Is there life in the universe, and if so has it visited Earth?

[DaveC426913]

How do you date gene divergence?

Um. You got me there.

But I know that we can tell how long ago humans and chimps diverged (recent) versus humans and orangutans (less recent) or fungi and vertebrates diverged (a zillion years ago) based directly on the commonality of their genes.

 

[baywax]

Um. You got me there.

But I know that we can tell how long ago humans and chimps diverged (recent) versus humans and orangutans (less recent) or fungi and vertebrates diverged (a zillion years ago) based directly on the commonality of their genes.

Right. We are also finding new species and new gene pools today that we have never seen before... right here in the oceans of earth. When we compare these new genes to genes we theoretically find on Mars... and let's say there's a match... we still don't know if its the Martian egg or the Terrestrial chicken that came first since we don't know the age of the new genes. If there are only an estimated 4 billion new genes on Earth and 600 billion on Mars... this would indicate the population began there on the red planet.

But I still see what you're saying where commonality will play a part in identifying which came first.

But that's the easier scenario... comparing life on Earth to life from mars... because of the relative proximity. It is the "harder thing" when you try to match some dna on Earth to a galaxy like Andromeda.

By the way... Happy Independence Day!

 

[BoomBoom]

But that's the easier scenario... comparing life on Earth to life from mars... because of the relative proximity.

That would be working on the assumption that they would be related. Chances are if there is life on Mars, it would not share any genes with Earth life...any more than it would with life in Andromeda for that matter. If it did come up with any sort of match to earthly genes, that would be THE most compelling evidence for planetary life-transfer I think.

That said, I kind of doubt there is any life on Mars at all...just a hunch.

IMHO, I believe all the millions of "new" genes they are finding in the oceans that you mentioned that don't match to anything else may be new forms of life formed here on Earth.

http://www.jcvi.org/cms/research/projects/gos/overview/"

 

[baywax]

That would be working on the assumption that they would be related. Chances are if there is life on Mars, it would not share any genes with Earth life...any more than it would with life in Andromeda for that matter. If it did come up with any sort of match to earthly genes, that would be THE most compelling evidence for planetary life-transfer I think.

It would be very cool.

That said, I kind of doubt there is any life on Mars at all...just a hunch.

There's already some evidence that life "was" on Mars in this meteor...

http://nssdc.gsfc.nasa.gov/planetary/marslife.html

IMHO, I believe all the millions of "new" genes they are finding in the oceans that you mentioned that don't match to anything else may be new forms of life formed here on Earth.

I was speaking hypothetically, using the "new genes" as an example for a hypothetical comparative study.(comparing 4 billion genes found on Earth with an hypothetical 600 billion genes hypothetically found on mars.)

 

[BoomBoom]

There's already some evidence that life "was" on Mars in this meteor...

http://nssdc.gsfc.nasa.gov/planetary/marslife.html

It was my understanding that assertion had been debunked...or at least a lot of doubt anyways. Though it is possible it may have had some of the "building blocks" of life:

http://www.sciam.com/article.cfm?id=martian-meteorite-life-buliding-blocks"

I was speaking hypothetically, using the "new genes" as an example for a hypothetical comparative study.(comparing 4 billion genes found on Earth with an hypothetical 600 billion genes hypothetically found on mars.)

Not to be a pessimist, but 600 BILLION genes on Mars??! Surely you jest! :P


The reason I doubt it exists is based on what we know of the resiliency of life on earth. If it ever existed there, it should be there still in abundance...this does not seem to be the case. Seems to me there would be a better chance of life being on Venus than on Mars.

 

[baywax]

It was my understanding that assertion had been debunked...or at least a lot of doubt anyways. Though it is possible it may have had some of the "building blocks" of life:

http://www.sciam.com/article.cfm?id=martian-meteorite-life-buliding-blocks"





Not to be a pessimist, but 600 BILLION genes on Mars??! Surely you jest! :P


The reason I doubt it exists is based on what we know of the resiliency of life on earth. If it ever existed there, it should be there still in abundance...this does not seem to be the case. Seems to me there would be a better chance of life being on Venus than on Mars.

