Nasa's James Webb Space Telescope finds its first planet – and it is very similar to Earth

Nasa's James Webb Space Telescope has found its first planet – and it appears to be very similar to Earth.

The celestial body, known as LHS 475 b and located outside of our solar system, is almost exactly the same size as Earth. The rocky world is 41 light-years away in the Octans constellation, reports CNN.

Previous data collected by NASA's Transiting Exoplanet Survey Satellite, or TESS, had suggested the planet might exist.

It is expected to be just the beginning of a range of planets found by Nasa's new space telescope. What's more, it will be able to see those planets in much finer detail than ever before, as the only telescope that is able to characterise the atmosphere of distant planets, Independent reported.

For now, however, scientists have only been able to say what is not present in the planet's atmosphere. It can't have a thick methane-dominated atmosphere, for instance, akin to that on Titan, Saturn's moon.

Researchers hope to be able to better characterise the distant planet's atmosphere with time. But the findings also show JWST's use in studying other planets – with many more discoveries expected to come in the following weeks and months.

"These first observational results from an Earth-sized, rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb," agreed Mark Clampin, Astrophysics Division director at Nasa Headquarters in Washington.

"Webb is bringing us closer and closer to a new understanding of Earth-like worlds outside the Solar System, and the mission is only just getting started.", Independent reported.

Much is still unknown about the world. But early observations have confirmed some details about it: it has a diameter 99 per cent of Earth's and is a few hundred degrees warmer than our planet.

Such small, rocky planets have remained elusive, because their small size requires powerful instruments to see. The new findings suggest however that the increased power of JWST will allow them to be seen relatively easily using the new technology.

"This rocky planet confirmation highlights the precision of the mission's instruments," said Kevin Stevenson from Johns Hopkins University, who helped lead the work. "And it is only the first of many discoveries that it will make."