Not What We Expected

Rosetta_animatedThis animated sequence combines 36 interpolated images of comet 67P/Churyumov-Gerasimenko, each separated by 20 minutes. This comet is the destination for the European Space Agency’s Rosetta mission. As the spacecraft is slowly approaching the comet, it’s proving to be full of surprises. These images obtained by OSIRIS, the onboard scientific imaging system, confirm the nucleus’s peculiar shape hinted at in earlier pictures. The comet’s nucleus consists of two distinctly separated parts. Comet 67P is very different from other comets spacecraft have encountered before.

NGC 1433

Composite_NGC_1433This detailed view shows the central parts of the nearby active galaxy NGC 1433. The dim blue background image, showing the central dust lanes of this galaxy, comes from the Hubble Space Telescope. The other colored structures near the middle of the image are from ALMA observations. ALMA is the Atacama Large Millimeter/sub-millimeter Array, an astronomical interferometer of radio telescopes in the Atacama desert of northern Chile.

Image Credit: ESO / NASA / ESA

Dark Side of the Moon

Craters_at_the_Moon_s_south_poleBoth the far side and near side of the Moon receive sunlight during a month. Still, Pink Floyd fans may be cheered to know that there are parts of the Moon that never see the Sun. There is a dark side of the Moon. The Moon’s axis has a tilt of 1.5º which causes the bottoms of some craters to be in permanent shadow.

This picture was assembled from images taken during summertime in the Moon’s southern hemisphere by the Advanced Moon Imaging Experiment on ESA’s SMART-1 spacecraft and shows a crater-riddled region around the lunar south pole. It is made up of around 40 individual images taken between December 2005 and March 2006, and covers an area of about 500 x 150 km.

Image Credit: ESA


In a Coma

Comet_comaESA’s Rosetta spacecraft is closing in for its rendezvous with a comet. It’s target has started to develop dusty veil over the last six weeks. This sequence of images presented here of comet 67P/Churyumov–Gerasimenko was taken between 27 March and 4 May, as the gap between craft and comet closed from about 5 million to 2 million km. By the end of the sequence, the comet’s dusty coma extends some 1300 km into space. By comparison, the nucleus is roughly only 4 km across, and cannot yet be resolved as more that a point of light.

The coma has developed as a result of the comet moving closer to the Sun along its 6.5 year orbit. Even though it is still more than 600 million km from the Sun, more than 4X the distance between Earth and Sun, its surface has begun to warm, and its surface ices have begun to sublimate and gas to escape from its rock–ice nucleus. As the gas escapes, it also carries a cloud of tiny dust particles out into space, which slowly expands to create the coma. As the comet comes closer to the Sun, the warming continues and activity rises. Pressure from the solar wind will eventually cause some of the material to stream out into a long tail.

Rosetta and the comet will be closest to the Sun in August 2015, between the orbits of Earth and Mars.

Image Credit: ESA

Rosetta Puts on the Brakes

Video Credit: ESA

The Tadpole

The_TadpoleWhen I was a kid, one of the pleasures of spring was going to the creek and catching tadpoles. This bright blue tadpole seems to swim through the inky blackness of space. Catalogued as IRAS 20324+4057, “The Tadpole” is a clump of gas and dust giving birth to a bright protostar, one of the earliest steps in building a star.

There are multiple protostars in the tadpole’s head; the glowing yellow one in this image is the most luminous and massive. When this protostar has gathered together enough mass from its surroundings, it will become a fully-fledged young star.

The intense blue glow is caused by intense ultraviolet radiation from nearby stars. Pressure from that UV sculpts the tail into a long, wiggly shape. The Tadpole spans roughly a light-year from head to tail-tip, and contains gas with about four times the mass of the Sun.

Image Credit: NASA / ESA

Rendezvous With A Comet

This animation is a visualization of how comet 67P/Churyumov-Gerasimenko will appear in Rosetta’s OSIRIS narrow angle camera between May and August, 2014.  As the spacecraft approaches, the 4 km wide comet will expand from a fraction of a single pixel to well over 2000 pixels. That will yield a resolution of around 2 m per pixel, so large surface features will be visible.

The comet featured in this animation is an artist’s impression. It is shown to scale, but the shape and surface details are pure guesswork, and the real comet will be rotating during Rosetta’s approach. The spacecraft will eventually rendezvous with the comet.

The planets aren’t shown to scale.

Video Credit: ESA

Herschel’s View of the Horsehead Nebula

Horsehead_Nebula (Herschel)

ZoomHorseHeadThis image from ESA’s Herschel space observatory shows the Horsehead Nebula in the context of its surroundings. The image is a composite of the infrared wavelengths of 70 µm (blue), 160 µm (green) and 250 µm (red), and covers 4.5 x 1.5 degrees of the night sky.

The Horsehead Nebula is in the constellation Orion about 1300 light-years away and is part of the vast Orion Molecular Cloud complex. The Horsehead appears to rise above the surrounding gas and dust in the far right-hand side of this scene, and points towards the bright Flame Nebula. Intense radiation streaming away from newborn stars heats up the surrounding dust and gas, making it shine brightly in infrared.

