A gigantic cold front in the Perseus galaxy cluster has been observed by a trio of X-ray telescopes.
The ancient cold front can be seen at the left of the image, drifting away from the inner, younger front closer to the centre. Galactic cold fronts are nothing like the cold fronts we experience on Earth – instead they are caused by galaxy clusters colliding into one another. The gravitational pull of a larger cluster tugs a smaller cluster closer, resulting in gas in the core of the cluster being sloshed around like liquid in a glass. This creates a cold front in a spiral pattern moving outwards from the core and these sloshing cold fronts can provide a probe of the intercluster medium.
Cold fronts are the oldest coherent structures in cool core clusters and this one has been moving away from the centre of the cluster for over five billion years – longer than our Solar System has been in existence. The long curving structure spans around two million light years and is travelling at around 50 kilometres per second.
The image combines data from NASA's Chandra X-Ray observatory, ESA's XMM-Newton and the German Aerospace Centre-led ROSAT satellite. Chandra also took a separate close-up of the upper left of the cold front, revealing some unexpected details.
The Perseus galaxy cluster contains thousands of galaxies and a supermassive black hole at the centre. The black hole is responsible for creating a harsh environment of sound waves and turbulence that should erode a cold front over time, smoothing out the previously sharp edges and creating gradual changes in density and temperature. Instead, the high-resolution Chandra image showed a surprisingly sharp edge on the cold front, and a temperature map revealed that the upper left of the cold front is split in two.
The sharpness of the cold front suggests it has been preserved by strong magnetic fields wrapped around it, essentially acting as a shield against the harsh environment. This magnetic "draping" prevents the cold front from diffusing and is what has allowed it to survive so well for over five billion years as it drifts away from the centre of the cluster.
The geology field training course Pangaea is back for its third leg.
Designed to train astronauts and explorers on planetary formation and detecting signs of life, the Pangaea course combines classroom lectures with field trips to sites of geological interest.
Led by European scientists, this year’s participants include ESA astronaut Thomas Reiter, Roscosmos cosmonaut Sergei Kud-Sverchkov and ESA expert Aidan Cowley. They were introduced to geological processes, how to interpret rock formations and explorationtools before moving out into the field to put their knowledge into practice.
Starting in Germany, the team learned about impact craters at the world’s best preserved impact site: the Ries crater. The team then moved on to explore landscapes that resemble Mars at the Bletterbach canyon in the Italian Dolomites.
Exercises for the astronauts included describing rocks, identifying minerals and sketching the landscape as a means to read its history in detail.
From 11 to 16 November the team will get to explore the most Martian of all Earth-based landscapes: Lanzarote, in the Canary Islands.
This alien landscape is one of the best areas on Earth to understand the geological interactions between volcanic activity and water – two key factors in the search for life.
To be found among the rugged terrain are many lava tubes, such as the one pictured here.
Lava tubes are underground structures that also occur on the Moon and Mars. Being underground structures, they offer good shelters from radiation. They may contain subsurface water, and therefore be interesting in the search of extraterrestrial microbial life. This makes them an ideal site to explore for future planetary explorers.
During Pangaea-X from 19-23 November, the team will conduct a sample-return mission to test technologies for future space missions.
They will lay the groundwork for an exciting experiment to take place in 2019 from the International Space Station. The experiment will have an astronaut on the Space Station controlling a rover in Lanzarote to test robotics and relay communications, mission control logistics and robotic capabilities for future lunar and Martian missions.
A Halloween view inside one of the darker recesses of ESA’s technical heart. Shaded to resemble the blackness of deep space, the GNC Rendezvous, Approach and Landing Simulator, or GRALS, is seen being used to test vision-based navigation algorithms under development for the proposed Hera binary asteroid mission.
A camera, mounted on a robot arm that moves along a 33-m long track, approaches a pair of 3D-printed asteroid models.
Hera, Earth’s first mission to a binary asteroid system, would use vision-based algorithms to map surface features on an automated basis to plot its position in space and plan its onward route.
To simulate space, the chamber is kept dark for the testing, except for a single Sun-like light source.
Part of the Agency's Orbital Robotics and Guidance, Navigation and Control Laboratory in its ESTEC technical centre in the Netherlands, GRALS is used to simulate close approach to uncooperative targets such as asteroids or drifting satellites.
The Copernicus Sentinel-2B satellite takes us over Semarang, Indonesia. A port city on the north coast of Java, Semarang is the fifth-largest city in the country, covering some 374 sq km and home to just over 1.5 million people.
