Institute of Astronomy

Astronomy News

Black hole caught feasting on a star

22 October 2015 - 8:38am

Astronomers have detected the last 'cry' from a star that passed too close to the central black hole of its host galaxy and was being destroyed and 'swallowed' – a phenomenon known as a tidal disruption event. The study, based on the observations of X-rays emitted by leftover material from the star in the vicinity of the black hole, allowed the astronomers to measure, for the first time, the physical properties of a newly formed accretion disc, enabling them to investigate the initial phases of such a powerful event.

ExoMars preference is for Oxia Planum

22 October 2015 - 8:26am

The robot rover that Europe is building to send to Mars is likely to be targeted at an equatorial region known as Oxia Planum.

Most Earth-Like Worlds Have Yet to Be Born, According to Theoretical Study

21 October 2015 - 8:22am

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Astronomers are conducting extensive observations to estimate how many planets in our Milky Way galaxy might be potential abodes for life. These are collectively called "Earth-like" in other words, Earth-sized worlds that are at the right distances from their stars for moderate temperatures to nurture the origin of life. The search for extraterrestrial intelligent life in the universe (SETI) is based on the hypothesis that some fraction of worlds, where life originates, go on to evolve intelligent technological civilizations. Until we ever find such evidence, Earth is the only known abode of life in the universe. But the universe is not only vastly big, it has a vast future. There is so much leftover gas from galaxy evolution available that the universe will keep cooking up stars and planets for a very long time to come. In fact, most of the potentially habitable Earth-like planets have yet to be born. This theoretical conclusion is based on an assessment of star-birth data collected by the Hubble Space Telescope and exoplanet surveys made by the planet-hunting Kepler space observatory.

VIDEO: Is life possible on the south pole of the Moon?

19 October 2015 - 8:11am

Dr James Carpenter of the European Space Agency explains why an unexplored area of the moon may be rich in resources for a human colony.

Saturn’s ice moon Enceladus revealed in unprecedented detail

19 October 2015 - 8:10am

NASA's Cassini spacecraft made its closest fly-by of the north pole of Saturn's icy moon Enceladus – and saw a world covered in craters and cracks

Icy plains and snakeskin terrain among Pluto’s lingering puzzles

16 October 2015 - 8:20am

The team behind NASA's New Horizons probe has just released their first official paper on Pluto's geology, atmosphere and moons – but big mysteries remain

Pluto mission's first journal paper

16 October 2015 - 8:07am

The first scientific paper to come out of the New Horizons probe's historic flyby of Pluto is published and raises questions about its formation.

Two independent and primitive envelopes of the bilobate nucleus of comet 67P

15 October 2015 - 8:49am

Two independent and primitive envelopes of the bilobate nucleus of comet 67P

Nature 526, 7573 (2015). doi:10.1038/nature15511

Authors: Matteo Massironi, Emanuele Simioni, Francesco Marzari, Gabriele Cremonese, Lorenza Giacomini, Maurizio Pajola, Laurent Jorda, Giampiero Naletto, Stephen Lowry, Mohamed Ramy El-Maarry, Frank Preusker, Frank Scholten, Holger Sierks, Cesare Barbieri, Philippe Lamy, Rafael Rodrigo, Detlef Koschny, Hans Rickman, Horst Uwe Keller, Michael F. A’Hearn, Jessica Agarwal, Anne-Thérèse Auger, M. Antonella Barucci, Jean-Loup Bertaux, Ivano Bertini, Sebastien Besse, Dennis Bodewits, Claire Capanna, Vania Da Deppo, Björn Davidsson, Stefano Debei, Mariolino De Cecco, Francesca Ferri, Sonia Fornasier, Marco Fulle, Robert Gaskell, Olivier Groussin, Pedro J. Gutiérrez, Carsten Güttler, Stubbe F. Hviid, Wing-Huen Ip, Jörg Knollenberg, Gabor Kovacs, Rainer Kramm, Ekkehard Kührt, Michael Küppers, Fiorangela La Forgia, Luisa M. Lara, Monica Lazzarin, Zhong-Yi Lin, Josè J. Lopez Moreno, Sara Magrin, Harald Michalik, Stefano Mottola, Nilda Oklay, Antoine Pommerol, Nicolas Thomas, Cecilia Tubiana & Jean-Baptiste Vincent

The factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary and primordial processes. The peculiar bilobed shape of comet 67P/Churyumov–Gerasimenko may be the result of the fusion of two objects that were once separate or the result of a localized excavation by outgassing at the interface between the two lobes. Here we report that the comet’s major lobe is enveloped by a nearly continuous set of strata, up to 650 metres thick, which are independent of an analogous stratified envelope on the minor lobe. Gravity vectors computed for the two lobes separately are closer to perpendicular to the strata than those calculated for the entire nucleus and adjacent to the neck separating the two lobes. Therefore comet 67P/Churyumov–Gerasimenko is an accreted body of two distinct objects with ‘onion-like’ stratification, which formed before they merged. We conclude that gentle, low-velocity collisions occurred between two fully formed kilometre-sized cometesimals in the early stages of the Solar System. The notable structural similarities between the two lobes of comet 67P/Churyumov–Gerasimenko indicate that the early-forming cometesimals experienced similar primordial stratified accretion, even though they formed independently.

A Cosmic Sackful of Black Coal

15 October 2015 - 8:45am
Dark smudges almost block out a rich star field in this new image captured by the Wide Field Imager camera, installed on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile. The inky areas are small parts of a huge dark nebula known as the Coalsack, one of the most prominent objects of its kind visible to the unaided eye. Millions of years from now, chunks of the Coalsack will ignite, rather like its fossil fuel namesake, with the glow of many young stars.

Hubble's Planetary Portrait Captures New Changes in Jupiter's Great Red Spot

14 October 2015 - 9:01am

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Scientists using NASA's Hubble Space Telescope have produced new global maps of Jupiter the first in a series of annual portraits of the solar system's outer planets from the Outer Planet Atmospheres Legacy program (OPAL). The two Jupiter maps, representing nearly back-to-back rotations of the planet on Jan. 19, 2015, show the movements of the clouds and make it possible to determine the speeds of Jupiter's winds. The Hubble observations confirm that the Great Red Spot continues to shrink and become more circular. In addition, an unusual wispy filament is seen, spanning almost the entire width of the vortex. These findings are described in a new paper published online in the October 10 issue of The Astrophysical Journal.

The collection of maps to be obtained over time from the OPAL program will not only help scientists understand the atmospheres of our giant planets, but also the atmospheres of planets being discovered around other stars. For more visuals and information about this study, visit: .

And to learn even more about Jupiter and Hubble, join the live Hubble Hangout discussion at 3:00 pm on Thurs., Oct. 15 at .

Cassini Begins Series of Flybys with Close-up of Saturn Moon Enceladus

14 October 2015 - 9:00am
NASA's Cassini spacecraft will wrap up its time in the region of Saturn's large, icy moons with a series of three close encounters with Enceladus starting Wednesday, Oct. 14. Images are expected to begin arriving one to two days after the flyby, which will provide the first opportunity for a close-up look at the north polar region of Enceladus.

Pufferfish planets could explain how hot Jupiters get so big

14 October 2015 - 8:58am

Many of the gas giant planets we've seen orbiting other stars are up to twice as large as theory says they should be. A new class of planets could explain why

Meteorite impact turns silica into stishovite in a billionth of a second

14 October 2015 - 8:57am

The Barringer meteor crater is an iconic Arizona landmark, more than 1km wide and 170 metres deep, left behind by a massive 300,000 tonne meteorite that hit Earth 50,000 years ago with a force equivalent to a ten megaton nuclear bomb. The forces unleashed by such an impact are hard to comprehend, but a team of Stanford scientists has recreated the conditions experienced during the first billionths of a second as the meteor struck in order to reveal the effects it had on the rock underneath.

The sandstone rocks of Arizona were, on that day of impact 50,000 years ago, pushed beyond their limits and momentarily – for the first few trillionths and billionths of a second – transformed into a new state. The Stanford scientists, in a study published in the journal Nature Materials, recreated the conditions as the impact shockwave passed through the ground through computer models of half a million atoms of silica. Blasted by fragments of an asteroid that fell to Earth at tens of kilometres a second, the silica quartz crystals in the sandstone rocks would have experienced pressures of hundreds of thousands of atmospheres, and temperatures of thousands of degrees Celsius.

What the model reveals is that atoms form an immensely dense structure almost instantaneously as the shock wave hits at more than 7km/s. Within ten trillionths of a second the silica has reached temperatures of around 3,000℃ and pressures of more than half a million atmospheres. Then, within the next billionth of a second, the dense silica crystallises into a very rare mineral called stishovite.

