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Cosmic Microwave Background
Today, the star-formation rate across the Universe is a mere trickle: just 3% of what it was at its peak. Here's what it was like back then.
For 550 million years, neutral atoms blocked the light made in stars from traveling freely through the Universe. Here's how it then changed.
The Big Bang's hot glow faded away after only a few million years, leaving the Universe dark until the first stars formed. Oh, the changes!
U.S. particle physicists recently recommended a list of major research projects that they hope will receive federal funding.
The first elements in the Universe formed just minutes after the Big Bang, but it took hundreds of thousands of years before atoms formed.
In the early stages of the hot Big Bang, matter and antimatter were (almost) balanced. After a brief while, matter won out. Here's how.
When the hot Big Bang first occurred, the Universe reached a maximum temperature never recreated since. What was it like back then?
Everything we observe beyond our Local Group is speeding away from us, omnidirectionally. If the Universe is expanding, where is the center?
Back during the hot Big Bang, it wasn't just charged particles and photons that were created, but also neutrinos. Where are they now?
Measurements of the acceleration of the universe don’t agree, stumping physicists working to understand the cosmic past and future. A new proposal seeks to better align these estimates — and is likely testable.
A spherical structure nearly one billion light-years wide has been spotted in the nearby Universe, dating all the way back to the Big Bang.
The "Ring Nebula," known for almost 250 years, is so much more than a Ring. With JWST's capabilities, we're seeing more than ever before.
Two fundamentally different ways of measuring the expanding Universe disagree. What's the root cause of this Hubble tension?
How scientists are hearing the gravitational background "hum" of the Universe for the very first time.
Today, our observable Universe extends for 46 billion light-years in all directions. But early on in our history, things were much smaller.
For many years, cosmologists have claimed the Universe is 13.8 billion years old. A new paper says no, it's 26.7 billion. How do we decide?
There are two methods to measure the expansion rate of the Universe. The results do not agree with each other, and this is a big problem.
The odds are slim, but the consequences would be literally world-ending. There really is a chance of a black hole devouring the Earth.
Before there were planets, stars, and galaxies, before even neutral atoms or stable protons, there was the Big Bang. How did we prove it?
What began as an annoyance ended as a Nobel Prize-winning discovery about the Big Bang and the origin of the Universe.
The cosmic microwave background offers clues.
Einstein called his idea "abominable," but the world of physics came around to embracing the views of Georges Lemaître.
With a bigger, better, and more sensitive detector, the XENON collaboration joins LZ and PANDA-X in constraining WIMP dark matter.
Nobel Laureate Roger Penrose, famed for his work on black holes, claims we've seen evidence from a prior Universe. Only, we haven't.
The secret ingredient is violence, and it just might indicate that "moonmoons" aren't as uncommon as most astronomers think.
In just a few seconds, a gamma-ray burst blasts out the same amount of energy that the Sun will radiate throughout its entire life.
In the grand scheme of the cosmic story, a single year isn't all that significant. But over time, the annual changes really add up!
The answer to this question is key to understanding why anything exists.
We confidently state that the Universe is known to be 13.8 billion years old, with an uncertainty of just 1%. Here's how we know.
We're used to scientists telling us about the math and physics behind astronomical events. But what does studying space make us feel?