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Astrophysics
Early on, the Universe needed near-perfect flatness, or atoms, stars, and galaxies couldn't form. What happens once dark energy takes over?
The image you're seeing isn't a hole in the Universe, and the cosmic voids that do exist aren't hole-like at all.
Looking up at the night sky gives us a glimpse of the Universe beyond our terrestrial concerns. Here's the science of what's out there.
No matter what physical system we consider, nature always obeys the same fundamental laws. Must it be this way, and if so, why?
When what we predict and what we measure don't add up, that's a sign there's something new to learn. Could it be a new fundamental force?
In theory, the fabric of space could have been curved in any way imaginable. So why is the Universe flat when we measure it?
Binary black holes eventually inspiral and merge. That's why the OJ 287 system is destined for the most energetic event in history.
Over billions of years, fewer stars form, galaxies mutually recede, and the Universe becomes ever darker. Here's how fast it all happens.
Nothing lives forever, at least, not in the known Universe. But relativity allows us to get closer than ever: from a physics perspective.
The path to exploring the high-energy Universe was clear and compelling. Here's how 2025's cuts are still causing NASA casualties in 2026.
Resembling a cosmic brain, the Exposed Cranium Nebula instead shows a dying, massive star, as JWST reveals. Its fate remains uncertain.
In traveling through the expanding Universe, particles slow down while light and gravitational waves redshift. What degrades and what won't?
The discovery of CDG-2, a galaxy that's more than 99.9% dark matter, could reveal a new population of ultra-faint galaxies. But is it real?
No human has ever left the Solar System, and only six already-launched spacecraft will ever exit it. Will Voyager 1 remain the most distant?
Quantum entanglement links information between particles across space and time. So what happens when one of them falls into a black hole?
Forget about the terawatt lasers we're making on Earth. The Universe makes natural ones thousands of times more powerful than the Sun.
Even space and time are relative in Einstein's universe. That means our old notions of "where" and "when" no longer apply on cosmic scales.
The fundamental building blocks of reality are indivisible: quanta that cannot be split or divided. Our understanding remains incomplete.
Long after the last star burns out, the Universe will experience its end state: a heat death. Will everything prior then be meaningless?
Many reactions emit energy, often in large amounts, but cosmic efficiency is another metric altogether. Here's how to maximize your output.
The Universe is expanding, the expansion is accelerating, and some galaxies even recede faster-than-light. Can we see a change in real time?
Before Sun-like stars die, they transition from AGB red giants into preplanetary nebulae. Here's how Hubble sees the famous Egg Nebula.
No claim has even made it halfway up the Confidence of Life Detection (CoLD) scale, but 21st century science is just beginning to unfold.
Here in our modern Universe, it's cosmic dust that forms planets, complex molecules, and enables life. But how did the Universe create it?
13.8 billion years have passed since the Big Bang, but many stars will survive for longer than that. What's the longest-lived a star can be?
Even at its faintest, Venus always outshines every other star and planet that's visible from Earth, and then some!
The Universe formed stars, galaxies, and even galaxy clusters extremely early on in our cosmos. This new marvel is one more JWST surprise.
At the upper limits of what's energetically possible, cosmic rays still persist. What happens if a human gets hit by the most energetic one?
Our great hope is that today's indirect, astrophysical evidence will someday lead to successful direct detection. What if that's impossible?
Just like animals, galaxies often have bizarre, unusual, or even unique properties. But finding many, all at once, really does raise alarms.