Five years ago, the Nobel Prize in Physics was awarded to three astronomers for their discovery, in the late 1990s, that the universe is expanding at an accelerating pace. Now, a team of scientists led by Professor Subir Sarkar of Oxford University’s Department of Physics has cast doubt on this standard cosmological concept.
An international team of astrophysicists has for the first time witnessed a black hole swallowing a star and ejecting a flare of matter moving at nearly the speed of light. The scientists tracked the Sun-sized star in the galaxy PGC 43234 some 300 million light-years away as it shifted from its customary path, slipped into the gravitational pull of the supermassive black hole and was sucked in.
When a star collapses forming a black hole, a space-time singularity is created wherein the laws of physics no longer work. In 1965, Sir Roger Penrose presented a theorem where he associated that singularity with so-called ”trapped surfaces” that shrink over time. That hypothesis — one of the results of the general theory of relativity — is now celebrating its 50th anniversary.
Around 37,000 citizen scientists combed through 430,000 images to help an international team of researchers to discover 29 new gravitational lens candidates through Space Warps — an online classification system which guides citizen scientists to become lens hunters, giving the public a chance to make their own scientific discoveries.
UK researchers have just signed an agreement to lead one of the first instruments for what will become the World’s largest visible and infrared telescope, the European Extremely Large Telescope (E-ELT). The spectrograph, called HARMONI, will provide the European Southern Observatory’s telescope with a sensitivity that is up to hundreds of times better than any current telescope of its kind.
In his second report from the Royal Astronomical Society’s National Astronomy Meeting 2015, Kulvinder Singh Chadha ponders the nature of dark matter and whether cosmic jets — jets of material from active galaxies travelling close to the speed of light — may correlate with dense regions of dark matter in the Universe.
A new study finds that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centres, in the same way that spiral galaxies do. In these very different types of galaxies, stars and dark matter somehow conspire to redistribute themselves to produce this effect, or does modified Newtonian dynamics offer an explanation?
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