The Hubble Space Telescope

Created and launched by NASA.

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Celestial nomad takes centre stage

In this new ESO image, nightfall raises the curtain on a theatrical display taking place in the cloudless skies over La Silla.

In a scene humming with activity, the major players captured here are Comet Lovejoy, glowing green in the centre of the image; the Pleiades above and to the right; and the California Nebula, providing some contrast in the form of a red arc of gas directly to the right of Lovejoy.

A meteor adds its own streak of light to the scene, seeming to plunge into the hazy pool of green light collecting along the horizon.

The telescopes of La Silla provide an audience for this celestial performance, and a thin shroud of low altitude cloud clings to the plain below the observatory streaked by the Panamericana Highway.

Comet Lovejoy’s long tail is being pushed away from the comet by the solar wind. Carbon compounds that have been excited by ultraviolet radiation from the Sun give it its striking green hue.

This is the first time the comet has passed through the inner Solar System and ignited so spectacularly in over 11 000 years. Its highly elliptical orbit about the Sun — adjusted slightly due to meddling planets — means that it will not grace our skies for another 8000 years once it has rounded the Sun and begun its lonely voyage back into the cold outer regions of the Solar System.

Image credit: P. Horálek/ESO

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Hubble 30 Doradus Nebula Credit: NASA/Hubble, Color/Effects thedemon-hauntedworld

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NGC 4676: when mice collide

These two mighty galaxies are pulling each other apart. Known as the “Mice” because they have such long tails, each spiral galaxy has likely already passed through the other. The long tails are created by the relative difference between gravitational pulls on the near and far parts of each galaxy. Because the distances are so large, the cosmic interaction takes place in slow motion – over hundreds of millions of years. NGC 4676 lies about 300 million light-years away toward the constellation of Bernice’s Hair (Coma Berenices) and are likely members of the Coma Cluster of Galaxies. The above picture was taken with the Hubble Space Telescope’s Advanced Camera for Surveys in 2002. These galactic mice will probably collide again and again over the next billion years until they coalesce to form a single galaxy.

Image credit: ACS Science & Engineering Team; Hubble Space Telescope, NASA

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Hubble captures rare triple moon transit of Jupiter

These new NASA/ESA Hubble Space Telescope images capture a rare occurrence as three of Jupiter’s largest moons parade across the giant gas planet’s banded face. Hubble took a string of images of the event which show the three satellites — Europa, Callisto and Io — in action. There are four Galilean satellites — named after the 17th century scientist Galileo Galilei who discovered them. They complete orbits around Jupiter ranging from two to seventeen days in duration. The moons can commonly be seen transiting the face of Jupiter and casting shadows onto its layers of cloud. However, seeing three of them transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade. The image on the left shows the Hubble observation at the beginning of the event. On the left is the moon Callisto and on the right, Io. The shadows from Callisto, Io and Europa are strung out from left to right. Europa itself cannot be seen in the image. The image on the right shows the end of the event, just over 40 minutes later. Europa has entered the frame at lower left with slower-moving Callisto above and to the right of it. Meanwhile Io — which orbits significantly closer to Jupiter and so moves much more quickly — is approaching the eastern limb of the planet. Whilst Callisto’s shadow seems hardly to have moved, Io’s has set over the planet’s eastern edge and Europa’s has risen further in the west. The event is also shown from start to finish in a video. Missing from this sequence is the Galilean moon Ganymede which was outside Hubble’s field of view. The moons of Jupiter have very distinctive colours. The smooth icy surface of Europa is yellow-white, the volcanic sulphur surface of Io is orange and the surface of Callisto, which is one of the oldest and most cratered surfaces known in the Solar System, is a brownish colour.

Image credit: NASA, ESA, Hubble Heritage Team

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Stellar partnership doomed to end in catastrophe

Astronomers using ESO facilities in combination with telescopes in the Canary Islands have identified two surprisingly massive stars at the heart of the planetary nebula Henize 2-428. As they orbit each other the two stars are expected to slowly get closer and closer, and when they merge, about 700 million years from now, they will contain enough material to ignite a vast supernova explosion.

