Sentinel-2A takes us over central-eastern Brazil – more specifically where the Bahia, Tocantins and Goiás states meet.
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Here we can see a large, flat plateau blanked with fields benefiting from rich soils and an apparent abundance of water, before falling off into a green, hilly valley (left). The straight lines in the image are roads, such as the highway running in a nearly straight line from the centre-top to bottom of the image.
The area is particularly known for soybean production. The country’s soybean output has increased by more than 3000% since the 1970s, and Brazil is the second largest global producer of soybeans after the US.
Other crops in this area include corn, coffee and cotton.
A distinctive feature in this image is the circles – mainly at the centre. These shapes were created by a central-pivot irrigation system, where a long water pipe rotates around a well at the centre of each plot. The varying colours show different types of crop, or different stages of growth.
The two-satellite Sentinel-2 mission is designed to monitor changing lands, including crop type and health. While the first satellite has been in orbit since 2015, its Sentinel-2B twin was launched on 7 March. Together, the satellites will provide new images of Earth’s land surfaces every five days.
This image, also featured on the Earth from Space video programme, was captured by the Copernicus Sentinel-2A satellite on 8 August 2016.
This may look like a brightly decorated Easter egg wrapping, but it actually represents how ESA’s Gaia satellite scanned the sky during its first 14 months of science operations, between July 2014 and September 2015.
The oval represents the celestial sphere, with the colours indicating how frequently the different portions of the sky were scanned. Blue represents the regions scanned most frequently in that time period; the lighter colours lesser so.
The satellite scans great circles on the sky, with each lasting about six hours. During the first month, the scanning procedure was such that the ecliptic poles were always included. This meant that Gaia observed the stars in those regions many times, providing an invaluable database for the initial calibration of the observations.
Then, the satellite started its main survey, scanning in such a way to achieve the best possible coverage of the whole sky.
These initial 14 months provided the first catalogue of the brightness and precise position of more than a billion stars, the largest all-sky survey of celestial objects to date.
Over its five-year mission, Gaia will survey one billion stars in our Galaxy and local galactic neighbourhood, measuring their position and motion at unprecedented accuracy, in order to build the most precise 3D map of the Milky Way and answer questions about its structure, origin and evolution.
Watch an animation of how Gaia scans the sky here.
The positions of two million stars in our Galaxy, based on data from the Tycho-Gaia Astrometric Solution, one of the products of the first Gaia data release.
The stars are plotted in Galactic coordinates and using a rectangular projection: in this, the plane of the Milky Way stands out as the horizontal band with greater density of stars. The stripes visible in the early frames reflect the way Gaia scans the sky and the preliminary nature of the first data release.
The shape of the Orion constellation can be spotted towards the right edge of the frame, just below the Galactic Plane. Two stellar clusters – groups of stars that were born together and consequently move together – can be seen towards the left edge of the frame: these are the alpha Persei (Per OB3) and Pleiades open clusters.
Despite all efforts galaxy formation and evolution are still far from being fully understood. Fortunately, the conditions we see within certain galaxies — such as so-called starburst galaxies — can tell us a lot about how they have evolved over time. Starburst galaxies contain a region (or many regions) where stars are forming at such a breakneck rate that the galaxy is eating up its gas supply faster than it can be replenished!
NGC 4536 is such a galaxy, captured here in beautiful detail by the Hubble’s Wide Field Camera 3 (WFC3). Located roughly 50 million light-years away in the constellation of Virgo (The Virgin), it is a hub of extreme star formation. There are several different factors that can lead to such an ideal environment in which stars can form at such a rapid rate. Crucially, there has to be a sufficiently massive supply of gas. This might be acquired in a number of ways — for example by passing very close to another galaxy, in a full-blown galactic collision, or as a result of some event that forces lots of gas into a relatively small space.
Star formation leaves a few tell-tale fingerprints, so astronomers can tell where stars have been born. We know that starburst regions are rich in gas. Young stars in these extreme environments often live fast and die young, burning extremely hot and exhausting their gas supplies fairly quickly. These stars also emit huge amounts of intense ultraviolet light, which blasts the electrons off any atoms of hydrogen lurking nearby (a process called ionisation), leaving behind clouds of ionised hydrogen (known in astronomer-speak as HII regions).