This true-colour image shows the heart of the bustling regional commercial centre in the bottom-left, where a range of industries from fishing to glass manufacture and textiles operate. Exports of rubber, coffee, shrimp, tobacco, and cacao, among other products, pass through the city’s harbour, which can also be seen in the bottom-left of the image.
The Java Sea dominates the left part of the image. Flood management remains an ongoing challenge for the area, with the city being prone to tidal flooding.
The island nation of Indonesia is particularly vulnerable to sea-level rise. Some parts of Semarang, such as the residential area of Candi Baru, shown in the bottom-left of the image, stand just above sea level.
In the right of the image we can see mainly agricultural land, with rice fields stretching across the landscape. Land subsidence has been widely reported in the area, particularly in the northern part of Semarang, accelerated by population increases and urban development.
The impacts of subsidence include the wider expansion of (coastal) flooding areas, cracking of buildings and infrastructure, and increased inland seawater intrusion.
Sentinel-2 is a two-satellite mission for land monitoring, providing imagery of soil and water cover, inland waterways and coastal areas, for Europe’s Copernicus environmental monitoring programme. Wide swath Sentinel-2 data can also contribute to monitoring land-use change that triggers erosion, forest and wildfires, and the onset of floods.
This image, which was captured on 9 May 2018, is also featured on the Earth from Space video programme.
ESA’s plans to deploy a network of asteroid-detecting ‘Flyeye’ telescopes has come one step closer to reality. Last week, the Agency signed an agreement with the Italian Space Agency (ASI) to locate the first-ever Flyeye telescope atop the 1865-metre Monte Mufara mountain in Sicily.
The revolutionary Flyeye design is similar to that of a fly’s compound eye — it uses multiple cameras and optics, splitting a section of the sky into 16 smaller images, to expand the telescope’s field of view.
This telescope, nestled within the building in the artist’s illustration above, will be the first in a potential network of four telescopes across the globe, that together will have the ability to run nightly surveys of the entire sky, automatically scanning for near-Earth objects — potentially hazardous space rocks that could impact our planet.
With this agreement, ASI becomes responsible for developing the overall infrastructure going to the site — including the access road and power, water and data links — and ESA will deliver the telescope itself and prepare the building, including the telescope dome and associated structures.
In early 2016, ESA awarded a contract for the development of the Flyeye telescope to a consortium led by OHB Italy, in Milan, with the participation of industry from seven European countries.
Click here for more information on ESA’s activities dedicated to planetary defence.
Spacebus Neo is a new telecom satellite product line by Thales Alenia Space, developed under ESA’s Neosat programme. Its first new electric propulsion module is seen in Thales UK’s Belfast assembly centre before being shipped to Cannes for final spacecraft assembly. This first satellite will be Eutelsat’s KONNECT, which will provide broadband to Europe and Africa.
The new Spacebus Neo product line is developed in the frame of ESA's Advanced Research in Telecommunications Systems (ARTES) programme, in cooperation with space agencies from ESA Member States, particularly CNES and the UK Space Agency.
The Neosat programme comprises both Spacebus Neo by Thales Alenia Space and Eurostar Neo by Airbus Defence and Space. It includes development and in-orbit validation of the new satellite product lines for both companies, allowing the two European satellite prime integrators to deliver competitive satellites for the commercial satellite market.
This image, taken with the NASA/ESA Hubble Space Telescope shows the Serpens Nebula, a stellar nursery about 1300 light-years away. Within the nebula, in the upper right of the image, a shadow is created by the protoplanetary disc surrounding the star HBC 672. While the disc of debris is too tiny to be seen even by Hubble, its shadow is projected upon the cloud in which it was born. In this view, the feature — nicknamed the Bat Shadow — spans approximately 200 times the diameter of our own Solar System. A similar looking shadow phenomenon can be seen emanating from another young star, in the upper left of the image.
The Space Station's Expedition 57 crew in fancy dress for Halloween, posted by ESA astronaut and Station Commander Alexander Gerst on social media with the comment: "Having a scary day in space. The crew of the International @Space_Station wish you a happy #Halloween".
The European Service Module that will power and propel the Orion spacecraft on its first mission around the Moon is prepared for shipping from Bremen to the United States. The ESM took off in an Antonov An-124 aircraft in the early hours of 5 November and arrived at Kennedy Space Center in Florida, USA on 6 November.
ESA’s European service module will provide power, water, air and electricity to NASA’s Orion exploration spacecraft that will eventually fly beyond the Moon with astronauts. The European Service Module is now complete for Orion’s first mission that will do a lunar flyby without astronauts to demonstrate the spacecraft’s capabilities.
Week in images
29 October - 2 November 2018