Earth has remained unique among the planets in the solar system and among those planets, identified so far, outside the solar system. One of Earth’s main features is the presence of carbon and oxygen in its atmosphere. Now, Earth shares this unique distinction with another planet outside our solar system. Indeed, the Hubble Space Telescope has detected, for the first time ever, the presence of oxygen and carbon in the atmosphere of a planet outside our solar system.
This planet, HD 209458b, orbits a sun - like star, 150 light years from Earth and completes its orbit around it in just four days. The planet HD 209458b has several unique features: It is the first extrasolar (planet outside the solar system) planet known to have an atmosphere. This atmosphere was so far known to be only hydrogen, evaporating from its surface. Which is why it belongs to a class of planets called "hot Jupiters." Now it has been found that its atmosphere also contain oxygen and carbon. However, unlike Earth, the oxygen naturally exists and is not produced by any sort of life on the planet.