[NTD News, Beijing time, September 30, 2024]Astronomers discovered an Earth-like planet in the Milky Way that is thousands of light-years away from the Earth and orbiting a star. This terrestrial planet is similar to the Earth 8 billion years from now, so people can use this to predict what the Earth will look like 8 billion years from now.
The University of California, Berkeley, stated in a press release on September 26 that astronomers from the school observed the Earth-like planet using the WM Keck Observatory in Hawaii.
The rocky planet, 4,000 light-years from Earth, orbits a white dwarf star about twice the size of Earth today that is only half the mass of the Sun.
This may be the future fate of the Earth. The Sun will eventually expand like a balloon to a size larger than Earth’s orbit today, swallowing up Mercury and Venus in the process. As the Sun expands into a red giant, its loss of mass will force planets to migrate to more distant orbits, making Earth’s chances of surviving farther from the Sun slim.
The red giant’s outer layers will eventually be lost, leaving behind a dense white dwarf. It would be no larger than a planet, but would have the same mass as a star. If Earth survives by then, its orbit may be twice its current size, beyond the current orbit of Mars.
The discovery tells scientists about the evolution of main-sequence stars like our sun from the red giant stage to white dwarfs, and how this affects the planets around them.
Some studies argue that for the Sun, this process would begin in about a billion years, eventually evaporating Earth’s oceans and doubling its orbital radius, but only if the Sun does not engulf the Earth as it expands. The sun’s transformation from a red giant to a white dwarf is estimated to be 8 billion years from now.
Keming Zhang (transliteration), a former doctoral student at the school who led the study and is currently a postdoctoral researcher at the University of California San Diego, said that there is no question about whether the earth will be destroyed within 6 billion years. Astronomers have not yet reached a consensus on the engulfment of the sun that became a red giant.
But Zhang Keming said: “In any case, the earth’s habitable time is only about 1 billion years, by which time the earth’s oceans will evaporate due to the runaway greenhouse effect – long before it may be swallowed by a red giant star.”
Jessica Lu, associate professor of astronomy at the University of California, Berkeley, said it is still unknown whether life on Earth could survive the period when the sun became a red giant, but the most important thing is that the Earth did not After the sun became a red giant, it was devoured.
She said: “The (star) system discovered by Zhang Keming is an example of a planet (possibly an Earth-like planet with an original orbit similar to the Earth) that survived the red giant phase of its parent star.”
Zhang Keming mentioned that even if the earth is swallowed up in the red giant stage of the sun, humans can take refuge outside the solar system. Several moons of Jupiter, such as Europa (also known as Europa), Callisto (also known as Callisto), Ganymede (also known as Ganymede), and Saturn’s The moon Enceladus (also known as Enceladus) appears to have frozen oceans that may thaw as the sun expands.
Zhang Keming said: “When the sun becomes a red giant, the habitable zone will move near the orbits of Jupiter and Saturn, and many of these moons will become planets with oceans. I think that in this case, humans may be able to go out Migrate there.”
The above research results were published in the journal Nature Astronomy on September 26.
(Reprinted from The Epoch Times/Editor: Ye Ping)
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