If extra dimensions are large, part of the gravitational field would “leak” into the extra dimensions and gravitational waves would be weaker than expected.
The 20th International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI 2018) was held in Nagoya, Japan.
Some 180 years ago, a relatively normal star called Eta Carinae suddenly brightened to become the second brightest star in the sky, before almost disappearing at the end of the 19th century.
The discovery of large-scale features in the gamma-ray sky in approximately the same direction continues to puzzle researchers.
Gravity behaves the same way on a galactic scale as it does in our solar system, and alternative gravity models which remove the need for dark energy are disfavoured.
Carlo Bradaschia reviews in 2009 Gravitational Waves Vol 1: Theory and Experiments.
NASA’s Chandra X-ray Observatory have revealed a dozen stellar-mass black holes at the centre of the galaxy, providing the first observational evidence for such a black-hole cluster.
To celebrate its 15th anniversary, the HESS collaboration has published its largest set of scientific results to date.
Adam Riess from the Space Telescope Science Institute and colleagues have now made a more precise, direct measurement that reinforces the mismatch and could signal new physics.
Radiation emitted around a distant black hole has revealed the existence of extragalactic planets in a galaxy 3.8 billion light years away.