First of all its baywax, not Shirley! Second of all, life may be extinct or receding in abundance on Mars because a

Texas-Size Asteroid Slammed Early Mars, Studies Say

http://news.nationalgeographic.com/news/2008/06/080625-mars-impact.html

from the June 25/2008 edition.

Its always been obvious in the telescope that something very large (1000 to 1800 miles in diameter) hit Mars and popped its centre out the other side slightly while loosening most of the northern hemisphere's crust and sending it into orbit. Life likes living where there are still oceans and an atmosphere and both of these necessities left Mars the day this incident happened.

About the 600 billion genes, exaggeration is the stuff of hypothetical arrangements.

 

[baywax]

The first half of the question is answered more and more every time we discover a group of super Earth's in a distant solar system. The more we see planets similar to our own, the more we are going to be looking at the actuality of life taking place on planets other than earth.

 

[Ivan Seeking]

To clear up a few common misconceptions: David Morrison, interim director of NASA's Lunar Science Institute, has never seen a Martian. He has no idea what's in Area 51, the infamous place in Nevada where some people claim the government has captured and experimented on aliens, but he suspects it is merely a testing ground for aircraft. He has never seen a UFO, but he promises that NASA would tell us if a real one were spotted.

These are facts that Morrison explains on a daily basis to the readers of his column on the NASA website, "Ask an Astrobiologist." Formerly the director of astrobiology and space research at NASA's Ames Research Center in California, Morrison envisioned the column as a place for inquiring minds to ask about recent research—but instead has found himself having to disprove what seems like every Photoshopped-alien hoax that makes its way through cyberspace. He leaves readers' queries unedited so as to capture the nuances in questions such as: "I read some one elses question about rosewell, what is NASA hiding? the government is covering up something,i think we the american people should know. my question what are the NASA people dong in space so much? Mars and the moon could not be so interesting."

His reply? "Mars, the Moon, and the search for evidence of life beyond the Earth are indeed very interesting...They are far more interesting subjects than the fiction you refer to."
. . . .

http://www.usnews.com/articles/scie...earch-for-aliens-a-lot-of-dumb-questions.html

 

[engineroom]

Given the vastness of space I cannot rule out the existence of life on another planet. It is possible that life does exist and I don't think one has to believe in Creation or Evolution to accept the possibility, my argument is:

1) Creation: Just as God created Earth, Adam & Eve etc He would be free to create Paul & Jess and another planet somewhere else.

2) Evolution: If one believes in Evolution then one must believe in the basic scientific principle that anything is possible until proven not and no one has categorically proven life does not exist elsewhere in the Universe.

Whether alien life has visited Earth sometime in the eons of this planets existence is another matter and to that I have no answer other than I think it is possible but as yet unproven.

 

[CEL]

Given the vastness of space I cannot rule out the existence of life on another planet. It is possible that life does exist and I don't think one has to believe in Creation or Evolution to accept the possibility, my argument is:

1) Creation: Just as God created Earth, Adam & Eve etc He would be free to create Paul & Jess and another planet somewhere else.

2) Evolution: If one believes in Evolution then one must believe in the basic scientific principle that anything is possible until proven not and no one has categorically proven life does not exist elsewhere in the Universe.

Whether alien life has visited Earth sometime in the eons of this planets existence is another matter and to that I have no answer other than I think it is possible but as yet unproven.

Your reasoning is sound, but there is a confusion in it, that is common in creationists arguments, but not in this forum.
Evolution is a scientific theory that deals with how life has developed once it existed. The theory of how life arose from nonliving matter is called abiogenesis.
Evolution is solid, no matter if life began by abiogenesis, by divine intervention, or by seeding by aliens.

 

[DaveC426913]

the basic scientific principle that anything is possible until proven not

Sorry but this is not a scientific principle.


In fact, the most pertintent scientific principle might be Occam's razor: which model fits the facts with the least exceptions. Since there are zero facts indicating ET life, the implication would be that it's not out there until more compelling evidence shows otherwise.


Also, evolution has absolutely nothing to say about the creation of life on another planet. Evolution only acts on existing life. Evolution and creation are apples and oranges.

