While snow continues to cause chaos in Austria and Germany, the cold snap has also reached Turkey as shown in this Copernicus Sentinel-3 image from 9 January. The snow, which started falling in Turkey on Sunday 6 January, has led to villages in remote areas being cut off and the authorities having to close offices and schools. The snowfall mainly affected eastern and northern provinces, but big cities in the west, including Ankara, have not been spared a thick covering of snow. The weather is also causing serious problems further west, in particular in Germany and Austria which are on red alert.
South Africa’s Western Cape often falls victim to fires during the dry hot summer months. Fires can ignite naturally but can also be the result of careless or deliberate human behaviour. This Copernicus Sentinel-2B image from 6 January shows several blazes around the Kogelberg Nature Reserve to the east of Cape Town. Smoke from the fires can also be seen blowing across False Bay towards the Cape Peninsula in the extreme southwest of South Africa. These fires are reported to be just some of those that firefighters have been dealing with in the region over the last weeks. The fires have posed serious risk to life, property and the environment, as well as incurring huge financial costs. Roads and resorts, which experience high volumes of traffic and visitors during the holiday season, have also been closed. The Kogelberg Nature Reserve is currently closed because of the fires, but it is considered to be very beautiful with an array of different plant species, many of which are endemic.
The two Copernicus Sentinel-2 satellites carry multispectral cameras designed to monitor changes in Earth’s vegetation and plant health.
Here's the finalised frame of the mobile gantry that will cover Ariane 6 pre-launch.
Completed on November 30 2018, even though it is 90 metres tall and weighs more than the Eiffel Tower, the entire structure is able to move on rails to uncover Ariane 6 as shortly as possible before takeoff.
The Copernicus Sentinel-2B satellite takes us along the lower reaches of the brown, sediment-rich Uruguay River. Here, the river forms the border between Argentina and Uruguay and is the site of the Esteros de Farrapos e Islas del Río Uruguay wetlands.
Composed of lagoons, swamps and 24 islets, the Esteros are a haven for wildlife, protected as a national park and included on the List of Wetlands of International Importance of the Ramsar Convention.
This wetland system is home to 130 species of fish, 14 species of amphibian, 104 species of bird – a quarter of all birds found in Uruguay – and 15 species of mammal, including the maned wolf, the largest canid (meaning dog-like) species in South America.
A tourist attraction and a waterway for transport, the Esteros also play an important role in regulating flood levels and maintaining water quality, as well as safeguarding the banks of the Uruguay River from erosion.
Visible to the lower left – its built structures shown in grey-white – is the Argentinian town of Gualeguaychú. On the eastern shore of the Uruguay River is the Uruguayan city of Fray Bentos, an important national harbour, famous for a plant that once exported corned beef around the world. Now inactive, this sprawling industrial complex has become a World Heritage Site.
The dark green area to the east of the Esteros is devoted to forestry, an important industry for the region. A pulp mill is located close to Fray Bentos.
Sentinel-2 is a two-satellite mission to supply the coverage and data delivery needed for Europe’s Copernicus environmental monitoring programme. The mission’s main instrument has 13 spectral bands, and is designed to provide images that can be used to distinguish different types of vegetation and monitor plant growth.
This image, acquired on 17 August 2018, is also featured on the Earth from Space video programme.
The cosmic source called ASASSN-14li, concealing a black hole at least one million times as massive as the Sun that shredded and devoured a nearby star, as viewed by the European Photon Imaging Camera (EPIC) on ESA's XMM-Newton X-ray observatory.
Observations of ASASSN-14li have revealed an exceptionally bright and stable signal that oscillated over a period of 131 seconds for a long time: 450 days.
By combining this with information about the black hole’s mass and size, the astronomers found that the hole must be spinning rapidly – at more than 50% of the speed of light – and that the signal came from its innermost regions.
The Atmosphere-Space Interactions Monitor – ASIM – is performing well outside the European Columbus laboratory module on the International Space Station.
Launched in April 2018, the storm-hunter is a collection of optical cameras, photometers and an X- and gamma-ray detector designed to look for electrical discharges born in stormy weather conditions that extend above thunderstorms into the upper atmosphere.
These ‘transient luminous events’ sport names such as red sprites, blue jets and elves.
