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Astrophysics
Wavelengths stretch, distances grow, and temperatures cool as the Universe expands with time. How are the various cosmic parameters related?
Weird-looking galaxies, with tentacle-like tails or prominent dual streams, appear like jellyfish or bunny ears. But that’s just the start.
For over 10 billion years, the cosmic star-formation rate has been dropping and dropping. Someday, the final star in the Universe will die.
We first measured G, the gravitational constant, back in the 18th century. As the least well-known fundamental constant, can it be improved?
In 2017, a kilonova sent light and gravitational waves across the Universe. Here on Earth, there was a 1.7 second signal arrival delay. Why?
Planets grow from protostellar material in disks, leading to full-grown planetary systems in time. At last, the final gap has been filled.
Until the late 20th century, there wasn't a truly universal standard. Under our current definition, everyone agrees on what "one meter" is.
Do aliens speak the same physics that we do, with similar laws, observables, and underlying mathematics. Maybe not, argues Daniel Whiteson.
We've now detected hundreds of gravitational waves with LIGO, Virgo, and KAGRA. What if we tried Weber's original method in the modern day?
The first world beyond Earth for human habitability should be the Moon, not Mars. This is why we should terraform our lunar neighbor first.
Times dilate and lengths contract near the speed of light. Bizarre and confusing? Sure. But under relativity, it can't be any other way.
Stellar streams are faint trails of stars that appear to "stream" out of galaxies. A new one, escaping galaxy M61, may point to many others.
When dying, Sun-like stars have binary companions, spectacular sights arise from the ionization. JWST spots the Red Spider Nebula in action!
There's some, but not overwhelming, evidence that dark energy is evolving. What would it take for a "Big Crunch" to be our cosmic fate?
Scientists are notoriously resistant to new ideas. Are they falling prey to groupthink? Or are our current theories just that successful?
Physicist Daniel Whiteson challenges the notion that all intelligent species would eventually uncover the same laws of nature. Do you agree?
Nearly 100 years after being theorized, the strange behavior of the neutrino still mystifies us. They could be even stranger than we know.
The planet, the Solar System, and the galaxy aren't expanding. But the whole Universe is. So where does the dividing line begin?
For 13.8 billion years, the Universe has been expanding. But that couldn't have been the case for an eternity, and science has proven it.
Dark matter has never been directly detected, but the astronomical evidence for its existence is overwhelming. Here's what to know.
We've long known we can't go back to infinite temperatures and densities. But the hottest part of the hot Big Bang remains a cosmic mystery.
Found by Hubble before JWST's launch, GNz7q looked like a mix of a galaxy and a quasar. Was it actually our first known "little red dot"?
Observations with the Hubble space telescope helped cement dark energy and reveal the Hubble tension. How are these two things so different?
"Think of it like a transcontinental railroad — not the fastest way to move a lot of mass, but certainly the most efficient,” Jared Isaacman said about nuclear electric propulsion.
Solar power has the disadvantage that there's no Sun at night. Satellite startup Reflect Orbital wants to change that, but at what cost?
Inflation's two main criticisms, that it can predict anything and that the "measure problem" remains unsolved, can't erase its successes.
The Orionids meteor shower peaks October 20th/21st here in 2025, coinciding with a new Moon. See the brightest shooting stars of the year!
To learn how our Universe grew up, we have to look at large numbers of galaxies at all distances to find out. Good thing we have JWST!