Institute of Astronomy

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First visit to Pluto could rewrite the solar system's story

Astronomy News - 11 June 2015 - 9:56am

Rivers of neon, geysers of nitrogen, an oddly giant moon: the New Horizons probe promises revealing spectacles – and insights into deep solar system history (full text available to subscribers)







Our exploration of the solar system is just getting started

Astronomy News - 11 June 2015 - 9:55am

Pluto might be the final stop on NASA's Grand Tour, but our visit marks the start of a new wave of exploration of the myriad worlds in our neighbourhood







Small particles dominate Saturn’s Phoebe ring to surprisingly large distances

Astronomy News - 11 June 2015 - 9:53am

Small particles dominate Saturn’s Phoebe ring to surprisingly large distances

Nature 522, 7555 (2015). doi:10.1038/nature14476

Authors: Douglas P. Hamilton, Michael F. Skrutskie, Anne J. Verbiscer & Frank J. Masci

Saturn’s faint outermost ring, discovered in 2009 (ref. 1), is probably formed by particles ejected from the distant moon Phoebe. The ring was detected between distances of 128 and 207 Saturn radii (RS = 60,330 kilometres) from the planet, with a full vertical extent of 40RS, making it well over ten times larger than Saturn’s hitherto largest known ring, the E ring. The total radial extent of the Phoebe ring could not, however, be determined at that time, nor could particle sizes be significantly constrained. Here we report infrared imaging of the entire ring, which extends from 100RS out to a surprisingly distant 270RS. We model the orbital dynamics of ring particles launched from Phoebe, and construct theoretical power-law profiles of the particle size distribution. We find that very steep profiles fit the data best, and that elevated grain temperatures, arising because of the radiative inefficiency of the smallest grains, probably contribute to the steepness. By converting our constraint on particle sizes into a form that is independent of the uncertain size distribution, we determine that particles with radii greater than ten centimetres, whose orbits do not decay appreciably inward over 4.5 billion years, contribute at most about ten per cent to the cross-sectional area of the ring’s dusty component.

Astronomy: Megaflare seen on star surface

Astronomy News - 11 June 2015 - 9:48am

Astronomy: Megaflare seen on star surface

Nature 522, 7555 (2015). doi:10.1038/522131d

Astronomers have spotted an enormous surge of light and magnetic energy on a nearby star.A team led by Wouter Vlemmings at Chalmers University of Technology near Gothenburg, Sweden, pointed the ALMA radio telescope in northern Chile at the red giant Mira A, a star

Ceres' spots seen in more detail

Astronomy News - 11 June 2015 - 9:38am

The US space agency releases a new, higher-resolution picture of the brightest spots on the dwarf planet Ceres.

Sharpest View Ever of Star Formation in the Distant Universe

Astronomy News - 9 June 2015 - 10:13am
ALMA’s Long Baseline Campaign has produced a spectacular image of a distant galaxy being gravitationally lensed. The image shows a magnified view of the galaxy’s star-forming regions, the likes of which have never been seen before at this level of detail in a galaxy so remote. The new observations are far sharper than those made using the NASA/ESA Hubble Space Telescope, and reveal star-forming clumps in the galaxy equivalent to giant versions of the Orion Nebula in the Milky Way.

In so many words: How to ride the space-wind to the stars

Astronomy News - 5 June 2015 - 9:47am
If you want to go to another world, one of the biggest problems is how to power your space-car. One idea is to catch the light from the sun







Listening to meteorites hitting Mars will tell us what's inside

Astronomy News - 5 June 2015 - 9:46am

NASA's InSight mission may be able to use seismic waves from meteorite strikes to probe the Red Planet's interior







A new perspective on steady-state cosmology: from Einstein to Hoyle. (arXiv:1506.01651v1 [physics.hist-ph])

Astronomy News - 5 June 2015 - 9:44am

We recently reported the discovery of an unpublished manuscript by Albert Einstein in which he attempted a 'steady-state' model of the universe, i.e., a cosmic model in which the expanding universe remains essentially unchanged due to a continuous formation of matter from empty space. The manuscript was apparently written in early 1931, many years before the steady-state models of Fred Hoyle, Hermann Bondi and Thomas Gold. We compare Einstein's steady-state cosmology with that of Hoyle, Bondi and Gold and consider the reasons Einstein abandoned his model. The relevance of steady-state models for today's cosmology is briefly reviewed.

