Category Astronomy/Space

LAMOST spectra of LAMOST-HVS1 (top), LAMOST-HVS2 (middle) and LAMOST-HVS3 (bottom). The inset in each panel shows the enlarged normalized blue-arm spectrum. Credit: Huang et al., 2017.

A group of Chinese astronomers has detected 2 new unbound hypervelocity stars located over 70,000 light years away. The discovery could help scientists better understand the nature of these peculiar stars. Hypervelocity stars (HVSs) are rare objects with velocities so great that they exceed the escape velocity of the galaxy. Astronomers believe that they originate near the center of the Milky Way galaxy by dynamical interactions between binary stars and the central massive black hole. While ordinary stars have velocities around 100 km/s, the velocities of HVSs can reach even 1,000 km/s.

Although scientists e...

The ALPHA team at the ALPHA facility, CERN. Credit: CERN

New research has enabled recent experiments to make the first measurement of the 1S – 2S atomic state transition in antihydrogen. A theoretical approach was developed for the ALPHA experiment at CERN, and provides the insight needed to make high precision spectroscopic measurements of the transition energy between the 1S and 2S energy levels. As a result, successful measurements have now been made to a precision of better than one part in a billion.

The research presented by Dr Rasmussen, Professor Niels Madsen, and Professor Francis Robicheaux, also points the way forward to even higher precision measurements of the properties of antihydrogen...

1. The theory that primordial black holes collide with neutron stars to create heavy elements explains the lack of neutron stars in the center of the Milky Way galaxy, a long-standing mystery. Credit: University of California, Los Angeles
2. A black hole captured by a neutron star. Credit: Alexander Kusenko/UCLA

UCLA physicists have proposed new theories for how the universe’s first black holes might have formed and the role they might play in the production of heavy elements such as gold, platinum and uranium. A long-standing question in astrophysics is whether the universe’s very first black holes came into existence less than a second after the Big Bang or whether they formed only millions of years later during the deaths of the earliest stars.

Alexander Kusenko, a UCLA professor of phys...

Geometric configuration of Apollo seismic stations and deep moonquake source regions. The lunar globe was taken from Lunar Reconnaissance Orbiter Camera (LROC)coutresy of NASA, and Apollo stations and deep moonquake nests were marked by the study’s authors. Credit: NASA and Kawamura et al/Journal of Geophysical Research/AGU

The same gravitational force responsible for creating tides on Earth could be causing deep quakes on the moon, a new study confirms. A new analysis of data gathered by the Apollo missions confirms that tidal stress – the gravitational pull of the moon on the Earth and of the Earth on the moon – is responsible for causing deep moonquakes, the lunar equivalent of earthquakes.

Seismometers placed on the moon during the Apollo 12, 14, 15 and 16 missions revealed the m...