The team of astronomers, led by Miguel Santander-García (Observatorio Astronómico Nacional, Alcalá de Henares, Spain;Instituto de Ciencia de Materiales de Madrid (CSIC), Madrid, Spain), has discovered a close pair of white dwarf stars — tiny, extremely dense stellar remnants — that have a total mass of about 1.8 times that of the Sun. This is the most massive such pair yet found and when these two stars merge in the future they will create a runaway thermonuclear explosion leading to a Type Ia supernova. The team who found this massive pair actually set out to try to solve a different problem. They wanted to find out how some stars produce such strangely shaped and asymmetric nebulae late in their lives. One of the objects they studied was the unusual planetary nebula known as Henize 2-428. “When we looked at this object’s central star with ESO’s Very Large Telescope, we found not just one but a pair of stars at the heart of this strangely lopsided glowing cloud,” says coauthor Henri Boffin from ESO. This supports the theory that double central stars may explain the odd shapes of some of these nebulae, but an even more interesting result was to come. “Further observations made with telescopes in the Canary Islands allowed us to determine the orbit of the two stars and deduce both the masses of the two stars and their separation. This was when the biggest surprise was revealed,”  reports Romano Corradi, another of the study’s authors and researcher at the Instituto de Astrofísica de Canarias (Tenerife, IAC). They found that each of the stars has a mass slightly less than that of the Sun and that they orbit each other every four hours. They are sufficiently close to one another that, according to the Einstein’s theory of general relativity, they will grow closer and closer, spiralling in due to the emission of gravitational waves, before eventually merging into a single star within the next 700 million years. The resulting star will be so massive that nothing can then prevent it from collapsing in on itself and subsequently exploding as a supernova. “Until now, the formation of supernovae Type Ia by the merging of two white dwarfs was purely theoretical,” explains David Jones, coauthor of the article and ESO Fellow at the time the data were obtained. “The pair of stars in Henize 2-428 is the real thing!” “It’s an extremely enigmatic system,” concludes Santander-García. “It will have important repercussions for the study of supernovae Type Ia, which are widely used to measure astronomical distances and were key to the discovery that the expansion of the Universe is accelerating due to dark energy”.

Image credit: ESO/L. Calçada

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Space station flyover of Gulf of Aden and Horn of Africa

European Space Agency astronaut Samantha Cristoforetti took this photograph from the International Space Station and posted it to social media on Jan. 30, 2015. Cristoforetti wrote, “A spectacular flyover of the Gulf of Aden and the Horn of Africa. #HelloEarth”

Image credit: NASA/ESA/Samantha Cristoforetti

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The eight planets of our solar system image credits: [x]

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Big surprises can come in small packages

Astronomers using the NASA/ESA Hubble Space Telescope have found a monster lurking in a very unlikely place. New observations of the ultracompact dwarf galaxy M60-UCD1 have revealed a supermassive black hole at its heart, making this tiny galaxy the smallest ever found to host a supermassive black hole. This suggests that there may be many more supermassive black holes that we have missed, and tells us more about the formation of these incredibly dense galaxies.

Lying about 50 million light-years away, M60-UCD1 is a tiny galaxy with a diameter of 300 light-years — just 1/500th of the diameter of the Milky Way. Despite its size it is pretty crowded, containing some 140 million stars. While this is characteristic of an ultracompact dwarf galaxy (UCD) like M60-UCD1, this particular UCD happens to be the densest ever seen.

Despite their huge numbers of stars, UCDs always seem to be heavier than they should be. Now, an international team of astronomers has made a new discovery that may explain why — at the heart of M60-UCD1 lurks a supermassive black hole with the mass of 20 million Suns.

"We’ve known for some time that many UCDs are a bit overweight. They just appear to be too heavy for the luminosity of their stars," says co-author Steffen Mieske of the European Southern Observatory in Chile. "We had already published a study that suggested this additional weight could come from the presence of supermassive black holes, but it was only a theory. Now, by studying the movement of the stars within M60-UCD1, we have detected the effects of such a black hole at its centre. This is a very exciting result and we want to know how many more UCDs may harbour such extremely massive objects."

The supermassive black hole at the centre of M60-UCD1 makes up a huge 15 percent of the galaxy’s total mass, and weighs five times that of the black hole at the centre of the Milky Way. "That is pretty amazing, given that the Milky Way is 500 times larger and more than 1000 times heavier than M60-UCD1," explains Anil Seth of the University of Utah, USA, lead author of the international study. "In fact, even though the black hole at the centre of our Milky Way galaxy has the mass of 4 million Suns it is still less than 0.01 percent of the Milky Way’s total mass, which makes you realise how significant M60-UCD1’s black hole really is."

