Well, I’ll give you a spoiler: they’re ridiculously far away.
Let’s consider for a moment what a light-year actually means. It sounds like a unit of time, but it’s actually the distance that light travels in one Earth year.
Think of it this way: if your name is Bob, and you can travel a certain distance in one year, that distance could be called a Bob-year.
I know it’s strange to think of light traveling at a certain speed. When you flip a light switch, the room immediately brightens. When you shine a flashlight, its beam immediately falls across the nearest surface.
But that just goes to show how insanely fast light travels. If it takes 2 million years for light to get from one object to another…imagine how far apart those objects are?
Well, that’s the case for our home galaxy, the Milky Way, and our nearest galactic neighbor, the Andromeda Galaxy.
Above is a theoretical rendering of a white dwarf, the collapsed husk of a low-mass or medium-mass star. Interestingly enough, these strange cosmic objects—which begin their existence as intensely hot balls of carbon the size of the Earth—may eventually cool off and crystalize into giant space diamonds.
White dwarfs are made up of free-floating hydrogen and helium nuclei and degenerate electrons—and their mass is supported by the nature of these electrons.
But degenerate electrons, like any other material, have a specific material strength. What happens if they’ve, well…just got too much stuff to support?
This is one topic I bet you guys have been looking forward to since I first started posting about stellar evolution. Well, I won’t disappoint you!
In my last post, we covered how a massive star gets to the point of supernova. When it exhausts all the nuclear fuel in its core, iron ash is left behind—which can’t be fused or split for energy. That’s a dead end for the star, and the core begins to freely collapse…
Until a shockwave, originating in the center of the star, pushes outward. It’s stalled at first, but convection as in-falling material bounces off the dense core gives it a boost, and the star bursts apart.
Now, we’ll cover all the ins and outs of these spectacular explosions.
Now that we’re finally talking about white dwarfs, we’re getting into the really cool stuff.
In my last post, we explored planetary nebulae, and we left off with a question: where does the fast wind that forms planetary nebulae come from? Well, remember that planetary nebulae are formed from the atmospheres of medium-mass stars, but there’s still the stellar interior to worry about.
White dwarfs are objects comparable in size to our own Earth. They are the remains of medium-mass stars like our own sun. Often, you can see a white dwarf at the center of a planetary nebula with a large telescope. Together, they form what’s left of a star after it loses stability completely.