This too shall pass. Even stars.
Stars seem eternal, but they’re not. They may live for billions of years, but they eventually die. How exactly they do this depends on lots of things, most importantly their mass: High-mass stars explode, while stars that are more Sun-like in their mass do so more slowly.
The Sun is many billions of years away from swelling into a red giant, shedding its outer layers, revealing its core as a tiny, hot white dwarf, and then fading away over time. But the star T Ursae Minoris (or T UMi) is already a red giant, and has been showing signs it’s entering its terminal count.
What’s really cool about this is that it’s changing rapidly right now, quickly enough that astronomers have been able to watch these changes occurring over just a few years (though it’s more obvious over many decades). T UMi is dying, and we’re watching it happen.
The engine behind all this lies deep inside the star. During a star’s “normal life”, hydrogen fuses into helium in the core. The helium takes far higher pressures and temperatures to fuse, so it builds up in the center, inert. If the star has enough ...