Astronomers Discover a Planet that Offers a Glimpse of Earth’s Future

Astronomers have discovered a distant planet, KMT-2020-BLG-0414, 4,000 light-years away, that offers a glimpse of what Earth could look like 8 billion years from now. The planet orbits a white dwarf, the remnant of a star, which our sun is expected to become after expanding into a red giant. This transformation could engulf Mercury, Venus, and possibly Earth.

If Earth survives, it may resemble this distant world, drifting away from the cooling remains of the sun. Scientists speculate that in the distant future, humanity might migrate to the moons of Jupiter and Saturn, which could become ocean worlds as the sun evolves.

Astronomers have identified a distant planet, KMT-2020-BLG-0414, located 4,000 light-years away, that could provide a preview of what Earth might look like 8 billion years from now. This rocky planet orbits a white dwarf, the remnants of a star, which our sun is expected to become in about 5 billion years.

Before turning into a white dwarf, our sun will expand into a red giant, potentially consuming Mercury, Venus, and possibly Earth and Mars. If Earth survives, it may resemble this distant planet, slowly drifting away from the cooling remains of the sun. The findings were published on September 26 in the journal *Nature Astronomy*.

Lead author Keming Zhang, an astronomer at the University of California San Diego, noted that there’s no consensus on whether Earth will escape being engulfed by the red giant. Regardless, Earth will likely only remain habitable for another billion years before a runaway greenhouse effect evaporates its oceans.

Stars like our sun burn hydrogen into helium for most of their lives. Once they run out of hydrogen, they start fusing helium, dramatically increasing their energy output and expanding into red giants. This process could engulf any nearby planets.

The distant planetary system was first observed in 2020 when it passed in front of a more distant star, acting as a gravitational lens and making its presence detectable. The planet, about twice the size of Earth, orbits its white dwarf at a distance similar to Earth’s distance from the sun. The system also includes a brown dwarf, a failed star, with about 17 times the mass of Jupiter.

The fate of humanity in such a distant future is uncertain. Scientists are unsure if life could survive the red giant phase or if humans could prevent the warming that will eventually boil Earth’s oceans. Zhang speculated that humans might eventually migrate to the icy moons of Jupiter and Saturn, such as Europa and Enceladus, which could become ocean worlds as the sun evolves.

“As the sun becomes a red giant, the habitable zone will shift to around Jupiter and Saturn’s orbits, potentially turning many of these moons into ocean planets,” Zhang said. “In that scenario, humanity might find a new home there.”