Well, I've been thinking about this sometime now, and I've reached the conclusion that humanity, even it's topmost scientists, is arrogant. Why?
Because after searching the skies for 50 years with our radio telescopes and listening devices, we came to conclusion that there are is no intelligent life form other than ourselves, or rather - that such life forms are very rare.
We discovered alot of new extra-solar planets, and evidence suggest that rocky planets such as Earth surrounding stars such as our Sun are very common.
Heck, we even have our own solar candidates that might harbor primitive life forms (Europa, Mars).

But, because we couldn't find any intelligent message on our radio devices saying "Live Long and Prosper", or "Give us your planet" we assume that there are no advanced civilizations around us. That assumption is even supported by notable scientists, such as Stephen Hawkins.

Well, after a thought about the entire issue, I have come to the conclusion that they are all arrogant, or simply stupid (I hope it's the former).
Why, do you ask?

Well, consider the following - we discovered radio transmission when? 150 years ago? For a very long time, humanity had an advanced civilization with no radios, or without anything to transmit to space. But let's assume that we have no interest in such civilizations, because we can't communicate with them anyhow, and they leave no signature in space for us to find them out (that's a weak argument - I think a medieval alien world or a roman alien world might be very interesting to study. But then again - it holds water, cause you simply can't find those worlds).

But, and look at how fast our technology is growing - what makes us think that radio technology is the best way to communicate? Perhaps our own radio age will be over by the end of this century, with advance in Quantum Physics or some other unknown field of science, thus making that technological era last less than 3 centuries, which is a glimpse considering even our own civilization's age (it's as if a less advance civilization somewhere on earth would discover our own civilization, and come to the conclusion that we have no means of transportation because we don't have horses in our backyards. Horses were, after all, the main transportation method for the majority of our written history).

And even if radio technology is the best way to go, which I doubt considering the vast distances of space (but let's assume no civilization is able to over come relativity, and so electromagnetism remain the main communication medium), what makes us be so certain that civilizations some 3,000 light years from ours haven't discovered it, only 2500 years ago, and so we'll have to wait atleast 5 centuries until getting their first, early 20th century parallel, transmissions. Think of where we will be 2500 years the discovery of radio. And those distances are still around the corner and in our galaxy.
Sure, some might say "well, why won't a nearer civilization discover radio and then we could hear of them". Well, who said that intelligent life form is a common evolutionary path? as a matter of fact, intelligent life form should be favored against because it breach evolutionary law - that is, to adjust to nature. Instead, intelligent life forms adjust nature to their convenience, which puts the entire ecological system at risk (ie global warming, mass extinction, pollution etc.). I think it is safe to say that intelligence is a rather unwanted evolutionary path, which make it quite rare. Even if consider that there are millions of planets with life forms evolved on them, some even older than our own, it might very well be that intelligence didn't develop there, and it is governed by another, not less successful, life forms.

So, considering all the factors that mentioned here, we can sum it up that:
A. perhaps there are many civilizations out there, but most of them are invisible as a result of technological backwardness.
B. some might be invisible because of technological advancement - ie They came up with a more efficient way to communicate, and their "radio bubble" passed us long time ago.
C. maybe there is no better way than radio waves, but intelligent life forms with radio technology lurk far away, light centuries or even millenias away from us, and their radio bubble haven't reached us yet.
D. intelligent life forms are not as common as life itself, making possibility C and even more likely case.

And the last, but not least possibility, is that perhaps we are the first, at least in our neighborhood. Perhaps we are the first to discover radio, perhaps we are the first to get to space, and perhaps we are the most advanced life forms in our galaxy. It's not that unlikely considering the time it took intelligent life form to evolve here on earth, almost 3.8 billion years since life first appeared here.

What's your opinion?

Very nice summation. I'm not so sure that there's really any way to know which of the options you mentioned would be most likely though. We are just now discovering other planets, SETI hasn't been active for all that long, and we haven't even fully explored our own solar system yet! I suspect that as we begin to know more we should be able to hypothesize a bit better in the future.

