Sadly, this will only change when someone else wakes up.
Will Life Exist in the Solar System After the Death of the Sun?
(Image credit: Greg Wyatt)
The Sun is ~4.6 billion years old. Within ~5 billion years, the hydrogen fuel in its core will run out, and the Sun will begin expanding into a red giant star. In ~6.5 billion years, the helium in its core will ignite and the Sun will settle into a helium-burning phase lasting ~100 million years. In ~7.5 billion years, the helium will be exhausted, and the Sun will enter the asymptotic giant branch, and its envelope will swell to near Earth’s orbit.
(Image credit: Greg Wyatt)Most of the outer layers of the Sun will be shed off over a few hundred thousand years, so that in ~8 billion years the ejected gas will create an extended planetary nebula. The exposed hot core, a dense carbon-oxygen white dwarf, will carry about 0.55 solar masses. This massive remnant of the Sun will settle to a size comparable to that of the Earth.
As a result of this predictable evolution, the solar system will become a ghostly remnant of its former self once the age of the Universe will exceed 21.8 billion years. Its transformation will follow the following stages.
(Image credit: Greg Wyatt)
During the red giant phase, the Sun will engulf and completely incinerate the inner solar system. Mercury and Venus will be swallowed first. Earth will likely be engulfed as well, in which case the Moon will crash on Earth’s surface as a result of drag on the puffed-up stellar envelope. The mass loss from the Sun will initially weaken the Sun’s gravity and push Earth out to about 1.7 times the current Earth-Sun separation, namely, 1.7 AU. But the bloated Sun will also drag Earth’s orbit inward, and the most detailed models find that Earth will be pulled in and be vaporized. Even if Earth narrowly escapes being swallowed, its oceans will boil, its atmosphere will be ripped away, and its surface will melt into a sea of lava, leaving behind a scorched, lifeless rock.
(Image credit: Greg Wyatt)
The white dwarf remnant will start with a surface temperature over 100,000 degrees Kelvin and gradually cool over time. With less gravitational pull from the dead Sun, the surviving planets: Mars, Jupiter, Saturn, Uranus, and Neptune, will drift outward. Their orbits will roughly double in size, shifting Jupiter to ~10 AU and Neptune to ~60 AU. The white dwarf’s luminosity will drop below a thousandth of the current solar luminosity within a few hundred million years. The subsurface oceans of Europa and Enceladus will eventually freeze solid. The Kuiper belt and Oort cloud will expand, and the loosely bound objects in the outer Oort cloud will be lost as interstellar objects. The changing gravity will also disrupt the asteroid belt, sending many space rocks towards interstellar space.
(Image credit: Greg Wyatt)
The white dwarf will contain no nuclear fuel and will only glow from leftover trapped heat. As it will cool down over trillions of years, the outer planets and their remaining moons will plunge into a deep freeze, with temperatures dropping down to tens of degrees above absolute zero.
Because of the chaotic shifts in gravity during the Sun’s death throes, millions of comets and asteroids from the Kuiper Belt and the Oort Cloud will fall inward toward the white dwarf. The immense gravitational tidal forces close to the dead Sun will shred these rocky objects into dust, forming a debris ring around the white dwarf that it will slowly consume over time.
(Image credit: Greg Wyatt)
Such debris disks are commonly found around old white dwarfs which represent the corpses of billions of ancient suns that died by now in the Milky-Way galaxy. The Sun was born and evolved in the last third of cosmic history. Most stars formed billions of years before the birth of the Sun.
The future solar system will lose its current inner planets, while the outer planets will survive on wider orbits around a cooling ember, and over trillions of years even that arrangement will slowly break apart.
(Image credit: Greg Wyatt)
Spectra of about a quarter to a half of white dwarfs show heavy elements in their atmospheres that gravity should have removed in days to centuries, so they must be continually fed by rocky debris. The surviving planets’ gravity, once the stabilizing mass of the star is reduced, scatters asteroids and comets onto orbits that pass close to the white dwarf, where they are shredded by tides into debris disks and accreted. Several white dwarfs show transiting fragments doing exactly this. The Solar System’s white dwarf will likely be polluted by rocky material the same way for billions of years, and its spectrum will carry the chemical signature of the asteroid belt.
With the Sun’s mass halved, the planets’ mutual perturbations are relatively stronger. Long-term simulations find the giant planets usually remain stable for tens of billions of years, but on timescales of trillions of years, passing stars and chaotic interactions will eventually eject planets one by one or send them into the star. Over such long timescales the white dwarf itself will cool dramatically and become a black dwarf, radiating almost nothing after 10 trillion years.
(Image credit: Greg Wyatt)
Interestingly, a white dwarf has a habitable zone, close in at a few hundredths of an AU, and it persists for billions of years as the star cools. No planet of the current Solar system will be there, since anything that close will be engulfed. But some white dwarfs have been found with planets that migrated inward or formed after the giant phase. If life could get a foothold on such a world, it would have a far longer stable habitable era than the Sun currently offers.
