how many earth like planets are known as of now?

Question

I know it is only 30-40 but I need an exact number...

the size of earth, with an atmosphere. Also about the same distance from a star as we are.

Answer 1

Try this link below. I hope it helps. Take care.

Answer 2

Until today we have found none, zero, nada! All the planets found(about 50) are all gas giants similar to Jupiter.

However it is true that current planet finding methods are not really suited for finding earth like planets in the galaxy. Thankfully NASA and ESA are working together to send in orbit a cool instrument that is called Kepler. This one is going to have the capability of finding earth like planets by the transit method, the only method known to have this capability.

When a planet crosses in front of its star as viewed by an observer, the event is call a transit. Transits by terrestrial planets produce a small change in a star's brightness of about 1/10,000 (100 parts per million, ppm), lasting for 2 to 16 hours. This change must be absolutely periodic if it is caused by a planet. In addition, all transits produced by the same planet must be of the same change in brightness and last the same amount of time, thus providing a highly repeatable signal and robust detection method.

Once detected, the planet's orbital size can be calculated from the period (how long it takes the planet to orbit once around the star) and the mass of the star using Kepler's Third Law of planetary motion. The size of the planet is found from the depth of the transit (how much the brightness of the star drops) and the size of the star. From the orbital size and the temperature of the star, the planet's characteristic temperature can be calculated. From this the question of whether or not the planet is habitable (not necessarily inhabited) can be answered.

Answer 3

i think it is either none, or only a couple. Off the top of my head the smallest one found so far is 2 or 3 earth masses.

the thing is, the search for exoplanets has started with a method that will detect most easily large planets close to their star (gravitational wobble).

As a result this has not detected (m)any small rocky planets a bit further out.

Another method introduced more recently is that of the transit, i.e. the light of the star sips very very little when the planet passes in front. Again, this will best detect larger planets, at least as long as it is used from an Earth-based station, given perturbations from the atmosphere.

As for small, rocky planets in reality, it seems likely that they are very common, even though few have been found so far. It's a bit as if you use one of those side of the road scales to weigh trucks, and you let car and truck and pedestrian traffic pass on it, and you "detest" only the trucks, because pedestrians or cars are just too light for your tool to detect them.

New detection tools, probe-based, in orbit, are due to be launch in the near future, and will likely quickly detect large numbers of planets, including small, rocky ones.

Answer 4

No earth-like planets have been found (not counting Earth itself). Our instruments aren't sensitive enough to detect them. We have found many planets around other stars (hundreds I think). These are all very massive planets similar in size to Jupiter. We only detect these planets by how they make the sun wobble as the heavy planet pulls the sun around when it orbits. If we are lucky enough that the planet crosses in front of the sun from our point of view, we can also tell how big (diameter) the planet is by how much it darkens the sun.

Answer 5

9

Answer 6

51 Pegasi Solar System, solar system composed of a star similar to the sun and one known planet orbiting the star. The solar system is located 50 light-years from the earth in the constellation Pegasus. The star, 51 Pegasi, is more massive than the sun and is about 1.6 times the sun’s diameter.
the planet hasn't been named.

Answer 7

As of yet I do not believe that scientist have found any Earth like planets.

Answer 8

One

Answer 9

earth-like?

As in a solid mass, or size, or temperature, or location?

I would say just ONE, earth, seeing as how this is the only one known to have LIFE on it and your question was not specific at all....

Answer 10

I was not aware of any earth like planets being found yet...

Answer 11

If you meant rocky planets, there are four in our solar system. As of today, no extrasolar rocky planets have been found, yet.