Beijing time:2022-03-25 08:07
[NTD, Beijing, March 25, 2022]NASA announced that the cumulative number of exoplanets discovered has reached 5,000, a milestone in the history of exoplanet exploration in the past 30 years.
On March 21, the exoplanet counter jumped to the 5,000-count after NASA confirmed the discovery of 65 new exoplanets. Some of these planets are about the size of Earth and have rocky surfaces; some are giant gas planets, larger than Jupiter; and some are “mini-Neptunes”, which are similar to Neptune in various characteristics, but smaller than Neptune.
“It’s not just a number, every planet is a world,” said Jessie Christiansen, program chief scientist at NASA’s Exoplanet Science Institute. It’s exciting because we don’t know anything about what’s going on up there.”
NASA says the Milky Way is likely to be home to billions of exoplanets. In so many worlds, there must be other beings.
Of the 5,000 exoplanets discovered so far, 35% are Neptune-like, possibly giant ice spheres, or slightly warmer; 31% are “super-Earths,” which are planets with rocky surfaces that are between the size of Earth and Neptune. in between; and about 30 percent are gas giant planets.
In 1992, astronomers discovered the first exoplanet. Since then, detection techniques have evolved considerably, with new exoplanets being discovered at an ever-increasing rate.
Initially, astronomers speculated on the traces of surrounding planets by observing the tiny wobble of stars as they were pulled by the gravitational pull of the surrounding planets. Later, scientists launched space telescopes that have observed more than 170,000 stars in total. By observing the changes in the brightness of stars, infer the traces of surrounding planets. This method is called the transit method, and several of the exoplanets that have received the most attention so far have been detected by this method.
(Transfer from The Epoch Times/Editor-in-charge: Ye Ping)
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