Institute of Astronomy

Astronomy News

Cloudy Days on Exoplanets May Hide Atmospheric Water

9 June 2016 - 9:14am

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Water is a hot topic in the study of exoplanets, including "hot Jupiters," whose masses are similar to that of Jupiter, but lie much closer to their parent star than Jupiter is to the sun. They are estimated to be a scorching 2,000 degrees Fahrenheit, meaning any water they host would take the form of water vapor.

Cold, clumpy accretion onto an active supermassive black hole

9 June 2016 - 9:13am

Cold, clumpy accretion onto an active supermassive black hole

Nature 534, 7606 (2016). doi:10.1038/nature17969

Authors: Grant R. Tremblay, J. B. Raymond Oonk, Françoise Combes, Philippe Salomé, Christopher, P. O’Dea, Stefi A. Baum, G. Mark Voit, Megan Donahue, Brian R. McNamara, Timothy A. Davis, Michael A. McDonald, Alastair C. Edge, Tracy E. Clarke, Roberto Galván-Madrid, Malcolm N. Bremer, Louise O. V. Edwards, Andrew C. Fabian, Stephen Hamer, Yuan Li, Anaëlle Maury, Helen R. Russell, Alice C. Quillen, C. Megan Urry, Jeremy S. Sanders & Michael W. Wise

Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds—a departure from the ‘hot mode’ accretion model—although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z = 0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities produce a rain of cold clouds that fall towards the galaxy’s centre, sustaining star formation amid a kiloparsec-scale molecular nebula that is found at its core. The observations show that these cold clouds also fuel black hole accretion, revealing ‘shadows’ cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole, which serves as a bright backlight. Corroborating evidence from prior observations of warmer atomic gas at extremely high spatial resolution, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it.

Astrophysics: Relativity passes black-hole test

9 June 2016 - 9:09am

Astrophysics: Relativity passes black-hole test

Nature 534, 7606 (2016). doi:10.1038/534154e

General relativity holds true, even under the extreme conditions of colliding black holes.In 2015, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) saw the first evidence of gravitational waves, which had been created by two merging black holes. Walter Del Pozzo at the University of

Flamingo stars turn pink when they gobble iron-rich planets

9 June 2016 - 9:08am

Consuming a metal-rich planet or two early in its life can change a star’s colour – making them the flamingos of space

Spongy minerals could explain why Mars gives off methane burps

9 June 2016 - 9:07am

Zeolites – volcanic minerals that easily trap and release gases – could be responsible for the burps of methane that occasionally come from the Red Planet

Gravity space mission passes big test

9 June 2016 - 9:03am

The Lisa Pathfinder mission, which was designed to demonstrate the technologies needed to detect gravitational waves in space, has been a stunning success, say officials.

Hubble finds Universe may be expanding faster than expected [heic1611]

6 June 2016 - 10:15am

Astronomers have used Hubble to measure the distances to stars in nineteen galaxies more accurately than previously possible. They found that the Universe is currently expanding faster than the rate derived from measurements of the Universe shortly after the Big Bang. If confirmed, this apparent inconsistency may be an important clue to understanding three of the Universe's most elusive components: dark matter, dark energy and neutrinos.

Mars Webcam goes pro

6 June 2016 - 10:14am

A modest 'webcam' on Mars Express has proven useful for outreach, education and citizen-science. Now ESA have decided to adopt it as a professional science instrument.

NASA's Hubble Finds Universe Is Expanding Faster Than Expected

6 June 2016 - 10:13am

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When astronomer Edwin Hubble discovered nearly 100 years ago that the universe was uniformly expanding in all directions, the finding was a big surprise. Then, in the mid-1990s, another shocker occurred: astronomers found that the expansion rate was accelerating perhaps due to a repulsive property called "dark energy." Now, the latest measurements of our runaway universe suggest that it is expanding faster than astronomers thought. The consequences could be very significant for our understanding of the shadowy contents of our unruly universe. It may mean that dark energy is shoving galaxies away from each other with even greater or growing strength. Or, the early cosmos may contain a new type of subatomic particle referred to as "dark radiation." A third possibility is that "dark matter," an invisible form of matter that makes up the bulk of our universe, possesses some weird, unexpected characteristics. Finally, Einstein's theory of gravity may be incomplete.

Why is the universe expanding 9 per cent faster than we thought?

6 June 2016 - 10:11am

Two ways of measuring how quickly the universe is flying apart come up with increasingly different numbers. Are our measurements wrong, or is physics?

Red and Golden Planets at Opposition

6 June 2016 - 10:10am

Mars and Saturn are getting together in the constellation Scorpius for back-to-back oppositions in May and June 2016.

Astronomers probe below Jupiter's clouds

6 June 2016 - 10:09am

US astronomers have managed to peer deep into the atmosphere of Jupiter using a radio telescope here on Earth.

Hubble clocks faster cosmic expansion

6 June 2016 - 10:09am

The Universe may be expanding up to 9% faster than previously thought, according to new measurements from the Hubble Space Telescope.

Astronomy: Cosmic detectives

2 June 2016 - 11:06am

Astronomy: Cosmic detectives

Nature 534, 7605 (2016). doi:10.1038/534034a

Author: Bernie Fanaroff

Bernie Fanaroff surveys a study that probes telescopes in history and across the electromagnetic spectrum.

Astronomy: Galaxy from the cosmic dark ages

2 June 2016 - 11:05am

Astronomy: Galaxy from the cosmic dark ages

Nature 534, 7605 (2016). doi:10.1038/534008b

Astronomers have found the faintest example yet of a galaxy from the early Universe.Kuang-Han Huang of the University of California, Davis, and his colleagues spotted the 13-billion-year-old galaxy using the Keck Observatory in Hawaii and the Hubble Space Telescope. A cluster of galaxies in

Asteroids 'dumped water in molten Moon'

1 June 2016 - 9:20am

Water found deep in the Moon was delivered when icy asteroids splashed into magma oceans 4.3 billion years ago, a study suggests.

Rosetta's comet contains ingredients for life

31 May 2016 - 9:37am

Ingredients regarded as crucial for the origin of life on Earth have been discovered at the comet that ESA's Rosetta spacecraft has been probing for almost two years.

Alma telescope peers into space

31 May 2016 - 9:34am

Alma telescope peers into space from Chile