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Universe Expansion
For nearly 60 years, the hot Big Bang has been accepted as the best story of our cosmic origin. Could the Steady-State theory be possible?
Two parts of our Universe that seem to be unavoidable are dark matter and dark energy. Could they really be two aspects of the same thing?
"A person’s mass is made not of 'stuff' in the way we normally think about it, but rather our mass is made of energy."
Since the mid-1960s, the CMB has been identified with the Big Bang's leftover glow. Could any alternative explanations still work?
The most massive early galaxies grew up faster, and have more stars, than astronomers expected, according to JWST. What does it all mean?
There are a few small cosmic details that, if things were just a little different, wouldn't have allowed our existence to be possible.
When we see pictures from Hubble or JWST, they show the Universe in a series of brilliant colors. But what do those colors really tell us?
The last naked-eye Milky Way supernova happened way back in 1604. With today's detectors, the next one could solve the dark matter mystery.
Since 1930, type Ia supernovae have been thought to arise from white dwarfs exceeding the Chandrasekhar mass limit. Here's why that's wrong.
The race to find dark matter could grow more complex with high-energy neutrino interference.
In astronomy, a star's initial mass determines its ultimate outcome in life. Unless, that is, a stellar companion alters the deal.
Black holes are the most massive individual objects, spanning up to a light-day across. So how do they make jets that affect the cosmic web?
Humans, when we consider space travel, recognize the need for gravity. Without our planet, is artificial or antigravity even possible?
All the stars, stellar corpses, planets, and other large, massive objects take on spherical or spheroidal shapes. Why is that universal?
Why hasn’t matter fallen apart over billions of years? The mystery might start with protons.
NASA's space telescopes and observatories bring humanity unrivaled science images and scientific discoveries. Here's what should be next.
In the year 1181, a "guest star" was recorded in the constellation of Cassiopeia. Its modern supernova remnant is weirder than we imagined.
Almost everyone asserts that the Big Bang was the beginning of everything, followed by inflation. Has everyone gotten the order wrong?
More than two years after JWST began science operations, our Universe now looks very different. Here are its biggest science contributions.
What are dark matter and dark energy? The large-scale structure of the cosmos encodes them both, with ESA's Euclid mission leading the way.
The most common visual depictions of the history of the Universe show the Big Bang as a growing tube with an "ignition" point. Why is that?
The fabric of spacetime is four-dimensional, with three for space and only one for time. But wow, time sure is different from space!
Could life be widespread throughout the cosmos, in the subsurface oceans of ice-covered worlds? NASA's Europa Clipper mission investigates.
An in-depth interview with astronomer Kelsey Johnson, whose new book, Into the Unknown, explores what remains unknown about the Universe.
There are a number of factors to consider when choosing where to build a telescope. These 3 locations, on their merits, surpass all others.
Watching for changes in the Red Planet’s orbit over time could be new way to detect passing dark matter.
National Geographic's first James Webb Space Telescope book shows us the cosmos like never before.
The earliest Milky Way-like galaxy, REBELS-25, was spotted rotating about its axis. It's only 700 million years old: 5% of our present age.
Interferometry gave us a black hole's event horizon, but that was in the radio. What can we accomplish with a new optical interferometer?
Today, the deepest depths of intergalactic space aren't at absolute zero, but at a chill 2.73 K. How does that temperature change over time?