The results are particularly exciting because stishovite is exactly the mineral found in shocked rocks at the Barringer Crater and similar sites across the globe. Indeed, stishovite (named after a Russian high-pressure physics researcher) was first found at the Barringer Crater in 1962. The latest simulations give an insight into the birth of mineral grains in the first moments of meteorite impact.


Simulations show how crystals form in billionths of a second


The size of the crystals that form in the impact event appears to be indicative of the size and nature of the impact. The simulations arrive at crystals of stishovite very similar to the range of sizes actually observed in geological samples of asteroid impacts.

Studying transformations of minerals such as quartz, the commonest mineral of Earth’s continental crust, under such extreme conditions of temperature and pressure is challenging. To measure what happens on such short timescales adds another degree of complexity to the problem.

These computer models point the way forward, and will guide experimentalists in the studies of shock events in the future. In the next few years we can expect to see these computer simulations backed up with further laboratory studies of impact events using the next generation of X-ray instruments, called X-ray free electron lasers, which have the potential to “see” materials transform under the same conditions and on the same sorts of timescales.

Simon Redfern, Professor in Earth Sciences, University of Cambridge

This article was originally published on The Conversation. Read the original article.

Inset image: Barringer meteor Crater, Arizona (NASA Earth Observatory).

Simon Redfern from the Department of Earth Sciences discusses a study that has recreated the conditions experienced during the meteor strike that formed the Barringer Crater in Arizona.

United States Geological Survey/D. RoddyBarringer Crater aerial photo

The text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.


VIDEO: Jupiter's Red Spot revealed in 4K

14 October 2015 - 8:55am

New ultra-high definition imagery, rendered in 4K, has revealed details of Jupiter's famous Great Red Spot.

China has had a telescope on the moon for the past two years

13 October 2015 - 9:23am

The robotic telescope, mounted on the Chang'e 3 lander, is the first of its kind and provides unique views of the night sky that aren't possible from Earth

Astrophysics: Surprisingly fast motions in a dust disk

8 October 2015 - 10:55am

Astrophysics: Surprisingly fast motions in a dust disk

Nature 526, 7572 (2015). doi:10.1038/526204a

Authors: Marshall D. Perrin

A recently commissioned planet-finding instrument has been used to study a young solar system around the star AU Microscopii, leading to the discovery of rapidly moving features in the dust disk around the star. See Letter p.230

NASA narrows its list of planetary targets

8 October 2015 - 10:54am

NASA narrows its list of planetary targets

Nature 526, 7572 (2015).

Author: Alexandra Witze

Venus and asteroids take the spotlight as the agency chops list of Discovery-class candidates from 27 to 5.

Mysterious Ripples Found Racing Through Planet-forming Disc

8 October 2015 - 10:51am
Using images from ESO’s Very Large Telescope and the NASA/ESA Hubble Space Telescope, astronomers have discovered never-before-seen structures within a dusty disc surrounding a nearby star. The fast-moving wave-like features in the disc of the star AU Microscopii are unlike anything ever observed, or even predicted, before now. The origin and nature of these features present a new mystery for astronomers to explore. The results are published in the journal Nature on 8 October 2015.

Mysterious Ripples Found Racing Through Planet-Forming Disk

8 October 2015 - 10:51am

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Though astronomers have discovered thousands of planets orbiting other stars, very little is known about how they are born. The conventional wisdom is that planets coagulate inside a vast disk of gas and dust encircling newborn stars. But the details of the process are not well understood because it takes millions of years to happen as the disk undergoes numerous changes until it finally dissipates.

The young, nearby star AU Microscopii (AU Mic) is an ideal candidate to get a snapshot of planet birthing because the disk is tilted nearly edge on to our view from Earth. This very oblique perspective offers an opportunity to see structure in the disk that otherwise might go unnoticed. Astronomers are surprised to uncover fast-moving, wave-like features embedded in the disk that are unlike anything ever observed, or even predicted. Whatever they are, these ripples are moving at 22,000 miles per hour fast enough to escape the star's gravitational pull. This parade of blob-like features stretches farther from the star than Pluto is from our sun. They are so mysterious it's not known if they are somehow associated with planet formation, or some unimagined, bizarre activity inside the disk.

Learn even more about AU Mic by joining the live Hubble Hangout discussion at 3:00 pm EDT on Thurs., Oct. 8 at

Charon moon seen in super detail

5 October 2015 - 8:47am

Pluto's major moon, Charon, takes centre stage in this week's release of new pictures from the New Horizons mission.