Darkish matter halos (yellow) kind round galaxies
Ralf Kaehler/SLAC Nationwide Accelerator Laboratory
Delicate won’t be the primary phrase that springs to thoughts whenever you consider the Milky Approach. However when Mariangela Lisanti began tinkering with the recipe for our galaxy, she discovered it surprisingly fragile.
Lisanti, a particle physicist at Princeton College, was simulating what would occur if darkish matter – the mysterious stuff thought to account for over 80 per cent of all of the matter within the universe – was extra unique than researchers usually assume. She swapped a small fraction of normal darkish matter with one thing extra complicated. “We thought, we’re only adding 5 per cent, everything will be fine,” she says. “And then we just broke the galaxy.”
There’s good cause for such meddling. Because the Eighties, astronomical indicators have pointed in the direction of darkish matter being a single sort of slow-moving particle that doesn’t work together with itself. Particle physicists have gone to nice lengths to seek for that particle. However a long time later, it stays a no-show – maybe as a result of darkish matter isn’t how we’ve got tended to think about it.
Just lately, a sequence of galactic anomalies has sparked a scramble to discover options. This “complex” darkish matter is likely to be so simple as sub-atomic particles that bounce off one another, or as difficult as households of darkish particles that kind darkish atoms, stars and even galaxies. There’s a daunting number of prospects.
However now, observations of anomalies in our galaxy lastly promise to assist us slim down the choices. And with…
