If our planet ever leaves the Sun, it will turn into a dead icy world hurtling through the stars and ending up in the maw of a black hole, scientists warn.
In the novella “The Wandering Earth”, which was first published in 2000, Chinese science fiction writer Liu Cixin describes a situation where the Sun dies and turns into a red giant.
This giant is about to fry our planet. However, humanity will build thousands of fusion engines and with the whole Earth will set off on a journey lasting thousands of years to the nearest star, Proxima Centauri.
It is mere literary fiction. Magazine Live Science still wondered if it was possible for Earth to leave the solar system.
A rogue invader can upend the planet
“It’s highly unlikely,” replied Matteo Ceriotti, an expert on spacecraft engineering at the University of Glasgow. “But improbable doesn’t mean impossible,” he pointed out, describing a way a planet could go on a spacewalk.
“Earth could be pulled out of its orbit by a massive interstellar object entering the solar system and passing close by,” he said.
“In this close encounter, the Earth and the object would exchange energy and momentum, and if the object was fast, massive and close, it could deflect the Earth onto an escape path outside the solar system,” Ceriotti explained
Professor of Physics and Astronomy Timothy Davis from Cardiff University agrees with this interpretation. However, he recalled that the Earth could be ejected from the solar system by another star.
“The planets as they exist right now are in stable orbits around the Sun. But if the Sun were to meet another star, then the mutual gravitational interaction of these bodies could disrupt these orbits and eject the Earth from the system,” Davis explained to the magazine Live Science.
However, the scientist noted that while this scenario is possible, it is unlikely, at least in the foreseeable future.
“Such star encounters are rare. The star Gliese 710 is expected to make a close approach to the Sun in about a million years, but this flyby is unlikely to disturb the planets’ orbits,” Davis reported.
So if the Earth is not pushed out of the system by external forces, then we should ask ourselves whether humanity could build the machines that will be able to do that, which Liu Cixin mentions in “The Wandering Earth”?
This possibility is slim.
“The energy required to detach the Earth from its orbit and eject it from the solar system is unimaginably enormous – equivalent to a trillion (ones with 21 zeros) megaton nuclear bombs going off at once. So it seems unlikely,” Davis calculated.
It would remain a dead and icy world
Still, we can ask ourselves what would happen if the Earth broke away from the solar system? What effects would this have on people’s lives?
“Earth would fly into interstellar space until it was captured or swallowed by another star or black hole,” Ceriotti said. He warned that if the Earth were to leave the solar system, it would lead to the decimation of the planet and life on it.
“If the Earth were to leave the solar system, its atmosphere would disappear and with it the vast majority of life as we know it. “Almost all the energy used by living organisms on Earth comes from the Sun – plants photosynthesize, herbivores eat plants, and carnivores eat herbivores,” Ceriotti said.
“The further the Earth would move away from the Sun, the lower its temperature would be. Eventually she would freeze completely. The only natural source of heat that would be left would be the decay of radioactive elements in the earth’s crust,” added Davis.
“Some extremophiles (animals and plants capable of living in extreme environments) could feed on this energy, Davis says, but complex life would disappear entirely. Radioactive heat would only allow Earth to maintain a temperature of around minus 230 degrees Celsius
“Earth would end up as a dead ice world hurtling through the stars,” predicted Professor Davis.