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Cosmology
Since 1998, we've known our Universe isn't just expanding, but the expansion is accelerating. Could the Big Bang itself be the reason why?
Photons come in every wavelength you can imagine. But one particular quantum transition makes light at precisely 21 cm, and it's magical.
According to Stephen Hawking, spontaneously emitted radiation should cause all black holes to decay. But we've never seen it: not even once.
Empty space itself, the quantum vacuum, could be in either a true, stable state or a false, unstable state. Our fate depends on the answer.
Perhaps no existential question looms larger than that of our ultimate cosmic origins. At long last, science has provided the answers.
25 years ago, our concordance picture of cosmology, also known as ΛCDM, came into focus. 25 years later, are we about to break that model?
It's difficult to project a sphere onto a flat, two-dimensional surface. All maps of the Earth have flaws; the same is true for the cosmos.
The Kalam cosmological argument asserts that everything that exists must have a cause, and the "first" cause must be God. Is that valid?
We understand many things about our Universe, and our home within it, extremely well. The number of stars in the Milky Way isn't among them.
The Multiverse isn't just a staple of science fiction; there's real-life science behind it, too. Here are 10 facts to expand your mind.
Large, massive, rotating galaxies like the Milky Way are common today. So how could one form a mere ~2 billion years after the Big Bang?
DESI, by mapping galaxies, has claimed they see evidence for dark energy evolving by getting weaker. But that's only one interpretation.
Someday, we'll look back and see a young galaxy forming stars for the first time. JADES-GS-z14-0, the farthest ever, isn't early enough.
Einstein's general relativity has reigned supreme as our theory of gravity for over a century. Could we reduce it back down to Newton's law?
Some nebulae emit their own light, some reflect the light from stars around them, and some only absorb light. But that's just the beginning.
When we see spiral galaxies, some are face-on, others are edge-on, but most are tipped at an angle. But which side is closest to us?
The tiniest galaxies of all are the most susceptible to violence by their larger, bullying siblings. That's why we need them in isolation.
The Universe is expanding, and individual, bound structures are all receding away from one another. How, then, are galaxies still colliding?
Since the dawn of history, humans have pondered our ultimate cosmic origins. Now in the 21st century, science has gone beyond the Big Bang.
There are some 26 fundamental constants in nature, and their values enable our Universe to exist as it does. But where do they come from?
One of the most promising dark matter candidates is light particles, like axions. With JWST, we can rule out many of those options already.
Astronomers see spiral and elliptical nebulae nearly everywhere, except by the Milky Way's plane. We didn't know why until the 20th century.
Perhaps the most well-known equation in all of physics is Einstein's E = mc². Does mass or energy increase, then, near the speed of light?
From the tiniest subatomic scales to the grandest cosmic structures of all, everything that exists depends on two things: charge and mass.
The CMB gives us critical information about our cosmic past. But it doesn't give us everything, and galaxy mapping can fill in a key gap.
Dark matter doesn't absorb or emit light, but it gravitates. Instead of something exotic and novel, could it just be dark, normal matter?
When we divide matter into its fundamental, indivisible components, are those particles truly point-like, or is there a finite minimum size?
The ultimate multi-messenger astronomy event would have gravitational waves, particles, and light arriving all at once. Did that just occur?
A young, nearby, massive star, whose protoplanetary disk appears perfectly edge-on, was just viewed by JWST, with staggering implications.
If humanity lives in an otherwise barren Universe, we'll have to forge philosophy that fills the void.