I see no physical reason why an infinite universe couldn't expand, so I don't agree with the bold bit. Either way the infinity or not of the universe is an open question, no one knows if it's infinite or not, although people have their hunches, it's all just maths.

 

But about aliens, I agree with Arthur C. Clarke:

 

Sometimes I think we're alone. Sometimes I think we're not. In either case, the prospect is staggering.

- Arthur C.Clarke,

[Skully]

I think anybody who doesn't believe it should go and watch 'The Fourth Kind'.

[tortilliachp]

Hehe, a common misconception. I will prove to you that the universe is not infinite by use of Olber's paradox, and Enstein's solution: The sky is dark at night. The universe is not static. The universe has a limited age.

 

explanation: if the universe WAS infinite, the sky would be infinitely light as there are infinitely many stars in any given direction. With this infinity, supernovae would cover the nightsky completely at all times. The sky is dark, so the universe must be finite.

 

You could still have an infinite universe if the boundaries of the universe (whatever that means) were expanding faster than the speed of light so light from those stars could never reach us. Same principle as the horizon problem

 

The universe is not static. An infinite universe could not expand. Due to the redshift observed when examining distant objects in the night sky, we know the universe expands, the universe is therefore not infinite. This relation is quantified by Hubble's law.

 

I see no physical reason why an infinite universe couldn't expand, so I don't agree with the bold bit. Either way the infinity or not of the universe is an open question, no one knows if it's infinite or not, although people have their hunches, it's all just maths.

 

But about aliens, I agree with Arthur C. Clarke:

 

Sometimes I think we're alone. Sometimes I think we're not. In either case, the prospect is staggering.

- Arthur C.Clarke,

 

The horizon problem does not apply, as any object beyond our "horizon" would be moving faster than the speed of light. Thus, they can never decelerate to slower than the speed of light, and that mass may never be observed. The universe which we can interact with is limited by the speed of light barrier.

 

There are no "boundries of the universe" that's a misconception. Only the space between particles expands. It's like stretching out an elastic band. however much you strech the elastic band, the band is still finite.

 

1+1 = 2. the universe is not infinite. that is the certainty of the maths involved. There is no fancy maths, it's all linear regression, or even simpler mathematics. It's not a hunch, it's science, just as the theory of gravity is science, and factual evolution occurs (whatever our origin is). You have a hunch. your hunch is wrong. science has proven your hunch wrong, just as the earth is not flat.

 

How much astrophysics have you guys looked into? I provide scientific evidence. You disregard that evidence because you have a different opinion, as you haven't heard of the facts before. How can you continue to hold your predetermined opinion when it's proven to be wrong? It's like i were to claim Australia is not a country, being proven it is, and still not believing it!

 

the concept of an infinite universe is absurd. Olber's paradox was solved, Hubble was right, Newton was wrong, enstein was right, the planck relation is correct. Modern science has proven those thesies; it is not pseudoscience, like climate models or any science that enlightened professionals disagree with. It is as absolute as gravity and the lambda-force of universal expansion.

[assassin_696]

The horizon problem does not apply, as any object beyond our "horizon" would be moving faster than the speed of light. Thus, they can never decelerate to slower than the speed of light, and that mass may never be observed. The universe which we can interact with is limited by the speed of light barrier.

 

There are no "boundries of the universe" that's a misconception. Only the space between particles expands. It's like stretching out an elastic band. however much you strech the elastic band, the band is still finite.

 

1+1 = 2. the universe is not infinite. that is the certainty of the maths involved. There is no fancy maths, it's all linear regression, or even simpler mathematics. It's not a hunch, it's science, just as the theory of gravity is science, and factual evolution occurs (whatever our origin is). You have a hunch. your hunch is wrong. science has proven your hunch wrong, just as the earth is not flat.

 

How much astrophysics have you guys looked into? I provide scientific evidence. You disregard that evidence because you have a different opinion, as you haven't heard of the facts before. How can you continue to hold your predetermined opinion when it's proven to be wrong? It's like i were to claim Australia is not a country, being proven it is, and still not believing it!

 

the concept of an infinite universe is absurd. Olber's paradox was solved, Hubble was right, Newton was wrong, enstein was right, the planck relation is correct. Modern science has proven those thesies; it is not pseudoscience, like climate models or any science that enlightened professionals disagree with. It is as absolute as gravity and the lambda-force of universal expansion.

 

If you're going to sound so confident of your own knowledge at least maybe do a little more research before spouting such dogmatic statements. Of course there's 'fancy' maths, the size of the universe is a problem largely investigated using General Relativity, the maths of which is pretty damn 'fancy'. What scientific evidence have you provided? Hubble's constant (it's actually a parameter because the error boundaries are so large) tells us that the universe is expanding, this has nothing to do with the potential for the universe to be infinite. Don't let your intuition as to what infinity is guide you because intution doesn't work with infinity. And don't try and sound smarter than you are.

