Kepler 90

If you squished the planets of our solar system much closer to the Sun, you’d have something similar to the system known as Kepler 90. The smaller planets are closer to the star, while the giant planets are farther out.

The star is bigger, brighter, and heavier than the Sun, and about half the Sun’s age. Most important, it’s the only star system besides ours with eight known planets. The planets that are close to the star are a little bigger than Earth, the ones in the middle are bigger still, and the two at the outer edge of the system are giants.

There’s one big difference between Kepler 90 and the solar system. The Sun’s farthest major planet is Neptune — about 30 times farther from the Sun than Earth is. But at Kepler 90, the most-distant planet is only as far out as Earth. That means the planets are crowded together — smushed in close to their sun.

When our solar system was young, its giant planets moved much closer to the Sun. That could have scattered any planets that were even closer. But the planets of Kepler 90 appear to be stable. They align in such a way that the gravity of each planet helps keep the others in place — a tightly packed family of planets.

Kepler 90 is in Draco. Although the star is much too faint to see without a telescope, you can get an idea of its location. It’s low in the northwest at nightfall, to the upper right of the bright star Vega. And it’s in the northeast at dawn, to the left of Vega.
 

Script by Damond Benningfield