In Liu Cixin’s short story”The Wandering Earth (opens in a new tab)” (first published in the Chinese magazine Science Fiction World in July 2000), Cixin depicts a scenario in which the leaders of the planet agree to propel Earth out of solar system to escape an impending Solar eruption which should decimate all terrestrial planets.
This story is, of course, based in the realm of fiction, but could Earth ever really leave the solar system?
“It’s very unlikely”, Matteo Ceriotti, aerospace and space systems engineer engineering lecturer at the University of Glasgow in the UK, Live Science said in an email.
However, as Ceriotti explained, “unlikely” doesn’t mean it’s “impossible”, and suggested a theoretical way to do it.
“Earth could be pulled out of orbit by the action of a massive interstellar object, flying through interstellar space and entering the solar system and passing close to Earth,” he said.
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“In this close encounter, known as a ‘flyby,’ the Earth and object would exchange energy and momentum, and Earth’s orbit would be disrupted. If the object were fast, massive and close enough, it could knock Earth into an escape orbit directed outside the solar system.”
Timothy Davis, a lecturer in physics and astronomy at Cardiff University in the UK, agreed that Earth could theoretically be pushed out of the solar system and has his own hypothesis as to how that might happen.
“The planets, as they now exist, are in stable orbits around the Sun. However, if the Sun were to have a close encounter with another star, then the gravitational interactions of these bodies could disrupt these orbits and potentially cause Earth’s ejection from the solar system,” Davis told Live Science in an email.
However, Davis noted that while this scenario is feasible, it’s extremely doubtful that it will happen — at least, in the foreseeable future.
“Such stellar encounters are quite rare,” Davis said. “For example, we know that the star Gliese 710 is expected to approach quite close, in astronomical terms, to the Sun in about a million years – but even that flyby is unlikely to disturb planets.”
While outside forces are unlikely to drive Earth out of the solar system anytime soon, could humanity build machines capable of moving the planet to such a degree that it would eventually be ejected?
“The energy required to pull the Earth out of its orbit and eject it from the solar system is so massive – equivalent to a sextillion (a 1 followed by 21 zeros) megatons of nuclear bombs exploding at the same time – that it seems little likely,” Davis said. .
Even if such an event is far from probable, what would happen if the Earth were to detach from the solar system? What impacts would occur if our home planet ends up being permanently launched into the depths of the universe?
“Earth would fly through interstellar space until it was captured or swallowed by another star or a black hole,” Ceriotti said, adding that if Earth left the solar system it would likely lead to the decimation of Earth. much – if not all – of the planet. life.
“The atmosphere is unlikely to remain: Earth’s global climate is very delicate due to a subtle balance between radiation coming from the sun and energy dissipated into deep space. If this were to vary, the temperatures would change immediately and dramatically,” Ceriotti said.
Related: Why isn’t the Earth perfectly round?
Davis agreed that most life on Earth would not survive this cataclysmic move away from the solar system.
“If the Earth were to leave the solar system, it is very likely that the vast majority of life as we know it would disappear. Almost all of the energy used by living organisms on Earth comes from the Sun, either directly (for example plants that photosynthesis), or indirectly (e.g. herbivores eating plants and carnivores eating herbivores).
“In this scenario, the further the Earth is from the Sun, the more its Temperature would become. It would eventually freeze entirely. The only remaining natural source of heat would be the decay of radioactive elements in the Earth’s crust left over from the formation of the solar system,” Davis said.
Davis explained that some life might linger but would ultimately be doomed. “Some ‘extremophiles’ (animals/plants that can live in extreme environments) could live on this energy, but complex life would probably die out entirely. This radioactive heat would only allow the Earth to maintain a temperature of about minus 230 degrees. VS [Celsius, or minus 382 degrees Fahrenheit]. At those temperatures, most of the atmosphere would also freeze, leaving Earth like a dead, icy world rushing between the stars,” Davis said.
Looking far into the future, Ceriotti added that our solar system will eventually be so badly disrupted that Earth will either be kicked out of it or destroyed entirely.
“We predict that our galaxy is about to collide with Andromeda [our nearest neighbouring galaxy] in about 4.5 billion years. Such a large-scale collision of millions of stars is likely to cause a major disruption in the solar system!” Ceriotti said. “The Sun is also predicted within the next 5 billion years to expand and swallow up the Earth. “, added Ceriotti
So while Earth will eventually leave the solar system one way or another, it’s not something we’ll have to worry about for a few billion years. Most likely.
Originally posted on Live Science.