Do Aliens Really exist?

[B@ttery]

My personal opinion is that, maybe there is an unknown life form. But that doesn't mean that i do think that. It's that little green man or something like that Alien movie. I hope that the life form is more advanced than us. And is so smart that it. doesn't ever show to us. Because knowing a an humanity, We probably gonna destroy it before. We can communicate to them.

[Briggsy]

 

[dragonfoxSL]

My personal opinion is that, maybe there is an unknown life form. But that doesn't mean that i do think that. It's that little green man or something like that Alien movie. I hope that the life form is more advanced than us. And is so smart that it. doesn't ever show to us. Because knowing a an humanity, We probably gonna destroy it before. We can communicate to them.

 

Yes, Aliens are not defined it can be any sort of life form a single organic Bactria to even a organism without a carbon structure which are made of elements we do not know of. We only know a very small part of the universe

So Yes i think there are aliens in one way or another , There is the mathematical probability there are life in the universe 

[bob345]

With how enormously large the universe is, i find it highly unlikely that there is not other life. Weather that life is intelligent or not is a totaly different question though.

[Octagoncow]

In my mind there's absolutely aliens; just maybe not flying around in space ship kind. With how vast our universe is there have to be more planets which have the correct properties for life to occur. My question is just how many of those planets there are and if the aliens on those planets are anything more than just single cell organisms.

[Yoinkerman]

As the number of stars, planets, galaxies is currently an unknown number approaching infinity, how can there not be? How do we know there aren't rock based life forms that eat solid methane? How do we know there aren't other planes of existence we can use to shortcut through regular space?

We don't know nearly enough to even begin to say things in definite terms.

[ShadowCaptain]

Sorry, could not resist

[Prokart2000]

Where ever they are, they are there. We might NEVER see them EVER in humankind, but they are there.

well of what we know the solar system is never ending sooooo im with you

[B@ttery]

Yes, Aliens are not defined it can be any sort of life form a single organic Bactria to even a organism without a carbon structure which are made of elements we do not know of. We only know a very small part of the universe

So Yes i think there are aliens in one way or another , There is the mathematical probability there are life in the universe 

 

And it's also that, why other wise we wan't to think that. Maybe there is unknown life form out there... I mean even those humans, who hasn't ever went to space. Or even doesn't think that there is an option to travel up there. Does think that there would be some extings among us.. 

[Tech_Dreamer]

Technically if you mean by other live organism , there is already proof i think, But if you mean by the one's that look like tall greenish human like aliens zapping around in UFO's , maybe no

[pspfreak]

Yes, aliens came up with this: http://hampsterdance.tk/

[kingkickolas]

In my mind there's absolutely aliens; just maybe not flying around in space ship kind. With how vast our universe is there have to be more planets which have the correct properties for life to occur. My question is just how many of those planets there are and if the aliens on those planets are anything more than just single cell organisms.

 

I just wanna share a part of an exam I had to take in an astronomy class, in which we used the Drake equation to estimate the number of intelligent civilizations in the Milky Way, and the number of planets which might have any kind of life at all.

My calculations came out to about 5 planets that have intelligent life, and around 5 billion which have primordial life of some form.

It's also a great exercise to try it out for yourself and see what you get too.

 

The Drake Equation is the following:

N_civ = ( N_stars  f_p  n_p ) ( f_life  f_{int. life} ) ( f_civ ) L_civ/L_star

 

Where

N_{civ is} the number of civilizations in the Milky Way,

N_stars is the number of stars in the Milky Way,

f_p is the fraction of stars that are suitable for life that have planets,

n_p is the average number of planets around such a star,

f_life is the fraction of these planets that can develop life,

f_{int. life} is the fraction of planets with intelligent life,

f_civ is the fraction of planets with intelligent civilizations,

L_civ is the lifetime of an intelligent civilization, and

L_star is the lifetime of a star suitable for life.

 

Note that f_p is usually broken down into smaller fractions as such:

f_p = f_AFG f_pop.1 f_single f_planets

Where

f_AFG is the fraction of stars which are A, F, G stars (those that can have planets with life),

f_pop.1 is the fraction of stars which are population 1 stars,

f_single is the fraction of stars which are single systems (not binary/tertiary star systems),

f_planets is the fraction of these stars which have planets.

 

 

The purpose of the equation is to estimate the number of intelligent civilizations in the Milky Way.

 

The values of the first 3 terms are known astronomical figures, they are: 

N_stars = 2*1011

f_p   = 1/40

n_p = 10

 

The value of f_life can vary between 1/3 and 1/100 depending on how likely it is that life will develop on a planet. I will choose the value f_life = 1/10. As shown from life on the Earth, once you have a planet that is suitable for life, life develops almost immediately. And if our solar system is any indication, at least one in ten planets (or bodies) will be suitable for life and develop it.

 

The value of f_{int. life} also can vary between 1/10 and 1/1000 depending on what is considered intelligent life. I will choose intelligent life to be any land-dwelling mammal. This is somewhat in the middle of rarity and difficulty when developing intelligent life, so I will assign it a value of f_{int. life} = 1/100. 

The value of f_civ depends on the value of f_{int. life} and varies between 1/10 and 1/1000 depending on how difficult it is to rise from whatever intelligent life was chosen to be to life which is able to build a radio telescope and communicate with the rest of the universe. For this reason, having chosen intelligent life to be already a mammal, I will choose f_civ = 1/100. That is, one in every hundred groups of life that reaches the mammal level will develop into highly intelligent life.

The final value L_civ can vary depending on various risks that can destroy a civilization: disease, overpopulation, global nuclear war, etc. On the plus side, any reasonably intelligent civilization will be able to stop any of these risks and will have the capacity to do so. For this reason, I will be optimistic and say that, on average, a civilization will survive 10⁵ or 100,000 years.

 

Using these values, I calculate N_civ to be:

 

N_civ = ( N_stars  f_p  n_p ) ( f_life  f_{int. life} ) ( f_civ ) L_civ/L_star

N_civ = (2*10¹¹ x 1/40 x 10) (1/10 x 1/100) (1/100) 10⁵/10¹⁰

N_civ = 5

 

Perhaps there are 5 other intelligent civilizations in our galaxy. This seems rather small though, and given the roughness of our estimates, I think this number could vary anywhere from 0 to 50. But if it is possible that it is 5 or 50, and they are interested in finding us, why haven’t they? We also have to consider that they may be hundreds of light-years away from us, so it might take a while for us to receive their signals and vice-versa. If there are other civilizations out there, this is likely the reason that we have not had contact with them.

 

N_{any life} = ( N_stars  f_p  n_p ) ( f_life ) = (2*10¹¹ x 1/40 x 10) (1/10) = 5 x 10⁹, or 5 Billion planets are likely to have developed life.

They may be very close to us indeed. And while it is uncertain that many of these planets will develop intelligent life, we can be relatively sure that around 5 Billion planets have some sort of life on them!

[dfsdfgfkjsefoiqzemnd]

I always thought there were no aliens.  then I arrived on this planet.

 

 

 

 

 

Of course there are aliens.  One of them even had his own TV show.