Topic
Dark Matter
Episodes and research papers from From First Principles that help explain Dark Matter from the ground up.
Episodes
Conversations and explainers connected to Dark Matter.
How Scientists Actually Study Dark Matter
A first principles interview with astrophysicist Dan Gilman on what dark matter is, why strong gravitational lensing matters, and how the next generation of surveys could reveal the universe’s hidden structure.
Dark Galaxies, Fuzzy Dark Matter, and an Alzheimer’s Breakthrough
A candidate “dark galaxy”, plus the exercise may protect against Alzheimer’s.
Research
Papers and studies featured by the show.
Candidate Dark Galaxy-2: Validation and Analysis of an Almost Dark Galaxy in the Perseus Cluster
Imagine trying to find a nearly invisible ghost town in space. That's essentially what astronomers did when they discovered CDG-2. This "galaxy" is so faint that it's almost entirely made of dark matter - the mysterious invisible stuff that makes up most of the universe. The only way scientists could spot it was by noticing four very old, dense star clusters (called globular clusters) floating together in space. It's like finding four lighthouses in the fog and realizing there's an almost invisible island underneath them. What makes this discovery special is that CDG-2 is 99.9% dark matter, making it one of the "darkest" objects ever found. Most galaxies are a mix of stars, gas, and dark matter, but this one is almost pure dark matter with just a tiny bit of starlight.
Turbocharging constraints on dark matter substructure through a synthesis of strong lensing flux ratios and extended lensed arcs
Imagine you're looking at a distant flashlight through a glass marble — the marble bends the light and creates multiple distorted images of the flashlight. Now imagine tiny invisible lumps scattered around the marble. Those lumps would subtly warp the images in ways we can measure. That's gravitational lensing! Dark matter forms these invisible lumps (called subhalos), and different theories of what dark matter IS predict different sizes and numbers of these lumps. This paper combines two ways of studying those warped images — the brightness of the multiple images AND the smeared arc of light from the galaxy around the flashlight — to get a much sharper picture of those tiny lumps. They also built a mathematical shortcut that makes the calculations 100 to 1000 times faster. The upshot: they can now test whether dark matter clumps exist down to sizes smaller than has ever been probed before, helping us rule out certain types of dark matter particles.