Browse Physics

The first results from the space-borne Alpha Magnetic Spectrometer confirm an unexplained excess of high-energy positrons in Earth-bound cosmic rays.

Much can be learned about hypothetical particles called axions by studying the evolution of massive stars.

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 comparison between the density in surrounding galaxies today and a few billion years ago provides a new upper bound on neutrino mass.

New calculation of quark matter properties tells us what an exotic quark-neutron star might look like.

New measurements with the Fermi Large Area Telescope extend our knowledge of the extragalactic diffuse gamma-ray background and may help resolve the question of its origins.

The insights of a provocative connection between general relativity and quantum field theory, called the AdS/CFT correspondence, have been extended to rotating black holes that can occur astrophysically.

New connections have been made between experimental astrophysical signatures and theories that unify the electromagnetic, weak, and strong forces, called grand unified theories.

New results from the Fermi Gamma-Ray Space Telescope, the most precise to date in the energy range $20\text{GeV}$ to $1\text{TeV}$, should help resolve whether cosmic rays composed of the lightest charged particles, i.e., electrons and positrons, come from dark matter or some other astrophysical source.

Many cosmologists believe that antiprotons in cosmic rays come from the annihilation of dark matter. Data from the PAMELA experiment on board a Russian satellite provide an important test of this possibility.

New upper limits on the spin-independent interaction of WIMPs and nucleons marks the latest volley in the worldwide effort to detect and identify particle dark matter.

New arguments based on astrophysical phenomena constrain the possibility that dangerous black holes will be produced at the CERN Large Hadron Collider.

Forty years ago, it was predicted that there would be a sharp cutoff in the intensity of the very-high-energy cosmic rays that strike the earth’s surface. Two collaborations—the HiRes and Auger telescopes—are providing compelling evidence for this so-called “GZK effect.”