Natural History Wanderings

EarthSky reports

Before 1992, when astronomers found the first exoplanets, they assumed other solar systems – if they existed – would be similar to ours. Now, we’ve found more than 5,000 exoplanets. These known worlds orbit fewer than 4,000 distant stars (of the hundreds of billions of stars in our Milky Way galaxy). And only about 850 of these stars have at least two confirmed planets. So … about 850 known multi-planet systems so far. Most don’t resemble ours. That’s the conclusion of a new study, announced on February 14, 2023, which categorized exoplanet systems into four basic classes. Our local solar system – our sun and its planets – fall into what these scientists are calling the Ordered class. Our class if the rarest of the four, they said.

Read more at  EarthSky | Of 4 types of planetary systems, ours is rarest