I don't think that many scientists are going to conclude that there are no aliens, or so few it's worthless to search. What Mr. Hawking thinks is his personal opinion on the matter. I happen to share the opinion that aliens aren't so rare as the universe is big. That is, fifty years of searching doesn't mean anything when the universe, even our galaxy, is as big as it is. They're probably not a rarity, we're just not searching enough.

Take, for example, the Paul Allen array. It's privately funded. The government doesn't give it crap because they probably don't care if we ever find life or not. I'm convinced that based on calculations, we'll find alien life out there around 2020. Probably not much sooner, or not much later. If we don't, I think there's something we may be missing.

But if we're here, they're there.

Agreed, absence of evidence is not evidence of absence.


Again agreed BUT probably is not the same as definitely. All the calculations are fine but ultimately they are just an educated guess. We only have one example of a planet where life occurred... Earth.

Extrapolating from a single data point is crazy science. It involves huge assumptions, not least of which is that Earth is a typical planet and the because life occurred quickly here then that is typical elsewhere. Whilst there is no reason to assume that Earth is not a typical planet there is simply no evidence to discount the possibility either. If Earth is exceptional then all the calculations are wildly wrong.


I think this is a bit of an over simplification. The whole are of searching for alien life has often had the perception of being a field for oddballs in tinfoil hats rather than an area for serious scientific research. As a democratic government is answerable to the citizens (at least in theory) this perception would make it very difficult to justify large scale financing. Also there are a long waiting lists to use the available radio telescopes for far less speculative research, which means SETI only has a limited amount of time to do its searching.



How do you derive at a date for when we will find aliens when no one knows how common terrestrial planets are, what percentage are habitable and what percentage of those life will actually emerge on. In fact no one knows for certain ANY of the figures in the Drake equation. Your date is nothing more than a pure guess.


We simply can not make that conclusion. If we are here it is LIKELY they are there, but likely is not the same as definitely. We maybe alone or at least separated from the nearest advance civilisation by enough distance that we will never know of each other. I hope not, the discovery of alien life would be one of the greatest discoveries of all time.

i think we could only pick up sounds from alien worlds if sound could travel through space, which it cant, i am just really confused about how radio waves could travel through space from long distances. we might see aliens more if it was possible to travel to distant stars in a matter of days or hours.

You are correct about sound, but radio waves are not sound.

They are electromagnetic radiation the same as light, gamma rays, x-rays, etc, they are all similar but have different wave lengths. Just as light can travel through a vacuum (otherwise we wouldn't be able to see the stars) so can radio waves.

oh okay now i know

I think radiation gets absorbed fairly easily.

That depends on the type of radiation and the material doing the absorbing. Light is radiation and telescopes can detect galaxies billions of light years away. Radio waves are radiation and radio telescopes can detect signals from billions of light years away. The atmosphere blocks out many wavelengths, but your statement is a huge over simplification.

I think light is a composite of both energy and mass if I recall correctly.

Again wrong. You are thing of the duality of electromagnetic particles, that the are both waves and particles.

The particles of which light is comprised are photons, one of the distinguishing features of which are that they have no mass.

Nothing with mass can achieve the speed of light.

It is only a theory that a photon at rest has zero mass, and clearly photons in light are not at rest.
Or call it relative mass and energy if that is more appropriate. I am sorry that I often express myself differently and confuse people. It really was not my intent.

It is a theory backed up by vast amounts of observations and research. To my knowledge there is no evidence that points to photons having mass.

Waspie, perhaps some scientists do agree that intelligent life exist somewhere, but the truth is that many in recent year begin to question such a possibility (while not the mere existence of primitive alien life) simply because with all out knowledge, we came up with nothing.

I think that the possibility of using another form of communication carrier beside electromagnetic radiation is very much likely - after all, about 96% of the universe is made out of dark matter and energy, which do not react with normal matter or with electromagnetic radiation. Any advance enough civilization, including probably our own in few decades, would have to explore that part of the universe and so will probably come up with some new ways of communication.

