The Drift by Sanford Lab, where our
researchers answer your giant science
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Facebook Instagram and Twitter. Hi, I'm Dr. Sally Shaw, and I work on the LZ
dark matter experiment. Now I'm talking
about what makes dark matter dark. So we
usually use photons, or particles of
light, to look deep into space with
telescopes and all the matter that we
know about in the universe—so that's the
atoms that make up stars, galaxies, the
earth, you and me—they all interact
through the electromagnetic interaction. And this means they produce photons
which carry the electromagnetic force. So
when you see you with your eyes, you're
actually detecting photons that have
been produced by this electromagnetic
interaction. But out there in space we've
managed to find something that doesn't
produce any of these photons or seem to
interact electromagnetically at all. It
is in fact many many times more abundant than
normal matter and the only way we know
it's there is because we can see its
gravitational pull on the motion of
nearby stars or galaxies. And it's
because this stuff doesn't produce any
light that we give it the name "dark
matter."
