Category Astronomy/Space

This is a simulation of gravitational waves from a collapsing Neutron star. Credit: Luciano Rezzolla

Astrophysicists have found a simple formula for the maximum mass of a rotating neutron star and hence answered a question that had been open for decades. Neutron stars are the most extreme and fascinating objects known to exist in our universe: Such a star has a mass that is up to twice that of the sun but a radius of only a dozen kilometres: hence it has an enormous density, thousands of billions of times that of the densest element on Earth.

An important property of neutron stars, distinguishing them from normal stars, is their mass cannot grow without bound. Indeed, if a nonrotating star increases its mass, also its density will increase...

Simulated structure of planet candidate 9. Credit: © Esther Linder, Christoph Mordasini, Universität Bern

Astrophysicists at the Uni of Bern have modelled the evolution of the putative planet in the outer solar system. They estimate the object has a present-day radius equal to 3.7 Earth radii and a temperature of -226C/ 47K. How big and how bright is Planet 9 if it really exists? What is its temperature and which telescope could find it? These were the questions that Prof Christoph Mordasini, Uni of Bern, and Esther Linder, PhD student wanted to answer when they heard about the possible additional planet in the solar system suggested by Konstantin Batygin and Mike Brown of the California Institute of Technology in Pasadena.

The Swiss scientists are experts in modelling the evolution of p...

False color image of Cassiopeia A using Hubble and Spitzer telescopes and Chandra X-ray Observatory. Credit: NASA/JPL-Caltech

An international team of scientists has found evidence of a series of massive supernova explosions near our solar system, which showered Earth with radioactive debris. The scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans. The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms.

“We were very surprised that there was debris clearly spread across 1.5 million years,” said Dr Wallner, a nuclear physicist in the ANU Research School of Physics and Engineering. “It suggests there were a series of supernovae, one after another...

A sky survey image of the massive galaxy NGC 1600, and a Hubble Space Telescope closeup of the bright center of the galaxy where the 17-billion-solar-mass black hole — or binary black hole — resides. Credit: ESA/Hubble image courtesy of STScI.

A near-record 17-billion-sun supermassive black hole discovered in a sparse area of the local universe indicates these monster objects may be more common than once thought. Until now, the biggest supermassive black holes – those with masses ~10 billion times that of our sun – have been found at the cores of very large galaxies in regions loaded with other large galaxies. The current record holder, discovered in the Coma Cluster tips the scale at 21 billion solar masses and is listed in the Guinness Book of World Records.

The newly discovered black ho...