Like snowflakes, no two planetary systems are the same. Astronomers have now observed one of the most unique planetary arrangements ever seen: four miniature Neptunes locked in perfect synch with each other—and it’s been like this for billions of years.
The Milky Way appears to be peppered with so-called Super-Earths — distant exoplanets that are between two to 10 Earth masses. Many of them have even been detected within habitable zones. But a new study shows it doesn't matter. They're all just dead worlds.
Among the 860 exoplanets documented so far, a good portion of them are so-called super-Earths — planets that feature a mass greater than Earth's, but lower than our solar system's smaller gas giants, namely Uranus and Neptune (both of which are about 15 Earth masses). And as the name implies, some of these…