New studies suggest the Nancy Grace Roman Space Telescope could detect primordial black holes from the early universe, potentially confirming their role in cosmic inflation and as components of dark matter.

When astrophysicists observe the cosmos, they see different types of black holes. They range from gargantuan supermassive black holes with billions of solar masses to difficult-to-find intermediate-mass black holes (IMBHs) all the way down to smaller stellar-mass black holes.

But there may be another class of these objects: primordial black holes (PBHs) that formed in the very early Universe. If they exist, the Nancy Grace Roman Space Telescope should be able to spot them.

Domain walls, long a divisive topic in physics, may be ideal explanations for some bizarre cosmic quirks.

By Anil Ananthaswamy

“As long as they live for long enough, they will always become large cosmological beasts,” says Ricardo Ferreira, a cosmologist at the University of Coimbra in Portugal. He’s not talking about actual beasts but rather about hypothetical humongous sheets of spacetime that could divide one region of the universe from another. Such so-called domain walls are the natural outcome of theories that try to solve some of the deepest mysteries in physics, such as the origins of gravity. As Ferreira says, however, had they formed after the big bang, by today they’d be the dominant source of energy in our universe, and there’s no evidence that’s the case. So any theory invoking their existence has been considered suspect—until now, perhaps.