Scientists have found a “lost” planet, in a breakthrough that could help us discover alien life.
The planet is thought to be among hundreds of worlds that have gone missing and now can be discovered once more using new techniques.
NGTS-11b, as the planet is known, was first seen in 2018 by Nasa, just one of a huge number of exoplanets to be discovered by the space agency’s TESS telescope. Like all the worlds discovered by that technology, it was spotted when it passed in front of its star and caused a dip in the light that could be seen from Earth – but it was never seen again, and without a second observation, the planet was all but lost.
Now researchers hope they can detect those missing worlds all over again, allowing them to find cooler planets like those within our own solar system. Some of those planets could be habitable, scientists hope.
NGTS-11b is found 620 light-years away, and is in orbit five times closer to its star than we are to the Sun. It is the mass and size of Saturn, and takes 35 days to orbit around its star – though it is too near to its star, and so too hot, to support life, it is closer to the “Goldilocks zone” of being neither too hot or cold than many other planets.
It disappeared because the TESS telescope only scans most parts of the sky every 27 days, and so they can often only be seen passing their star once. Before it could come around again, the telescope was surveying another part of the sky, leaving astronomers unable to conduct further work on it.
The new research saw University of Warwick scientists examine the lost planets using a different telescope, the Next-Generation Transit Survey (NGTS) in Chile. With that technology, they were able to observe the star for 79 nights, letting them see the world a second time, nearly a year after it was first spotted.
“By chasing that second transit down we’ve found a longer period planet. It’s the first of hopefully many such finds pushing to longer periods,” Warwick’s Samuel Gill said in a statement.
“These discoveries are rare but important, since they allow us to find longer period planets than other astronomers are finding. Longer period planets are cooler, more like the planets in our own solar system.
“NGTS-11b has a temperature of only 160°C — cooler than Mercury and Venus. Although this is still too hot to support life as we know it, it is closer to the Goldilocks zone than many previously discovered planets which typically have temperatures above 1,000°C.”
Scientists now hope to use the same technique to find many more of those planets, allowing them to track down other worlds that could be habitable or even inhabited.
“There are hundreds of single transits detected by TESS that we will be monitoring using this method,” Dr Gill said. “This will allow us to discover cooler exoplanets of all sizes, including planets more like those in our own solar system. Some of these will be small rocky planets in the Goldilocks zone that are cool enough to host liquid water oceans and potentially extraterrestrial life.”
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