LEEVENSPARK

"...when we look at galaxies alone, the gas and stars become relatively more important and begin to influence dark matter..." The interaction of dark matter with stars and gas in individual galaxies is more complicated than previously thought, according to International Centre for Radio Astronomy Research (ICRAR). After discovering a correlation between the concentration and mass of dark matter around clusters of galaxies, Dr Alan Duffy from ICRAR found this relationship breaks down around single galaxies, like our own Milky Way. “A basic assumption that astronomers often make is that the dark matter is so dominant that we can ignore the effects of gas and stars on its dynamics. “For massive clusters of galaxies this is a good approximation and there's a nice relation that drops out of the simulations between the mass of the cluster and the dark matter concentration, in full agreement with observations. “The problem is that when we look at galaxies alone, the gas and sta

All planets move around their stars in the same direction as the star spins—at least that’s what we thought. But now ANU astronomer Dr Daniel Bayliss and his colleagues have found a planet that breaks the mould. Dr Bayliss, from the Research School of Astronomy and Astrophysics, is one of 16 early-career scientists unveiling their research to the public at Fresh Science – a national program sponsored by the Australian Government. Using one of the world’s largest telescopes in Chile, Daniel and his collaborators discovered that a distant planet WASP-17b is moving in the opposite direction to the spin of the star around which it orbits. The discovery throws traditional theories about how planets form around stars into doubt. "Until now it has been assumed that any planets orbiting a star would be moving in the same direction as the star’s spin." Planets form from the same disk of rotating material that gives birth to the star around which they move. So until now it has bee

"The universe really was filled with a new kind of energy that was causing it to expand at an increasing speed." A survey of more than 200,000 galaxies led by Australian astronomers has shown that ‘dark energy’ is real and not a mistake in Einstein’s theory of gravity. The finding is conveyed in two papers led by Dr Chris Blake from Swinburne University’s Centre for Astrophysics and Supercomputing, which will be published in the  Monthly Notices of the Royal Astronomical Society . Using the Anglo-Australian Telescope, 26 astronomers contributed to the ‘WiggleZ Dark Energy Survey’ which mapped the distribution of galaxies over an unprecedented volume of the Universe. Because light takes so long to reach Earth, it was the equivalent of looking seven billion years back in time – more than half way back to the Big Bang. The survey, which took four years to complete, aimed to measure the properties of ‘dark energy’ a concept first cast by Einstein in his original Theory of Gener

Researchers have uncovered a new stellar neighbour with the discovery of the closest young star to Earth. The international team, including Simon Murphy, a final-year PhD student from the ANU Research School of Astronomy and Astrophysics, have shown that the star, named AP Columbae, is the closest so-called `pre main-sequence’ star. Their paper has been published this week in The Astronomical Journal. “Pre main-sequence stars are much younger than the Sun. Using telescopes in Coonabarabran, Chile, Hawaii and California we have shown that the faint, red-dwarf star AP Columbae is the closest such star to the Earth,” said Mr Murphy. “For decades it was believed that young stars only resided in vast star-forming regions like the Orion Nebula. These regions are typically several hundred light years away from the Earth. With the advent of accurate, all-sky surveys we can now find young stars much closer to home.” AP Columbae, an otherwise innocuous red-dwarf star in the constellation of Col