Frigid alien planet may offer a glimpse at Earth’s distant future
In a groundbreaking study, astronomers have identified the first rocky planet ever spotted orbiting a white dwarf, providing a chilling glimpse into the fate of Earth billions of years from now. This distant planet, located approximately 4,200 light-years from our solar system near the Milky Way’s center, may illustrate how our own planet could survive the death of the sun, albeit in a cold and desolate form.
The newly discovered planet has a mass about 1.9 times that of Earth and was once positioned within the “habitable zone” of its star, where conditions were favorable for liquid water. After its host star transitioned into a white dwarf—a stellar remnant resulting from the collapse of a star that was one to two times the mass of the sun—the planet now orbits at a distance 2.1 times that of Earth from the sun.
“This planet has become a freezing world because its white dwarf host is faint compared to its former self,” said Keming Zhang, an astronomer at the University of California, San Diego, and lead author of the study published in “Nature Astronomy”.
The sun, currently around 4.5 billion years old, is destined to follow a similar path. It will swell into a red giant and eventually shed its outer layers, leaving behind a white dwarf. This transition, expected to occur in about seven billion years, raises questions about the fate of the planets in our solar system.
“There is ongoing debate among astronomers about whether Earth will be engulfed during this phase,” explained Jessica Lu, a co-author of the study from UC Berkeley. “While Venus will certainly be consumed, Mars is expected to survive. Our findings suggest that Earth may have a better chance than previously thought.”
The rocky planet’s journey through its star’s death throes likely involved intense conditions. “It may have been a lava planet when the star transitioned to a red giant, eventually cooling to its current state,” Zhang noted.
In addition to the rocky planet, the white dwarf is orbited by a brown dwarf—an object larger than a planet but smaller than a star—highlighting the diverse outcomes for celestial bodies in such extreme environments.
While Earth remains habitable for less than another billion years, as the sun ages and heats up, its habitable zone will shift outward. “By that time, Earth’s oceans will likely have evaporated,” Zhang warned. “We need to consider migrating away from Earth well before then.”
Potential refuge could be found in large moons of the outer solar system, such as Ganymede, Titan, and Enceladus, which may offer conditions suitable for life as Earth becomes less hospitable.
This discovery not only enhances our understanding of planetary systems but also serves as a reminder of the long-term challenges that lie ahead for humanity and life on Earth.