 

[D H]

Given the vastness of space I cannot rule out the existence of life on another planet.

We aren't talking about life here. We're talking about intelligent life. I would argue that even if primitive life is somewhat abundant, complex life will be rare and intelligent life, extremely rare. If the closest extant intelligent life is in some nearby galaxy or even more remote than that it doesn't really matter if that life exists. We are essentially alone.

If one believes in Evolution then one must believe in the basic scientific principle that anything is possible until proven not and no one has categorically proven life does not exist elsewhere in the Universe.

The first step is a non sequitur, the second clause is a falsehood, and the third clause is a red herring.

 

[baywax]

Yes, I think its a case of "if you say its out there you have to prove what you say" and not "I think its out there now prove me wrong". This is because when you make a statement as monumental as " there is life on 51 Pegasi" you don't just leave it up to someone else to prove it or to prove you wrong... you prove it for yourself and others.

So, get to work!

 

[D H]

Yes, I think its a case of "if you say its out there you have to prove what you say" and not "I think its out there now prove me wrong".

The first statement is a basic scientific principle. The second statement, which is essentially the same as engineroom's "the basic scientific principle that anything is possible until proven not" is the basic principle upon which crackpots operate.

Science underlying operating principles are similar to those of law. In both law and in science the burden of proof lies with the claimant. In both law and in science, placing the burden of proof on the claimant keeps claimants honest and helps reduce the number of frivolous claims.

 

[towerdp]

We aren't talking about life here. We're talking about intelligent life. I would argue that even if primitive life is somewhat abundant, complex life will be rare and intelligent life, extremely rare. If the closest extant intelligent life is in some nearby galaxy or even more remote than that it doesn't really matter if that life exists. We are essentially alone.


The first step is a non sequitur, the second clause is a falsehood, and the third clause is a red herring.

I would disagree with the fact that it would be rare to find "intelligent life" it struck twice on our planet. Us as humans have the ability to adapt and make somewhat sense of what's going on around us, and dolpins our other intelligent life form on Earth doesn't have the structure we do, but there brains are indeed intelligent. Like us they can be asked to create a new trick/movement that they have not been trained to do.

 

[Ivan Seeking]

2) Evolution: If one believes in Evolution then one must believe in the basic scientific principle that anything is possible until proven not

As stated already, you are way out of bounds with that one.

 

[D H]

I would disagree with the fact that it would be rare to find "intelligent life" it struck twice on our planet.

Dolphins, chimpanzees, and crows are all very smart, but do they qualify as "intelligent life"? It depends on your definition of "intelligent life". Do dolphin, chimpanzee, or crow have anything approaching the ability to receive signals from or send signals to other stars? Are there dolphin, chimpanzee, or crow cities? towns?? hamlets? Humans have been "intelligent life" for 5,000 years or so if intelligence is couched in terms of the demonstrated ability to form a civilization, and for less than 100 years if intelligence is couched in terms of the ability to receive signals from or send signals to other stars.

Dolphins and crows in fact exemplify the rarity of intelligent life. While they are very intelligent animals, their evolution has pushed them down a path that precludes the ability to advance beyond that stage.

The pre-conditions for life have to be right. Most star systems are inimical to life: they are too close to the galactic core, binary stars, or have hot jupiters. Of those that remain, an earth-like planet must form that escapes the run-away global warming of Venus thanks to a freak collision with a Mars-sized object and escapes the run-away cooling of Mars thanks to being a bit larger than Mars. Of those that remain, primitive life has to form and live through disasters such as the Late Bombardment. Of those that survive this, complex monocellular life has to form and escape its own pollution (Snowball Earth). Of those that survive this, multicellular life has to arise. Then pre-intelligence (dolphins, crows, hominids) has to arise. Then intelligence has to arise -- and not kill itself off. Intelligent life is, IMHO, exceptionally rare.

 

[vivesdn]

National Geographic november issue features some photos of The Cave of Crystals. On it, sveral crystals of selenite have grown up to 10m long and upt to two meters thick.
Conditions required: a cave in limestone, below water level, kept warm (112ºF) by an underlying magma chamber, undisturbed for hundreds of thousands of years.

