e: dark matter

I want to reveal one of the greatest mysteries in science to you:

Look at this gif, notice any patterns in the orbits? I’m talking about the speeds. The planets orbiting around the Sun get slower the farther out they go.

Why is this? Kepler’s Third Law of Planetary Motion.

The stars in the Milky Way orbit around the Galactic Center just as our planets do around the Sun. We find that the farther you get from the center of the galaxy… there’s approximately no change in orbital velocity.

Just like that, one of our most well-established tools in astronomy (Kepler’s Third Law) becomes ineffective for some reason.

It’s become apparent to astronomers that when something orbits around a center of mass, it’s orbital speed has a relationship with the distance from the center of mass.

Right now we don’t think most of the mass of the Milky Way is focused in the galactic center, but hidden in darkness surrounding the galaxy on all sides.

What we know is that it’s impossible to see and so far has eluded detection: we’ve started calling this mysterious mass dark matter.

oldschooldedede  asked:

(For the bothering thing) "Um... Smart Other Me? I-I have something I wanna know about that's really bugging me..." *Deep breath* "I'm terrified about something called Dark Matter that a bunch of the Grey-faces keep asking me about, then either telling me they're sorry, or laughing in a creepy way!"

I… I dunno if telling you is such a good idea, I mean — m-maybe you’d be happier not knowing…

…Guess it’s too late for that, though. I know if I were you — uh… if I’d known back then what you do now, I’d wanna know the details, too. Maybe it won’t even… maybe you can find some way to avoid it.

I’ll… I’ll tell you whatever I can, if… if you’re sure.

Scientists believe dark energy makes up about 68% of the universe and dark matter about 27%. That leaves just 5% for us and everything we can actually see.

But what’s the dark stuff made of?

From the TED-Ed Lesson Dark matter: The matter we can’t see - James Gillies

Animation by TED-Ed