Institute of Astronomy

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Hubble Finds That Monster 'El Gordo' Galaxy Cluster Is Bigger Than Thought

Astronomy News - 3 April 2014 - 7:00pm

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If someone told you there was an object in space called "El Gordo" (Spanish for "the fat one") you might imagine some kind of planet-eating monster straight out of a science fiction movie. The nickname refers to a monstrous cluster of galaxies that is being viewed at a time when the universe was just half of its current age of 13.8 billion years. This is an object of superlatives. It contains several hundred galaxies swarming around under a collective gravitational pull. The total mass of the cluster, and refined in new Hubble measurements, is estimated to be as much as 3 million billion stars like our Sun (about 3,000 times more massive than our own Milky Way galaxy) though most of the mass is hidden away as dark matter. The cluster may be so huge because it is the result of a titanic collision and merger between two separate galaxy clusters. Thankfully, our Milky Way galaxy grew up in an uncluttered backwater region of the universe.

Cassini-Huygens:Icy moon Enceladus has underground sea

Astronomy News - 3 April 2014 - 7:00pm
Saturn's icy moon Enceladus has an underground sea of liquid water, according to the international Cassini spacecraft.

Buried 'Lake Superior' seen on Saturn's moon Enceladus

Astronomy News - 3 April 2014 - 7:00pm
Gravity readings suggest that the jets Enceladus spits out come from a deep ocean in contact with a rocky core, raising hopes that the moon hosts life

NASA Space Assets Detect Ocean inside Saturn Moon

Astronomy News - 3 April 2014 - 5:00pm
NASA's Cassini spacecraft and Deep Space Network have uncovered evidence Saturn's moon Enceladus harbors a large underground ocean of liquid water, furthering scientific interest in the moon as a potential home to extraterrestrial microbes.

NASA Satellite to Continue Gathering Data Up to Planned Lunar Impact

Astronomy News - 3 April 2014 - 5:00pm
NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft is gradually lowering its orbital altitude to continue making science observations prior to its planned impact on the moon’s surface on or before April 21.

NASA Hubble Team Finds Monster "El Gordo" Galaxy Cluster Bigger Than Thought

Astronomy News - 3 April 2014 - 5:00pm
NASA's Hubble Space Telescope has weighed the largest known galaxy cluster in the distant universe, catalogued as ACT-CL J0102-4915, and found it definitely lives up to its nickname -- El Gordo (Spanish for "the fat one").

Radioactive waste used to peek inside a star explosion

Astronomy News - 3 April 2014 - 4:00pm
Scrap from an old particle accelerator helps solve riddle of how chemical elements are created in supernovae

Treasures of the RAS: Urania's Mirror (1824) This beautiful set of cards shows...

Astronomy News - 3 April 2014 - 2:02pm
Treasures of the RAS: Urania's Mirror (1824)

This beautiful set of cards shows the constellations. The bright stars have pin-pricked holes, so the layout of the night sky can be seen when the card is held up to a light.

Treasures of the RAS: Urania's Mirror
A teaching aid for astronomy, Urania's Mirror, published in 1824. Victorians could learn about the night sky using these pretty pictures of the constellation...

Gaggle of dwarf planets found by dark energy camera

Astronomy News - 2 April 2014 - 11:12pm
Designed to study distant galaxies, the world's largest digital camera is also uncovering faint, distant worlds on the outskirts of the solar system

Galactic Serial Killer

Astronomy News - 2 April 2014 - 11:00am
This new image from the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile shows two contrasting galaxies: NGC 1316, and its smaller neighbour NGC 1317. These two are quite close to each other in space, but they have very different histories. The small spiral NGC 1317 has led an uneventful life, but NGC 1316 has engulfed several other galaxies in its violent history and shows the battle scars.

Solar system: Cracking up on asteroids

Astronomy News - 2 April 2014 - 1:00am

Solar system: Cracking up on asteroids

Nature 508, 7495 (2014). doi:10.1038/nature13222

Authors: Heather A. Viles

A combination of laboratory experiments and modelling shows that diurnal temperature variations are the main cause of rock breakdown and the ensuing formation of powdery rubble on the surface of small asteroids. See Letter p.233

Thermal fatigue as the origin of regolith on small asteroids

Astronomy News - 2 April 2014 - 1:00am

Thermal fatigue as the origin of regolith on small asteroids

Nature 508, 7495 (2014). doi:10.1038/nature13153

Authors: Marco Delbo, Guy Libourel, Justin Wilkerson, Naomi Murdoch, Patrick Michel, K. T. Ramesh, Clément Ganino, Chrystele Verati & Simone Marchi

Space missions and thermal infrared observations have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by micrometeoroid impact. Laboratory experiments and impact models, however, show that crater ejecta velocities are typically greater than several tens of centimetres per second, which corresponds to the gravitational escape velocity of kilometre-sized asteroids. Therefore, impact debris cannot be the main source of regolith on small asteroids. Here we report that thermal fatigue, a mechanism of rock weathering and fragmentation with no subsequent ejection, is the dominant process governing regolith generation on small asteroids. We find that thermal fragmentation induced by the diurnal temperature variations breaks up rocks larger than a few centimetres more quickly than do micrometeoroid impacts. Because thermal fragmentation is independent of asteroid size, this process can also contribute to regolith production on larger asteroids. Production of fresh regolith originating in thermal fatigue fragmentation may be an important process for the rejuvenation of the surfaces of near-Earth asteroids, and may explain the observed lack of low-perihelion, carbonaceous, near-Earth asteroids.

Rare exoplanet alignment set for April Fool's Day 2026

Astronomy News - 1 April 2014 - 6:00am
A distant solar system will be the arena for an unusual celestial arrangement, one sure to please Scrabble players as well as astronomers

Cosmology: Polar star

Astronomy News - 31 March 2014 - 1:00am

Cosmology: Polar star

Nature 508, 7494 (2014).

Author: Ron Cowen

After years of work in the Antarctic, John Kovac and his team have captured strong evidence for a long-held theory about the Universe’s birth.

Comet lander checks in with Earth

Astronomy News - 28 March 2014 - 3:58pm
The Philae lander, which Europe hopes to put on the surface of a comet later this year, is re-activated after three years in deep-space hibernation.

Director's Desk:ESA and CERN sign cooperation agreement

Astronomy News - 28 March 2014 - 1:06pm
ESA, the European Space Agency, and CERN, the European Organisation for Nuclear Research, signed a cooperation agreement on 28 March to foster future collaborations on research themes of common interest.

The Opposition of Mars

Astronomy News - 28 March 2014 - 5:44am
Earth and Mars are converging for a close encounter in April, an event astronomers call "the opposition of Mars."

Dead exoplanets can have oxygen-rich atmospheres too

Astronomy News - 27 March 2014 - 10:00pm
If Earth's ostensible twin is out there, it might be a lifeless rock – dead worlds can build up oxygen in their atmospheres as well as living ones

NASA's Hubble Space Telescope Spots Mars-Bound Comet Sprout Multiple Jets

Astronomy News - 27 March 2014 - 4:30pm
NASA released Thursday an image of a comet that, on Oct. 19, will pass within 84,000 miles of Mars -- less than half the distance between Earth and our moon.

Rosetta:Rosetta sets sights on destination comet

Astronomy News - 27 March 2014 - 4:13pm
ESA's Rosetta spacecraft has caught a first glimpse of its destination comet since waking up from deep-space hibernation on 20 January.