How many "Known Planets", are there, in the Universe?

Answer 1

8 in the solar system

218 exoplanets in the Milky Way at distances from 10 to 21,500 light years away.

226 so far.

The galaxy is about 100,000 light years across so we are only finding them in our immediate vicinity. Though several detection methods are used, they can only readily detect gas giants ("Hot Jupiters") so we are missing a significant percentile of terrestrial rocky planets that are doubtless there but we haven't got sufficiently sophisticated detection methods in place yet and so they are eluding detection.

Obviously nothing yet from other galaxies. But if there are 226 in just our corner of our galaxy we can be confident there are many thousands in the universe.

In 1807 we knew of just 4 asteroids. We now have automated search facilities which are unearthing 5,000 a month and we currently know of 368,000. In 200 years of looking. Our planet hunting is less than 15 years old and exponential growth can be expected there too, as our technology becomes more refined.

But will any of these support life?

We already know of 20 stars with more than 1 planet. (2 that have four planets, 4 that have 3 planets and 14 that have two planets) so systems in which at least one planet can be expected to be in the habitable zone will occur,

And interestingly two stars are now (in 2005) known to have asteroid belts, 10 and 25 times as massive as our own. And there is evidence that comets abound around other stars too, so features we once throught unique to our solar system would now appear to be more prevalent than we first thought.

Answer 2

As of 13 April 2007 we know of 218 planets outside our Solar System (the current rate is 2 or 3 planets being discovered and added to this catalog every month). Add to this figure the 8 planets of our Solar System. This will give you a total of 226 known planets so far.

Answer 3

That is an open question, since the research is on going. However at the last count we had 150 exo-planets, with the count growing into the projected 230 some odd planets to date with the count still ongoing.

Answer 4

There are 8 of our own not encluding Pluto. 8
3 Dwarf planets 3
ANd about 230 other planets in the universe +230
So that means it is probably 240 something.
Hope this helps.

Answer 5

Well, there's 8 major and 3 minor planets in the solar system, so that makes 11.

Then there are about 220 extrasolar planets that we know about.

So, call it 230-some?

Answer 6

brucebr.. has the best answer, but it is probably wrong. Any time you read a number for planets, there have been more discovered since the number was written. It would be very difficult to have the right answer.

Answer 7

Just eight planets is known in the universe. From Mercury to Neptune. The rest in simple speculation.

Answer 8

Our own 9 (I still call Pluto a planet) plus 204 others according to NASA/JPL/Caltech:

http://planetquest.jpl.nasa.gov/news/harps4NewPlanets.cfm

.

Answer 9

I would say some where between 220 and 240 but there are most likley milions we don't know about.