In the earliest stages of the hot, dense, expanding Universe, a whole slew of particles and antiparticles were created. As the Universe expands and cools, an incredible amount of evolution happens, but the neutrinos created early on will remain virtually unchanged from 1 second after the Big Bang until today. (BROOKHAVEN NATIONAL LABORATORY)

Earliest Signal Ever: Scientists Find Relic Neutrinos From 1 Second After The Big Bang

Before we formed stars, atoms, elements, or even got rid of our antimatter, the Big Bang made neutrinos. And we found them.

The idea of the Big Bang has captivated the imagination of humanity since it was first proposed. If the Universe is expanding today, then we can extrapolate back, earlier and earlier, to when it was smaller, younger, denser, and hotter. You could go back as far as you can imagine: before humans, before the stars, before there were even neutral atoms. At the earliest times of all, you’d make all the particles and antiparticles possible, including the fundamental ones that we cannot create at our low energies today.

If this were true, there would be an early signal left over from when the Universe was just one second old: neutrinos and antineutrinos. Known as the cosmic neutrino background (CNB), it was theorized generations ago, but was dismissed as undetectable. Until now. A very clever team of scientists has just found a way to see it. The data is in, and the results are incontrovertible: the cosmic neutrino background is real, and agrees with the Big Bang.