What is the time table for the Sun's expansion and contraction? New discussion It is my understanding that Earth's Sun is a middle-age star moving into old age. Currently, Earth's Sun appears to be growing hotter, and consequently, its gravitational pull is getting stronger. Plans to use Earth's Moon as a launching site for travel to Mars seem predicated on belief of scientists that we need to make way for the Sun's expansion. But do we have factual knowledge, a tentative time table for the expansion and an estimate of how big the Sun will become (ditto for the contraction of the Sun). Perhaps subterranean towns can be constructed, like a gigantic "Noah's Ark" during the expansion and contraction. After all, humans lived in caves for 10,000 years during the Ice Age. Gigantism Moon caves Sun
Dear Nancy, I've given you this link a couple of times but I understand you may lose your other account so I'll repeat it here:
Article Distant future of the Sun and Earth revisited
The original preprint is on arxiv at arxiv:0801.4031
That gives a detailed and quite accurate timetable including changes to radius, temperature and luminosity.
PLEADE FIND ATTACHED LINK
The short story of the sun
https://www.livescience.com/62507-what-happens-when-sun-dies.html
All stars die, and eventually — in about 5 billion years — our sun will, too. Once its supply of hydrogen is exhausted, the final, dramatic stages of its life will unfold, as our host star expands to become a red giant and then tears its body to pieces to condense into a white dwarf.
The length of a star's life span depends on its size. Our sun is a yellow dwarf with a diameter of around 864,000 miles (1.4 million kilometers), or about 109 times the size of Earth, according to NASA. Yellow dwarf stars live for about 10 billion years, and at 4.5 billion years old, our middle-age sun is about halfway through its lifetime.
An accurate timetable is in the document I cited previously by Schr ̈oder and Smith:
https://arxiv.org/pdf/0801.4031.pdf
I attach a copy of Table 1 which gives the key values.