I dont know if this is the right thread to ask, but its something I always wondered. Is there only one Mars? Or does every galaxy have one? Similar to how there multiple moons in out solar system.
Not sure if serious?
Mars is a planet, about half as wide as Earth. It goes round the sun, as do the other 6 planets in our solar system (Mercury, Venus, Earth and Mars are small and rocky. Jupiter, Saturn, Uranus, Neptune are much bigger and mostly gas). Most of those planets have moons of various sizes going round them. Earth is unusual for how big its moon is compared to itself.
There are planets going round other stars too. We've detected lots of them in our galaxy and it's fair to assume that every star has some planets. We haven't directly detected planets as small as Mars around other stars, but again it's fair toassume they exist. None of them will be exactly like Mars, just as none of them will be exactly like Earth or Jupiter. There are 100s of billions of stars in our galaxy alone, and something like 2 trillion galaxies in the universe (although they are smaller the older they are). So the number of planets in the universe is probably more than 40,000,000,000,000,000,000,000.
It will be a *very* long time, if ever, before we can get detailed looks at planets around other stars because they're so far away. So it's a tough subject to make definitive statements about.