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

[baywax]

For a life form to develope far enough to engage in space travel and travel to distant solar systems, I think it would be safe to assume that would take billions of years. In other words, how soon in the age of the universe could "intelligent" life have emerged?

For a virus, which can withstand the extremities of space, it would take as long as a virsus takes to develop... probably not billions but millions of years.

Intelligent life is not too far behind the development of rudimentary life forms. But you're right in that it would be around 3 billion years. However, if we look at whales as intelligent or primates with the ability to sign and recognize symbols etc... we can knock about 25 million years off the 2-3 billion.

So, we still need to know at what period during the development of the universe there were areas of stability and materials and conditions that would support life's origins.

 

[DaveC426913]

Intelligent life is not too far behind the development of rudimentary life forms. But you're right in that it would be around 3 billion years.

Which means they've could have been around for 10 billion years. Which poses the rather famous question:

So where are they?

 

[baywax]

Which means they've could have been around for 10 billion years. Which poses the rather famous question:

So where are they?

Actually we're trying to determine when, in the history of the universe, there were the proper conditions, materials and intervals for the first signs of life to develop in the universe.

This question will be answered partially if we know when the first supernovae were beginning to take place in the young universe.

Does anyone have the stats on that. I still haven't found any info on when the first supernovae started happening in the universe.

 

[DaveC426913]

Does anyone have the stats on that. I still haven't found any info on when the first supernovae started happening in the universe.

Look up "population III stars".

https://www.physicsforums.com/showthread.php?t=113668" that discusses at least the possibility of a Pop III star at a mere 900My after BB.

 

[BoomBoom]

Which means they've could have been around for 10 billion years. Which poses the rather famous question:

So where are they?

Intelligent life formed only 3.7B years after the BB? I think that is being VERY generous there.

We took nearly 5 billion years to arise and I would assume you could tack on a big chunk of time for the gases from the supernova we came from to condense into a new solar system...perhaps another billion or so?

As far as "where are they?":
Even giving the most optimistic assessments for the Drake equation, the nearest intelligent life could be 1,000+ LYs away. We have only been sending out signals that could be detected for 100 years or so. Chances are that an alien civilization wouldn't even be capable of detecting us for eons.

Then there is the other issue of whether or not interstellar travel is even physically possible in a reasonable span of time. So IMO the chance of aliens visiting Earth has got to be as close to 0% as you can get.

 

[baywax]

Look up "population III stars".

https://www.physicsforums.com/showthread.php?t=113668" that discusses at least the possibility of a Pop III star at a mere 900My after BB.

Thanks Dave.

This probability gives us about 13 billion years to develop life in the universe.

As we know, there are always spurts of development and evolution then catastrophes that can undo millions of years of evolution. Take for example the plight of the dinosaurids. So, with this factor in mind, we need to try to take down our expectations a fair amount to account for this phenomenon.
This is because a stable environment doesn't always stay stable.

 

[DaveC426913]

As far as "where are they?":
Even giving the most optimistic assessments for the Drake equation, the nearest intelligent life could be 1,000+ LYs away. We have only been sending out signals that could be detected for 100 years or so. Chances are that an alien civilization wouldn't even be capable of detecting us for eons.

Then there is the other issue of whether or not interstellar travel is even physically possible in a reasonable span of time. So IMO the chance of aliens visiting Earth has got to be as close to 0% as you can get.

The question though is: why have we not detected any radio or other leakage from them? They could be anywhere in the galaxy and, as long as they beat us to intelligence by a mere 100,000 years, we could detect them - if the signals were strong enough and if they weren't deliberately hiding.

 

[baywax]

The question though is: why have we not detected any radio or other leakage from them? They could be anywhere in the galaxy and, as long as they beat us to intelligence by a mere 100,000 years, we could detect them - if the signals were strong enough and if they weren't deliberately hiding.

Whether we've detected them or not may depend on the signals they're using. Could be very different technology like... micro waves or lasers or something that we either wouldn't look for or would miss completely.

 

[DaveC426913]

Whether we've detected them or not may depend on the signals they're using. Could be very different technology like... micro waves or lasers or something that we either wouldn't look for or would miss completely.

I suppose I forget just how darned big the sky is, and how big a light year is. It's not like they're going to have Christmas lights strung between the constellations.

 

[baywax]

I suppose I forget just how darned big the sky is, and how big a light year is. It's not like they're going to have Christmas lights strung between the constellations.

What are the possibilities of using laser to transmit info... and power even...?

 

[BoomBoom]

The question though is: why have we not detected any radio or other leakage from them? They could be anywhere in the galaxy and, as long as they beat us to intelligence by a mere 100,000 years, we could detect them - if the signals were strong enough and if they weren't deliberately hiding.

Good point. Although a mere billion years or so doesn't sound like much as far as the age of the universe is concerned, it is a VERY long time for a civilization to develope.

Even though the distances would probably be much to vast to send any type of signals back and forth (much less travel them), I would love to check out what they had on TV some 1000 years ago! :)

 

[Chronos]

The fact remains, there is no incontrovertable evidence 'aliens' have visited earth.