 

Here's an interview with Joseph Silk, the head of the astrophysics department at Oxford University. The full interview is here

 

ESA: Is the Universe finite or infinite?

 

Joseph Silk: We don't know. The expanding Universe theory says that the Universe could expand forever [that corresponds to a 'flat' Universe]. And that is probably the model of the Universe that we feel closest to now. But it could also be finite, because it could be that the Universe has a very large volume now, but finite, and that that volume will increase, so only in the infinite future will it actually be infinite.

 

ESA: It sounds like a game of words, is it?

 

Joseph Silk: No. We do not know whether the Universe is finite or not. To give you an example, imagine the geometry of the Universe in two dimensions as a plane. It is flat, and a plane is normally infinite. But you can take a sheet of paper [an 'infinite' sheet of paper] and you can roll it up and make a cylinder, and you can roll the cylinder again and make a torus [like the shape of a doughnut]. The surface of the torus is also spatially flat, but it is finite. So you have two possibilities for a flat Universe: one infinite, like a plane, and one finite, like a torus, which is also flat.

[Jeffwilson99]

I have a feeling we aren't the only ones in this universe.

 

Hell, for all we know aliens have been here before but we simply don't have the means to see them, haha.

 

Well, if you think about it, life could have visited earth, Millions, or billions of years of years ago, and seen no life, or no intelligent life, and moved on etc. Yeah, whatever You want to say, the concept of space and the universe is so amazingly staggering, you can't help but be overwhelmed by it.

[tortilliachp]

 

If you're going to sound so confident of your own knowledge at least maybe do a little more research before spouting such dogmatic statements. Of course there's 'fancy' maths, the size of the universe is a problem largely investigated using General Relativity, the maths of which is pretty damn 'fancy'. What scientific evidence have you provided? Hubble's constant (it's actually a parameter because the error boundaries are so large) tells us that the universe is expanding, this has nothing to do with the potential for the universe to be infinite. Don't let your intuition as to what infinity is guide you because intution doesn't work with infinity. And don't try and sound smarter than you are.

 

Here's an interview with Joseph Silk, the head of the astrophysics department at Oxford University. The full interview is here

 

ESA: Is the Universe finite or infinite?

 

Joseph Silk: We don't know. The expanding Universe theory says that the Universe could expand forever [that corresponds to a 'flat' Universe]. And that is probably the model of the Universe that we feel closest to now. But it could also be finite, because it could be that the Universe has a very large volume now, but finite, and that that volume will increase, so only in the infinite future will it actually be infinite.

 

ESA: It sounds like a game of words, is it?

 

Joseph Silk: No. We do not know whether the Universe is finite or not. To give you an example, imagine the geometry of the Universe in two dimensions as a plane. It is flat, and a plane is normally infinite. But you can take a sheet of paper [an 'infinite' sheet of paper] and you can roll it up and make a cylinder, and you can roll the cylinder again and make a torus [like the shape of a doughnut]. The surface of the torus is also spatially flat, but it is finite. So you have two possibilities for a flat Universe: one infinite, like a plane, and one finite, like a torus, which is also flat.

 

That was an interesting, but outdated interview. the nine years of the hubble space telescope have had a profound effect on astrophysics:

 

The most recent observational determination of the proportionality constant obtained in 2009 by using the Hubble Space Telescope (HST) yielded a value of H0 = 74.2 ± 3.6 (km/s)/Mpc.[4] The results agree closely with an earlier measurement of H0 = 72 ± 8 km/s/Mpc obtained in 2001 also by the HST.[5] In August 2006, a less-precise figure was obtained independently using data from NASA's Chandra X-ray Observatory: H0 = 77 (km/s)/Mpc or about 2.5×10−18 s−1 with an uncertainty of ± 15%.[6] NASA summarizes existing data to indicate a constant of 70.8 ± 1.6 (km/s)/Mpc if space is assumed to be flat, or 70.8 ± 4.0 (km/s)/Mpc otherwise.[7]

 

so the measurements in question are much newer. Further:

The age and ultimate fate of the universe can be determined by measuring the Hubble constant today and extrapolating with the observed value of the deceleration parameter, uniquely characterized by values of density parameters (ΩM and ΩΛ). A "closed universe" with ΩM > 1 and ΩΛ = 0 comes to an end in a Big Crunch and is considerably younger than its Hubble age. An "open universe" with ΩM ≤ 1 and ΩΛ = 0 expands forever and has an age that is closer to its Hubble age. For the accelerating universe with nonzero ΩΛ that we inhabit, the age of the universe is coincidentally very close to the Hubble age

 

and, the sinker:

The value of the Hubble parameter changes over time either increasing or decreasing depending on the sign of the so-called deceleration parameter q which is defined by

 

 

In a universe with a deceleration parameter equal to zero, it follows that H = 1/t, where t is the time since the Big Bang. A non-zero, time-dependent value of q simply requires integration of the Friedmann equations backwards from the present time to the time when the comoving horizon size was zero.