Satellites have probed them and observations have even been made from mountain tops but because they occur above thunderstorms they are difficult to study in greater detail from Earth.
In contrast, the International Space Station’s low orbit covers a large part of Earth along the equator and is ideally placed to capture the sprites and jets.
ESA astronaut Andreas Mogensen managed to catch the elves and sprites in action with the help of a camera during his 2015 mission on board the International Space Station.
Now months into regular operations, ASIM is performing well. Using data continuously collected by ASIM, researchers are investigating the relationship between terrestrial gamma-ray bursts, lightning and high-altitude electric discharges across all seasons, different latitudes and different times of day and night.
Aside from being a little-understood phenomenon and part of our world, these powerful electrical charges can reach high above the stratosphere and have implications for how our atmosphere protects us from radiation from space.
ASIM is keeping researchers busy. Data collected so far have prompted over eight presentations so far at the December meeting of the American Geophysical Union, the largest international gathering of Earth and space scientists.
Learn more about ASIM and electric storms in the upper atmosphere with this infographic.
New Year’s Eve may be past, but we are not done with fireworks just yet. This image, which includes data from ESA’s Herschel Space Observatory, shows the remnants of an explosion – not of the colourful type ignited during celebrations, but of the stellar kind.
The object in the image, dubbed G54.1+0.3, is a supernova remnant, the leftovers of a massive star that died a violent death. It is located about 20,000 light-years away from us, in the northern constellation of Sagitta, the arrow.
As the star ran out of fuel, it shed its outer layers in a powerful explosion while its core collapsed due to gravity, eventually forming an extremely dense neutron star. The remnant of this particular explosion is a pulsar, a fast-rotating neutron star that shines brightly in the radio and X-ray parts of the electromagnetic spectrum.
Besides the stellar remnant, the dust and gas in the surrounding envelope are also quite remarkable. According to a recent study by J. Rho and collaborators, these layers contain silica – also known as silicon dioxide, or SiO2 – a major component of many types of rocks on Earth, making up about 60 percent of our planet’s crust. The study is the first to show that this key ingredient of everyday materials like glass and sand can be formed in supernova explosions.
This image combines infrared and X-ray data collected by three space observatories and radio observations obtained from the ground.
The data from Herschel, shown in green hues in this view and corresponding to the far-infrared wavelength of 70 microns, played a key part in helping astronomers detect silica in the dusty envelope of this supernova remnant, along with mid-infrared observations from NASA’s Spitzer Space Telescope, corresponding to 24 microns and shown in blue.
The radio data, obtained with the Karl G. Jansky Very Large Array in New Mexico, USA, are shown in red, while yellow hues show the X-ray data from NASA’s Chandra X-ray Observatory.
Operating between 2009 and 2013, Herschel left a legacy of treasured data that are still producing a multitude of scientific results every year. The study of supernova remnant G54.1+0.3 is based on archival data from one of the observatory’s key programmes, the Herschel infrared Galactic Plane Survey (Hi-GAL).
This Proba-V view shows all that is left of the Aral Sea, once one of the four largest lakes in the world and now one of the world’s major ecological disaster areas. It has shrunk into separate lakes, surrounded by Earth’s youngest desert.
The Aral Sea was once a large land-locked lake between Kazakhstan in the North and Uzbekistan in the South, possessing an area of 68 000 sq. km – twice that of Belgium.
However, the Aral Sea has dramatically shrunk since the 1960s when Soviet irrigation projects diverted water from the rivers supplying it. By the 2000s, the lake had shrunk to about 10% of its original size and by 2014 the horseshoe-shaped Southern Lake had virtually dried up.
Groundwater levels also fell, vegetation was laid waste and a once-thriving fishing industry collapsed. The exposed lakebed formed the newly-christened Aralkum Desert, spawning pesticide-laced sandstorms that can reach as far as the Himalayas.
Efforts to stabilise the situation are ongoing, including the replanting of hardy vegetation to reduce sandstorms. In 2005, the Kok-Aral Dam was completed to restore water levels in the Northern Lake – located at its bottom-east side. In addition, a sluice is periodically opened to replenish the Southern Lake.
