Institute of Astronomy

Feed aggregator

Auroras on Mars

Astronomy News - 12 May 2015 - 10:31am
NASA's MAVEN spacecraft has detected widespread auroras on Mars.

Millions of missing galaxies found hiding in plain sight

Astronomy News - 12 May 2015 - 10:30am

A type of galaxy thought to be all but extinct has turned up in our own backyard in the same abundance as in the early universe







Supernova blast shows stars die in lopsided explosions

Astronomy News - 11 May 2015 - 10:08am

A closer look at a supernova confirms simulations that an asymmetric explosion is required to trigger stellar death







Hubble Finds Giant Halo Around the Andromeda Galaxy

Astronomy News - 8 May 2015 - 10:08am

Get larger image formats

The Andromeda galaxy is our Milky Way's nearest neighbor in space. The majestic spiral of over 100 billion stars is comparable in size to our home galaxy. At a distance of 2.5 million light-years, it is so close to us the galaxy can be seen as a cigar-shaped smudge of light high in the autumn sky. But if you could see the huge bubble of hot, diffuse plasma surrounding it, it would appear 100 times the angular diameter of the full Moon! The gargantuan halo is estimated to contain half the mass of the stars in the Andromeda galaxy itself. It can be thought of as the "atmosphere" of a galaxy. Astronomers using Hubble identified the gas in Andromeda's halo by measuring how it filtered the light of distant bright background objects called quasars. It is akin to seeing the glow of a flashlight shining through a fog. This finding promises to tell astronomers more about the evolution and structure of one of the most common types of galaxies in the universe.

Mercury's magnetic heart was beating soon after its birth

Astronomy News - 8 May 2015 - 10:07am
The planet's molten core became magnetic nearly 4 billion years ago – potentially making Mercury's magnetic field the most enduring in our solar system







Send your drawing into space with CHEOPS

Astronomy News - 7 May 2015 - 10:30am

Do you want to send your art into space on the new CHEOPS satellite? ESA and its mission partners are inviting children to submit drawings that will be miniaturised and engraved on two plaques that will be put on the satellite.

Curtain eruptions from Enceladus’ south-polar terrain

Astronomy News - 7 May 2015 - 10:15am

Curtain eruptions from Enceladus’ south-polar terrain

Nature 521, 7550 (2015). doi:10.1038/nature14368

Authors: Joseph N. Spitale, Terry A. Hurford, Alyssa R. Rhoden, Emily E. Berkson & Symeon S. Platts

Observations of the south pole of the Saturnian moon Enceladus revealed large rifts in the south-polar terrain, informally called ‘tiger stripes’, named Alexandria, Baghdad, Cairo and Damascus Sulci. These fractures have been shown to be the sources of the observed jets of water vapour and icy particles and to exhibit higher temperatures than the surrounding terrain. Subsequent observations have focused on obtaining close-up imaging of this region to better characterize these emissions. Recent work examined those newer data sets and used triangulation of discrete jets to produce maps of jetting activity at various times. Here we show that much of the eruptive activity can be explained by broad, curtain-like eruptions. Optical illusions in the curtain eruptions resulting from a combination of viewing direction and local fracture geometry produce image features that were probably misinterpreted previously as discrete jets. We present maps of the total emission along the fractures, rather than just the jet-like component, for five times during an approximately one-year period in 2009 and 2010. An accurate picture of the style, timing and spatial distribution of the south-polar eruptions is crucial to evaluating theories for the mechanism controlling the eruptions.

An extremely young massive clump forming by gravitational collapse in a primordial galaxy

Astronomy News - 7 May 2015 - 10:15am

An extremely young massive clump forming by gravitational collapse in a primordial galaxy

Nature 521, 7550 (2015). doi:10.1038/nature14409

Authors: A. Zanella, E. Daddi, E. Le Floc’h, F. Bournaud, R. Gobat, F. Valentino, V. Strazzullo, A. Cibinel, M. Onodera, V. Perret, F. Renaud & C. Vignali

When cosmic star formation history reaches a peak (at about redshift z ≈ 2), galaxies vigorously fed by cosmic reservoirs are dominated by gas and contain massive star-forming clumps, which are thought to form by violent gravitational instabilities in highly turbulent gas-rich disks. However, a clump formation event has not yet been observed, and it is debated whether clumps can survive energetic feedback from young stars, and afterwards migrate inwards to form galaxy bulges. Here we report the spatially resolved spectroscopy of a bright off-nuclear emission line region in a galaxy at z = 1.987. Although this region dominates star formation in the galaxy disk, its stellar continuum remains undetected in deep imaging, revealing an extremely young (less than ten million years old) massive clump, forming through the gravitational collapse of more than one billion solar masses of gas. Gas consumption in this young clump is more than tenfold faster than in the host galaxy, displaying high star-formation efficiency during this phase, in agreement with our hydrodynamic simulations. The frequency of older clumps with similar masses, coupled with our initial estimate of their formation rate (about 2.5 per billion years), supports long lifetimes (about 500 million years), favouring models in which clumps survive feedback and grow the bulges of present-day galaxies.

