Emily Chan
A new planetary system was discovered about 4,000 light-years away from our own. The findings may provide answers as to what will happen to Earth when the sun finally burns out.
In the newfound system, a frozen, desolate world similar to Earth was orbiting the faint remnant of a star much like the sun.
The Earth-like planet circled a white dwarf star at a distance about twice that of Earth’s current orbit around the sun.
The discovery was made in 2020 using a technique called gravitational microlensing. It allowed astronomers to detect the brief brightening of a faraway star.
The star was magnified significantly by the gravity of a planetary system that consisted of an Earth-sized planet, a star about half the size of the sun, and a brown dwarf star about 17 times the size of Jupiter. A brown dwarf star is also known as a failed star.
The system has been dubbed KMT-2020-BLG-0414. A former doctoral student at the University of California-Berkeley named Keming Zhang and his colleagues used the Keck II telescope in Hawaii to take a closer look at the planetary system.
“Our conclusions are based on ruling out the alternative scenarios since a normal star would have been easily seen,” said Zhang. “Because the lens is both dark and low mass, we concluded that it can only be a white dwarf.”
The star at the center of the system had already lived its life, transformed into a red giant, and finally settled as a white dwarf. The system also demonstrates what will happen to Earth in the future as the sun ages.
Sometime in about a billion years, the sun will start to swell and possibly swallow up the inner planets. It might force the outer planets, including Earth, into wider orbits.
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