nasa tess

Nasa’s planet-hunting satellite discovers its first two alien worlds

Image credit: reuters

Nasa’s Transiting Exoplanet Survey Satellite (Tess) has discovered two distant planets five months after its launch, the space agency has announced.

Tess was launched in April to build on the work of its predecessor, the Kepler space telescope, which discovered the bulk of some 3,700 exoplanets documented by astronomers during the past 20 years and was running out of fuel. 

Nasa used a SpaceX Falcon 9 rocket for the launch, which was unexpectedly delayed for two days after an 11th-hour technical glitch was discovered.

Tess made an early discovery of “super-Earth” and “hot-Earth” planets in solar systems at least 49 light years away, marking the satellite’s first discovery since its April launch.

The satellite is expected to spend around two years orbiting the Earth in a $337m (£258m) mission to expand astronomers’ known catalogue of so-called exoplanets - worlds circling distant stars.

While the two planets are too hot to support life, Tess deputy science director Sara Seager expects many more such discoveries.

“We will have to wait and see what else Tess discovers,” Seager said, while speaking to Reuters. “We do know that planets are out there, littering the night sky, just waiting to be found.”

Nasa expects to pinpoint thousands more previously unknown worlds, perhaps hundreds of them Earth-sized or “super-Earth” sized - no larger than twice as big as our home planet.

Those are believed the most likely to feature rocky surfaces or oceans and are thus considered the best candidates for life to evolve. Scientists have said they hope Tess will ultimately help catalogue at least 100 more rocky exoplanets for further study in what has become one of astronomy’s newest fields of exploration.

MIT researchers on Wednesday announced the discovery of Pi Mensae c, a “super-Earth” planet 60 light years away orbiting its sun every 6.3 days. The discovery of LHS 3844 b, a “hot-Earth” planet 49 light-years away that orbits its sun every 11 hours, was announced on Thursday.

Pi Mensae c could have a solid surface or be a waterworld, as the composition of such planets is a mixed bag, Martin Spill, Nasa’s program scientist for Tess, said.

The two newest planets, which still need to be reviewed by other researchers, offer the chance for follow-up study, officials said.

“That, of course, is Tess’ entire purpose - to find those planets around those brightest nearby stars to do this really detailed characterisation,” Spill said.

With four special cameras, Tess uses a detection method called transit photometry, which looks for periodic dips in the visible light of stars caused by planets passing, or transiting, in front of them.

Last weekend, an ocean monitoring satellite built by UK engineers was launched from an Indian space centre. 

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