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Universe Expansion
On December 9, 2023, Halley's Comet reached aphelion: its farthest point from the Sun. As it returns, here are 10 facts you should know.
Since JWST first glimpsed the Universe, we've entered a new era in understanding the earliest objects in the Universe. What have we learned?
The first elements in the Universe formed just minutes after the Big Bang, but it took hundreds of thousands of years before atoms formed.
The brilliant mind who discovered the spacetime solution for rotating black holes claims singularities don't physically exist. Is he right?
Nearly half of all stars are born in binary systems, with the most massive ones dying the fastest. It's not pretty for the "second" star.
The Big Bang theory is not threatened, but astrophysicists have some explaining to do.
In the early stages of the hot Big Bang, there were only free protons and neutrons: no atomic nuclei. How did the first elements form from them?
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.
In 2022, Hubble owned the record for most distant galaxy. Today, that galaxy is down to the 9th most distant object. Thanks, JWST.
For a substantial fraction of a second after the Big Bang, there was only a quark-gluon plasma. Here's how protons and neutrons arose.
In the very early Universe, practically all particles were massless. Then the Higgs symmetry broke, and suddenly everything was different.
In the earliest stages of the hot Big Bang, equal amounts of matter and antimatter should have existed. Why aren't they equal today?
When the hot Big Bang first occurred, the Universe reached a maximum temperature never recreated since. What was it like back then?
Some 13.8 billion years ago, the Universe became hot, dense, and filled with high-energy quanta all at once. Here's what it was like.
Cosmic inflation is the state that preceded and set up the hot Big Bang. Here's what the Universe was like during that time period.
Two of the answers add a dimension to physics that doesn’t belong there. Maybe we could call it "astrotheology."
Bang bang all over the Universe.
38mins
Our host Kmele went inside Fermilab, America’s premiere particle accelerator facility, to find out how the smallest particles in the universe can teach us about its biggest mysteries.
In 1667, a core-collapse supernova happened right here in the Milky Way, invisible to all humans. ~350 years later, here's what JWST sees.
When we look at our Sun, its properties are incredibly constant, varying by merely ~0.1% over time. But all stars don't play by those rules.
In our Universe, all stable atomic nuclei have protons in them; there's no stable "neutronium" at all. But what's the reason why?
All matter particles can act as waves, and massless light waves show particle-like behavior. Can gravitational waves also be particle-like?
With JWST, Chandra, and gravitational lensing combined, evidence has emerged for the earliest black hole ever. And wow, is it a surprise!
What do ghosts and anomalous galaxy rotation rates have in common? Some sci-fi enthusiasts believe the answer involves "parallel universes."
Sometimes, going "deeper" doesn't reveal the answers you seek. By viewing more Universe with better precision, ESA's Euclid mission shines.
If the Universe is expanding, and the expansion is accelerating, what does that tell us about the cause of the expanding Universe?
Everything we observe beyond our Local Group is speeding away from us, omnidirectionally. If the Universe is expanding, where is the center?
In 1054, a core-collapse supernova occurred 6500 light-years away. In 2023, JWST imaged the remnant, and might solve a massive mystery.
For the first time, astronomers have created a data-driven estimate for how many black holes are in our Universe: more than anyone expected.
12mins
When black holes disappear, what happens to the stuff that fell in? Physicist Brian Cox explains.