Undisturbed: no water movement, no pH changes, no temperature changes, ..
And of course, water saturated on calcium sulphate. For 600000 years.

What would have been the probability of bus size crystals forming naturally?

Life on universe? That's easy? Intelligent? A matter of time.
Visited earth? This one is slightly more difficult.
Proofs? Not available (yet?).

 

[CEL]

...
What would have been the probability of bus size crystals forming naturally?
...

The probability of an event that has occurred is 1.

 

[Hanfonius]

I keep finding the words, 'The basic scientific principle that everything is possible until proven not.', and I cannot help but consider it accurate.

While it is misused in the sense of, 'I believe in UFO's - you prove me wrong.', how can it conceivably be wrong when used in the sense of, 'therefore, I shall attempt to prove it right, then present it to my peers for validation.'?

The von Daniken approach illustrates the former, and perhaps Gallileo the second.

The scientific mind must necessarily examine the unorthodox views of the day. Isn't that what most of us are doing right now in this section of the site?

 

[D H]

I keep finding the words, 'The basic scientific principle that everything is possible until proven not.', and I cannot help but consider it accurate.

Pearl S. Buck was not a scientist. You can find some very pithy statements about the impossible by politicians, philanthropists, writers, and scientists. You can even find mathematicians who recommend thinking of six impossible things before breakfast. You will not find something stating that "everything is possible until proven not" is a basic scientific principle.

 

[Hanfonius]

Pearl S. Buck was not a scientist. You can find some very pithy statements about the impossible by politicians, philanthropists, writers, and scientists. You can even find mathematicians who recommend thinking of six impossible things before breakfast. You will not find something stating that "everything is possible until proven not" is a basic scientific principle.

I had never heard of Pearl Buck - I guess this shows a local of formal education!

OK, so the offending words here are 'basic scientific principle'. If semantics can be bent slightly, and another phrase inserted to substitute three words, do you consider my assertions to be valid? Perhaps 'The enquiring mind will consider everything possible until proven not.'?

 

[vivesdn]

what would have been, not what is.
If 10 years ago (the cave was discovered on 2000) one crazy scientist would have said that 10m crystals were possible, I'm sure you would not assumed a probability of 1.

By the way, if the probability of an event is not zero, you cannot say that it was one just because it happenned.
I mean that the probability to get one specific side of a coin is 1/2. And when you got one of the possibilities, that event had still 1/2 of having occurred.

 

[CEL]

what would have been, not what is.
If 10 years ago (the cave was discovered on 2000) one crazy scientist would have said that 10m crystals were possible, I'm sure you would not assumed a probability of 1.

By the way, if the probability of an event is not zero, you cannot say that it was one just because it happenned.
I mean that the probability to get one specific side of a coin is 1/2. And when you got one of the possibilities, that event had still 1/2 of having occurred.

Wrong! The a priori probability of getting a tail when tossing a coin is 1/2. If you toss a coin and get a tail,the a posteriori probability of getting a tail in that trial is 1. It does not change the a priori probability for the next toss, that is still 1/2.
The probability of finding 10 m crystals in any cave on Earth is 1, since those crystals have been found. The probability of finding similar crystals in another place is nonzero. I cannot calculate what it is, since I am not a mineralogist.
The probability of life existing in the Universe is 1, since we know that life exists on Earth. The probability of life existing elsewhere is nonzero. Even not being an exobiologist, I would say that it is somewhat high.

 

[gareth]

Wrong! The a priori probability of getting a tail when tossing a coin is 1/2. If you toss a coin and get a tail,the a posteriori probability of getting a tail in that trial is 1. It does not change the a priori probability for the next toss, that is still 1/2.
The probability of finding 10 m crystals in any cave on Earth is 1, since those crystals have been found. The probability of finding similar crystals in another place is nonzero. I cannot calculate what it is, since I am not a mineralogist.
The probability of life existing in the Universe is 1, since we know that life exists on Earth. The probability of life existing elsewhere is nonzero. Even not being an exobiologist, I would say that it is somewhat high.

According to the findings of quantum physics, is there not a non-zero probability that everything will occur? It's just a matter of time, whether we're still around to witness the event or not is a different matter.