I would say that the vast majority still believe that there is intelligent life out there, however we also have to face the possibility that we are alone. It is healthy that both possibilities are considered. The fact is that we simply do not know one way or the other.

Those that believe we are alone will never be proven correct (unless we explore the entire Universe). Just because we haven't found them doesn't mean they don't exist.

I think it was Clarke that said, "if we ever discover alien life, we will find monkeys or angels, but not men"

What he was saying is that our entire history is such a miniscule fraction of the universe's age or even the history of life on earth that the odds of finding anyone out there remotely similar are infinitesimal. Looking at the history of life on earth for the last 4 billion years, you see that until 500 million years ago the most complex life on earth was thimble sized sponges. So for only one eighth of the time life has existed on earth have you had anything particularly complex at all and we are only the last hundred thousand years or so - the blink of an eye.

That being said, my own calculations using reasonable values for the Drake equation show a technological civilizations within a few thousand years of us being rather rare - after taking my astrophysics class and understanding the timescales and rare events required for us to have appeared on this planet (but making a few generosities because hey I don't know everything about how intelligence could come about) I come up with an estimate of about 2-3 civilizations within 10,000 years of age of us in the galaxy. That being said, it would put us tens of thousands of lightyears apart on average. In addition, radio really isn't the best method for interstellar communication. It spreads out and attenuates like crazy unless you send out directional beams - using our current SETI technology I believe I have heard it said we could only detect another Earth about a lightyear away. Plus, in all the theoretical studies I have read about possible interstellar probes, the engineers have proposed to communicate with the probe via a highly directional optical communication laser rather than any radio contact.

We would need to detect deliberate directional radio messages sent out by their scientists - we have sent VERY few of those out ourselves and they were each VERY brief. What are the odds that another civilization will both send signals out and them be pointed at us when we are looking in their direction? HOWEVER, everyone here should look up the "WOW" signal - it is far from a concrete case but it is the thing we have seen that has the characteristics most like what we would expect from an interstellar signal.

Another thing worth noting - our own radio traffic is going down as we use cable and the wired internet for more and more. Satellites use directional antennas with far lower powers to do the job of hundreds of high power broadcast towers. Wireless networks use less than a tenth of a watt each - thats a thousandth as much energy as a lightbulb puts out. The trend with higher technology is less omnidirectional brightness and more small scale or long distance dimness.

No one has ever seen or detected a photon at rest with zero mass that I know of.
Please post a link to this information for me please, if it is not a bother.
I would appreciate it, as I always like to learn new things.

I would love for us to see proof there was any kind of other life out there in our universe! And I will give you this, there may be some where. BUT if there is we are pretty certain it's rare and far apart. One thing for sure, no life in our solar system. Not very likely there is any in our galaxy too! And we can detect the ingredients needed for life billions of light years away, at least for our kind of life, and none have been detected. So no radio signals, no form of detection, no evidence at all to suggest there is life. What argument is left? Please don't say the odds. because actually the odds favor there is no other life.

But lets assume for one minute that this planet we live on is the only planet in our universe that has any form of life. Consider it for one minute if you can! How marvelous would that be? Perhaps we will be that advanced civilization thousands of years from now that will one day travel to find a distant planet and find life remarkably similar to ours is now! Perhaps our universe is simply a 13 billion year old baby?! Why does there have to be life some where else now at this stage of life of our universe? Could it be possible we were the first and others will follow? It's a pretty safe bet there are no more advanced or intelligent life near by or we would have detected them some how.

What if one or two planets with life is the most you can hope for for in one universe? We know there are other universes, so the life could be there!

No offense but it cracks me up to hear some people proclaim it is short sighted of people to assume there is no other planet with life in our universe and claim we need a more open mind lol. My friend, we have a open mind, it works in both directions! Not just the direction we would like it to be in. Of course we would love for there to be life every where! But sadly if there is life, we certainly do not have a over populated galaxy or universe. It takes a open mind to accept BOTH that there could be life or we may be alone! Thats not short sighted at all. Short sighted would be believing one or the other with out any proof!

