How will the solar system change in the future?

The sun is in the middle of its main sequence life and is gradually becoming hotter, so planets will receive extra heating. The solar system is currently fairly stable.

The Milky Way and Andromeda galaxies will collide in about 4 billion years, and during that collision, another solar system might approach closely enough to cause planet orbits to be disturbed or even eject planets from the solar system.

The solar system will undergo a major transition in roughly 5 billion years when it runs out of hydrogen fuel and expands into a red giant, swallowing Mercury, Venus, and possibly Earth in the process while simultaneously warming the other planets.

The sun will eventually collapse into a white dwarf, leaving the surviving planets in a state of extreme cold because they can no longer receive heat from the sun.

Future alterations to the solar system will come from natural processes like star development and aging, possible encounters or collisions between celestial bodies, and the continuous dynamics of planetary orbits.