What do you guys think of UFO's?

[Macgyverthehero]

"Habitable" is defined by our experience. There are assumptions attached to it that wouldn't necessarily apply to every possible organism in existence. Even if a "habitable" planet existed billions of light years away, if in fact these aircrafts are driven by aliens from outerspace, you would have to accept that it is in fact possible to travel at humanly-impossible distances and our knowledge of physics may be denied. Unfortunately, we don't know who drives these aircrafts, but that may be revealed some day.

Well actually no. The basic substance of EVERY organism is water H2O. Water above 373 Kelvin becomes gas and bellow 273 Kelvin it becomes ice. So there is not any organism who can live in a temperature higher than 373 Kelvin and not in a temperature bellow 173 Kelvin(that's because some organisms are more resistant). Also half of the planets in our solar systems are made by gas (have no ground like Earth) and have strong gravitational forces. The other planets have way too high or way too low temperatures (you can confirm that in wikipedia). There is no possible way an alien can live in a planet in our solar system. I cannot deny that there could be aliens light years away from us,but there is no point. The max speed limit in nature is the speed of light. So far so good, that means even if they were travelling nearly with the speed of light it would still take them several years to come here on earth and even more years to come back to their planet. Let's also calculate the possibility of choosing another direction to explore on the universe (not the one leading to our planet which is on of the many possible directions) and the possibility of reaching our solar system.

Given all that. The possibility of us seeing an alien is 0,00000000000001%

---

It's possible we don't meet them RIGHT NOW, but maybe in a few centuries or a couple of thousand years we meet them.

Maybe millions of years, and more possibly never. The universe is too huge and I don't think the aliens will just travel A STRAIGHT line to Earth. It is almost certain they will go somewhere else in the universe. And that' IF they exist and IF they have advanced technology and IF they can travel WAY TOO FAST. Too much if's.

---

Or maybe in decades, because technology right now is advancing quite fast and I'm hoping in around 20 to 30 years we will be able to revolutionize space travel. First contact with aliens might take abit longer then that, but I'm sure we will meet E.Ts at some point in our future.

Anything is possible, because Impossibility is only an opinion.

You are completely incorrect. There is no chance we are going to meet and allien in around 20-30 years. However fast the technology is advancing there is a a limit nature decided to apply and it's called "speed of light".

Did I say we would be meeting aliens in 20 to 30 years? I said that First Contact with E.Ts would take abit more than that.