Astronomy

Astronomy

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 person with hair floating upwards looks out of a spacecraft window at Earth, filled with hope as clouds and oceans shimmer below—a view reminiscent of the Artemis II mission’s journey.
NASA has just sent astronauts back to the Moon for the first time since 1972 with Artemis II. So why would we cut NASA and NSF science now?
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.
Antimatter rocket with a glowing blue exhaust travels through deep space, showcasing the marvels of interstellar travel amid distant galaxies and stars.
Our dream of journeying to other star systems has a big obstacle to overcome: the vast interstellar distances. Can antimatter get us there?
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 hexagonal storm formation with a dark central vortex on a planet’s surface, showing swirling blue and tan cloud patterns.
From 2004 through 2017, Saturn was imaged many times and from many angles up close by Cassini. This new viral image isn't real; it's AI.
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.
Two highways, "Early Route" and "Late Route," marked 67.2 and 73.5, traverse a cosmic background with gradients and data—highlighting the Hubble tension and potential bad measurement in determining universal expansion rates.
The distance ladder and the CMB give incompatible values for the expansion rate. A new study shows just how robust the Hubble tension is.
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.
apollo 8 earthrise
As the world teeters on the brink of nuclear war, distant, advanced civilizations would never know it. Earth appears peaceful from far away.
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.
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?
bok globule barnard 68 dust wavelength
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.
travel straight line
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.
M81 Group
Over billions of years, fewer stars form, galaxies mutually recede, and the Universe becomes ever darker. Here's how fast it all happens.
A satellite with large solar panels orbits above Earth against a colorful space background, where the cosmic clouds resemble the Hand of God carved by a dead star.
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.
Millikan Lemaitre and Einstein
Not everyone accepts the scientific consensus; some even make careers out of challenging it. But only a select few do it the right way.
Side-by-side images of a nebula in space, showing colorful, wispy gas and dust shells surrounding a bright central region with numerous stars in the background.
Resembling a cosmic brain, the Exposed Cranium Nebula instead shows a dying, massive star, as JWST reveals. Its fate remains uncertain.
warm-hot intergalactic medium sculptor wall
In traveling through the expanding Universe, particles slow down while light and gravitational waves redshift. What degrades and what won't?
No civilization, no matter how successful, can last forever. What does the non-detection of intelligent aliens mean for our own longevity?
A view of a star-filled night sky with numerous bright stars and distant galaxies, including Hubble-dark galaxy formations, scattered across a dark background.
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?
Voyager
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?