Why is the Universe silent?

louis · 2008-04-13 19:54:32

Terraformer -

Actually squid and other similar creatures are very intelligent.

I have long been fascinated by the capacity for evolution to make use of the colour displays on such creatures - which indicate a range of quite complex behaviour. One can easily see how such creatures might with the right evolutionary pressures evolve a language which would be simultaneously communicative and written.

I think such creatures could then go on to develop artificial limbs and artificial islands.

nickname · 2008-04-18 06:12:47

The set of rules needed to have another earthlike place is going to be long indeed.
So many things are needed for earth that another world similar to earth i think will be 1 in a trillion or worse.
A moon, magnetic field, perfect mix of water/gas, perfect distance from host star, stable circular planetary mix, perfect mix of land/water, etc etc.

That number is 1 in a trillion of the long term stable stars so maybe 1 planet very similar to earth in every 5 or 10 galaxies.

A few 100 Earth like places might exist in all the universe, but in a few billion year history needed for life to become intelligent.
Of them how many get hit by 100 km asteroids or have a nearby star go super nova or have the host sun fry the world with a active day or giant solar flare.
Or a minor event like a small 10km asteroid strikes every 100 million years to reset the life clock.
Or nothing happens on the world and dinosaur like creatures rule them till the end of time on that planet, like nearly happened to our world.

It's not a giant stretch of the imagination that we are alone in the universe or at best the next door intelligent neighbor is so far away in some very distant galaxy we will never discover them.

Our closest neighbors will be algae and mould on some punished semi earth world.
We will find lots of those worlds.

I think the large moons in orbit around gas giants at the right location to the star are an overlooked place for intelligent life.
The odds are much better for life on them than an earthlike place having a big moon and other mix of necessities.

idiom · 2008-04-18 19:55:49

Be aware that we have no good abiogenesis theories at the moment.

The oldest fossil we have is a eurkaryote making it look like bacteria devolved from more complex organisms that arrived or were seeded from space.

nickname · 2008-04-19 05:40:35

idiom,

A big problem for interstellar panspermia is having material move from star to star from a world that already has life with a sun that is already lit.

Once a star starts to fuse material it creates a distant bubble that material cant get out of or into.
It's supported by stellar wind pressure from all stars.

All stars that could have a planet with life also do a fantastic job of removing life from the system as they go through the red giant phase.

It's possible to spread life to other star systems from a super nova, but the couple hundred million years before a star goes super nova it sterilizes everything in the solar system in the red giant phase.

The only possible way i can get life to spread from star to star is life starting very fast on planet at a very big star that goes super nova with no red giant phase.
It's still difficult to move that material to an already lit star system, so the panspermia material must arrive to a system before the sun fires up.
Then that material has to be extremely lucky to survive the planetary forming process that is sure to fry any dormant bacteria.

Not real good odds for interstellar panspermia unless it happened very early before the bulk of stars started.

Spaniard · 2008-04-19 12:53:16

Perhaps the channel of comunication is not appropriate.

Some people believe that electromagnetic radiation interfere too much with living beings so, if a new faster method (faster than light particules for example) is developed and it could be easily adapted to small devices, electromagnetic comunications could be deprecated by advanced civilizations.

Terraformer · 2008-04-19 14:30:16

(Complex) Life can't exist on Ocean worlds. The sediment would settle and deprive the Ocean of sustenance. Plus it would be supersaline due to there being no methos of the salt being removed.

noosfractal · 2008-04-19 17:00:21

Recent article on the Fermi paradox ...

...
“The Earth’s biosphere is now in its old age and this has implications for our understanding of the likelihood of complex life and intelligence arising on any given planet,” said [Prof.] Watson.
...

http://www.universetoday.com/2008/04/19 … -universe/

idiom · 2008-04-19 18:38:29

Our only example of life so far is a fairly complex nanotechnology.

Panspermia, especially accidental panspermia is highly unlikely, but currently seems more likely than a-biogenesis.

