What Was It Like When There Were No Stars In The Universe?
“It takes just half a million years to take all the normal matter in the Universe and have it be completely neutral, but 100-to-200 times as long before that neutral matter can collapse down enough to form the very first star in the Universe. Until that happens, the only light to see will be the leftover glow from the Big Bang, which falls to low enough energies to make it invisible after just 3 million years. For 47-to-97 million years, the entire Universe is truly dark. But as the first star ignites, “let there be light” is finally, once again, a part of our cosmic history.”
When you hear the term dark ages, you generally think about a time where whatever illuminated humanity’s existence ceased to do so. Well, the Universe itself had a dark ages. After neutral atoms first formed, there was still a hefty, visible glow of leftover radiation from the Big Bang, but the expansion of the Universe finally makes it invisible after about 3 million years. Yet the first stars in our cosmic history, emerging from the largest, rarest density fluctuations of all, won’t arrive until the Universe is 50-to-100 million years old. These cosmic dark ages are real, and vital to our existence. There’s an incredible story to them, and a reason why no visible, energetic light could have existed during this time.
Come get the full story on what it was like back before there were any stars in the Universe!
Science Uncovers The Origin Of The First Light In The Universe
“Before there were stars, there was matter and radiation. Before there were neutral atoms, there was an ionized plasma, and when that plasma forms neutral atoms, those allow the Universe to deliver the earliest light we see today. Even before that light, there was a soup of matter and antimatter, which annihilated to produce the majority of today’s photons, but even that wasn’t the very beginning. In the beginning, there was exponentially expanding space, and it was the end of that epoch — the end of cosmic inflation — that gave rise to the matter, antimatter, and radiation that would give rise to the first light we can see in the Universe.”
We normally think of “let there be light” as when the Universe got its start. In a particular sense, this is true, since you can go back to a time before stars and galaxies existed, when the Universe was only a few million years old or less. But even before the first star, there was still light. And while that light’s origin can be traced back to the cosmic microwave background and the formation of neutral atoms, there was light even earlier than that. In fact, the very first light arose from the annihilation of matter and antimatter, and from the end of cosmic inflation at the very beginning of as far back as we can trace.
There was no light until the hot Big Bang occurred, and it’s the end of cosmic inflation that triggers this true “first light.”