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Galaxies Demystified

/ Emma / 3 Comments

From the smallest of irregular and dwarf galaxies, to the most spectacular of spirals, to the most massive of ellipticals, there’s no denying that galaxies are incredible objects.

On this blog, we’ve covered a great deal of information about galaxies. We’ve followed their stories from the dawn of time in the universe to the present day, and we’ve explored all their different shapes and sizes, their masses, and the forces that shape their evolution.

If it seems like a lot, I understand.

So, let’s round up what we know and boil it down to a summary. Hopefully I can make galaxies more easily digestible!

(Though I do hope none of you actually try to eat one… 😉)

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How Big and Bright are Galaxies?

/ Emma / Leave a comment

The brightest galaxy in our night sky is the Andromeda Galaxy, our nearest intergalactic neighbor.

Hey…notice we’re talking about intergalactic neighbors now? 😀

In most of the posts on this blog, we’ve talked about interstellar neighbors, interstellar space, etc. But now, we’ve graduated to the intergalactic frontier, and we’re not turning back–at least not for a little while!

Anyway. The Andromeda Galaxy is the brightest galaxy in our night sky. But as you may remember from my eons-old article on apparent visual magnitude…that doesn’t tell us much about how bright it actually is.

It is the closest galaxy to us, the denizens of the Milky Way, so that tells us one thing: if it appears brighter than other galaxies, it probably is.

But…let’s say we put all galaxies in the universe on an even playing field, magically all exactly the same distance from Earth.

How big and bright would they appear then?

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How Far Away are Galaxies?

/ Emma / Leave a comment

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.

But…wait a second. How do we know that?

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