A new study shows our planet is much closer to the supermassive black hole at the galaxy’s center than previously estimated.
Scientists were expecting to find an intermediate-mass black hole at the heart of the globular cluster NGC 6397, but instead they found evidence of a concentration of smaller black holes lurking there. New data from the NASA /ESA Hubble Space Telescope have led to the first measurement of the extent of a collection of black holes in a core-collapsed globular cluster.
Globular clusters are extremely dense stellar systems, in which stars are packed closely together. They are also typically very old — the globular cluster that is the focus of this study, NGC 6397, is almost as old as the Universe itself. It resides 7800 light-years away, making it one of the closest globular clusters to Earth. Because of its very dense nucleus, it is known as a core-collapsed cluster.
Over the past few years, many physicists worldwide have conducted research investigating chaos in quantum systems composed of strongly interacting particles, also known as many-body chaos. The study of many-body chaos has broadened the current understanding of quantum thermalization (i.e., the process through which quantum particles reach thermal equilibrium by interacting with one another) and revealed surprising connections between microscopic physics and the dynamics of black holes.
We argue that extensions of the SM with a warped extra dimension, together with a new $${\mathbb {Z}}_2$$ Z 2-odd scalar singlet, provide a natural explanation not only for the hierarchy problem but also for the nature of fermion bulk masses and the observed dark matter relic abundance. In particular, the Kaluza-Klein excitations of the new scalar particle, which is required to naturally obtain fermion bulk masses through Yukawa-like interactions, can be the leading portal to any fermion propagating into the bulk of the extra dimension and playing the role of dark matter. Moreover, such scalar excitations will necessarily mix with the Higgs boson, leading to modifications of the Higgs couplings and branching ratios, and allowing the Higgs to mediate the coannihilation of the fermionic dark matter.
Chair emeritus, SETI institute — the search for extraterrestrial intelligence.
Dr. Jill Tarter is Chair Emeritus for SETI (Search for Extraterrestrial Intelligence) Research at the SETI Institute, a not-for-profit research organization whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to apply the knowledge gained to inspire and guide present and future generations.
Scientists have discovered the first evidence for a rare type of stellar explosion, or supernova in the Milky Way. This intriguing object lies near the center of our galaxy in a supernova remnant called Sagittarius A East (Sgr A East). Chandra data revealed that Sgr A East may belong to a spec.
Eventually, galaxies stop making new stars. But why did some stop so much sooner than others? Hint: black holes play a role.
A galaxy’s main business is star formation. And when they’re young, like youth everywhere, they keep themselves busy with it. But galaxies age, evolve, and experience a slow-down in their rate of star formation. Eventually, galaxies cease forming new stars altogether, and astronomers call that quenching. They’ve been studying quenching for decades, yet much about it remains a mystery.
A new study based on the IllustrisTNG simulations has found a link between a galaxy’s quenching and its stellar size.
Scientists are finally figuring out how much dark matter — the almost imperceptible material said to tug on everything, yet emit no light — really weighs.
Astronomy owes George Ellery Hale and the Palomar Observatory a great debt of gratitude for persevering with the construction of a telescope that forever changed cosmology.
