The Dying Sun Will Cough. Saturn May Not Survive the Fit.

When the Sun dies, it may not go gently. Simulations suggest it will shed its outer layers in thousands of separate lurches, each jolting our star off in some arbitrary direction, and that the jolts could fling Saturn out of our planetary neighborhood.

The older picture was reassuring. As the Sun swells and loses nearly half its mass, the planets were expected to drift outward in orderly fashion. Earlier estimates gave the four giants about a billion billion years on their own, or tens of billions before a passing star broke them up.

The trouble is that dead stars appear to have been kicked. Gaia spacecraft measurements suggest newborn white dwarfs, the dense cores left behind by stars like ours, pick up a shove of roughly 0.75 kilometers per second (about 1,700 mph). The leading explanation is that a dying star throws off its outer layers in lumps, recoiling slightly with each.

Konstantin Batygin, Jim Fuller and Fred C. Adams modeled that. In their main scenario the Sun absorbs about 4,600 tiny recoils, typically near 7 meters per second (roughly 16 mph). Arriving at random, they send the planets' orbits wandering.

In about 40 percent of runs, the planets were wrecked or violently scattered before the dying Sun had settled into its final form. Within 3 billion years, about 90 percent had come apart. Saturn was sometimes thrown out within mere millions of years.

Everything hinges on how lumpy those final exhalations really are. The authors say the measured kicks favor the violent end.

Mercury, with its roughly 1 percent risk, was supposed to be the fragile one. On these numbers, Saturn should be packing a bag.

Read the full story at The Astrophysical Journal Letters, September 21, 2026

Hot Take: Newton suspected the planets would come undone; later mathematicians proved they wouldn't. The Sun, reviewing that proof from its deathbed, has flagged an unstated assumption.