You need to look at the big picture and consider all possibilities, even undesirable possibilities! Until there is proof, we simply do not know for sure one way or the other. If you go by odds, its verry unlikely.

Regards!

It is very hard to directly prove the mass of the photon is zero. No matter how accurately you measure it there is always the possibility that it has a tiny mass that is lower than the limit of your detector. For this reason you will not see a claim that zero mass of a photon has been detected... by definition it can't be. However there has never been any detection OF MASS in a photon.

From a scientific point you do not need to measure the rest mass of the photon to prove it is zero. You only need to show that relativity is right about mass and the speed of light.

Since the mass of other particles have been measured both at trest and at high velocities, and it has been shown that mass increases with velocity exactly as predicted by Einstein then it has been shown, experimentally, that no particle with a rest mass of greater than zero can travel at the speed of light. A particle with mass would have infinite mass at the speed of light, requiring infinite energy to accelerate it to that seed. This is not possible.

As photons travel at the speed of light they must, therefore, have zero mass.

if we(humans) found an alien planet with trees, does that mean we've (humans) have found alien life?

There could be a point here.This is a question Waspie but dont astronomers use the word alien as a term for that it is not found also in this world.

It doesn't need to be any thing as advanced as a tree, a simple bacterium would do.

However we need to differentiate what we can find in our own solar system and what we can fing using something such as SETI.

Probes to Mars and other planets could indeed find primitive alien life (if it exists in our solar system). Using something like SETI, searching for signals sent out by other civilisations we can only find intelligent life.

The planets on the stars around us could be teeming with simple life forms but until we can master interstellar travel we will continue to be ignorant of their existence. Their are space based telescopes on the drawing board which will be powerful enough to take spectra of the atmospheres of nearby terrestrial extra-solar planets. From such spectra we will be able to look for the tell tale signs of life.. for example an oxygen rich atmosphere. From this it will be possible to infer the existance of life on other planets although I doubt it will be far from conclusive proof.

Finding an oxygen-rich atmosphere would actually be pretty conclusive proof... molecular oxygen is one of the most reactive molecules out there and tends to combine with EVERYTHING else to form oxides on pretty short (geologically speaking) timescales; it is not formed in any significant amount by any natural process except photosynthesis that I can think of either.

some astronomers believe that there might be life on titan as we all know it is one of saturns moon and it's one of the biggest in the solar system, but the problem is that there is not enough heat (it's too cold) for the bacteriums to thrive off

Extremely strong evidence yes. Conclusive proof no, and the reason for that is contained at the end of your post.


It is the "I can think of either" bit that is the reason why the discovery of oxygen will not be conclusive proof. Whilst it is simple to eliminate all known processes it is, by definition, not possible to eliminate unknown ones. Because we know of no processes that release oxygen into an atmosphere except life doesn't mean such processes exist.



There are very few that think that Titan has life at the moment (and for pretty much the reason you have given). What a few believe it that it is an ideal world for life to emerge in the future. When the sun goes red giant Titan will have a temperature conducive to life. Sadly if life does emerge there it will be very short lived. Once the sun has finished it's red giant stage it will become a far cooler star than it is now and Titan will freeze again.

Europa is considered a far more likely place to fing life in the solar system than Titan and Mars still can not be ruled out either.

You're absolutely right. Bad phrasing on my part, shouldn't have called it "proof" at all.

Well said Waspie_Dwarf also iv,e heard of the supposed WOW signal from the seventies I know that they couldn,t find a repeat signal but its still ofers some hope

Lets see. Posible places where life (not necesarily inteligent life) could be found in our Solar System. Correct me f i am wrong.

Mars (It had the right setting to support life in the past)
Europa (Posible liquied water oceans under de ice sheet)
Titan (also posible very primitive life)

More extravagant theories:
Jupiter (there wee the crazy theory of floating lifeforms on jupiter, isnt?)