Hubble studies Pluto's wobbly moons

Astronomy News - 5 June 2015 - 9:35am

Hubble reveals fascinating new details about Pluto's four smaller moons - Styx, Nix, Kerberos and Hydra.

Three candidates for ESA's next medium-class science mission

Astronomy News - 4 June 2015 - 9:52am

Exoplanets, plasma physics and the X-ray Universe are the topics chosen by ESA to be considered for the fourth medium-class mission in its Cosmic Vision science programme, for launch in 2025.

ESA and Chinese Academy of Sciences to study SMILE as joint mission

Astronomy News - 4 June 2015 - 9:52am

European and Chinese scientists have recommended the Solar wind Magnetosphere Ionosphere Link Explorer as their candidate for a collaborative science mission for launch in 2021.

Hubble observes chaotic dance of Pluto's moons

Astronomy News - 4 June 2015 - 9:52am

In a new study, scientists have gathered all available NASA/ESA Hubble Space Telescope data on the four outer moons of Pluto to analyse the system in more depth than ever before. The observations show that at least two of Pluto's moons are not neatly rotating on their axes but are in chaotic rotation while orbiting around Pluto and its companion Charon. The study also hints that one of the moons has a mysterious jet-black colouring. These surprising results appear in the 4 June issue of the journal Nature.

Hubble Finds Two Chaotically Tumbling Pluto Moons

Astronomy News - 4 June 2015 - 9:51am

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Two of the most reliable changes in the sky are the daily rising of the sun in the east and setting of the sun in the west. But if you lived on a couple of Pluto's moons you wouldn't know when the day would begin, or even what direction the sun would rise. That's because, unlike Earth's moon, at least two of Pluto's small moons, Hydra and Nix, are tumbling chaotically through space. Why? Because they orbit inside a dynamically shifting gravitational field caused by the system's two central bodies, Pluto and Charon, that are whirling around each other. The moons are also football shaped, and this contributes to the chaotic rotation.

NASA’s Hubble Finds Pluto’s Moons Tumbling in Absolute Chaos

Astronomy News - 4 June 2015 - 9:50am
If you lived on one of Pluto’s moons, you might have a hard time determining when, or from which direction, the sun will rise each day. Comprehensive analysis of data from NASA’s Hubble Space Telescope shows that two of Pluto’s moons, Nix and Hydra, wobble unpredictably.

Giant telescope in Hawaii gets go-ahead, if others shut down

Astronomy News - 4 June 2015 - 9:49am
Protests over the construction of the Thirty Meter Telescope on Mauna Kea halted its progress. Now construction is back on, but three other scopes will have to close







Pluto's strange family of moons are locked in a mysterious waltz

Astronomy News - 4 June 2015 - 9:48am

Three of Pluto's four small moons are moving in step, and the fourth looks darker than the rest – creating a puzzle as to how they formed







Resonant interactions and chaotic rotation of Pluto’s small moons

Astronomy News - 4 June 2015 - 9:46am

Resonant interactions and chaotic rotation of Pluto’s small moons

Nature 522, 7554 (2015). doi:10.1038/nature14469

Authors: M. R. Showalter & D. P. Hamilton

Four small moons—Styx, Nix, Kerberos and Hydra—follow near-circular, near-equatorial orbits around the central ‘binary planet’ comprising Pluto and its large moon, Charon. New observational details of the system have emerged following the discoveries of Kerberos and Styx. Here we report that Styx, Nix and Hydra

Astronomy: Pluto leads the way in planet formation

Astronomy News - 4 June 2015 - 9:45am

Astronomy: Pluto leads the way in planet formation

Nature 522, 7554 (2015). doi:10.1038/522040a

Authors: Scott J. Kenyon

Images from the Hubble Space Telescope cast new light on the orbits, shapes and sizes of Pluto's small satellites. The analysis comes just before a planned reconnaissance by the first spacecraft to visit them. See Article p.45

Hawaii prunes Mauna Kea telescope hub

Astronomy News - 4 June 2015 - 9:41am

Hawaii prunes Mauna Kea telescope hub

Nature 522, 7554 (2015). http://www.nature.com/doifinder/10.1038/522015a

Author: Alexandra Witze

Cultural fight over sacred mountain accelerates observatory closures.