Search
Universe Expansion
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.
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.
If you said "with the Big Bang," congratulations: that was our best answer as of ~1979. Here's what we've learned in all the time since.
Einstein's theory of general relativity introduced the concept of space having a shape. So, what is the shape of space?
“To take this in, you need to ride inside the mathematical symbols.”
JWST has already broken many of Hubble's cosmic records. Perhaps additional record-breakers already exist within this data-rich image?
Back during the hot Big Bang, it wasn't just charged particles and photons that were created, but also neutrinos. Where are they now?
Although we still don't know the question, we know that the answer to life, the Universe, and everything is 42. Here are 5 possibilities.
The Universe, although violent, is filled with creation events following destructive ones. 1850 light-years away, both types are unfolding.
Between the least massive star and most massive planet lies the mysterious brown dwarf: a class of objects that are neither star nor planet.
From the Big Bang to black holes, singularities are hard to avoid. The math definitely predicts them, but are they truly, physically real?
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.
In the largest star-forming region close to Earth, JWST found hundreds of planetary-mass objects. How do these free-floating planets form?
2023's Nobel Prize was awarded for studying physics on tiny, attosecond-level timescales. Too bad that particle physics happens even faster.
With so many early galaxies of unexpectedly large brightnesses, JWST surprised us all. Here's how scientists made sense of what we see.
The question of why the Universe is the way it is is an ancient one, and none of the answers we have come up with are satisfying.
The laws of physics don't prefer matter over antimatter. So how can we be certain that distant stars & galaxies aren't made of antimatter?