Mysterious galactic signal points LHC to dark matter

Astronomy News - 7 May 2015 - 10:12am

Mysterious galactic signal points LHC to dark matter

Nature 521, 7550 (2015). http://www.nature.com/doifinder/10.1038/521017a

Author: Davide Castelvecchi

High-energy particles at centre of Milky Way now within scope of Large Hadron Collider.

Pluto-bound craft hunts for hazardous moons

Astronomy News - 7 May 2015 - 10:12am

Pluto-bound craft hunts for hazardous moons

Nature 521, 7550 (2015). http://www.nature.com/doifinder/10.1038/521014a

Author: Alexandra Witze

Unknown satellites pose danger to New Horizons mission as it journeys to the edge of the Solar System.

Astronomers Set a New Galaxy Distance Record

Astronomy News - 6 May 2015 - 10:50am

Get larger image formats

The universe is incredibly big. But how do astronomers know that? Billion-mile-long tape measures can't be found at the hardware store. Instead, astronomers use the expansion of the universe itself to establish milepost markers. The light from remote objects is attenuated and weakened as space stretches like a rubber band. The consequences are that starlight will look redder relative to a nearby star of the same temperature. When starlight is spread into its component color via spectroscopy, features in the light will be shifted to the red end of the spectrum. This "redshift" can be used to reliably calibrate distances. The challenge is the farthest objects in the universe are typically too faint for spectroscopy to work. So instead, astronomers deduce a galaxy's distance by precisely measuring its colors in visible and infrared light. This technique has found candidates for the farthest object in the universe.

Meteors from Halley's Comet

Astronomy News - 6 May 2015 - 10:48am
The annual Eta Aquariid meteor shower peaks on May 5-6 when Earth passes through a stream of debris from Halley's Comet.

Galactic smash-ups turn on the lights around black holes

Astronomy News - 6 May 2015 - 10:47am
Trails of stellar debris suggest that ancient galactic crashes funnelled gas toward a central black hole, sparking active galaxies' inner glow







Microwave baffles space scientists

Astronomy News - 6 May 2015 - 10:46am

Australian scientists discover that mysterious signals hitting a renowned space telescope are actually from microwaves.

Fire and Ice: A MESSENGER Recap

Astronomy News - 5 May 2015 - 11:57am
NASA's MESSENGER spacecraft crashed into Mercury on April 30th, ending a years-long mission that made many unexpected discoveries about the innermost planet. Today's story summarizes some of MESSENGER's most surprising finds.

The Pillars of Creation Revealed in 3D

Astronomy News - 5 May 2015 - 11:56am
Using the MUSE instrument on ESO’s Very Large Telescope (VLT), astronomers have produced the first complete three-dimensional view of the famous Pillars of Creation in the Eagle Nebula, Messier 16. The new observations demonstrate how the different dusty pillars of this iconic object are distributed in space and reveal many new details — including a previously unseen jet from a young star. Intense radiation and stellar winds from the cluster’s brilliant stars have sculpted the dusty Pillars of Creation over time and should fully evaporate them in about three million years.

AKARI far-infrared all-sky data released

Astronomy News - 5 May 2015 - 11:54am

The AKARI space telescope's far-infrared all-sky image data are now available to researchers everywhere. The new all-sky maps have four to five times better spatial resolution than conventional far-infrared all-sky images, and include data at longer wavelengths.

The Presidents of the RAS and IoP welcome the decision to site the permanent hea...

Astronomy News - 5 May 2015 - 11:54am
The Presidents of the RAS and IoP welcome the decision to site the permanent headquarters of the Square Kilometre Array (SKA) project at Jodrell Bank in the UK.

The SKA will be the world's most powerful radio telescope, funded by 11 countries and expected to begin operations in 2020.

http://www.ras.org.uk/news-and-press/2626-ras-and-iop-presidents-ska-hq-is-great-news-for-radio-astronomy-and-uk-science


RAS and IOP Presidents: SKA HQ is great news for radio astronomy and UK science
www.ras.org.uk
The Presidents of the Royal Astronomical Society and the Institute of Physics have welcomed the decision to site the permanent headquarters of the Square Kilometre Array (SKA) in the UK.

