The Sun is expected to become a red giant in about 5 billion years. Since one galactic year (the time it takes for the Sun to orbit the Milky Way) is roughly 225 to 250 million years, the Sun will complete about 20 to 22 galactic years before it transforms into a red giant.
But 42 makes a good answer to any question about Brexit!
Estimates vary between 4 and 8 million before it becomes a RD. However our galaxy and Andromeda are set to start to collide in about 4 to 4 1/2 million years – I’m guessing the two galaxies will merge and be reconfigured as a ‘super galaxy’?
Apparently the final ‘merging’ will occur in 9 billion years time?
