This is how Earth can escape ultimate death after the sun explodes
A planetary system anchored by a white dwarf star, located about 4,000 light-years away, offers astronomers insight into what could happen to our Sun and Earth in about 8 billion years. This scenario will unfold if Earth survives the Sun’s transformation into a red giant, which is expected to occur in 5 to 6 billion years. During this phase, the Sun will expand, possibly engulfing Mercury, Venus, and possibly Earth before shrinking into a white dwarf.
The potential for Earth’s survival
One scenario for Earth’s survival involves migration to an orbit similar to Mars or beyond, resulting in a radiation-ravaged yet frozen world orbiting a burned-out star, according to a study published in the journal Nature Astronomy. The newly discovered system reveals a white dwarf with half the mass of the Sun and an Earth-sized planet in a wider orbit, showing what a surviving Earth might look like.
Keming Zhang, a researcher from the University of California, San Diego, emphasized that there is no consensus on whether Earth could escape being engulfed by the red giant Sun. This system is notable because it also contains a massive companion, likely a brown dwarf, a stellar body that fails to ignite nuclear fusion.
The discovery process
The planetary system was identified through a microlensing event, in which the gravitational influence of a body distorts light from a more distant source. Observations of this event, named KMT-2020-BLG-0414, were made using the Korea Microlensing Telescope Network. The research continued with the Keck telescopes in Hawaii and eventually confirmed the nature of the central star as a white dwarf, based on the absence of light expected from a main sequence star.
Future habitable possibilities
While this discovery suggests that Earth could escape destruction, it raises questions about the potential for the continued existence of life on our planet. Jessica Lu, an astronomer at UC Berkeley, noted that while Earth may avoid being engulfed, it may not remain habitable during the Sun’s red giant phase. The habitable zone will shift beyond Earth’s orbit, with Zhang suggesting that humanity may need to consider migrating to the moons of Jupiter or Saturn, which could become viable ocean worlds as the Sun grows larger.
Conclusion
This research illustrates the importance of microlensing in exploring planetary systems. The upcoming Nancy Grace Roman Telescope, scheduled for launch in 2027, is expected to expand our ability to discover and study exoplanets, potentially revealing more unique configurations in the cosmos.
