Send a probe or alalyse the light they reflect using optical telescopes.
They're all distant. The gas giants (Jupiter, Saturn) are more distant than the inner planets (Mars, Venus). Exoplanets (planets around other stars are even (far) more distant.
No. We know what the stars are. They are not planets. They are distant suns, many of which do have undiscovered planets.
No, the solar system planets are all in stable orbits. That may not be the case for the asteroids, comets, and distant planetesimals.
They could, but as of now, no astronauts have travelled to any other planets in the solar system.
It's called an APHELION
No. Our solar system includes the sun and the planets that orbit it.
eight hours
Ufo's and aliens are not real Aliens are real. They live on distant planets and distant galaxies. They do not come here to abduct humans. It is silly to think that.
An exobiologist would study life forms in distant planets, A common occupation in Sci Fi.
A biquintile is an aspect of two planets which are distant from each other by two fifths of a great circle.
We do not know. So far, organic molecules have been located on planets and in distant stars, but this is not proof that organic life exists there.
Some names of unmanned missions include Voyager, Curiosity, Juno, and Hubble. These missions have explored distant planets, comets, asteroids, and galaxies, providing valuable information about the universe.