Dark matter halos (yellow) type round galaxies
Ralf Kaehler/SLAC National Accelerator Laboratory
Delicate may not be the primary phrase that springs to thoughts whenever you consider the Milky Way. But when Mariangela Lisanti began tinkering with the recipe for our galaxy, she discovered it surprisingly fragile.
Lisanti, a particle physicist at Princeton University, was simulating what would occur if dark 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 sometimes assume. She swapped a small fraction of ordinary dark matter with one thing extra advanced. “We thought, we’re only adding 5 per cent, everything will be fine,” she says. “And then we just broke the galaxy.”
There is sweet motive for such meddling. Since the Nineteen Eighties, astronomical indicators have pointed in the direction of dark matter being a single kind of slow-moving particle that doesn’t work together with itself. Particle physicists have gone to nice lengths to seek for that particle. But a long time later, it stays a no-show – maybe as a result of dark matter isn’t how now we have tended to think about it.
Recently, a collection of galactic anomalies has sparked a scramble to discover alternate options. This “complex” dark matter is likely to be so simple as sub-atomic particles that bounce off one another, or as sophisticated as households of dark particles that type dark atoms, stars and even galaxies. There is a frightening number of potentialities.
But now, observations of anomalies in our galaxy lastly promise to help us slim down the choices. And with…