Do you know if NASA has evidence of alien life?

Yes, I do know the answer to this. It’s no, NASA has no evidence of alien life to date. We only have theories and speculation, but without evidence there is no proof of alien life anywhere else in the universe other than good ol’ Earth.

That being said, most scientist believe life probably exists elsewhere in the universe, but until we actually find even a fossil of a microbe of alien life, there’s no evidence to date.

What are the chances of two planets from the same solar system having sentient species that reach space exploration around the same time?

This is a great question, but unfortunately no one will be able to give a definitive answer as to the chances.

This is simply because we do not yet know if life exists anywhere other than Earth. It is still within the realm of possibility that Earth is the only place where any kind of life, what to speak sentient life, exists.

Finding such life would be an affront to many religions that contend that God created life on Earth only, and therefore finding even a fossil of a microbe on another celestial body would be the holy grail of science and have reverberating effects throughout human society. The theory of evolution would be proven.

It is believed to be highly likely that life does exist elsewhere in the universe simply by the laws of probability, but that being said, we have found no evidence to support this theory.

So now we can come back to your original question: “What are the chances of two planets from the same solar system having sentient species that reach space exploration around the same time?” Based on the fact that life has not been discovered anywhere, the chances to sentient life forms existing in the same solar system is practically nil (but not impossible).

Does anyone believe in extraterrestrial life? If yes, why? If no, why not?

Pretty much all of science and scientists in the world believe in extraterrestrial life, even though no evidence of extraterrestrial life has ever been found to date. Why do scientists believe in extraterrestrial life? Simply because there are billions of stars in the Milky Way galaxy and billions of galaxies in the universe. Somewhere it is highly likely that extraterrestrial life exists. It is even possible that extraterrestrial life of some form or another exists on Titan, within our own solar system!

Will an alien invasion by secular and militaristic extraterrestrials solve a lot of problems on Earth?

An alien invasion by secular and militaristic extraterrestrials would solve one of the biggest problems we have here on Earth. That problem being: does life exist on other planets? Finally we would have an answer!

Using our current technology, how close to us would an alien spacecraft have to be before it could detect Life on Earth?

During Earth’s night you can see the lights of major cities from the moon. So this would imply that further out from the moon one could detect light. Then there are the radio and television waves. They go out infinitely into space, but they become four times weaker every time the distance doubles. In any case, we pick up radio signals from Voyager I and II even though they have left the solar system, so I would suppose people could pick up our radio signals quite far away.

Why is there a stigma around attempting to discover extraterrestrial life?

There is no stigma. All of science is dedicated to discover extraterrestrial life. We would be completely excited to find even a fossil of a microbe from space because it would be the ultimate affirmation that life can evolve from matter on another world other than Earth. Our best hope at present is to find some kind of life on one of the moons of Jupiter or Saturn, or perhaps some fossils on Mars as of yet undiscovered. We are even spending billions of dollars with the SETI program to listen for radio waves from space!

However, much to the surprise and dismay of scientists, we have yet to discover anything at all.