Aliens are real but UFOlogy is a mythology of the space age. Rather than angels ... we now have ... extraterrestrials. It is the product of the creative imagination. It serves a poetic and existential function. It seeks to give man deeper roots and bearings in the universe. It is an expression of our hunger for mystery...our hope for transcendental meaning. The gods of Mt. Olympus have been transformed into space voyagers, transporting us by our dreams to other realms.

The reported perception of an object or light seen in the sky or upon land the appearance, trajectory, and general dynamic and luminescent behavior of which do not suggest a logical, conventional explanation and which is not only mystifying to the original percipients but remains unidentified after close scrutiny of all available evidence by persons who are technically capable of making a common sense identification, if one is possible.

The Drake which was devised by Dr. Frank Drake  allows a person to estimate the probability of several factors and come up with a number for say, the number of intelligent civilizations in the galaxy. It includes factors like rate of new star formation, probability of sun-like stars, probability of planets, probability of life, probability of intelligent life, probability of civilization and technology. Another important factor is the lifetime of such civilizations. When you multiply them all together and multiply that times the number of stars in the galaxy, you get a number.

Since some of these probabilities can't be estimated with any degree of reliability, the numbers you get aren't worth much. The doubt is compounded by the fact that there might be factors which are important, but we haven't considered yet, like the importance of the moon in abiogenesis

When all is said and done, you only get a probability, so even if the figures are all good and all factors considered, it could still be way off.

N = R* X fp X ne X fl  X fi X fc X L

where

N = The number of communicative civilizations
R* = The rate of formation of suitable stars (stars such as our Sun)
fp = The fraction of those stars with planets. (Current evidence indicates that planetary systems may be common for stars like the Sun.)
ne = The number of Earth-like worlds per planetary system
fl = The fraction of those Earth-like planets where life actually develops
fi = The fraction of life sites where intelligence develops
fc = The fraction of communicative planets (those on which electromagnetic communications technology develops)
L = The "lifetime" of communicating civilizations

Frank Drake's own current solution to the Drake Equation estimates 10,000 communicative civilizations in the Milky Way. Dr. Drake, who serves on the SETI League's advisory board, has personally endorsed SETI's planned all-sky survey.

http://en.wikipedia.org/wiki/Drake_equation

Dunno much about UFO. but I heard most sightings in Malaysia are actually not UFOs...but what if UFO really do exist? I mean there gotta be another living organism/creature/etc out there right?

Life isnt just exist on earth. In universe, how many galaxies are they? Its almost impossible for earth only that got life. I believe there are billions of living thing that come from different galaxies in our universe. And the alien that we debated might be 1 of the 'billions living thing' out there. My theory is just my opinion. It might be faked or so. But the fact that i hope everyone to agree is, 'we are not alone'. 

Life isnt just exist on earth. In universe, how many galaxies are they? Its almost impossible for earth only that got life. I believe there are billions of living thing that come from different galaxies in our universe. And the alien that we debated might be 1 of the 'billions living thing' out there. My theory is just my opinion. It might be faked or so. But the fact that i hope everyone to agree is, 'we are not alone'. 

if these UFO is really another world, why couldn't they just land in front of KLCC tower and wave to fellow humanians?

nope...alien a.k.a ET is still a myth just like yeti and the other mythical monster as far as we really want to say that alien is for real but if there's no solid evidence prove along the way it will always remain as a myth regardless how many theories that human can came up with about the diversities of the universe...

We have higher chance that earth being bombarded with asteriod causing human kind of extinction than finding UFO or alien visting the earth.

Even alien is within the same galaxy with earth, milky way, under current law of physics speed on light, it might take hundred of thousand and million of year to reach us.

Human kind have how many year of history? several thosand year, compared to millions year needed to travel, the probability is starting with low point already, somemore, galaxy is so enormous wide, what is the chance alien spotting earth so probability goes even lower.
A thousand year is a relative too small time frame in universe standard.

I don't dispute there are potential life form out there (can be a lot of form, not necessary must be identical with human kind, a head, a body, pair of arm and leg), just the probability of alien reaching earth is not promising at all.

i found the information in serpo.org pretty convincing..hmmm

i believe the existence of aliens.. and i dont deny the possibilities that human had already contacted aliens. the evidences are just too hard for us to deny it..

Alien does not recognises us. They may think we are dangerous to them, imagine if those US millitary or other spot the ufo, they would probably fire a missile and do research on the UFO. And i do think that they are spying us right now. But again, nobody knows what is their motive. But hopefully not the real 'War of the World' 

hmm... if they are spying on us.. they should know their superweapons and technology is far more superior than us, so would not be afraid of losing to the US.

The topic here is about UFO. I do agree alien do exists. But those UFO that appears on earth is all fake. They have not discovered us 'yet'... i believe

if ever UFO did reached Earth, i think somehow the aliens will make some sort of communications with us.. i mean, they've travel many hundreds light years away, and just to stay at our sky for a mere second glimpse by us?! i believe curiosity is the universal feeling..

Yeah they may not afraid to lose. Not all the ufo spotted on earth are fake. Some of them are real. Even the videos about ufo on youtube are real, but mostly fake. UFO spotted on earth even during WWI or WW2, but not sure because i watched the documentary on astro, History Channel. Well ufo are not much spotted on earth. But outerspace, Nasa spotted them frequently.

Yeah they may not afraid to lose. Not all the ufo spotted on earth are fake. Some of them are real. Even the videos about ufo on youtube are real, but mostly fake. UFO spotted on earth even during WWI or WW2, but not sure because i watched the documentary on astro, History Channel. Well ufo are not much spotted on earth. But outerspace, Nasa spotted them frequently.

where did you get the idea that Nasa frequestly spotted alien??

i believe there must be other life form out there, but they will be so different from us that we may not be able to see them if they are infront of us. a lot of sci fi have story of alien come to enslave or give us technology, but really it is highly unlikely their technology can be used by us, like if you found an ant on the side of the road do you try to teach them human technology? the funniest sci fi plot about alien have to be Independent Day where all the alien ship are control by Mac compatible computer