NASA's astronomers have discovered a planet that resembles Earth like no other planet known until today. This planet is circling a star 500 light-years away from us. The first planet outside our planetary system was discovered 20 years ago. By now with the use of Kepler telescope about 2,000 planets have been discovered.

The Voice of Russia has talked to Oleg Korablev, deputy director of Space Research Institute, Russian Academy of Sciences, to find out more about the newly discovered planet which is almost the same size as Earth.

The astronomers named the planet Kepler 186f after NASA's Kepler planet finding mission. According to Elisa Quintana of NASA's Ames Research Center this is the "first validated, Earth-size planet in the habitable zone of another star." The habitable zone means that the planet is located far enough from its star and temperatures there could allow for liquid water to flow at the surface. This makes the planet potentially hospitable for life.

The gravity on Kepler 186f is likely to be roughly the same as the gravity on Earth. According to Stephen Kane, an astronomer at San Francisco State University you could far more easily imagine someone being able to go there and walk around on the surface.

However Kepler 186f is not a perfect replica of Earth. It is closer to its star that is smaller, cooler and fainter than the sun. The planet itself is 10 percent wider than Earth and the time it completes one orbit is 130 days, not 365.

The planet is also receiving less warmth, so perhaps more of its surface would freeze. "Perhaps it's more of an Earth cousin than an Earth twin," says Thomas S. Barclay a member of the discovery team. The Voice of Russia has talked to Oleg Korablev, deputy director of Space Research Institute, Russian Academy of Sciences, to find out more about the newly discovered planet.

According to astronomers the discovered planet is at the distance of 500 light years from us. How do astronomers measure the distance to a certain planet? How is it technically possible to measure a distance in light years?

Actually the distance to the planet is not really the distance to the planet, it is a distance to the apparent sphere, and 500 light years is quite large distance and it is not measured in light years, it is enumerated in light years. It means the light travels 500 years to this distance. It is pretty large.

It is about 32 million distances from Earth to the Sun and if we say it in kilometers, it will be really a very long number. So, it is a kind of astronomical number and light years is used to reduce it to make it more human. But about measuring the distances to the star, this distance is large and it is rather an estimation than the measurement because normally the distances are measured by triangulation and this works pretty well at one moment when Earth orbits around the Sun and in half a year it is in the opposite place, opposite position on its orbit around the Sun, and making triangulation from these two positions allows to measure very large distances but it is within 300-400 light years.

So, this is estimation from the greatness of the star although there is some relation from spectral properties, the color of the star, and its brightness, and it allows to make an estimation of the distance. That is how it works.

Astronomers say Kepler 186f is located in the habitable zone of another star. Does it mean that chances to detect some forms of life there is high?

I don't think there is a chance to detect any signs. You could maybe have some indirect information about the fact that life could exist on a planet, but for this case what we know is that it is a habitable zone. What is habitable zone? It means that the energy received by the planet from the star and the ratio of the energy received and the energy incepted make the temperature on

Source: Voice of Russia