What we find on Mars or don't find will give us additional data points.

nickname · 2008-04-21 05:55:55

idiom,

I personally belive life here started here or somewhere in our solar system then migrated to Earth after the planetary creation process was nearly done.
Any life that was or is on Mars for sure would give some serious answers on the how life came about.
Finding no trace of any life that existed on Mars would also give us a good answer on how life started.

Migrating life material from star to star just seems such a remote possibility to me.
Way to many 1 in a billion X 1 in a billion events for it to be likely.
The odds are a little different if it happened early on though.

The life creation process might be quite common in the universe, Earth like places might not even be needed for intelligent life.
We might be just very regional in our thinking and many places in the universe very different from Earth might host intelligent life.

Even on Earth life grows in some pretty hostile environments so we should expect life in all those places in the universe that are just as hostile.
Given enough time some of them will develop intelligence.

Earth might be an unusual oddity for intelligent life in the universe with most of intelligent life in places something like Titan or worlds far different from our thinking.

nickname · 2008-04-21 06:13:57

This is also a possibility.

Earth is so rare with so many freak occurrences as to be a one of a kind in the universe.
Life is very difficult to start and such a random freak event that this is the only place it has happened or will ever happen in this universe.

Then our next door neighbors might not even be in this universe but in a neighboring universe, distant and tough to contact indeed.

I personally don't believe this, but life does seem to go from nothing to complex pretty fast so it's possible it's so freakish to have life we are it alone, not even any bacteria or mould or anything anywhere else in this universe.

cIclops · 2008-04-23 14:55:51

Earth is so rare with so many freak occurrences as to be a one of a kind in the universe.
Life is very difficult to start and such a random freak event that this is the only place it has happened or will ever happen in this universe.

There is no evidence that shows Earth-like planets are rare, the frequency of exoplanets indicates quite the opposite. The Miller-Urey experiment demonstrated that precursors of life are very easily produced on Earth-like planets. Yes it's a big step from amino acids to a living organism, but there's no evidence or reason to show that it's impossible. Given the eons of time and the enormous numbers of likely planetary surfaces, there's every reason to say that life has appeared elsewhere.

nickname · 2008-04-23 18:44:07

cIclops,

I'm of the same opinion that life starts pretty much anywhere it can.
I think life is a numbers game, a time game and a location game, if you have all three then you probably have life on that world.

To have intelligent life i think we need the world to be just right with land and water and a host of other needs, with some freak events that allow simple life to evolve, then more freak events that allow that evolved life to be reworked a few times and lots of time for life to get the land ready for life on it.

If life starting as a normal process on most worlds that could support it isn't the case, and life is a freakish event then the universe might be a very very quiet place.

Needing an earthlike place then needing a freak event for life on it would make for very small odds for earthlike places to have life.
Then expecting the star it orbits to be as stable as ours for 4 billion years before intelligent life appears really makes the odds bad.

It all comes down to the how odd or normal is life in the universe before we can make an educated guess on the earthlike places with life.

Intelligent life i think at best will be a freakish event for most of those Earthlike worlds as ours was.
Over 4 billion years of planetary near disasters were needed for us to arrive for the short time we have been here.

Any solar system with asteroids much less frequent or more frequent than ours will probably not have intelligent life either.
Any solar system with a big planet not in circular orbit will cause constant disasters so we can exclude them.
Double star or multi star systems i think will be very poor places for Earthlike worlds, to much material moving around in them, and very odd heating and cooling of a planet in those systems.
All stars under 2 billion years of age, all stars that formed without a nearby super nova and all short lived large stars are all poor places.
Most of the center bulge of the galaxy is a poor place, to much radiation and to many other stars causing problems.

The list of must have items for intelligent life is much longer than the drake equation takes into account.

When we crunch the numbers of the places intelligent life won't be it only leaves maybe 5%- 10% of stars in a galaxy as possible places.
Maybe 1 in 100 of them has a long term friendly stable star with no near supernova stars.
Maybe 1 in 100 of them has formed with enough elements to form earthlike worlds collected from just the right nearby super nova.
Maybe 1 in 100 of them has an earthlike world in the right place.
Maybe 1 in 100 of them have a big moon.
Maybe 1 in 100 of them have all circular orbiting planets in the system.
Maybe 1 in 100 of them have life.
Maybe 1 in 100 of them have the correct land gas water etc etc mix to have land life evolve.
Maybe 1 in 100 of them have a few needed freak events that reworks life a few times without destroying life.
Maybe 1 in 100 of them have intelligent life.
Maybe 1 in 10 of them is a technical civilization asking the same question.

