A giant, geological wonder in the Sahara Desert of Mauritania is pictured in this satellite image.
The 40 km-diameter circular Richat structure is one of the geological features that is easier to observe from space than from down on the ground, and has been a familiar landmark to astronauts since the earliest missions.
Once thought to be the result of a meteor impact, researchers now believe it was caused by a large dome of molten rock uplifting and, once at the surface, being shaped by wind and water into what we see today. Concentric bands of resistant quartzite rocks form ridges, with valleys of less-resistant rock between them.
The dark area on the left is part of the Adrar plateau of sedimentary rock standing some 200 m above the surrounding desert sands. A large area covered by sand dunes – called an erg – can be seen in the lower-right part of the image, and sand is encroaching into the structure’s southern side.
Zooming in on the southern side of the bullseye, we can see individual trees and bushes as tiny dots. These follow a river-like structure that appears to have been dry when this image was acquired, a few weeks after the rainy season. Some areas to the south and east of the Richat appear to be covered with temporary lakes, which are dry for most of the year.
This image, also featured on the Earth from Space video programme, was acquired on 23 November 2010 by the Advanced Visible and Near Infrared Radiometer on Japan’s ALOS satellite.
This new Hubble picture is the sharpest ever image of the core of spiral galaxy Messier 61. Taken using the High Resolution Channel of Hubble's Advanced Camera for Surveys, the central part of the galaxy is shown in striking detail. Also known as NGC 4303, this galaxy is roughly 100 000 light-years across, comparable in size to our galaxy, the Milky Way.
Both Messier 61 and our home galaxy belong to a group of galaxies known as the Virgo Supercluster in the constellation of Virgo (The Virgin) — a group of galaxy clusters containing up to 2000 spiral and elliptical galaxies in total. Messier 61 is a type of galaxy known as a starburst galaxy. Starburst galaxies experience an incredibly high rate of star formation, hungrily using up their reservoir of gas in a very short period of time (in astronomical terms). But this is not the only activity going on within the galaxy; deep at its heart there is thought to be a supermassive black hole that is violently spewing out radiation.
Despite its inclusion in the Messier Catalogue, Messier 61 was actually discovered by Italian astronomer Barnabus Oriani in 1779. Charles Messier also noticed this galaxy on the very same day as Oriani, but mistook it for a passing comet — the comet of 1779. A version of this image was submitted to the Hubble’s Hidden Treasures image processing competition by Flickr user Det58.
This view from NASA's Cassini spacecraft features a blue planet, but unlike the view from July 19, 2013 (PIA17172) that featured our home planet, this blue orb is Uranus, imaged by Cassini for the first time.
Uranus is a pale blue in this natural color image because its visible atmosphere contains methane gas and few aerosols or clouds. Methane on Uranus -- and its sapphire-colored sibling, Neptune -- absorbs red wavelengths of incoming sunlight, but allows blue wavelengths to escape back into space, resulting in the predominantly bluish color seen here. Cassini imaging scientists combined red, green and blue spectral filter images to create a final image that represents what human eyes might see from the vantage point of the spacecraft.
Uranus has been brightened by a factor of 4.5 to make it more easily visible. The outer portion of Saturn's A ring, seen at bottom right, has been brightened by a factor of two. The bright ring cutting across the image center is Saturn's narrow F ring.
Uranus was approximately 28.6 astronomical units from Cassini and Saturn when this view was obtained. An astronomical unit is the average distance from Earth to the sun, equal to 93,000,000 miles (150,000,000 kilometers).
This view was acquired by the Cassini narrow-angle camera at a distance of approximately 614,300 miles (988,600 kilometers) from Saturn on April 11, 2014. Image scale at Uranus is approximately 16,000 miles (25,700 kilometers) per pixel. Image scale at Saturn's rings is approximately 4 miles (6 kilometers) per pixel. In the image, the disk of Uranus is just barely resolved. The solar phase angle at Uranus, seen from Cassini, is 11.9 degrees.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
The heart of a vast cluster of galaxies called MACSJ1720+35 is shown in this image, taken in visible and near-infrared light by the NASA/ESA Hubble Space Telescope.
The galaxy cluster is so massive that its gravity distorts, brightens, and magnifies light from more distant objects behind it, an effect called gravitational lensing. In the top right an exploding star, located behind the cluster can just be made out. It is catalogued as SCP/SN-L2 and nicknamed Caracalla.
The supernova is a member of a special class of exploding star called Type Ia, prized by astronomers because it provides a consistent level of peak brightness that makes it reliable for making distance estimates.
Finding a gravitationally lensed Type Ia supernova gives astronomers a unique opportunity to check the optical "prescription" of the foreground lensing cluster. The supernova is one of three exploding stars discovered in the Cluster Lensing And Supernova survey with Hubble (CLASH), and was followed up as part of a Supernova Cosmology Project HST program. CLASH is a Hubble census that probed the distribution of dark matter in 25 galaxy clusters. Dark matter cannot be seen directly but is believed to make up most of the universe's matter.
The image of the galaxy cluster was taken between March and July 2012 by Hubble's Wide Field Camera 3 and Advanced Camera for Surveys.
The majority of the stars in our Galaxy, the Milky Way, reside in a single huge disc, known as the Galactic Plane, spanning 100 000 light-years across. The Sun also resides in this crowded stellar hub, lying roughly halfway between its centre and its outer edges.
