In a groundbreaking observation using gravitational microlensing, astronomers have detected an Earth-like planet located 4,000 light-years away, orbiting a white dwarf star. This discovery offers a glimpse into the future of our own solar system.
The exoplanet, which has a mass 1.9 times that of Earth, may reflect what will eventually happen to our planet when the Sun transforms into a white dwarf after exhausting its hydrogen fuel in about five billion years.
The research team, led by astronomer Keming Zhang from the University of California, utilized the Keck Observatory in Hawaii to observe the distant system. They employed the gravitational microlensing phenomenon, where the gravity of a massive object amplifies the light from a more distant object, to study the white dwarf and the Earth-mass planet.
This distant system serves as a projection of the potential fate of the Sun-Earth system. As the Sun expands into a red giant, it could engulf Mercury and Venus, but some terrestrial planets may migrate to safer, more distant orbits.
The study, published in Nature Astronomy, indicates that planets formed between one and three astronomical units from their star might avoid destruction during their host star's red giant phase. This could provide a glimmer of hope for Earth's survival as the Sun sheds its outer layers, leaving behind a dense white dwarf.
While only gas giant planets have been observed around white dwarfs so far, this new finding suggests that at least one Earth-like planet has survived its host star's red giant phase, although it is unlikely to support life due to its distance from the habitable zone.
As the Sun gradually becomes more luminous, Earth will only remain habitable for another billion years before extreme greenhouse conditions render it inhospitable. The fate of Earth in the distant future remains uncertain, but this discovery provides a fascinating insight into the evolution of planetary systems.