Image Credit: ESA

A Glory on Venus

Venus_glory_largeA rainbow-like feature known as a “glory” has been seen by ESA’s Venus Express orbiter in the atmosphere of our nearest planetary neighbor—the first time one has been fully imaged on another planet.

Rainbows and glories occur when sunlight shines on cloud droplets—water particles here on Earth. While rainbows arch across the sky, glories are typically much smaller and are made up of a series of coloured concentric rings centred on a bright core. Glories are only seen when the observer is situated directly between the Sun and the cloud particles that are reflecting sunlight. On Earth, they are often seen from aircraft, surrounding the shadow of the aircraft on the clouds below.

In order for a glory to occur, the particles must be spherical and the same size. The atmosphere of Venus is thought to contain droplets rich in sulphuric acid.

Mission scientists at ESA hoped to find a glory in the atmosphere of Venus by imaging the clouds with the Sun directly behind the Venus Express spacecraft. They were successful. The glory in this image was seen at the Venus cloud tops, 70 km above the planet’s surface. It is 1,200 km wide as seen from the spacecraft, 6,000 km away.

Image Credit: ESA

Venus in UV

Global_dynamics_of_Venus_northern_hemisphere_node_full_imageThis false-colour movie was put together using ultraviolet images taken by the Venus Monitoring Camera on board ESA’s Venus Express spacecraft on 22 May, 2006. The spacecraft was flying over the northern hemisphere at distances ranging between about 39,100 and 22,600 km from the surface.

Video Credit: ESA

Don’t Panic

This animation shows the different components that make up our home galaxy, the Milky Way.  It starts at the black hole at the core of the Milky Way and the stars that orbit around it, before zooming out through the central Galactic Bulge, which hosts about ten billion stars. The zoom continues through a younger population of stars in the stellar disc, the home to most of the Milky Way’s stars. The discs and bulge are embedded in the stellar halo, a spherical structure that consists of a large number of globular clusters. These are the oldest stars in the Galaxy. An even larger halo of invisible dark matter is believed to surround the Milky Way. Its gravitational effect is evident in the motions of stars in the Galaxy.

Finally, this ESA-porduced video shows the extent of the stellar survey conducted by ESA’s Hipparcos mission, which surveyed more than 100,000 stars as far as 300 light-years from the Sun. ESA’s Gaia survey aims to study a billion stars up to 30,000 light-years away.

If you’re going hitchhiking, remember to take your towel.

Video Credit: ESA

Chasing a Comet

This animation details the European Space Agency’s Rosetta‘s journey from launch in March, 2004, to rendezvous with comet 67P/Churyumov-Gerasimenko in August 2014, including three flybys of Earth and one of Mars. By now, the spacecraft is about 9 million km from comet 67P/CG. By early May, Rosetta will be 2 million km from the comet, and, at the end of May, it will execute a major rendezvous manoeuvre to line up for orbit insertion at the start of August.

Video Credit: ESA

The comet and planets are not to scale.

A Day in the Life of Venus Express

These false color images of the cloud tops of Venus taken during nearly a full orbit of ESA’s Venus Express around the planet. The inset shows the corresponding position and relative speed of Venus Express as it approaches from its furthest distance of 66,000 km above the south pole, swooping down to 250 km above the north pole.

Video Credit: ESA

Phobos 360

Images from ESA’s Mars Express orbiter have been combined into a virtual rotation movie showing what the tiny moon would look like from an orbit around it. The rotation is actually a digital illusion: Phobos is tidally-locked with Mars and always keeps the same face toward its home planet as does our Moon. Phobos is losing about of centimeter of altitude a year and is expected to break up and crash onto Mars within the next 50 million years.

Video Credit: ESA

International Crab

International CrabThe Crab nebula is the remnant of a supernova explosion recorded by Chinese astronomers in the year 1054. This is composite view of the Crab nebula was assembled using data from the Herschel Space Observatory and the Hubble Space Telescope. Herschel is a European Space Agency (ESA) mission with important NASA contributions, and Hubble is a NASA mission with important ESA contributions.

Hubble‘s view of the nebula at visible wavelengths used three different filters sensitive to the emission from oxygen and sulphur ions and is shown here in blue. Herschel’s far-infrared image reveals the emission from dust in the nebula and is shown here in red.

Image Credit: ESA/NASA

A Not-So-Empty Hole

Lockman's HoleThere’s an area in the night sky called the “Lockman Hole.” It’s found in the constellation of Ursa Major (The Big Bear; the Big Dipper forms the lower body and tail of the larger constellation.) This “hole” appears almost empty to the naked eye and small telescopes. Regions like this one are almost completely devoid of objects in our Milky Way galaxy. With little local clutter in the way the Lockman ideal for studying galaxies in the distant universe.

