Is There Life On Other Planets?

Is there life on other planets? Well, the short answer is: "Yes. Probably".

There are a few things we need to consider when considering this question, though:

• The number of other space systems in the universe
• The ‘Goldilocks’ Zone
• The Drake Equation
• Current evidence
• The length of time needed for intelligent evolution
• Will contact with aliens be friendly?

Indeed, we have yet to make any sort of public, formal contact with beings from other worlds, but looking at the maths, and considering the vast number of stars out there that could support life in our galaxy (let alone the universe), then it is highly likely.

There are roughly 200 - 400 billion stars in the Milky Way. The 'Goldilocks' zone is the distance from a star which is deemed not too hot and not too cold to support life, and in which it would be possible for a planet to hold water in all three of its standard forms (solid/ice, liquid/water, gas/water vapor), water being the key ingredient for life.

If we just assume that each of those 200 - 400 billion Milky Way stars hosted a planet in the 'Goldilocks' zone, then that is 200 - 400 billion planets that COULD be capable of supporting life.

A famous mathematical equation, known as the Drake equation, can help us work out the probability of alien life in our galaxy. It runs as follows:

N = R* . Fp . Ne . Fl . Fi . Fc . L

Where: N = the number of civilizations in our galaxy with which communication might be possible;
and
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space.

---

In terms of our own solar system, there is strong evidence to suggest that conditions for life have been present over the histories of various world's.

Mars (often a centre for the ongoing search for life) has been found to have ridges in its frigid surface, which suggest flows of liquid as recently as only ten years ago, and rovers on the planet itself have identified water in soil samples.

Many of Jupiter's large moons have been identified as possibly having oceans of water under their icy hard crusts, perhaps heated internally from volcanic vents in the moon's cores. These would be positive breeding grounds for life.

But even so, if life was discovered on other planets, it would be unlikely to hold any sort of intelligence, and would most likely be bacterial in its composition.

The human race as we know it has only been around for 4 million years, which is a blink of an eye in terms of the Earth's whole history - and evolution takes millions of years to make any sort of noticeable impact.

Besides, if some sort of intelligent life force from some far-flung corner of the galaxy did make it to Earth, would they really be friendly? Think about it: If they had technology advanced enough to make it thousands of years across deepest, darkest space to get to us, what's to say they wouldn't try to take over the human race with their greatly-advanced power?

Even great minds such as the physicist Stephen Hawking have expressed their concerns, Hawking stating that "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans."

In layman's terms: Take a grain of sand, for example. Now try to imagine how many more grains of sand there are on all the beaches of the world.

There are more suns/stars than all the grains of sand on all the beaches of the world combined. What are the odds of there being a sun just like ours, with an earth just like ours, with the perfect atmosphere just like ours, with life just like ours? Huge. So, yes.

Is there life on other planets? This is a question I have wondered about for many years.

I don't know if there are very many planets in our galaxy that support life. We (humans) have probed some small part of it to find suitable conditions for life just like ours. I'm talking about humans, not whales or reptiles and such.

But shouldn't we first define life ?

• "social life"; "city life"; "real life"
• The experience of being alive; the course of human events and activities
• The course of existence of an individual; the actions and events that occur in living
• The condition of living or the state of being alive
• The period during which something is functional (as between birth and death)
• Animation and energy in action or expression.

According to Word Web, a free computer program dictionary, these are only a few definitions of life. Another is a being capable of reproduction, breathing, eating, thinking!

I don't know if there are very many planets just like earth, but I think in this universe where there are more stars than the earth has grains of sand, it is very hard to think all that is just meant for humans! Yes, there is life in all sorts of forms, to think there isn't is arrogant to say the least. No offense!

Now let's think this through to the idea of life visiting earth. If they were to do so, they would be a lot more advanced than humans - because they have developed the technology to get here.

That being said I would hope they are also evolved to a higher plane and are not interested in “Taking us over”!

Of course, they may have developed this technology as a last chance deal where they need our planet. But now I think I'm getting into a little science fiction.

But no matter if they are bipedal or swim - in my opinion, there are people just like us. So, yes, of course there is life !

There is another factor to consider: The Habitable Zone. This is the area within a galaxy that is habitable by life.

Too close to the galactic centres, and all the supernovae explosions will have sterilised the planets with gamma rays, so no life around the oldest stars.

There's some amusing answers given up there.

