Voyage into Space

"The surface of the Earth is the shore of the cosmic ocean... Recently, we've managed to wade a little way out, and the water seems inviting." - Carl Sagan

[thepoemarian]

If you can imagine

If you can imagine The eyes that shine bright Over the lines of ridges’ Grand silhouettes tonight, Cloudy cotton candies Disappearing behind the hills, The moon obediently  Following quietly still— The sky’s dark, the water silent, Ripples making their way Toward the end of Earth Awaiting dawn of a new day.  But there are yet more hours, Long before the stars sleep, Echoes of wishful whispers Throughout the mountains steep.  A million miles until I’m back in your embrace. Comets dancing in the night theater, Into the painted dusk I gaze, Watching constellations glide As their journeys are due.  Distance regardless, I know You’re under the same sky, too. 

[distant-traveller]

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

[distant-traveller]

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

[distant-traveller]

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

[distant-traveller]

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

[distant-traveller]

The tell-tale signs of a galactic merger

The NASA/ESA Hubble Space Telescope has captured this striking view of spiral galaxy NGC 7714. This galaxy has drifted too close to another nearby galaxy and the dramatic interaction has twisted its spiral arms out of shape, dragged streams of material out into space, and triggered bright bursts of star formation. NGC 7714 is a spiral galaxy at 100 million light-years from Earth — a relatively close neighbour in cosmic terms. The galaxy has witnessed some violent and dramatic events in its recent past. Tell-tale signs of this brutality can be seen in NGC 7714's strangely shaped arms, and in the smoky golden haze that stretches out from the galactic centre. So what caused this disfigurement? The culprit is a smaller companion named NGC 7715, which lies just out of the frame of this image — but is visible in the wider-field DSS image. The two galaxies drifted too close together between 100 and 200 million years ago, and began to drag at and disrupt one another’s structure and shape. As a result, a ring and two long tails of stars have emerged from NGC 7714, creating a bridge between the two galaxies. This bridge acts as a pipeline, funnelling material from NGC 7715 towards its larger companion and feeding bursts of star formation. Most of the star-forming activity is concentrated at the bright galactic centre, although the whole galaxy is sparking new stars. Astronomers characterise NGC 7714 as a typical Wolf-Rayet starburst galaxy. This is due to the stars within it; a large number of the new stars are of the Wolf-Rayet type— extremely hot and bright stars that begin their lives with dozens of times the mass of the Sun, but lose most of it very quickly via powerful winds. This Hubble image is a composite of data capturing a broad range of wavelengths, revealing the correlation of the gas clouds and stars in the galaxy. This new picture not only reveals the intricate structure of NGC 7714, but also shows many other objects that are much further away. These background galaxies resemble faint smudges of light, some of them with spiral forms.

Image credit: ESA, NASA

[thedemon-hauntedworld]

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

[distant-traveller]

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

[distant-traveller]

The polar ring of Arp 230

This Picture of the Week shows Arp 230, also known as IC 51, observed by the NASA/ESA Hubble Space Telescope.

Arp 230 is a galaxy of an uncommon or peculiar shape, and is therefore part of the Atlas of Peculiar Galaxies produced by Halton Arp. Its irregular shape is thought to be the result of a violent collision with another galaxy sometime in the past. The collision could also be held responsible for the formation of the galaxy’s polar ring.

The outer ring surrounding the galaxy consists of gas and stars and rotates over the poles of the galaxy. It is thought that the orbit of the smaller of the two galaxies that created Arp 230 was perpendicular to the disc of the second, larger galaxy when they collided. In the process of merging the smaller galaxy would have been ripped apart and may have formed the polar ring structure astronomers can observe today.

Image credit: ESA/Hubble & NASA

[distant-traveller]

Our galaxy's magnetic field from Planck

What does the magnetic field of our Galaxy look like? It has long been known that a modest magnetic field pervades our Milky Way Galaxy because it is seen to align small dust grains that scatter background light. Only recently, however, has the Sun-orbiting Planck satellite made a high-resolution map of this field. Color coded, the 30-degree wide map confirms, among other things, that the Galaxy's interstellar magnetism is strongest in the central disk. The rotation of charged gas around the Galactic center creates this magnetism, and it is hypothesized that viewed from the top, the Milky Way's magnetic field would appear as a spiral swirling out from the center. What caused many of the details in this and similar Planck maps -- and how magnetism in general affected our Galaxy's evolution -- will likely remain topics of research for years to come.

Image credit & copyright: ESA/Planck; Acknowledgement: M.-A. Miville-Deschênes, CNRS – IAS, U. Paris-XI

[spacettf]

Lovejoy on Jan 16, 2015, 03:15 UT by CajunAstro on Flickr.

