Are there aliens in the world?

Now we know that the earth is just an ordinary planet. In the Milky Way alone, there are at least 4 billion planets with natural conditions similar to the Earth. It is entirely possible that there is extraterrestrial life. But so far, whether there are "aliens" really needs further scientific proof.

If there are aliens, where will they be? The grand canyon, riverbed, polar cap and other phenomena on Mars once made people think that Martians might have existed on Mars. So, humans sent a Mars probe there to find out, but according to the probe, the climate on Mars is very bad, which does not meet the necessary conditions for existence at all. Man's desire to find Martians has also failed.

So now we can't say that there are aliens in the universe out of thin air, nor can we say that there are no aliens. That's nonsense!