This has got me to thinking though, someone mentioned something a few posts back about imagining something that is not possible.

I find this hard. Our thinking and perception of things is built from our daily experiments (life), so this is all we can imagine. We live in a 4D world, how can we imagine something that is not possible if we have no experience of it. It's like trying to imagine living in a 10dimensional universe, you simply can't.

So how can we imagine something that is not possible? The thing must be built from our prior building blocks of knowledge (time, space, matter) anything we imagine will just be a certain arrangement of these elements which has a nonzero probability of happening.

So not only is everything possible, but things are possible that we can't even possibly comprehend.

 

[DaveC426913]

Dolphins, chimpanzees, and crows are all very smart, but do they qualify as "intelligent life"?

Dolphins and chimps are mammals, just like humans. I would categorize intelligence as a trait of the mammalian order. I would count that as a single instance of the rise of intelligence.

Birds, OTOH, are a second instance.

 

[DaveC426913]

I keep finding the words, 'The basic scientific principle that everything is possible until proven not.', and I cannot help but consider it accurate.

It is certainly commonplace these days, what with 'Power of Attraction' and other such woo-wooism rampant these days.

But it has nothing to do with science.

 

[Hanfonius]

I find this hard. Our thinking and perception of things is built from our daily experiments (life), so this is all we can imagine. We live in a 4D world, how can we imagine something that is not possible if we have no experience of it. It's like trying to imagine living in a 10dimensional universe, you simply can't.

So how can we imagine something that is not possible? The thing must be built from our prior building blocks of knowledge (time, space, matter) anything we imagine will just be a certain arrangement of these elements which has a nonzero probability of happening.

So not only is everything possible, but things are possible that we can't even possibly comprehend.

This is so thought provoking. Our building blocks of knowledge are growing rapidly each generation, and this must serve to increase our scope of imagination. This is where the science fiction writers dwell - but much of what they imagined has become reality. Perhaps just around the corner, we will discover anti-gravity, matter transfer, warp drive, free and clean energy, even perpetual motion.

Many of the young people entering into the sciences today will be fortunate enough to work within fields way beyond what we think of as impossible dreams.

 

[Ivan Seeking]

We have to be careful when we consider possibilities, as opposed to known violations of the conservation laws, causality, etc. For example, there is no reason to believe that a perpetual motion machine would ever work because we have well tested theories that tell us why they don't. But, might it be possible that some unknown effect or phenomenon could appear to be perpetual motion? Could something fool us for a time before we began to understand it? I don't see how this can be ruled out. But, we would still expect that energy is conserved over the entire system.

Unlike a perpetual motion machine, the existence of which would violate the known laws of physics, the WARP drive foks are trying to exploit known physics to discover loopholes, if you will, that might allow us to work around limits that were only assumed to be absolute. And while other complexities may arise that makes the idea WARP drive implausible or impossible, the idea itself is not one that assumes a magical solution from the netherworld, as does the notion of a perpetual motion machine.

 

[gareth]

We have to be careful when we consider possibilities, as opposed to known violations of the conservation laws, causality, etc. For example, there is no reason to believe that a perpetual motion machine would ever work because we have well tested theories that tell us why they don't. But, might it be possible that some unknown effect or phenomenon could appear to be perpetual motion? Could something fool us for a time before we began to understand it? I don't see how this can be ruled out. But, we would still expect that energy is conserved over the entire system.

Unlike a perpetual motion machine, the existence of which would violate the known laws of physics, the WARP drive foks are trying to exploit known physics to discover loopholes, if you will, that might allow us to work around limits that were only assumed to be absolute. And while other complexities may arise that makes the idea WARP drive implausible or impossible, the idea itself is not one that assumes a magical solution from the netherworld, as does the notion of a perpetual motion machine.

Yes, the conservation laws etc. are our (current) reality. Can we imagine a perpetual motion machine? (the one Lisa makes on the Simpsons usually springs to mind)

What I'm really asking is can we imagine breaking one of our conservation laws? A machine that spins faster and faster? Easy to imagine, but the science behind it is currently unimaginable. That's why we still fill our cars with dead fish.