Artist’s impression of the BepiColombo spacecraft at Mercury. The mission comprises ESA’s Mercury Planetary Orbiter (foreground) and JAXA’s Mercury Magnetospheric Orbiter (background).
The image of Mercury was taken by NASA’s Messenger spacecraft.
Laser testing in ESA’s technical centre in the Netherlands.
The Opto-Electronics Laboratory investigates devices that generate, detect and manipulate light, such as high-performance lasers, photon detectors and fibre optics.
It works closely with its neighbouring Optics Laboratory, which specialises in design assessments and testing of optical components for space telescopes, cameras and imaging instruments, as well as assessing the optical properties of new materials and coatings and evaluating any laser-induced damage.
The two labs collaborate to support ESA missions and projects throughout their life cycles.
Volunteers are going to bed to help human spaceflight research. This ‘bedrest participant’ is performing a neuroscience experiment at the Medes Space Clinic in Toulouse, France. Developed with France’s space agency CNES, this protocol investigates if – and how – gravity affects hand–eye coordination.
Bedrest studies are a low-cost method of studying the effects of weightlessness on the human body. Participants spend up to 60 days in bed with the head tilted 6° below horizontal. By monitoring changes and learning why they occur, researchers learn and develop solutions for problems faced by astronauts in space as well as bedridden patients on Earth.
This experiment is being run on bedrest volunteers spending two months in bed with at least one shoulder in contact with the bed at all times. Researchers want to understand how the brain accomplishes reach and grasp tasks and whether new strategies develop to compensate for the downward tilt.
Equipped with a virtual reality headset, the subjects react to scenarios requiring them to reach and grasp for a object while motion sensors record their movements.
The assumption is that on Earth, in addition to visual cues, the brain uses gravity as a reference frame for coordinating hand movement. How then does the brain adapt to altered states of gravity or even the lack of it? Answers to this question will allow researchers to better understand the physiology behind complex hand–eye coordination and to shed light on how to treat patients with vertigo, spatial disorientation and other vestibular disorders.
ESA operates its Optical Ground Station (OGS) at the Teide Observatory on Tenerife, Spain, where a Zeiss 1 m-diameter telescope is used to survey and characterise objects near the ‘geostationary ring’ some 36 000 km above the equator. The telescope has RitcheyChrétien optics and highly efficient digital cameras.
The telescope can detect and track objects around geostationary altitudes down to 10–15 cm in size. With this performance, the ESA telescope is topranked worldwide.
The data provided by the telescope are a major input for space debris environment models.
The telescope is also capable of conducting photometric observations, to determine the ‘colour’ of objects. This enables the material properties of unknown objects to be characterised and provides valuable information on the potential origin of newly detected fragments.
In almost 60 years of space activities, more than 5250 launches have resulted in some 42 000 tracked objects in orbit, of which about 23 000 remain in space and are regularly tracked by the US Space Surveillance Network and maintained in their catalogue, which covers objects larger than about 5–10 cm in low orbit and 0.3–1 m at geostationary altitudes.
Only a small fraction – about 1200 – are intact, operating satellites today.
EDRS-C is put through its paces at OHB System AG in Bremen, Germany, on 7 April.
EDRS-C is the second node of the European Data Relay System and first dedicated satellite to complement the infrastructure. It is the second satellite to be based on ESA and OHB’s SmallGEO platform.
The European Data Relay System is designed to transmit data between low Earth orbiting satellites and the EDRS payloads in geostationary orbit using innovative laser communication technology. By relaying their findings to Europe via EDRS, Earth-observing satellites can transmit their information to the ground in near-realtime as they gather it, instead of having to store it onboard until they travel over one of their own ground stations.
Presentation of the comic preview 'C'è spazio per tutti' with cartoonist Leo Ortolani and ESA astronaut Paolo Nespoli. The two met at an event organised by Italian comic book publisher Panini, in cooperation with ESA and Italy's ASI space agency, on 7 April 2017 in Rome, Italy.
Paolo Nespoli is currently preparing for his third spaceflight to the International Space Station, set for launch later this year.
Week In Images
10-14 April 2017