Launched on 7 May 2013, Proba-V is a miniaturised ESA satellite tasked with a full-scale mission: to map land cover and vegetation growth across the entire planet every two days.
Its main camera’s continent-spanning 2250 km swath width collects light in the blue, red, near-infrared and mid-infrared wavebands at 300 m resolution and down to 100 m resolution in its central field of view.
VITO Remote Sensing in Belgium processes and then distributes Proba-V data to users worldwide. An online image gallery highlights some of the mission’s most striking images so far, including views of storms, fires and deforestation.
This 100 m-resolution image was acquired on 15 June 2018.
Proba-V is currently the subject of ESA’s latest ‘citizen science’ competition, requesting teams to produce ‘super-resolution’ images equivalent to its 100 m mode from sets of 300 m imagery.
This year, ESA's ground station boffins are planning to deploy a new cryogenically cooled 'antenna feed' – a gizmo used to transmit and receive deep space signals – on the Agency's three deep-space antennas.
The ground stations routinely communicate with missions like BepiColombo – heading to Mercury, Gaia – surveying stars in our Galaxy, and ESA's two spacecraft at the Red Planet, Mars Express and the ExoMars Trace Gas Orbiter.
ESA’s 35-metre antennas receive data from working spacecraft, in what’s called a ‘downlink’. As the Agency prepares to launch new missions deeper into our Solar System in the next few years, including Juice to Jupiter and the ExoMars Rover, as well as missions designed to generate large quantities of data, such as the future Sun-watching Lagrange mission, use of the stations' downlink capacity is set to grow significantly.
This means the stations have to 'up their game', and the new antenna feed is expected improve data return by 40% at the high frequencies used for spacecraft command and control. The feed must be cooled to just 10 K (just 10 degrees from absolute zero, about -263 C) for normal operation.
"While receiving extremely faint signals, the new feed should be capable of transmitting command signals to spacecraft at very high power of more than 25 kilowatts", says ESA ground station engineer Stéphane Halté.
"This is similar to the amount of power transmitted by 25 000 mobile phones switched on simultaneously."
The prototype antenna feed was mounted on NASA’s Deep Space Station 13 (pictured), at NASA's High Power Transmitter Test facility, in Goldstone, California. It was tested in December 2018 with the assistance of experts from the NASA Jet Propulsion Lab's Deep Space Network.
Testing successful, this ESA/NASA cooperation has cleared the way for the new technology to be rolled out at across ESA’s deep space ground stations, part of the Estrack network, within this year.
It might appear featureless and unexciting at first glance, but NASA/ESA Hubble Space Telescope observations of this elliptical galaxy — known as Messier 105 — show that the stars near the galaxy’s centre are moving very rapidly. Astronomers have concluded that these stars are zooming around a supermassive black hole with an estimated mass of 200 million Suns! This black hole releases huge amounts of energy as it consumes matter falling into it and causing the centre to shine far brighter than its surroundings. This system is known as an active galactic nucleus.
Hubble also surprised astronomers by revealing a few young stars and clusters in Messer 105, which was thought to be a “dead” galaxy incapable of star formation. Messier 105 is now thought to form roughly one Sun-like star every 10 000 years. Star-forming activity has also been spotted in a vast ring of hydrogen gas encircling both Messier 105 and its closest neighbour, the lenticular galaxy NGC 3384.
Messier 105 was discovered in 1781, lies about 30 million light-years away in the constellation of Leo (The Lion), and is the brightest elliptical galaxy within the Leo I galaxy group.
An image of supernova explosion AT2018cow and its host galaxy, CGCG 137-068, which is located some 200 million light years away. The image was obtained on 17 August 2018 using the DEep Imaging and Multi-Object Spectrograph (DEIMOS) on the W. M. Keck Observatory in Hawaii.
The supernova was first spotted on 16 June 2018 with the ATLAS telescope, also in Hawaii. Further observations performed with a large team of telescopes – including ESA’s high-energy space telescopes Integral and XMM-Newton – revealed a source of powerful X-rays at the centre of this unprecedentedly bright and rapidly evolving stellar explosion, suggesting that it could either be a nascent black hole or neutron star with a powerful magnetic field, sucking in the surrounding material.
Week in images
7 - 11 January 2019