Here’s what this empty part of the sky looked like when it was surveyed in infrared light by the Herschel Space Observatory. All of the little dots in this picture are distant galaxies. Their collective light is known as the cosmic infrared background. By studying this pattern, astronomers were able to measure various effects of dark matter.

Image credit: ESA

A Supervolcano …

supervolano… on Mars? New research suggests a volcano, not a large impact, may have formed Mars’s Eden Patera basin. The volcano is a vast circular basin on the face of the Red Planet which had previously had been classified as an impact crater. Researchers now suggest the basin may be the remains of an ancient supervolcano’s eruption. The finding is based on images and topographic data from NASA’s Mars Odyssey, Mars Global Surveyor, and Mars Reconnaissance Orbiter spacecraft and the European Space Agency’s Mars Express orbiter.

Left: Reds, yellows show higher elevations in the basin and surrounding area; blues, grays show lower elevations. Right: The dark color indicates younger material draped across the Eden Patera depression.

Image Credit: NASA/JPL/Goddard (left) and ESA (right)

Mergers and Acquisitions

galactic_mergerSeveral telescopes have teamed up to examine a rare and massive merger of two galaxies that took place when the universe was just 3 billion years old (that was over 10 billion years ago). The galaxies, collectively called HXMM01, were creating a couple of thousand new star a year as they merged. These days, our galaxy, the Milky Way, hatches about two to three a year. The total number of stars in both colliding galaxies averages is around 400 billion.

The Herschel Space Observatory first spotted the collision in images taken with infrared light (the image at left). Follow-up observations from other telescopes showed the extreme degree of star-formation taking place in the merger.

The merging galaxies are circled in the close up view (on the right). The red data from the Smithsonian Astrophysical Observatory’s Submillimeter Array atop Mauna Kea, Hawaii, show dust-enshrouded regions of star formation. The green data, taken by the National Radio Astronomy Observatory’s Very Large Array, near Socorro, N.M., show carbon monoxide gas in the galaxies.

Blue shows visible starlight. The blue blobs outside of the circle are galaxies located closer to us as seen via near-infrared light observations are from the Hubble Space Telescope and the W.M. Keck Observatory atop Mauna Kea, Hawaii.

Image credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO

A Shell in a Fish

supernova_shellThese thin wisps of gas are an object known as SNR 0519. The blood-red clouds are the remains from a violent explosion of a star as a supernova seen about 600 years ago. The star that exploded is known to have been a white dwarf star—a Sun-like star in the final stages of its life.

SNR 0519 is over 150 000 light-years from Earth in the southern constellation of Dorado (The Dolphinfish), a constellation that also contains most of our neighboring galaxy the Large Magellanic Cloud, a region of the sky is full of intriguing and beautiful deep sky objects. The Large Magellanic Cloud orbits the Milky Way galaxy as a satellite and is the fourth largest in our group of galaxies.

Image Credit: NASA/ESA

Water, Water, Everywhere:

Nor any drop to drink.Jupiter_water

Astronomers have finally found direct proof that almost all water present in Jupiter’s stratosphere, an intermediate atmospheric layer, was delivered by comet Shoemaker-Levy 9, which struck the planet in 1994. The findings are based on new data from the Herschel space observatory and reveal more water in Jupiter’s southern hemisphere, where the impacts occurred, than in the north. Herschel is a European Space Agency mission.

Jupiter_Shoemaker_LevyThe origin of water in the upper atmospheres of the solar system’s giant planets has been a hot topic among planetary astronomers since the late ’90s. Astronomers were quite surprised when water was found in the stratospheres of Jupiter, Saturn, Uranus and Neptune by ESA’s Infrared Space Observatory.

The composite photo at left was assembled from separate images of Jupiter and comet Shoemaker-Levy 9 taken by the Hubble Space Telescope in 1994.

Image Credits: Top, ESA. Left, NASA

Cool Andromeda

Cool_AndromedaThis view of the Andromeda galaxy from the Herschel space observatory shows relatively cool lanes of forming stars. Herschel is sensitive to the far-infrared light from cool dust mixed in with the gas where stars are born. This image reveals some of the very coldest dust in the galaxy (colored red here) that is only a few tens of degrees above absolute zero. Warmer regions such as the densely populated central bulge, home to older stars, appear as blue. Star-formation zones are in the spiral arms with several concentric rings interspersed with dark gaps where star formation is absent.

Andromeda (aka M31) is the nearest major galaxy to our own Milky Way about 2.5 million light-years away. Herschel is a European Space Agency mission.

Image Credit: ESA

The Whole Universe

Planck_light_mapThis is a map of oldest light in our universe. It is derived from data detected with the greatest precision yet by the Planck mission. The ancient photons, also called the cosmic microwave background, give us a view of the universe when it was about 370,000 years old. The variations are related to the tiny temperature fluctuations caused by regions of slightly different densities—the seeds of all the future structure of the Universe—the stars, galaxies, and life existing today.

Planck is a European Space Agency mission with significant participation from NASA’s Jet Propulsion Laboratory.

Image Credit: ESA