[distant-traveller]

Launch to Lovejoy

Blasting skyward an Atlas V rocket carrying a U.S. Navy satellite pierces a cloud bank in this starry night scene captured on January 20. On its way to orbit from Space Launch Complex 41, Cape Canaveral Air Force Station, planet Earth, the rocket streaks past brightest star Sirius, as seen from a dark beach at Canaveral National Seashore. Above the alpha star of Canis Major, Orion the Hunterstrikes a pose familiar to northern winter skygazers. Above Orion is the V-shaped Hyades star cluster, head of Taurus the Bull, and farther still above Taurus it's easy to spot the compact Pleiades star cluster. Of course near the top of the frame you'll find the greenish coma and long tail of Comet Lovejoy, astronomical darling of these January nights.

Image credit & copyright: Lynn Hilborn

[distant-traveller]

Searching the stars

From the photographer: "The Milky Way during the new moon, and a person shining a light into the heavens."

Image credit: Garret Suhrie

[distant-traveller]

Sunset and Moonset

This striking new image shows ESO’s Paranal Observatory in Chile soon after sunset. The last rays of the day create a spectacular orange haze as they pass through the dusty lower levels of the atmosphere, setting a perfect scene for this picture of the week.

In this long exposure image we can see star trails caused by the movement of stars across the sky as the earth rotates. These tracks look a little like dotted lines, an effect caused by combining a number of individual shots taken with short gaps in between. The crookedness at the bottom of the star trails is due to the camera moving out of place.

The path of the crescent Moon can also be seen towards the lower left of the frame as it slowly sets, appearing to sink into the Pacific Ocean. The moon is not trailed as it was taken with a series of very short exposures.

In the centre of the image a meteor is visible as a vertical streak, and the blinking lights of various planes can be seen tracking horizontally across the streaked sky.

This image was taken by ESO Photo Ambassador Gabriel Brammer soon after sunset on January 5, 2011. At the time Gabriel worked as an astronomer at the La Silla-Paranal Observatory, but is currently an astronomer supporting the Hubble Space Telescope at the Space Telescope Science Institute in Maryland, USA. This image was one of Brammer’s first ever night shots of Paranal, and remains one of his favourites.

Image credit: ESO/G. Brammer

[distant-traveller]

Dust filaments of NGC 4217

In this image the NASA/ESA Hubble Space Telescope takes a close look at the spiral galaxy NGC 4217, 60 million light-years away. The galaxy is seen almost perfectly edge on and is a perfect candidate for studying the nature of extraplanar dust structures — the patterns of gas and dust above and below the plane on the galaxy, seen here as brown wisps coming off NGC 4217.

These tentacle-like filaments are visible in the Hubble image only because the contrast with their surroundings is so high. This implies that the structures are denser than their surroundings. The image shows dozens of dust structures some of which reach as far as 7000 light-years away from the central plane. Typically the structures have a length of about 1000 light-years and are about 400 light-years in width.

Some of the dust filaments are round or irregular clouds, others are vertical columns, looplike structures or vertical cones. These structures can help astronomers to identify the mechanisms responsible for the ejection of gas and dust from the galactic plane of spiral galaxies and reveal information on the transport of the interstellar medium to large distances away from galactic discs.

The properties of the observed dust structures in NGC 4217 suggest that the gas and dust was driven out of the midplane of the galaxy by powerful stellar windsresulting from supernovae — explosions that mark the deaths of massive stars.

Image credit: ESA/Hubble & NASA; Acknowledgement: R. Schoofs

[distant-traveller]

Infrared Orion from WISE

The Great Nebula in Orion is an intriguing place. Visible to the unaided eye, it appears as a small fuzzy patch in the constellation of Orion. But this image, an illusory-color four-panel mosaic taken in different bands of infrared light with the Earth orbiting WISE observatory, shows the Orion Nebula to be a bustling neighborhood or recently formed stars, hot gas, and dark dust. The power behind much of the Orion Nebula (M42) is the stars of the Trapezium star cluster, seen near the center of the above wide field image. The orange glow surrounding the bright stars pictured here is their own starlight reflected by intricate dust filaments that cover much of the region. The current Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years.

Image credit: WISE, IRSA, NASA; Processing & Copyright : Francesco Antonucci

[distant-traveller]

Interior view from the International Space Station cupola

This image of the interior view from the International Space Station's Cupola module was taken on Jan. 4, 2015. The large bay windows allows the Expedition 42 crew to see outside. The Cupola houses one of the space station's two robotic work stations used by astronauts to manipulate the large robotic arm seen through the right window. The robotic arm, or Canadarm2, was used throughout the construction of the station and is still used to grapple visiting cargo vehicles and assist astronauts during spacewalks. The Cupola is attached to the nadir side of the space station and also gives a full panoramic view of the Earth.

Image credit: NASA