This tedious cosmic panorama exists as a result of the universe actually was boring as soon as. Shortly after the Large Bang, and for a whole bunch of hundreds of years after that, it was relentlessly uninteresting. All that existed was a thick red-hot haze of particles, stretching for trillions upon trillions of kilometers and filling each level within the universe nearly evenly, with minuscule variations within the density of matter between one spot and one other.
However because the universe expanded and cooled, gravity amplified these tiny variations. Slowly, over the next tens of millions and billions of years, the locations within the universe with barely extra stuff attracted much more stuff. And that’s the place we got here from—the profusion of issues within the universe right this moment ultimately arose as increasingly materials gathered, making these barely over-dense areas into radically sophisticated locations filled with sufficient matter to type stars, galaxies, and us. On the very largest scales, boredom nonetheless reigns, because it has for the reason that starting of time. However down right here within the dust, there’s ample selection.
This story nonetheless has some holes. For one factor, it isn’t clear the place the matter got here from within the first place. Particle physics calls for that something that creates matter should additionally create an equal quantity of antimatter, rigorously conserving the steadiness between the 2. Each form of matter particle has an antimatter twin that behaves like matter in almost each means. However when a matter particle comes into contact with its antimatter counterpart, they annihilate one another, disappearing and abandoning nothing however radiation.
That’s precisely what occurred proper after the Large Bang. Matter and antimatter annihilated, leaving our universe aglow with radiation—and a small quantity of leftover matter, which had barely exceeded the quantity of antimatter in the beginning. This tiny mismatch made the distinction between the universe we have now right this moment and an eternity of tedium, and we don’t know why it occurred. “By some means there was this little imbalance and it changed into all the things—particularly, us. I actually care about us,” says Lindley Winslow, an experimental particle physicist at MIT. “We’ve a variety of questions in regards to the universe and the way it advanced. However it is a fairly primary kindergarten type of query of, okay, why are we right here?”
Caught within the act
To reply this query, Winslow and different physicists around the globe have constructed a number of experiments to catch nature within the act of violating the steadiness between matter and antimatter. They hope to see that violation within the type of neutrinoless double-beta decay, a sort of radioactive decay. In the mean time, that course of is theoretical—it could not occur in any respect. But when it does, it could present a attainable rationalization for the imbalance between matter and antimatter within the early universe.
