Our Solar System’s Dark Twin: The Ghost Galaxy

Yup, it turns out our galaxy has a dark twin, a dimly lit “ghost galaxy” made up almost entirely of this crazy stuff called dark matter. It’s created from 99.99% dark matter, to be more precise. That’s one for the record books and it could rewrite our current theories about how galaxies are formed. Nice work, ghost galaxy dude. You rule with an iron fist.

Except that you’re called Dragonfly 44. That’s whack.

Sometimes scientists explain things in ridiculously big words, spouting formulae and generally confusing us normal people. Well Pieter van Dokkum at Yale University went completely in the other direction when he told Nature magazine:

“If you take the Milky Way and for every 100 stars you keep only one, then you’re getting pretty close. You also have to put those remaining stars in a blender and mix them all up into a blob.”

Thanks Pieter, nice one. Yeah, that really clears everything up for me about Dragonfly 44. You da big science man.


source: The Register

I think what he’s actually trying to tell us is that this ghost galaxy doesn’t have the spiral structure of our Milky Way and it isn’t a flat disc shape either. It’s more homogenous than that.

But let’s rewind for a second.

The Future Is Now, Sucker

This is proper new science that we’re looking at here. It was only in 2015 that these dark matter galaxies were discovered, using a telescope made up of a load of camera parts. True.

Pieter and his pals at Yale, backed up by a kickass posse from the University of Toronto, had one of those eureka moments. You know the drill, when you get in the zone that’s actually inside the zone and ultimate clarity becomes your vista.

Well they got this eureka moment and realized that a telephoto lens — that shnizzle that’s used for nature photography and sporting events — was well-suited for spotting the kind of large, dim objects that pose problems for typical telescopes.

Here’s Pieter!

Here we have our resident scientist dude Pieter van Dokkum explaining the telescope:

“By pulling them all together it makes them look like the eyes of an insect and we gather a lot more light.”

Thanks Pieter, you crazy kid. And they called the telescope The Dragonfly.

When the team aimed the telescope at a cluster of galaxies called the Coma cluster, they detected 47 faint smudges: galaxies that could be at least as large as the Milky Way, 100,000 light years from end to end, but which contain so few stars that they glow as dimly as dwarf galaxies


Coma galaxy, source: NASA, ESA and the Hubble Heritage Team

Cosmic Glue

There is no way that there is enough gravity and ‘cosmic glue’ to keep these planets together.

It’s as if a city as big as London is only emitting the amount of light that Driffield is chucking out. Aint no way London would survive on that.

With that few amount of stars, there’s just not enough mass and it should have just fallen apart and shouldn’t even exist.

These ‘Dragonfly galaxies’ are called ultra-diffuse galaxies and the rotational speed suggest a mass of about one trillion solar masses, about the same as the mass of the Milky Way. BUT THERE’S NOT REALLY ANYTHING THERE!!??!


source: Pieter van Dokkum, Roberto Abraham Gemini Sloan

It looks to us, that there’s less than 1% of the amount of stars that there should be to keep everything sweet.

So how can this be?

Enter Dark Matter

Dark matter is an unidentified type of matter that does not emit or interact with electromagnetic radiation, such as light. So basically it’s invisible to the entire electromagnetic spectrum. Hidden better than an Emo in his bedroom, dark matter has never been directly observed. We can only work out that this groovy stuff is there because of its effects in the cosmic microwave background. Dark matter is totally transparent to electromagnetic radiation and is so dense and small that it fails to absorb or emit enough radiation to be detectable, end of story.

Boom – this is the take home lesson. Boffins now know that only 5% of the universe is made up of normal matter that we can see and touch. Basically, 95% of stuff is weird.

Dark matter makes up 27%. Of our universe. And if that’s going to scramble your mind, then brace yourself. The remaining 68% of the universe is made from something even more baffling, dark energy: some kind of an anti-gravity force that appears to be repelling galaxies away from each other at an accelerating rate.

Dang, that crazy talk is dope.

I only understand a thin slice of this astro-dog-rabid-science-brain-strain, but I am trying to bend my brain around the theories.

Go Tell It To Yo’ Momma

All I know is that this is well weapon. Word to your momma. Increase the peace.

Now go and kick a can around with your stupid friends, you’ve been thinking about stuff for far too long. Go and stroke a rabid dog. Or maybe play with matches. On the motorway. In the dark. Just like your momma told you that you should. You are special. You are Stardust. You are golden. Google that.


source: sciencefiction.com

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