Places that are too agressive for life:
Mercury (too hot/cold)
Venus (too many acid/pressure/heat)
Luna (not atmosphere)
Gas Giants and its moons (expect for the ones listed, not other planetary formation have the right setting for supporting life)
Pluto and beyond (too cold)

is it possible that life can only begin when the planets is still fresh after it has been created?

In respect to that idea, all we have to go on is the Earth.
On Earth, no life existed for a loooong time after the planet formed (a really long time).

Also consider that when a planet forms...say, one which will be come a rocky, Earth-like one, it's a hot, molten cauldron of congealed matter, and it is incompatible with any life that we know of ( a nasty place).

I suspect it takes a planet a while to "chill out" to the point where life can begin to evolve. On Earth, the current theories indicate that it was about 1.5 billion years after the Earth formed that the first life arose.

Based on the current extent of our knowledge in that realm, I'd say, no, a planet probably has to be pretty old in order for life processes to start.

We actually have surprisingly little to go on regarding evidence for early life on Earth. The very oldest bits of evidence are up to 3.9 billion years old (pretty much the same age as the oldest rocks on earth) - bits of carbon encased in rock that have carbon isotope ratios consistent with biological processes sequestering the carbon. Not all scientists accept these as concrete enough evidence, however. The next oldest bits of evidence we have are stromatolites - the repeatedly building up mats of bacteria over time that can fossilize. The oldest stromatolite known to be of biological origin is 2.7 billion years old.

It seems to me that you have two separate bottlenecks in the formation of interesting alien lifeforms - the formation of a living system in the first place, followed by the diversification into COMPLEX life. Like I said, only in the last 500 million years have we had anything particularly interesting at all on the earth other than algae and tiny sponges.

Well, with Telescopes, we see things in light years in space. So, if I were to see something 100,000,000 LY....I would be seeing it 100,000,000 Million years ago. If there were simple forms of life, it would be really hard to find due to the fact that even if we found them, and if we reached them, the planet would be gone.

No, you would be seeing it 100,000,000 years ago not 100,000,000, Million. Your second figure would be impossible as it is more than 7500 time longer than the universe has existed.

this means that if you saw something 100,000 light years away, your seeing something that is 6,000,000,000,000,000 miles away

Dr...

You're off by a factor of approximately 100.


100,000 light years is actually ~ 600,000,000,000,000,000 miles.


600 quadrillion miles...you wrote 6 quadrillion miles....

there is 6 trillion miles in a light year. add 6 digits to the end to make it 100,000 light years and if im correct 1 trillion is a 10 digit number so in total there should be a 16 digit number
so correct me if i am wrong but the answer should be 6,000,000,000,000,000

I wounder if the IRS can move that decimal over for me on my return? LoL

Conceptually, you're correct.
But 1 trillion is actually a 13 digit number (1,000,000,000,000, also written 1 x 1012)
(....1 followed by 12 zeroes, or, 13 total digits). You'd need to add 6 digits to a 13 digit number...

A light year is 6 x 1012 miles.

The easy way to figure this out is to multiply the exponential expressions.


A Light year is 6 x 1012.
Multiply that by 100,000, also written as 1 x 105.

All you have to do is multiply the numbers (1x6), and add the value of the exponents (12 + 5), to get 6 x 1017...

Otherwise written as 600,000,000,000,000,000.
That's actually an 18 digit number.

Your number is two digits too short to be 100,000 LY.

So does that mean Uncle Sam will give me a trillion or a Gazillion bucks in the mail?LoL

Nah...


Probably just 6 x 102 bucks... ($600).
They'd have to make a hell of a mistake to send you an Uncountabillion dollars....

Heck, I've yet to even see my 600 bucks!

Yea...me too!

How long do you think it would take for them to send you 6 x 1017 bucks!!!???

Thats an oxymoron question,I think it all went to the men& women in that really smart overseas trip we planned for oil! IMO