Photo: Artist's impression of Poltergeist, Phobetor, and Draugr. (Pablo Carlos Budassi)
March 2022 has marked an astonishing milestone in the field of space exploration, the discovery of the 5,000th planet outside of our own solar system. Remarkably, the first 'exo-planet' was only discovered 30 years ago in 1992, meaning that the number of known exo-planets has grown massively in what is a relatively short period of time.
Jessie Christiansen of the NASA Exoplanet Science Institute said of the most recent discovery:
"It's not just a number. Each one of them is a new world, a brand-new planet. I get excited about every one because we don't know anything about them."
The first exo-planets discovered were pinpointed by astronomers Alexander Wolszczan and Dale Frail and found to be orbiting a dead star, a pulsar. These new planets were around 4 times the size of Earth. The discovery made headlines around the world, but it wasn't until 1994 that a third planet was discovered, this one being far smaller than Earth. The three planets were known as Poltergeist, Phobetor, and Draugr.
Since that first discovery astronomers have put more and more effort, funding, and focus, into finding new planets beyond our tiny local region of space. What captivated astronomers about the presence of exo-planets was the fact that the evidence seemed to point towards there being a huge number of them out there. This was because many of the planets were discovered around pulsars, stars that had died in huge explosions, and if planets could survive there then they were most likely hugely abundant across the galaxy.
Alexander Wolszczan says:
"If you can find planets around a neutron star, planets have to be basically everywhere. The planet production process has to be very robust."
One of the key changes to exo-planet discovery came with the launch of the Kepler Space Telescope, which allowed astronomers to peer deeper into space and make more accurate calculations about very distant bodies. Since 2009 the telescope has found 3,000 exo-planets that have been confirmed by peer review, while another 3,000 are still waiting to be evaluated for veracity.
William Borucki of NASA, who helped pioneer the technology used by the Kepler telescope, says:
"I get a real feeling of satisfaction, and really of awe at what's out there. None of us expected this enormous variety of planetary systems and stars. It's just amazing."
[Based on reporting by: science alert]
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