First thing is, don't go bringing ANY kind of religious belief into any such question - it's like saying you can now scientifically prove that ghosts exist, and also that Santa is likely to be true too. Religion is 100% a 'belief' and is a story you either agree with, or think is silly. I don't think either, I just know I exist, and that's that.

Aliens?  Well a lot of people have said there is no oxygen, which is a very basic and worryingly important requirement of life forms.

What do you class as life?  A big-eyed, long-fingered thin figure from far, far away?  The chances of meeting another form that happens to have evolved as we have is so remote, even if we did find other living objects. 

Every creature on this planet is based on an evolution, that gave wings to birds, thumbs to apes, gills to fish, and even took away our own tails.

On ice planets, of which we even have one in our own system, there may well be water-based bacteria.  But what if a human went back 900 million years from now, and found earth a dead rock - would that mean it cannot happen ?

Time for the universe is not time as we see it, based on a human life and history.  To the universe, a new life form in 5 trillion years is as relevant as it would be if it arrived tomorrow (human time). 

Maybe we should answer - Not that we have found yet, and not in our time ?

Hi, I'm Connor and I'm 13.

No-one knows exactly, but if a planet is in the Goldilocks zone, then there is a good chance that there could be life.

Take Keppler 22b for example: It's bigger than earth, but it is mainly blue, which hints it is either rocky (like Earth) or a gas giant (like Neptune). The thing is, we can't know for sure, because most of these planets are too far away to calculate things - but the fact is, if there are billions of galaxies and trillions of stars in our universe, then probably, yes.

The basic needs for life are mainly food and water and, for more advanced organisms, shelter.

Planets orbit stars, galaxies can have millions of planets orbiting stars. Most galaxies have more stars than planets but for a few, there is an exception. If planets are in the Goldilocks zone, which means the climate is perfect to support liquid water, then they can support living organisms.

Apparently, Mars had some simple life (cells and bacteria). There is some proof, but scientists don't know whether it is just a coincidence.

There has apparently been what looks like a cell splitting seen on Mars but inside a rock when Mars got hit with asteroids it may have engraved in it, but I think intelligent life is what scientists are focusing on.

Making first contact, I think, will change the world forever. Hope this helps, and thanks for reading.

Of course there's life on other planets, it's not like we're the only ones in the whole galaxy.

Stars are like the the sun, HUGE burning balls of gas with solar systems around them. There are billions of stars, therefore lots of solar systems and even more planets. That's a lot of planets! Who's to say that at least one may have anther form of life?

I do believe that something is out there, but I don't believe that whole huge-eyed, green beings thing. They'll probably look different from us, considering that they probably live in a WAY different environment. But I don't think there will be a whole alien invasion thing.

They are probably wondering about other life-forms like us, or scared of us, or even having a conversation like this about us!

I would say yes, because life does not mean only humans and animals; it could be that bacteria and other sorts of life could travel all over the universe.

Yes, the universe is big so it has to be possible.

Yes. I know someone who says they have seen an alien.

Probably because space is so big and we can't be the only planet that has life on it.

Yes, I believe there's life on other planets, because the universe is so huge and there's bound to be another planet with existing life....I mean, really, the universe is HUGE, so it wouldn't be much of a big surprise if there was.

There has to be. The universe is too big for the earth to be the only place with life. The universe is bigger than we think.. Science just hasn't gotten that advanced yet.

You kinda have to be open-minded about these things, because there are plenty of people on this earth that think we are the "only ones" - but it just seems impossible for earth to be the only planet being occupied by life-forms.

I'm sure there is a llife on other planets, because the universe is a huge and we don't have any idea how wide it is..

The proof is everything is evolving in a long period of time ..even the earth ... Maybe soon our earth will die just like the other planets.

Another proof is people on earth becoming more intelligent . We invented new things. Let's say some other planet is just like earth before, and the people there are more advanced than us. More sophisticated, intelligent, and maybe they are just watching us...

There is a lot of evidence that aliens arrived on our planet before, when people were not already civilized..

Don't just think that aliens are like us: Look around! Fish breathe in water - some creatures differ from us. It's called adaptation ..maybe some aliens have their own oxygen ... 

I'm sure of this, because I've already seen it with my own eyes.. That E.T  is real.. I didn't believe in aliens before, but the moment that I saw that strange thing, the only words I can say are OMG!

Why would there be "aliens?" There could be human life in the universe, but it might not be true because we need the exact amount of oxygen, food, water and resources (just like a pet).