This disc is filled with a diffuse mixture of gas and dust – the interstellar medium – that pervades space, filling the large gaps found between stars. Occasionally, these clouds of gas and dust cool, becoming denser and denser until they spark star formation, giving rise to new generations of stars.
This image is part of Hi-GAL, a survey of the Galactic Plane completed with ESA’s Herschel Space Observatory. Peering at the sky in infrared light, Herschel could detect the glow of dust particles dispersed between stars. This minor – but crucial – component of the interstellar medium allows astronomers to investigate how stars are born in the Milky Way, and how they affect their environment as they age.
Nestled in the Milky Way’s disc are pockets of gas and dust that have been heated by nearby newborn stars, causing them to glow brightly like cosmic gems. Through their higher temperatures, these regions glow at shorter infrared wavelengths and are depicted in violet and green, while the colder material in the surroundings – only a few tens of degrees above absolute zero – appears redder.
Laced amongst the stars is an intricate network of filaments sprinkled with tiny white spots: these are denser clumps of gas and dust that will likely evolve and give birth to new stars.
The image combines observations from the PACS and SPIRE instruments on Herschel. It spans about 12º on the longer side, corresponding to some 24 times the diameter of the full Moon. This is 1/30th of the entire Galactic Plane survey.
This image was first published in OSHI, the Online Showcase of Herschel Images, in 2011.
Mars' moon Phobos has already been extensively observed – this image is just one example, taken in 2009 – so its occultation of Mars Express on 28 April 2014 is not expected to yield dramatic discoveries.
But science lies in the smallest things – like obtaining a 'snapshot in time' of continuous change.
The occultation meant that, for a brief time, Phobos passed between Mars Express and Earth, blocking the spacecraft’s radio signal.
The break in the signal was small – about nine seconds – but the precise start and end times are valuable information. These will allow scientists to calculate the orbit of Phobos with great precision – specifically the mean distance from Mars, which is notoriously difficult to pin down because Phobos’ natural motion around the planet changes over time.
Phobos and sister moon Deimos are formidable scientific enigmas. There is no confirmed theory of their origin that offers a satisfactory explanation for their current orbits and appearances. They could be excellent targets for future robotic landings.
ESA experts analysed yesterday’s data from the tracking station and found the occultation to have started just before 01:08:24 GMT, lasting until shortly before 01:08:33 GMT.
Now, we’ll know the orbit of Phobos with just a little more precision, at least for a while.
The Mexican-American border separates the cities of Ciudad Juarez, Mexico with El Paso in Texas, USA. This image shows both cities at night, as pictured by an astronaut on the International Space Station circling Earth at around 400 km above.
From space, political borders are not visible but subtle differences in street-lighting can be revealing. In this image the international border between the cities is brightly-lit corresponding to the thick yellow line dividing the mass of lights. North of the border is El Paso with its well-illuminated major motorways such as the straight US Route 180 leading to the east. Just to the north of El Paso is Biggs Army Airfield that shows up as remarkably different to the residential areas and city centre of the town.
The city of Ciudad Juarez shows a different layout to its US sister city. Juarez is more densely illuminated and roads stand out less visibly. One exception is the ring road Periférico Carmino Real that seems to be partly illuminated by distinctive white-coloured streetlamps.
These night-time images of Earth from space clearly show the impact human settlement has on our planet. The light seen by astronauts is all wasted energy that could be better used for other purposes.
In May, as ESA’s comet-chasing Rosetta spacecraft begins a series of manoeuvres to bring it closer to its target, so another vehicle is closing in on its target here on Earth: the Rosetta truck, a touring exhibition that will rendezvous with 16 cities across Finland, Norway, Sweden and Denmark.
An impressive exhibition truck packed with information and interactive demonstrations about the mission will depart from Finland at the start of May, and embark on a 5000 km journey through Norway, Sweden and Denmark. The Rosetta truck will visit Vaasa, Oulu, Trondheim, Oslo, Borlänge, Gothenburg, Aarhus, Copenhagen, Linköping, Södertälje, Turku, Helsinki, Lahti, Tampere, Jyväskylä and Seinäjoki.
The full programme is available on our Rosetta blog: http://blogs.esa.int/rosetta/2014/04/22/rosetta-hits-the-road-in-scandinavia-and-finland/
As engineer Manuel Aiple moves his gauntleted hand, the robotic hand a few metres away in ESA’s telerobotics laboratory follows in sync.
In future, the hope is that human controllers can manipulate orbiting robots or planetary rovers in a similar fashion, across hundreds or thousands of kilometres of space.
Based at ESA’s ESTEC technical centre in Noordwijk, the Netherlands, the lab aims for robot operators to feel as though they are right there – up in orbit or down on a planet.
Stereo cameras offer 3D vision and the operator feels force-feedback, as found in high-end video game joysticks, to gain a working sense of touch as the robot manipulates objects.
This summer, ESA’s latest ATV space freighter will deliver the Lab’s Haptics-1 experiment to the International Space Station, testing how feedback operates in microgravity, as a prelude to demonstrating orbit-to-ground telerobotic control.
The third launch by Europe’s new small launcher, Vega, delivered Kazakhstan’s KazEOSat-1(DZZ-HR) satellite for high-resolution Earth observation into its planned orbit during a flight lasting 55 minutes. Liftoff of flight VV03 from Europe’s Spaceport in Kourou, French Guiana came at 01:35 GMT on 30 April 2014 (03:35 CEST; 22:35 local time on 29 April).
Week In Images
28 April - 02 May 2014