How many planets are there in this whole world?

Answer 1

With admiration and kudos to "Labouts" for his superb previous answer to the

same question, we reproduce it below. If you haven't the patience to read it,

the loss is all yours. In summary, the answer to your question is "Lots".

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Astronomers estimate there are 1021 stars in the universe. With a conservative estimate of three planets per star (some could have many more, some would have none at all) this puts the estimated number of planets into millions of billions.

The actual number of planets in the universe is difficult to ascertain. However, we do know that the number is very, very large, and the true figure is completely beyond human comprehension.

No offence to the person who wrote this, but this doesn't make any sence.

• Estimates for the number of stars in our galaxy vary between 100 billion and 400 billion, with most setting the figure at roughly 200 billion. There are very few estimates for the number of planets per star, as we have only discovered 429 'exoplanets' (planets that orbit another star than the Sun; as of 9th February 2010: http://planetquest.jpl.NASA.gov/atlas/atlas_index.cfm ).

• However, with approximately 200 billion galaxies in the part of the Universe that we can see, even if there were only one planet per star there would still be around 40 trillion billion in our observable Universe. It is likely that this estimation is very inaccurate, as we have no idea what the mean number of stars per galaxy is likely to be, nor have we counted every single galaxy in the Universe. Nonetheless, it is also likely that the number of planets in the Universe is greater than all the grains of sand on this planet Earth.

The number of known planets changes by the day. So far, we've confirmed the existence of the 8 main planets of the solar system, a handful of dwarf planets (including Ceres, Pluto, Sedna, Eris, and a few others), and 429 extra-solar planets in the nearby portion of our own galaxy. Estimates on the number of planets in the universe are based on the observed distribution of these relatively few known planets.
It's unknown just how many planets exist in the Universe. The number is likely huge - trillions upon trillions!
On average half the stars might have planets, assuming around 10 planets per star (so an average of 5 planets for each star) around 500 billion, billion planets.
According to current research, it seems likely that each star (or at least most stars) has at least one planet.
Outside the solar system some have been discovered orbiting other stars. It is suspected that most stars possess planets because of a thing called angular momentum.

In the solar system most of the angular momentum is contained in the planets, which means that if the planets were collapsed into the Sun it would rotate on its axis about 50 times faster, which might cause it to fly apart. It's the same effect as when a ballerina is rotating, and when she pulls her arms in she rotates faster because of the angular momentum of her arms and hands.

The Sun is a very average star in many ways and the total angular momentum of the solar system is probably typical, so when we see other stars sitting there without flying apart, it's a good bet that they possess their own solar systems. But we can detect only the very biggest of the planets going round other stars.

Answer 2

There has thought to be millions and billions of planets out there but, however, no one is exactly sure yet. The farthest they have seen was all of our planets in our solar system, the Milky Way!

Answer 3

Currently we have 8 planets in our solar system. The rest are called dwarf planets.

Answer 4

I guess you mean "in the Solar System" not in the Earth. The answer to that

is 8.

Answer 5

well the world is a planet on its own, so one. the UNIVERSE has uncountable planets as scientists believe it is still expanding, and we'll never be even 50% sure how many planets there are.

Answer 6

There are no planets in the world. The nearby planets are in the solar system.

Answer 7

There are 8 planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Answer 8

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