Browse Physics

The spatial distribution of dark matter around different types of galaxies can be explained if its particles scatter one another, theorist suggest, but only if the interaction has a finite range.

The IceCube neutrino detector buried in the Antarctic ice reports that high-energy neutrinos, expected from gamma-ray bursts, have yet to be observed.

The idea of inflation–an exponential expansion of the universe in its first moments–was published in 1981, in a paper that imported new ideas from particle physics into theoretical cosmology.

A modification of the theory of gravity can explain the dynamics of gas-rich galaxies without the need for dark matter.

LISA, a future gravitational wave detector, could find evidence that the early universe had fewer than three spatial dimensions.

A set of proposed relations among observable quantities may allow strong tests of whether a rapid expansion of the very early universe produced the seeds of the large-scale structure we see today.

A hypothetical particle might explain both the existence of dark matter and the prevalence of matter over antimatter.

Results from the first three weeks of running the XENON100 experiment show its promise as a sensitive detector of particle dark matter in the form of WIMPs.

How do gravitational singularities avoid being trapped by event horizons?

New data from the PAMELA satellite on the abundance of antiprotons in cosmic rays still leave the door open for dark matter theories, as well as other explanations.

Where do cosmic magnetic fields come from?

Theorists propose that a nanostructured material could show what happens when the structure of spacetime changes, as some cosmologists have suggested may have occurred in the early universe.

Refining a cosmic clock gives a more accurate reading of the age of our galaxy.

Theories of dark matter interacting with a light force carrier, proposed to explain the excess of high-energy positrons in the cosmic rays, turn out to have problems.

What are the uncertainties in determining how long ago nucleosynthesis of heavy elements occurred in astrophysical bodies?

New data are inconsistent with previous measurements that showed an unexpected excess of diffuse gamma-ray emission in the Galaxy.

Defects—in the form of vortices in superconductors or “strings” in the fabric of the universe—can reveal the state of a system at the time it was cooled.

Relic neutrinos from the big bang have come from a region of the universe much nearer than the famous cosmic microwaves, even though they are older.

A single neutrino left over from the big bang may have a quantum wave (wave function) that stretches across the universe.

Detectors buried beneath the Antarctic ice place stringent limits on the presence of dark matter particles, called neutralinos, in the sun.