We have an incredible amount of evidence that
most of the mass of the universe is in the
form of some kind of elementary particle that’s
different — that’s yet to be detected.
And we call this stuff dark matter.
Now the leading idea for what dark matter
is, is it’s something that doesn’t interact
first of all with light.
That’s why it’s called dark matter.
And it doesn’t interact very strongly with
normal stuff like us.
And it also doesn’t interact with itself
very much.
It’s basically a particle that it doesn’t
do a lot other than tug on other things gravitationally.
But there are new ideas out there, and one
of them is that there’s an entire dark sector
— that this huge chunk of the universe that’s
made of dark matter actually has its own set
of interactions going on.
Just like in our own sector with the periodic
table of elements and atoms and all the complexities
that’s going on in the normal matter, maybe
that kind of thing is going on in the dark
matter as well.
And so my line of research is I’m trying
to figure out what the universe would look
like if the dark matter had these kinds of
interactions.
And specifically we’re trying to predict
what would the cores of galaxies look like
if we actually had this different kind of
dark matter compared to this more standard
dark matter that’s called WIMPs.
The dark matter that I study we call self-interacting
dark matter.
And one of the cool things we’ve discovered
is that if you put this kind of dark matter
in these same kind of simulations that we’ve
done with other types of dark matter, you
tend to get things to actually match the data
better than you do with the sort of normal
type that doesn’t interact.
So it very well may be that there’s this
whole interesting dark sector going on and
the way we’re going to find the first hints
of it is by studying the way galaxies behave
and the speeds with which stars are rolling
around each other in the cores of galaxies.