 

[CEL]

What are the possibilities of using laser to transmit info... and power even...?

The main reason laser is efficient in transmitting information is that the bean is focused in a narrow solid angle, instead of omni directionally.
If an alien civilization was deliberately trying to communicate with us, they could use a laser bean focused at our solar system, but this presuppose they know we are here and are interested in talking to us.
An omni directional transmission would spread its energy and soon become less powerful than the background noise.
Of course, if you use special codification, you can transmit and be detected with negative signal to noise (SN) ratios, but this assumes that the receiver knows the transmitted code.

 

[DaveC426913]

The main reason laser is efficient in transmitting information is that the bean is focused in a narrow solid angle, instead of omni directionally.
If an alien civilization was deliberately trying to communicate with us, they could use a laser bean focused at our solar system, but this presuppose they know we are here and are interested in talking to us.
An omni directional transmission would spread its energy and soon become less powerful than the background noise.
Of course, if you use special codification, you can transmit and be detected with negative signal to noise (SN) ratios, but this assumes that the receiver knows the transmitted code.

Not to contradict CEL, he may be an expert Legumications Specialist for all I know, but I have never found beans to be efficient over interstellar distances.



(Once is a typo, but twice is mock-worthy )

 

[CEL]

Not to contradict CEL, he may be an expert Legumications Specialist for all I know, but I have never found beans to be efficient over interstellar distances.



(Once is a typo, but twice is mock-worthy )

I stand corrected. But it is not polite to mock a foreigner for not spelling correctly your language.
Since I cannot edit my post, I ask the moderator to do this for me. I obviously meant beams not beans. Thanks.

 

[DaveC426913]

I stand corrected. But it is not polite to mock a foreigner for not spelling correctly your language.
Since I cannot edit my post, I ask the moderator to do this for me. I obviously meant beams not beans. Thanks.

Actually, your grammar and spelling are so good I had no idea English wasn't your first language. Otherwise I wouldn't have teased you. No hard feelings.

 

[CEL]

Actually, your grammar and spelling are so good I had no idea English wasn't your first language. Otherwise I wouldn't have teased you. No hard feelings.

Apologies accepted. I trust the spell checker to correct my writings, but since bean is an existing English word, of course the mistake was not detected.
By the way, I was born and live in Brazil.

 

[baywax]

The fact remains, there is no incontrovertable evidence 'aliens' have visited earth.

None have been identified. There are, however, two suspicious bits of evidence that aliens have visited here... on earth... Zapper Z's orchids and the humanoids with pointy heads in Vatican City.

 

[CEL]

None have been identified. There are, however, two suspicious bits of evidence that aliens have visited here... on earth... Zapper Z's orchids and the humanoids with pointy heads in Vatican City.

Could you please provide links for these evidences?

 

[baywax]

Could you please provide links for these evidences?

You can find Zapper's orchids in the "How Does Your Garden Grow?" thread.

Here's one pc of photo evidence of the pointy headed aliens... not sure but this one looks like Yoda...

http://www.spurgeon.org/images/pyromaniac/TeamPyro/b16.jpg

 

[CEL]

You can find Zapper's orchids in the "How Does Your Garden Grow?" thread.

Here's one pc of photo evidence of the pointy headed aliens... not sure but this one looks like Yoda...

http://www.spurgeon.org/images/pyromaniac/TeamPyro/b16.jpg

Good evidences.

 

[baywax]

Good evidences.

Yes but of what I'm not sure. Devil worship?

 

[baywax]

I see no reason to disbelieve that life exists elsewhere in the universe. The development of life is a relatively simple process that appears to require some mud, prions and nucleotides in a hot and turbulent environment. I don't think there is a shortage of this combination in the universe.

Whether extraterrestrial life has visited Earth or not is hard to prove beyond a doubt. If we are the product of extraterrestrial viral seeding or the intervention of some intergalactic travelers remains to be proven. Proving it will be difficult since we have no way of comparing life on Earth with life in another galaxy... as of yet.

Even if we find microbes on Mars, they may appear the same as terrestrial microbes because all microbes look the same. DNA matching may or may not help to distinguish between Mars microbes and Earth microbes. However, if Earth seeded Mars or Mars seeded Earth with microbes, in what way could this be demonstrated?

 

[DaveC426913]

Even if we find microbes on Mars, they may appear the same as terrestrial microbes because all microbes look the same. DNA matching may or may not help to distinguish between Mars microbes and Earth microbes. However, if Earth seeded Mars or Mars seeded Earth with microbes, in what way could this be demonstrated?

Gene mapping can tell us how divergent the two strains are. Finding strains on Mars that indicate they diverged from Earth life a billion years earlier than Earth had cooled would be a good indicator that Mars seeded Earth.

 

[baywax]

Gene mapping can tell us how divergent the two strains are. Finding strains on Mars that indicate they diverged from Earth life a billion years earlier than Earth had cooled would be a good indicator that Mars seeded Earth.

How do you date gene divergence?

 

[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.