NASA Completes MESSENGER Mission with Expected Impact on Mercury's Surface

Astronomy News - 5 May 2015 - 11:54am
A NASA planetary exploration mission came to a planned, but nonetheless dramatic, end Thursday when it slammed into Mercury’s surface at about 8,750 mph and created a new crater on the planet’s surface.

Astronomers find first evidence of changing conditions on a super Earth

Astronomy News - 5 May 2015 - 11:49am

For the first time, researchers led by the University of Cambridge have detected atmospheric variability on a rocky planet outside the solar system, and observed a nearly threefold change in temperature over a two year period. Although the researchers are quick to point out that the cause of the variability is still under investigation, they believe the readings could be due to massive amounts of volcanic activity on the surface. The ability to peek into the atmospheres of rocky ‘super Earths’ and observe conditions on their surfaces marks an important milestone towards identifying habitable planets outside the solar system.

Using NASA’s Spitzer Space Telescope, the researchers observed thermal emissions coming from the planet, called 55 Cancri e – orbiting a sun-like star located 40 light years away in the Cancer constellation – and for the first time found rapidly changing conditions, with temperatures on the hot ‘day’ side of the planet swinging between 1000 and 2700 degrees Celsius.

“This is the first time we’ve seen such drastic changes in light emitted from an exoplanet, which is particularly remarkable for a super Earth,” said Dr Nikku Madhusudhan of Cambridge’s Institute of Astronomy, a co-author on the new study. “No signature of thermal emissions or surface activity has ever been detected for any other super Earth to date.”

Although the interpretations of the new data are still preliminary, the researchers believe the variability in temperature could be due to huge plumes of gas and dust which occasionally blanket the surface, which may be partially molten. The plumes could be caused by exceptionally high rates of volcanic activity, higher than what has been observed on Io, one of Jupiter’s moons and the most geologically active body in the solar system.

“We saw a 300 percent change in the signal coming from this planet, which is the first time we’ve seen such a huge level of variability in an exoplanet,” said Dr Brice-Olivier Demory of the University’s Cavendish Laboratory, lead author of the new study. “While we can’t be entirely sure, we think a likely explanation for this variability is large-scale surface activity, possibly volcanism, on the surface is spewing out massive volumes of gas and dust, which sometimes blanket the thermal emission from the planet so it is not seen from Earth.”

55 Cancri e is a ‘super Earth’: a rocky exoplanet about twice the size and eight times the mass of Earth. It is one of five planets orbiting a sun-like star in the Cancer constellation, and resides so close to its parent star that a year lasts just 18 hours. The planet is also tidally locked, meaning that it doesn’t rotate like the Earth does – instead there is a permanent ‘day’ side and a ‘night’ side. Since it is the nearest super Earth whose atmosphere can be studied, 55 Cancri e is among the best candidates for detailed observations of surface and atmospheric conditions on rocky exoplanets.

Most of the early research on exoplanets has been on gas giants similar to Jupiter and Saturn, since their enormous size makes them easier to find. In recent years, astronomers have been able to map the conditions on many of these gas giants, but it is much more difficult to do so for super Earths: exoplanets with masses between one and ten times the mass of Earth.

Earlier observations of 55 Cancri e pointed to an abundance of carbon, suggesting that the planet was composed of diamond. However, these new results have muddied those earlier observations considerably and opened up new questions.

“When we first identified this planet, the measurements supported a carbon-rich model,” said Madhusudhan, who along with Demory is a member of the Cambridge Exoplanet Research Centre. “But now we’re finding that those measurements are changing in time. The planet could still be carbon rich, but now we’re not so sure – earlier studies of this planet have even suggested that it could be a water world. The present variability is something we’ve never seen anywhere else, so there’s no robust conventional explanation. But that’s the fun in science – clues can come from unexpected quarters. The present observations open a new chapter in our ability to study the conditions on rocky exoplanets using current and upcoming large telescopes.”

The results have been published online today.

The study was also co-authored by Professor Didier Queloz of the Cavendish Laboratory and Dr Michaël Gillon of the Université of Liège.

Astronomers have detected wildly changing temperatures on a super Earth – the first time any atmospheric variability has been observed on a rocky planet outside the solar system – and believe it could be due to huge amounts of volcanic activity, further adding to the mystery of what had been nicknamed the ‘diamond planet’.

This is the first time we’ve seen such drastic changes in light emitted from an exoplanetNikku MadhusudhanNASA/JPL-Caltech/R. HurtArtist’s impression of super-Earth 55 Cancri e, showing a hot partially-molten surface of the planet before and after possible volcanic activity on the day side.


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

Yes