A groundbreaking discovery by astronomers has identified an Earth-like planet orbiting a white dwarf star in the constellation Sagittarius, located approximately 4,000 light-years from our solar system.
This rocky planet, possessing a mass similar to Earth, may provide critical insights into the long-term survival prospects of humanity as our sun approaches the end of its life cycle.
The planet, part of the KMT-2020-BLG-0414 system, was observed using the Keck Telescope in Hawaii by researchers from the University of California, Berkeley. This system not only includes the Earth-sized planet but also features a brown dwarf - an object roughly 17 times the mass of Jupiter. The planet orbits its white dwarf at twice the distance that Earth orbits the sun, suggesting a stable environment that could potentially support life.
A white dwarf represents the final evolutionary stage of a star like our sun, formed after it exhausts its nuclear fuel and sheds its outer layers. As the sun transitions into a red giant, it will expand significantly, potentially engulfing the inner planets, including Mercury and Venus. However, this new discovery hints that Earth might survive this expansion by being pushed into a more distant orbit due to the sun’s mass loss, thereby avoiding destruction.
Jessica Lu, an associate professor of astronomy at UC Berkeley, emphasized the importance of this finding: “Whether life can survive on Earth through that red giant phase remains uncertain. However, the key takeaway is that Earth itself may not be swallowed by the expanding sun.”
Keming Zhang, the lead author of the study and an Eric and Wendy Schmidt AI in Science Postdoctoral Fellow at UC San Diego, noted, “Currently, there is no consensus on whether Earth can avoid being engulfed by the red giant sun in six billion years. Nevertheless, Earth will remain habitable for another billion years before the runaway greenhouse effect renders it uninhabitable, long before the sun’s final stages pose a direct threat.”
The discovery opens up possibilities for future human migration within our solar system. As the habitable zone shifts outward due to the sun’s expansion, moons of Jupiter and Saturn - such as Europa, Callisto, and Enceladus - could become viable locations for sustaining human life. These moons, with their potential subsurface oceans, may offer the necessary conditions for life, presenting new frontiers for human habitation.
This remarkable discovery underscores the resilience of planetary systems and the potential for humanity to find refuge beyond Earth. As researchers continue to explore these distant worlds, the prospect of establishing new habitats in our solar system becomes increasingly feasible, offering a beacon of hope for the future of human civilization.