It was long thought that q was positive, indicating that the expansion is slowing down due to gravitational attraction. This would imply an age of the universe less than 1/H (which is about 14 billion years). For instance, a value for q of 1/2 (once favoured by most theorists) would give the age of the universe as 2/(3H). The discovery in 1998 that q is apparently negative means that the universe could actually be older than 1/H. However, estimates of the age of the universe are very close to 1/H.

 

thus, hubble's constant determines the age of the universe, the fate of the universe (big crunch, or eternal expansion) as gravity and the cosmological constant (http://en.wikipedia.org/wiki/Cosmological_constant) exist as opposite forces.

 

Further, the common conception today is that the spatial geometry of the universe is spherical, NOT flat. Any spherical universe is neccessarily finite (big crunch will ultimately ensue), as a spherical universe is neccesssarily a closed manifold:

 

On a sphere, the sum of the angles of a triangle is not equal to 180°. A sphere is not a Euclidean space, but locally the laws of the Euclidean geometry are good approximations. In a small triangle on the face of the earth, the sum of the angles is very nearly 180. The surface of a sphere can be represented by a collection of two dimensional maps. Therefore it is a two dimensional manifold.

 

sorry, i know what i'm talking about.

[assassin_696]

All very interesting but although of course I agree that the evidence shows that the universe is expanding at an accelerating rate, I disagree with your conclusions about the shape of the universe which is the more relevant issue here.

 

Thus the universe was known to be flat to within about 15% accuracy prior to the WMAP results. WMAP has confirmed this result with very high accuracy and precision. We now know that the universe is flat with only a 2% margin of error.

 

http://map.gsfc.nasa.gov/universe/uni_shape.html

http://www.universetoday.com/guide-to-space/the-universe/shape-of-the-universe/

 

Feel free to point me towards any new data that contradicts this.

[tortilliachp]

All very interesting but although of course I agree that the evidence shows that the universe is expanding at an accelerating rate, I disagree with your conclusions about the shape of the universe which is the more relevant issue here.

 

Thus the universe was known to be flat to within about 15% accuracy prior to the WMAP results. WMAP has confirmed this result with very high accuracy and precision. We now know that the universe is flat with only a 2% margin of error.

 

http://map.gsfc.nasa.gov/universe/uni_shape.html

http://www.universetoday.com/guide-to-space/the-universe/shape-of-the-universe/

 

Feel free to point me towards any new data that contradicts this.

 

well, the likelyhood of the universe actually being flat is so minute that i question every scientist who claims to have shown that to any degree of certainty: a single atom being placed differently would result in a non-flat universe. a single atom would ensure either a big rip, or big crunch. being able to count the atoms and the placement of all the atoms in the universe to within a "2% margin of error" is rediculous. yes, it might be so close we're arrive at an inflexion point of the graph that is almost flat for some billion years, but the likelyhood of a truely flat universe are merely a statistic. It makes no sense mathematically. It's like saying you can predict when flipping a coin and it will land on its side to within a 2% margin of error, i assume the probability is even lower. Further. you cannot confirm a flat universe, based on the heisenber uncertainty principle, because any tiny shift and the benefit of an infinite future of time, will result in a non-flat universe.

 

It doesn't make sense.

 

with dark energy and dark matter not being identified, and merely being theories (why do spiral galaxies not fall appart?) WIMPS and MACHOS, and so on.

 

The observations of dark energy and dark matter are indirect. Thus, the margin of error (in identifiying that which is unidentifiable) arguably lies towards the side of "there may be more of it than we know, we can only observe this much of it" Observing a "flat universe" therefore identifies the likelyhood of a sperical universe.

 

Matter or energy beyond light speed cannot be measured below light speed. That is a fundemental concept in the theory of relativity. Thus, this eventual mass and energy would also bring the universe out of a flat model, into a rounded model.

 

The observed universe is aproximately equal to the critical density, the unobserved universe taken into account leads to a logical belief in a round universe. it would be suicide for a scientist to claim they had no clue, after billions of funding have been spent, and unscientific, as the unobserved hasn't been observed yet. the fundemental physical model neccessitates the existence of the higgs particle, and all antiparticles that haven't been found yet. unless that model is completely incorrect, there is much matter and anti-matter still to be found. This all leads to a round universe.

 

Matter in the universe we can ever have contact with (sub-light speed) is finite, and that's what really matters for extraterrestrial life either way :)