Astrophysics

Astrophysics

black hole central singularity
Yes, "the laws of physics break down" at singularities. But relativity itself would have to be wrong for black holes to not possess them.
A chart showing the masses of black holes and neutron stars detected by LIGO-Virgo-KAGRA, highlighting how gravitational wave astronomy has become a mature science. Masses are plotted in solar masses on a logarithmic scale.
In 2016, humanity announced our first successful gravitational wave detection. 10 years and 389 events later, here's how far we've come.
colliding black holes
Many people, now with LLM assistance, regularly claim to discover game-changing revolutions. Scientists don't buy it. You shouldn't either.
A digital illustration exploring the origin of the universe—depicting a blue energy burst on the left and a geometric white grid forming a funnel shape on a purple background, evoking one of the biggest mysteries in science.
The original idea of the Big Bang was synonymous with a singularity: a point of zero volume. In this Universe, things never got that small.
A vivid image of a bright, colorful galaxy with swirling red, blue, and white clouds of gas and dust, where galaxies collide amid distant stars in the dark, expanding universe.
Astronomers study our cosmic history through stellar and galactic archaeology. But we can't conduct archaeology in space. At least, not yet.
Illustration of multiple spiral galaxies and stars being pulled toward a central black hole in deep space, with blue and purple light streaks tracing the motion along a dark energy curve that shapes the universe.
Today, in the here-and-now, a full 13.8 billion years have elapsed since the start of the hot Big Bang. But would that be true for everyone?
atom quantum
In physics, we reduce things to their elementary, fundamental components, and build emergent things out of them. That's not the full story.
Three side-by-side images of a spiral galaxy show increasing detail and brightness, highlighting dust, stars, and a bright galactic center with radiating diffraction spikes.
Messier 77 is one of the largest nearby spiral galaxies, with an active, brilliant core. Here's what JWST's incomparable eyes saw inside it.
A graph showing star brightness over time during a Kuiper Belt occultation event, with a grayish planet above and two plotted lines labeled Fukushima and Kiso Obs—shedding light on the discovery of distant atmospheres.
A relatively tiny world in the Kuiper belt, just 500 km in diameter, has an atmosphere after all, joining Pluto. Here's what we know today.
A deep space image showing numerous distant galaxies of various shapes and sizes scattered across a dark background, revealing just how empty is space between these cosmic islands.
There's a lot of room in interplanetary, interstellar, and intergalactic space, but just how low the densities go is truly mind-boggling.
two particles different wavelength speed of light
Contrary to common experience, not everything needs a medium to travel through. Overcoming that assumption removes the need for an aether.
pluto moons hubble
In 2006, the IAU defined "planet" for the first time, excluding Pluto and all other dwarf planets. In 2026, is it now time for a change?
A vibrant cosmic scene reveals a galaxy with bright jets of energy, hottest stars twinkling vividly amidst scattered stars against a dark backdrop.
From within our own galaxy to behemoths billions of light-years away, supermassive black holes create jets like nothing else in the cosmos.
A color-enhanced image shows Pluto planet in the foreground with its moon Charon in the background, both set against a black space backdrop.
In 2006, Pluto was controversially demoted to "dwarf planet" by the IAU. Unless you ignore most of astrophysics, it won't ever be one again.
Bullet Cluster separation mass gravity x-ray lensing
The first colliding galaxy cluster to reveal dark matter, empirically, turns 20 this year. Here's why it cements dark matter's existence.
A colorful nebula with a bright center and symmetrical, wing-like clouds of gas and dust extends outward in space, as seen in a JWST reveal that uncovers stars and galaxies in the universe beyond.
Many facts are well-known to professionals, but are unappreciated or even rejected outright by the public. "How stars work" takes the cake.
Illustration of Earth overlaid with a grid and energy types from the Kardashev Scale: Type I, II, and III, representing planetary, stellar, and galactic energy usage.
The famous framework ranks civilizations by energy use — but ignores a critical factor that can halt their progress.
Image of a galaxy cluster with bright yellow galaxies at the center, surrounded by blue regions representing dark matter in deep space—a striking view often used for dark matter cosmic test MOND studies.
On cosmic scales, only dark matter (or something equivalent) gives us the Universe we observe. Now, the Sunyaev-Zel'dovich effect agrees.
Colorful nebula with bright stars ignite glowing gas clouds in space, featuring red, yellow, and blue hues against a dark background.
Although a star's "birth" is well-defined, it doesn't correspond to an ignition event in its core. Here's how stars are actually born.
A bright, circular object with concentric rings and a surrounding halo set against a dark background, resembling a gap-clearing planet or other astronomical phenomena.
One parameter, alone, sets the dividing line between rocky planets, gas giants, brown dwarfs, stars, and much more. Here's why mass matters.
A distorted galaxy with two bright, horizontal bands and scattered stars, seen against a dark background. Image credit: NASA/ESA/CSA.
By looking at a giant, remarkable, edge-on protoplanetary system, astronomers have found a proto-protoplanet for the first time.
Four people wearing black shirts and eclipse glasses look up at the camera indoors, their excitement echoing the spirit of the Artemis II distance record mission.
Human beings have now traveled farther from Earth than ever before with Artemis II's flyby of the lunar far side. Here's how it happened.
Known as the "past hypothesis" problem, the Universe's initially low entropy has long puzzled scientists. Now, cosmic inflation solves it.
A labeled illustration shows the Large Magellanic Cloud, astronomers' most pristine star (SDSS J0715-7334), and the Milky Way galaxy connected by a wispy trail.
The 1st generation of stars formed, lived, and died very early on. But 2nd generation stars could still persist today. Did we just find one?
A person’s silhouette looks out a spacecraft window at Earth—a blue and white sphere against the darkness of space—reflecting the hope inspired by Artemis II’s journey to the moon.
As humanity journeys to the Moon for the first time since 1972, can we rediscover our shared responsibilities: to the world and each other?
black hole merger
As light travels across the Universe, it's subject to cosmic expansion, changing fields, and relative motion. How about gravitational waves?
moon landing Apollo 11
Even though no human has stepped foot on the Moon's surface in 50 years, the evidence of our presence there remains unambiguous.
logarithmic history of universe
In a 13.8 billion year old Universe, a few seconds hardly seems like it matters. But these minuscule changes sure do add up over time.
Two peculiar galaxies collide in deep space, forming bright clusters and swirling dust clouds—a striking scene that reveals the beauty and violence of the cosmos against a dark background.
Most massive galaxies are spiral or elliptical shaped. But peculiar galaxies showcase the beautiful violence that helps explain our cosmos.
Illustration of multiple spiral galaxies and stars being pulled toward a central black hole in deep space, with blue and purple light streaks tracing the motion along a dark energy curve that shapes the universe.
Early on, the Universe needed near-perfect flatness, or atoms, stars, and galaxies couldn't form. What happens once dark energy takes over?