This means the Gaia team could create an HR diagram of stars with a similar mass and composition to the Sun. For these stars, we know not only their size and spectral temperature but also know their chemical composition. In the latest data release, the Gaia team created an HR diagram of more than 4 million stars within 5,000 light-years of Earth. Whereas early stellar surveys had hundreds or thousands of stars, Gaia has more than a billion. Two stars similar in mass but different in composition can have very different lifetimes. We now know that while the mass of a star is an important aspect of stellar evolution, its chemical composition also plays an important role. Color is a measure of a star’s temperature, and absolute magnitude is a gauge of its size. Now known as Hertzsprung-Russell diagrams, or HR diagrams, they plot the color or spectral class of a star versus its absolute magnitude. First as a data table by Ejnar Hertzsprung in 1905, but more famously done as a diagram by Henry Norris Russell in 1914. One of the first snapshots of stellar evolution was done in the early 1900s. It’s similar to the way you might understand how humans live and die by looking at a collection of photographs all taken at the same time on a single day.
![the end of the sun the end of the sun](https://steamcdn-a.akamaihd.net/steam/apps/912840/ss_51653ff2641e71850c220f9bc1c8220526e463f8.1920x1080.jpg)
But we can understand stellar evolution by observing other stars that may be older or younger than the Sun.
![the end of the sun the end of the sun](https://steamcdn-a.akamaihd.net/steam/apps/912840/ss_a34998a1e8b0307fb3fd5030cdb9cd71d73cefbd.1920x1080.jpg)
We haven’t been around long enough to watch a star’s birth, life, and death. The timeline of human civilization is a mere blip in the lifetime of a star. Now, thanks to the latest data from Gaia, we know the Sun’s future in much greater detail. It’s a well-known story, and one astronomers have understood for decades. Billions of years from now, the Sun will deplete its hydrogen fuel and swell to a red giant before becoming a white dwarf.