The team discovered the supermassive black hole by observing M60-UCD1 with both the NASA/ESA Hubble Space Telescope and the Gemini North 8-metre optical and infrared telescope on Hawaii’s Mauna Kea, USA. The sharp Hubble images provided information about the galaxy’s diameter and stellar density, whilst Gemini was used to measure the movement of stars in the galaxy as they were affected by the black hole’s gravitational pull. These data were then used to calculate the mass of the unseen black hole.

The finding implies that there may be a substantial population of previously unnoticed black holes. In fact, the astronomers predict there may be as many as double the known number of black holes in the local Universe.

Additionally, the results could affect theories of how such UCDs form. One explanation is that M60-UCD1 was once a large galaxy containing 10 billion stars, and a supermassive black hole to match. "This galaxy may have passed too close to the centre of its much larger neighbouring galaxy, Messier 60," explains co author Remco van den Bosch of the Max Planck Institute for Astronomy in Heidelberg, Germany. "In that process the outer part of the galaxy would have been torn away to become part of Messier 60, leaving behind only the small and compact galaxy we see today."

The team believes that M60-UDC1 may one day merge with Messier 60 to form a single galaxy. Messier 60 also has its own monster black hole an amazing 4.5 billion times the size of our Sun and more than 1000 times bigger than the black hole in our Milky Way. A merger between the two galaxies would also cause the black holes to merge, creating an even more monstrous black hole.

Image credit: NASA, ESA, D. Coe, G. Bacon (STScI)

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Zoom-in from Earth to the surface of Mars

Credit: ESA/Hubble (M. Kornmesser & L. L. Christensen)

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Hubble finds dead stars “polluted” with planetary debris

The NASA/ESA Hubble Space Telescope has found signs of Earth-like planets in an unlikely place: the atmospheres of a pair of burnt-out stars in a nearby star cluster. The white dwarf stars are being polluted by debris from asteroid-like objects falling onto them. This discovery suggests that rocky planet assembly is common in clusters, say researchers.

The stars, known as white dwarfs — small, dim remnants of stars once like the Sun — reside 150 light-years away in the Hyades star cluster, in the constellation of Taurus (The Bull). The cluster is relatively young, at only 625 million years old.

Astronomers believe that all stars formed in clusters. However, searches for planets in these clusters have not been fruitful — of the roughly 800 exoplanets known, only four are known to orbit stars in clusters. This scarcity may be due to the nature of the cluster stars, which are young and active, producing stellar flares and other outbursts that make it difficult to study them in detail.

Hubble’s spectroscopic observations identified silicon in the atmospheres of two white dwarfs, a major ingredient of the rocky material that forms Earth and other terrestrial planets in the Solar System. This silicon may have come from asteroids that were shredded by the white dwarfs’ gravity when they veered too close to the stars. The rocky debris likely formed a ring around the dead stars, which then funnelled the material inwards.

The debris detected whirling around the white dwarfs suggests that terrestrial planets formed when these stars were born. After the stars collapsed to form white dwarfs, surviving gas giant planets may have gravitationally nudged members of any leftover asteroid belts into star-grazing orbits.

Besides finding silicon in the Hyades stars’ atmospheres, Hubble also detected low levels of carbon. This is another sign of the rocky nature of the debris, as astronomers know that carbon levels should be very low in rocky, Earth-like material.

This new study suggests that asteroids less than 160 kilometres across were gravitationally torn apart by the white dwarfs’ strong tidal forces, before eventually falling onto the dead stars.

Image credit:  NASA, ESA, STScI, and G. Bacon (STScI)

[odditiesoflife]

NASA Takes “Rose” Galaxy Photo for Hubble Telescope Anniversary

Who knew we had a “rose-shaped” galaxy in space? The astronomers who run the Hubble Space Telescope did. In celebration of the 21st anniversary of the Hubble Space Telescope’s deployment into space, astronomers at the Space Telescope Science Institute in Baltimore, Maryland, pointed Hubble’s eye to an especially photogenic group of interacting galaxies called Arp 273.

The larger of the spiral galaxies, known as UGC 1810, has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. A swath of blue jewels across the top is the combined light from clusters of intensely bright and hot young blue stars. These massive stars glow fiercely in ultraviolet light.

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Happy birthday to the Hubble Space Telescope, launched on April 24, 1990. (NASA/HubbleSite)

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"People love Hubble images. It tells them where they came from. It tells them where they’re going.”

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NASA Hubble Space Telescope Images (via Hubble Heritage)

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Flyaround of the Hubble Space Telescope (HST) after deployment on this second servicing mission (HST SM-02). Note the telescope’s open aperature door.

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Caldwell 27: a crescent or a brain? (by Trois_Merlettes)

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