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Dark Matter
If you think of the Big Bang as an explosion, we can trace it back to a single point-of-origin. But what if it happened everywhere at once?
Dark matter's hallmark is that it gravitates, but shows no sign of interacting under any other force. Does that mean we'll never detect it?
How do normal matter and dark matter separate by so much when galaxy clusters collide? Astronomers find the surprising, unexpected answer.
The Bullet Cluster has, for nearly 20 years, been hailed as an empirical "proof" of dark matter. Can their detractors explain it away?
The standard picture of our Universe is that it's dominated by dark matter and dark energy. But this alternative is also worth considering.
There was a time where no starlight was visible throughout the entire cosmos. That time was short-lived: shorter than astronomers imagined.
CERN's NA64 experiment used a high-energy muon beam technique to advance the elusive search for dark matter, offering new hope for solving one of astronomy's greatest mysteries.
There are two different ways to measure the expansion rate of the Universe, and they don't agree. And no, new measurements don't help.
The Universe is precisely dated at 13.8 billion years old, but astronomers claim the Methuselah star is 14.5 billion years old. What gives?
Predicted way back in the 1960s, the discovery of the Higgs boson in 2012 completed the Standard Model. Here's why it remains fascinating.
The expanding Universe, in many ways, is the ultimate out-of-equilibrium system. After enough time passes, will we eventually get there?
For nearly 25 years, we thought we knew how the Universe would end. Now, new measurements point to a profoundly different conclusion.
Scientists are searching for dark matter particles that are trillions or even quadrillion times lighter than the more traditional searches.
The mutual distance between well-separated galaxies increases with time as the Universe expands. What else expands, and what doesn't?
We normally think of dark matter as the "glue" that holds galaxies and larger structures together. But it's so much more than that.
There are many theories of gravity out there, and many interpretations of wide binary star data. What have we really learned from it all?
From the earliest stages of the hot Big Bang (and even before) to our dark energy-dominated present, how and when did the Universe grow up?
Our Universe requires dark matter in order to make sense of things, astrophysically. Could massive photons do the trick?
The majority of the matter in our Universe isn't made of any of the particles in the Standard Model. Could the axion save the day?
The Universe is 13.8 billion years old, going back to the hot Big Bang. But was that truly the beginning, and is that truly its age?
A great many cosmic puzzles still remain unsolved. By embracing a broad and varied approach, particle physics heads toward a bright future.
There are a wide variety of theoretical studies that call our Standard Model of cosmology into question. Here's what they really mean.
Ground-based facilities enable the greatest scientific production in all of astronomy. The NSF needs to be ambitious, and it's now or never.
Almost every large structure in the Universe displays a 5:1 dark matter-to-normal matter ratio. Here's how some galaxies defy that rule.
Our own galaxy, the Milky Way, is both completely normal and absolutely remarkable in a number of ways. Here's the story of our cosmic home.
Astronomers claim to have found structures so large, they shouldn't exist. With such biased, incomplete observations, perhaps they don't.
Observations of an enormous cosmic structure, dubbed the "Big Ring," seem to violate the Copernican principle.
For every proton, there were over a billion others that annihilated away with an antimatter counterpart. So where did all that energy go?
Finding it at all was a happy accident. Examining it further may help unlock the secrets hiding within the earliest galaxies of all.
Today, the star-formation rate across the Universe is a mere trickle: just 3% of what it was at its peak. Here's what it was like back then.