It is not known. Scientists are still not sure how many dwarf planets are in the solar system or how many true planets are in the galaxy. If estimates from our solar system apply elsewhere, however, the number is probably in the trillions.
No. There are dwarf planets in our own solar system that are smaller than Pluto and there are many undiscovered planets in the Milky Way that would be smaller than it, but are too far away to see.
It isn't even clear how many dwarf planets our own Solar System has (it may be some tens of them, hundreds, or even thousands) - much less how many there are in the entire Milky Way or in other galaxies.
There are millions, possibly billions, of planets in the Milky Way. An exact number will never be known.
Eris is not a planet in the Milky Way galaxy; it is a dwarf planet located in the outer solar system. It is the most massive dwarf planet known to exist and is part of the Kuiper Belt, a region beyond Neptune that is home to many icy bodies.
There are eight planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The Milky Way is our galaxy, which contains billions of stars with their own solar systems.
Saturn is in our galaxy, the Milky Way. Answer Saturn is indeed in the Milky Way, a spiral galaxy containing billions of stars and the particular star, the Sun at the centre of the Solar System we inhabit which contains all the planets from Mercury to Neptune and many dwarf planets and plutons like Pluto.
Planets orbit stars, stars orbit a galaxy. Planets are not "on" anything. A lot of stars out there have planets - we are just finding out how many now that we have better techniques to find them. So probably all galaxies have at least some stars with planets.
The Milky Way has somewhere between 100 and 400 billion stars; most of those are red dwarf stars.
The Kuiper Belt is the main group or cluster of asteroids and comets in our galaxy. But even though I am sure, I advise you to do research elsewhere. You can never trust the opinions of others. Have a nice day! Haha! :P
Nobody has any idea. Several hundred have been identified. But it's a hugely difficult process, and more keep being discovered all the time. It's beginning to look like most stars have planets, and nobody is even sure of how many STARS there are in the Milky Way Galaxy, because some of THEM are so hard to see..
Yes, astronomers have discovered hundreds if not thousands of other galaxies.
That is currently unknown. However, based on the planets found so far it seems there are at least as many planets as stars. Current estimates suggest 100 billion to 400 billion planets in our galaxy.