We could easily be alone with just those guesses that only just scratch the surface of the needs and odds of Earth2 with intelligent life.

Or we could be just 1 example of life in a countless number of examples around the universe more diverse than we could possibly imagine on strange worlds we could only imagine.

Life i think will be everywhere it can be, unless life is an odd freak event.
Intelligent life very very rare in either case.
If life is an odd freak event then we might be alone in the universe as the only inteligent species.

cIclops · 2008-04-24 11:14:56

Exactly so. The product of billions of years and billions of locations can be further expanded. The type of chemical reactions involving amino acids occur very quickly, so many happen per second and there are many many seconds in several billion years. Each of billions of suitable planetary surfaces has billions upon billions of locations for these reactions. The product of these is truly a large number.

Now during the early evolution of the universe, many of the precursors of carbon based life weren't available - carbon is a good example - however after the final nucleosynthesis of the first stars, these atoms were created. That still leaves several billion years for life to originate.

The big gap in the sequence is from basic living organisms to intelligent life - we know this took of the order of three billion years on Earth so it would depend on the stability of the planetary surface during this time. Many stars do appear to have this stability, but estimating the probability of this is guesswork right now as we've not even detected one Earth-like exoplanet.

The coefficients of the Drake equation are under constant revision, but at least we know the lower limit

nickname · 2008-04-24 16:26:06

cIclops,

My hope is that we don't even need places very much like Earth for intelligent life.
We probably don't need earthlike places for life of some forms.
Lots of moons and very different worlds i think will hold life.

We are probably very regional in our thinking about what is needed for intelligent life.
I bet that carbon isn't the only element for life in the universe either.

I picture the probable forms for life around the universe very much like the life in a drop of water, very diverse and unusual even at first glance.
The next drop of water just as diverse.
Then when you look at each drop even closer it gets even more diverse.

I guess whatever we find or don't find on Mars will answer some questions.
If Mars has always been baron then life probably is freakish, if Mars had life at some time then life probably pretty common.
If the Mars life is totally different than ours then life is everywhere possible and in many diverse types of life.
If life on Mars is an exact match to our dna then Mars and Earth just shared life.

We would get an interesting answer whatever we find.

I'm not even sure we are inteligent life, but since we don't have anything to measure ourselves against i guess we are until then.

Terraformer · 2008-04-26 04:56:04

cIclops, it reflects badly on you that you referenced to such a disproven experiment as the Miller-Urey experiment.

Taking the most probable atmosphere that the Early Earth had and repeating the experiment, you get Organic molecules that can give rise to biological molecules. True, but do you know what they are? Formalyhyde and Cyanide, and the biological molecule? Embalming fluid!

If life is common in the universe, then that would be the mos convincing evidence Intelligent Design would have. Ie. Very convincing.

JoshNH4H · 2008-04-26 06:16:24

Actually, if you add UV/excessive hat to the experiment, then you get Nitrogen bases and sugars.

nickname · 2008-04-26 07:21:10

Terraformer,

I remember an odds calculation about starting very basic life from amino acids as a random event.
The odds being more than the number of atoms in the universe to 1 against it per earthlike world.
That would be much less complex life than the first form of life on earth.
The random odds were something as unlikely as a fully functional car being created from amino acids with no plan and no intermediate steps, a pretty rare event i bet.

If that is the case then life on earth is probably a one of a kind event, or life has found a way to spread early on before most of the galaxy formed.

If life started early on as a very basic life, then spread as more complex dormant forms to just appear very complex as the first form of life on earth, it would explain the quantum jump life seems to take.