The way I see it, what if the life-forms of a planet are relevant to the conditions of the planet they were created on...?

For example: Every life form on this planet ranges between 40-80% water. The Earth's surface is 71% water (Due to the vast size of the Earth, it is hard to calculate the total amount of water composing our planet.)

The scientific community estimates that there are billions of planets. To think we are the only one that supports life is a not being realistic.

From a religious standpoint, we are it, but honestly a spaceship could land on the White House lawn, and the occupants can say we put (life) here on earth, and millions of people would still not believe it - that's why it's called faith.

There has to be, because if life on one planet is possible, then it has to be possible on another planet in our vast never-ending universe.

But I doubt it in our galaxy/solar system, as we have the best possible place for life to exist in this galaxy, not too far away and not too close. So life became possible on earth. But in another galaxy too far away for us to even dream of seeing, I believe that these extra terrestrials will not be as develpoed as us, and they could even be microscopic.

I watched a Stephen Hawking documentary ages ago, and it showed me that galaxies are contantly being destroyed and dying, and new ones are born. So earth was created from the remains of a dead galaxy, and will eventually die due to the sun eventually going supernova and exploding, and the sun will be the end of us, even when it also created us.

There is life out there, but you will never meet them. It may also take hundreds of thousands of years to send them a message, and hundreds of thousands of years to get a reply, if there is one.

So I am definite: I will not live to see that day unless I can find the holy grail.

On August 6, 2012 a Martian lander probe will activate live on the NASA channel and begin the process of finding life-forms on Mars.

We know life exists there from all the evidence, but we have not actually seen a "life-form" yet.

Right now, we are simply digging in the dirt for bacteria, but it is just a matter of time before we meet fellow travelers.

Who knows? Maybe some of Martian life-forms came to earth. Dinosaurs seem from other worlds to me - they grew to tall sizes. What if they never died out? What if some lived? Will they be smarter then us? I think it is highly likely.

Crocs are smart, they learn and all - but maybe with time, some dinosaurs became like humanoids.

Probabilities are good for something, mostly the simplest types. The prime directive for all life is to reproduce - it does not require much for that. It's survival of those who can get away with it.

Earth is the only planet in the solar system with life. But there might be life on Jupiter's moon Eropa.

There definitely is life on other planets - the mass of universes and solar systems are too much for earth to be the only planet with life inhabiting it.

Space is infinite, life is too - that's why there definitely is life on other planets.

We have no proof yet, but it would require the ultimate in arrogance to believe that, of all the uncountable stars in the universe, not even one would have a planet with conditions that would allow life as we know it to exist.

Beyond that, life has a way of adapting to conditions that we can't fathom as being hopitable. For example, there are organisms on our own planet that thrive in very hot water in the vicinity of volcanic vents deep in the ocean.  The conditions they thrive in would be deadly to us.

Well....I think so because Earth started the human race - correct? And God made earth and put Adam and Eve on this earth to start a human race.

God made all the other planets, too....he might have put other people on other planets too.

So I think there is - maybe not like us but, yes, living.

Yes, maybe, because we still cannot deny the fact that we are not alone in this world. The galaxy has many parts which are still unknown to us. But maybe one day, we will.

Yes - I've been seeing strange objects in space.

Of course there is. It would be crazy to think in this never-ending universe there wasn't. No proof but a great possibility.

Of course there is other life in the universe. Humanity would reach the pinnacle of arrogance to assume that we are the only intelligent life in the universe.

Yes, of course. There must be another life in other planets, just like we live on the Earth!

You don't even need a sun to support life now, that's proven, temperatures also don't matter. Life-forms just adapted to whatever conditions they migrated to over time, etc.

I think there is life on the other planets. That thing would not be impossible! Remember that we are not yet exploring all the parts of the universe!

If there's no other life in the universe, then it'd be an awful lot of wasted space. So, in that context, yes, there is other life in the physical universe. It may not neccessarily mean beings that meet the same conditions as Earth.

There most likely is life on other planets. We may never know for sure, because we haven't learned how to travel at the speed of light...yet. There are many other factors, but this is one of them that would be very useful.

I think it would be very odd if we were the only planet in the whole universe with conditions suitable for life. The universe is ever expanding, so there may not be a planet now, but in 50 years there very well could be.

I think so. Yes, definitely.

I think so because there is unlimited space, unlimited stars, and unlimited planets. There must be SOMETHING else out there.

