4,000 light-years from home, astronomers find a chilling vision of Earth’s potential future

BERKELEY, Calif. — What will happen to Earth when our Sun burns out? A newly discovered planetary system 4,000 light-years away might hold the answer, showing an Earth-like world orbiting the remnant of a star like our Sun.

Imagine Earth not as the vibrant, life-sustaining oasis we know but as a frozen, desolate world orbiting the faint ember of what was once a star like our Sun. This is the scene set by the newly discovered system, where an Earth-mass planet circles a white dwarf at a distance roughly twice that of Earth’s current orbit around the Sun. It’s a cosmic déjà vu, a preview of one possible fate awaiting our planet in the distant future.

The story of this remarkable find begins with a celestial magic trick known as gravitational microlensing. In 2020, astronomers detected a brief brightening of a distant star, magnified a thousandfold by the gravity of an intervening planetary system. This cosmic lens, dubbed KMT-2020-BLG-0414, revealed not just one but three bodies: a star about half the mass of our Sun, an Earth-sized planet, and a much larger object about 17 times the mass of Jupiter — likely a brown dwarf (a failed star).

However, the true nature of this system remained shrouded in mystery until Keming Zhang, a former doctoral student at the University of California-Berkeley, and his colleagues took a closer look using the powerful Keck II telescope in Hawaii. What they found—or rather, didn’t find—was the key to unlocking the system’s secrets. Their findings are published in the journal Nature Astronomy.

Leave a Comment