A very early big star with a ring of material going super nova could spread dormant life around the galaxy, as long as it was very early in the galaxy formation before most of the stars fire up.
That big early star would need a planet that could host basic life, then have another planet collide and smash it to rubble before the star goes super nova.

This is a pretty likely event early on as most of the stars would be giant blue short lived stars, so a second generation star could have all the elements it needs for life after only a few hundred million years.

We still need to get from very basic life to quite complex life that we see appear on earth as our first life, but the chaos in the early galaxy i think would ensure that, and the spread of that more complex life in its dormant form.

Life of basic forms might be pretty common in our galaxy but pretty rare or absent in most of the galaxies.

The odds for life in our galaxy with this method still don't leave many places for intelligent life, when we think that 90% of the stars in our galaxy are bad places, the remaining 10% maybe only 10% are lucky enough to have dormant life make it to them and endure the planet forming process, and nearly all of them don't have earthlike planets at the right location or do have earthlike planets and have rouge planets in odd orbits causing chaos or just a nearby star go nova sterilize the system.
Of the few stars that do have earthlike places in the right spot that are lucky enough to be seeded with life and have a stable solar system with a long term stable star, how many will be just perfectly right for intelligent life.
We could easily be alone.

Terraformer · 2008-04-26 10:53:27

Actually, if you add UV/excessive hat to the experiment, then you get Nitrogen bases and sugars.

Whoes around to make the Hat?

Seriously, where did you get that idea from.

JoshNH4H · 2008-05-01 14:41:28

I read it somewhere, I dont remember.

But really, a nucleotide is a nitrogen base, a sugar, a phosphoric acid. Nucleotides attract other nucleotides etc.

noosfractal · 2008-05-01 15:01:39

Perhaps you read about the famous Miller-Urey experiment?

http://en.wikipedia.org/wiki/Miller-Urey_experiment

dicktice · 2008-05-02 11:41:37

I believe we represent the only form of intelligence with the potential capability of populating the Milky Way Galaxy. We should stop wasting that potential warring amongst ourselves since (for all practical purposes) we are alone in our island universe, and just get on with it....

JoshNH4H · 2008-05-02 14:26:16

Perhaps you read about the famous Miller-Urey experiment?
http://en.wikipedia.org/wiki/Miller-Urey_experiment

That is exactly what I mean. An I beleive that this precludes dicktice's hypothesis because it has been shown to haqppen many times in the solar system alone.

Solution to the fermi paradox: there is no natural need to have as much intelligence as we do, and even those that do usually destroy themselves.

bobunf · 2008-05-03 23:50:05

I don’t see a large moon as being necessary for complex life to develop. Mars and Venus do not have large moons, but, as I understand it, have had climates at least as stable Earth’s for billions of years.

Also, I would think a likely abode for life would be large moons (perhaps Mars or even Earth sized) themselves orbiting gas giants. The large planet could be in the habitable zone or, if beyond, heat deficits might be supplied by radiation from the gas giants or tidal friction heating.

Earthlike moons orbitng gas giants might be much more common than planets that are Earthlike, and would entirely avoid the necessity for any moon orbiting the moon.

Bob

nickname · 2008-05-04 05:22:31

bobunf,

I think on earthlike places orbiting a star they will need a moon to be stable places for life to evolve beyond simple life.
Even small tilts and wobbles on earth would be very bad for complex organisms, even for complex plants.

Natural wobbles will be at a frequency fast enough to keep resetting the life clock on those worlds without a big moon.
Life might exist on those worlds but my guess would be very basic life.

I'm in 100% agreement that Earthlike moons will be much better candidates for intelligent life or any life.

I think we will find that Earthlike_world/large_moon systems are very rare, but Earthlike worlds orbiting gas worlds are numerous.

Will an earthlike world orbiting a gas world be a safe place though?
Gas worlds get many more impacts and most produce much more radiation, both are limiting factors in location of that world and time life can evolve after impacts settle down.

cIclops · 2008-05-12 04:27:54

The Moon actually causes wobbles in the Earth's rotation and tilt, without it the Earth would be more stable. It does however help to protect Earth from asteroid impact.

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Re: Why is the Universe silent?

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