Space is so big that there unlimited possibilities. But nothing has been proven yet.

So far, no one here has even dared explore the possibilities of non-carbon-based life-forms, life-forms that do not need either water or oxygen to exist, or life-forms that can survive in extreme temperatures and exotic atmospheres; those that wouldn't conform to our limited scope of knowledge(since this world and its life-forms are all we have to compare the universe to!)

Just because we require water, oxygen and a relatively-small margin of temperatures to exist, we tend to postulate that "any life" to be considered life, must be carbon-based, need oxygen and water, and have a limited range of temperature to be in existence.

When we open our minds to the infinite possibilities of a seemingly-infinite universe, the possibilities for a diversity of other types of life forms becomes apparent.

As far as intelligence, well, judging by the continued, knowing destruction of this wonderful, unique (so far) planet and its creatures, our intelligence could very easily be brought under suspicion!

No one knows for sure. But the only way to find out is to go to another planet. (Ain't going to happen!)

I am sure that there is life on other planets too.

Starting off life on a planet is just an event, and has a probability associated with it - and this probability increases with the life of planet.

And with so many planets out there in the universe, I am pretty sure that there is life in some other planet.

There is a possibility that there is life on other planets which are the most habitable. But we really can't say how distant or far these planets are from us.

All we know is what we're told - what if there aren't even planets up there? And who says those are stars? Okay, okay, they're stars - then what exactly are stars, then?

Could be an acronym for something else...think about it.

Yes, there is life on other planets. Only in a different way. (Humans are the most advanced life we know of) There are bacteria & things like that.

In Saturn, under its rings - astronaughts cannot get past the rings - they believe that Saturn is teeming with life underneath.

I'm pretty sure that they believe that Mars has some sort of life, my sister believes that, before Earth, there was life on Mars, until Mars got really hot & everything died out.

There must be some other universe that we do not know of. Astronomers have seen some planet just like Earth, & believe that when we die out, there will be life on that planet.

Iodine is why we are here. Put 5kg of iodine in every human's hand. You would be looking at Mars. Fossil fuels contain it. Earth has been dying for millions of years.

We are all iodine-based life. If you actually realise that we are just made from what is on the periodic table, iodine created life. So if it took 3.7 billion years to create what you see, the chances of life out there...

I would say stop looking up, like our ancestors, every breath you take is remarkable.

Just remember, if we did come from a different planet before here, it contained iodine. Therefore, if these "people" return, we know radioactive iodine will destroy them also.

I feel glad that we stockpile weapons to destroy our own planet. Aliens would look at us as a bunch of greedy dipshits.

No. Almost every comment here is based on wishful thinking with zero evidence. Most seem to go on the lines of:

• "The universe is so vast" - so what?
• "so there has to be aliens, we just haven't found it yet" - zero evidence for this and, what's more, it's utterly unprovable.
• "It's arrogant to believe there isn't alien life in this vast universe" - no, it's you who are being arrogant believing something with no evidence whatsoever, and then trying to insist others acept that ludicrous assumption.

Make no mistake, this is a religious belief you all have, which you are wrapping up so it sounds like science - but it is not. We do have some evidence, we have been searching hard for alien life for some time, result - we have found NONE.

The Drake equation is a theory, a very, very, very imprecise theory - because it doesn't allow for hundreds of other factors for life, which we know were needed in the one case where it happened i.e. Here on Earth.

The chances of life are so miniscule that it was severely against the odds that it happened once, here on earth. The chances of that happening anywhere else in the universe naturally are so remote as to be virtually zero.

You all go on believing in alien life if you want, that's your religious belief system, but I tell you it's just as logical to believe in the Flying Spaghetti Monster, fairies in your garden or Santa.

Stop worrying about aliens that don't exist, and go out and live your life.

I argue that there is life on the planets because it is a fact that our universe is infinite and there are  a number of stars. There are also planets revolving around those planets, and it may be possible that in any one planet, life is there.

I do believe there is life beyond earth, to me it's kind of "common sense" if you think about it. A vast amount of space with billions of planets within it, and there's no habitable life beyond our species?

Who's to say "God" didn't have plans elsewhere other then here? If you want to throw religion into the subject you must consider the true source, the ultimate answer that most people seem to avoid: We don't know.

A person of faith, in my opinion, should be open to the many possibilities of life, and so forth. No one should belittle anyone when simply no one has the true answers. I don't care what religion you are, you don't 100% know for sure.

