Space

Using NASA, Japanese, and European X-ray satellites, a team of Japanese astronomers has discovered that our galaxy’s central black hole let loose a powerful flare three centuries ago. The finding helps resolve a long-standing mystery: why is the Milky Way’s black hole so quiescent? The black hole, known as Sagittarius A* (pronounced "A-star"), is a certified monster, containing about 4 million times the mass of our Sun. Yet the energy radiated from its surroundings is billions of times weaker than the radiation emitted from central black holes in other galaxies. "We have wondered why the…

By studying in great detail the 'ringing' of a planet-harbouring star, a team of astronomers using ESO's 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way. The yellow-orange star Iota Horologii, located 56 light-years away towards the southern Horologium ("The Clock") constellation, belongs to the so-called "Hyades stream", a large number of stars that move in the same direction. Previously, astronomers using an ESO telescope had shown…

UK astronomers have produced the most sensitive infrared map of the distant Universe ever undertaken. Combining data over a period of three years, they have produced an image containing over 100,000 galaxies over an area four times the size of the full Moon. Some of the first results from the project were presented by Dr Sebastien Foucaud from the University of Nottingham at the RAS National Astronomy Meeting in Belfast. Due to the finite speed of light, these observations allow astronomers to look back in time over 10 billion years, producing images of galaxies in the Universe's infancy. The…

A study of active and inactive galaxies by Paul Westoby, Carole Mundell and Ivan Baldry from the Astrophysics Research Institute of Liverpool John Moores University has given new insights into the complex interaction between super-massive black holes at the heart of Active Galactic Nuclei (AGN) and star formation in the surrounding galaxy. The team studied the properties of light from 360,000 galaxies in the local Universe to understand the relationship between accreting black holes, the birth of stars in galaxy centres and the evolution of the galaxies as a whole. The study finds that gas…

Scientists have discovered a possible terrestrial-type planet orbiting a star in the constellation Leo. The new planet lies at a distance of 30 light years from the Earth and has a mass five times that of our planet but is the smallest found to date. One full day on the new planet would be equivalent to three weeks on Earth. A team of astronomers from the Spanish Research Council (CSIC) working with Dr Jean-Philippe Beaulieu, a visiting astrophysicist at University College London (UCL), made the discovery from model predictions of a new exoplanet orbiting a star in the constellation of Leo.…

A rare type of galax with a higher number of X-rays than thought possible has been detected. Quasars are cosmic 'engines' that pump energy into their surroundings - theorists speculate that an enormous black hole drives each one. As matter falls into the black hole, it collects in a swirling reservoir called the accretion disc, which heats up. Computer simulations suggest that powerful radiation and magnetic fields present in the region eject some of gas from the gravitational clutches of the black hole, throwing it back into space. Artist's impression of a rare type of quasar, called a…

Using data from the Hinode and RHESSI solar observatories, astronomers have discovered that solar flares - explosions in the atmosphere of the sun - get much hotter when they stay "focused." Dr Ryan Milligan of Oak Ridge Association of Universities, Tennessee, who is stationed at NASA’s Goddard Space Flight Center in the US, will present his result on Wednesday 2 April at RAS National Astronomy Meeting in Belfast. Solar flares are caused by the sudden release of magnetic energy. The largest can release as much energy as a billion one-megaton nuclear bombs. However, the flare observed in this…

There are many interactions between the Sun and the Earth but one of the most dynamic events is a ‘substorm’ - an explosive reshaping of the Earth’s outer magnetic field. To better understand substorms, scientists in Europe and North America are studying them from space using the Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites launched by NASA in 2007 and from the ground using a network of all-sky cameras. University of Lancaster solar-terrestrial scientist Dr Emma Woodfield gave a talk at the Royal Astronomical Society National Astronomy Meeting in…

The Sun has a very dynamic atmosphere, with huge fountains of hot gas erupting in the atmosphere, or corona, every few minutes, travelling at tens of thousands of kilometers per hour and reaching great heights. A team of scientists using the Hinode spacecraft has been searching for the origin and driver of these 'fountains', immense magnetic structures that thread through the solar atmosphere. On Wednesday 2 April at the Royal Astronomical Society National Astronomy Meeting in Belfast (NAM 2008), team leader Dr. Michelle Murray from the Mullard Space Science Laboratory (MSSL, University…

An international team of scientists, led by Prof Louise Harra, University College London, Mullard Space Science Laboratory, have found a source of the stream of particles that make up the slow solar wind using data from Hinode and SOHO. The solar wind can have low or high speeds. The low-speed or slow solar wind moves at only 1.5 million km/h. The high-speed wind is even faster, moving at speeds as high as 3 million km/h. As it flows past Earth, the solar wind changes the shape and structure of Earth's magnetic field. ESA’ s SOHO and Hinode Project Scientist, Bernhard Fleck says, “In the…