Just wanted to voice that out, not trying to offend or insult anyone - just keep in mind the many possibilities. Keep the mind going!

My suggestion is to look into the work of Nassim Haramein, (Resonance Institute), a radical theoretical physicist, who has been speculating in this realm for years and looked into real evidence that some scientists choose to ignore because it did not serve the interests of the industries that fund them.

Crop circles are already proven evidence of a different kind of related human life - you notice I did not say extra-planetary: Maybe,maybe not.

As to life having to include water: Limited thinking...there could be frozen life-forms in minerals in vacuums in space, or life that is not bound by time,or size.

Crystals are a life form, they do not require water and can grow at near white heat. And I think we know that crystals can participate in communication!

It has been demonstrated that mold spores can be trapped in meteors and embedded in the earth's surface, so there is definitely already life from other planets here with us. Could be we are of that.

I believe there is.

In a way we have found life already - the bacteria on rocks and in asteroids.

Life yes, intelligent life, very difficult.

Possibly, yes.

Yes, but not inteligant life, that we know of...

We have no proof that there is life on any other planet, but we don't know either way.

Life on other planets is irrelevant to religion, sadly. It all depends on the conditions of a planet to produce life. Even if it's not like us, and able to walk around, even the existence of certain germs and microscopic beings would count as 'life'.

Nothing in our solar system can contain life other than earth (as yet proven, Mars is being investigated), due to the size and position of our planet in accordance to the sun.

However, the chance of another planet like earth existing somewhere out there isn't high. If we can't prove it's not out there, we should assume there is.

There is a bigger possibility that there is a life in another planet. We are living on Earth, located in the Milky Way. Our sun is a star.

The other star might have another planet orbiting it with efficient resources to sustain a living creature. Consider the other galaxies.

I already thought about this when I was just 10 years' old, and until now, it's still orbiting my head...

Maybe, but no one's ever brought it back to earth.

Possibly, most scientists think life is possible on Mars, but have not yet seen any evidence.

Wow... Many of you seem pretty sure of your answers. Perhaps a quick call to NASA from one of you could clear up decades of debate. The answer is, we don't know.  Here's an interesting facet of the debate: dunningrb.wordpress.com

This is a very puzzling question, and has puzzled astronomers and scientists and normal people like ourselves. The answer is yes, and no.

There is no proof that there is life on other planets. Sure, people have said they found aliens in their back yards. Everyone has been proved wrong, it's like Big Foot. You either believe it or not.

Until we have proof, I will continue to believe that there is no such thing as aliens.

I know I didn't help, but maybe you'll re-think the matter and so on.

Beth x

To tell you the truth, it wouldn't surprise me. We have already found proof of extra terrestrial species.

Yes, and it has been proven.

Mars. Plant life is available there.

Answer is probably yes, but we don't have any foolproof evidence. This topic is still debatable. Many say yes and many say no.

No one knows. All of you seem like you really know what you're talking about and you have many reasons, but really, no one knows.

Simple - there could be, but we don't know. There are other galaxies with planets with the same climate as earth. Considering evolution (I'm Christian, I'm just creating a possible scenario) on different planets, we could be very similar.

Possibly!

Yes, there is. Done.

No! No life on other planets! And we know that there is no life and oxygen even on the moon!

Aliens are false! They are only imaginary things.

So this answer I hope may be helpful to you!

No, of course not. The stars and planets were created for the telling of time by man. I'm always surprised by how many people never learned Genesis, or choose to be ignorant by not believing it.

Yes, there is actually life on every single planet. Do not be fooled by what science tells you. Every theory that science holds gets proven false, every one.

Science is just the facts that we know up until this point. We will always learn more.

Besides, we actually came to this planet from other planets a very, very long time ago, inside spaceships. Trust me, I would know!

As far as I know, scientifically speaking, there is no life on other planets, because there is not sufficient oxygen on any of the other planets except earth to sustain living beings.

No. There are no life-forms on other planets. Probes have been sent to other planets to check for evidence, and the conditions weren't suitable for any form of life to survive. Therefore, there are no life-forms on any other planet.

Hope this helped.

I'd say probably not; the chances aren't too good. I mean, the planet would have to be exactly like ours - but there's a possibility that there might be....but we have no proof there is, or isn't.

Here's my proof that aliens probably don't exist: We haven't had an attack yet. But in the Bible, it says that God only created this world to have life on it.

Yes, they found a creature as big as an ant's head. They named it a fridder.