If you gazed at the night sky over the past few weeks, it is possible that you stumbled upon a very bright star near the Orion constellation. This is Sirius, the brightest star of the entire night sky, which is visible from almost everywhere on Earth except the northernmost regions. It is, in fact, a binary stellar system, and one of the nearest to our Sun – only eight light-years away.
Known since antiquity, this star played a key role for the keeping of time and agriculture in Ancient Egypt, as its return to the sky was linked to the annual flooding of the Nile. In Ancient Greek mythology, it represented the eye of the Canis Major constellation, the Great Dog that diligently follows Orion, the Hunter.
Dazzling stars like Sirius are both a blessing and a curse for astronomers. Their bright appearance provides plenty of light to study their properties, but also outshines other celestial sources that happen to lie in the same patch of sky.
This is why Sirius has been masked in this picture taken by amateur astronomer Harald Kaiser on 10 January from Karlsruhe, a city in the southwest of Germany.
Gaia 1 is an open cluster – a family of stars all born at the same time and held together by gravity – and it is located some 15 000 light-years away. Its chance alignment next to nearby, bright Sirius kept it hidden to generations of astronomers that have been sweeping the heavens with their telescopes over the past four centuries. But not to the inquisitive eye of Gaia, which has been charting more than a billion stars in our Milky Way galaxy.
Mr Kaiser heard about the discovery of this cluster during a public talk on the Gaia mission and zealously waited for a clear sky to try and image it using his 30 cm-diameter telescope. After covering Sirius on the telescope sensor – creating the dark circle on the image – he succeeded at recording some of the brightest stars of the Gaia 1 cluster.
Gaia 1 is one of two previously unknown star clusters that have been discovered by counting stars from the first set of Gaia data, which was released in September 2016. Astronomers are now looking forward to Gaia’s second data release, planned for 25 April, which will provide vast possibilities for new, exciting discoveries.
More information about opportunities for amateur astronomers to follow up on Gaia observations here.
This NASA/ESA Hubble Space Telescope image shows a spiral galaxy known as NGC 7331. First spotted by the prolific galaxy hunter William Herschel in 1784, NGC 7331 is located about 45 million light-years away in the constellation of Pegasus (The Winged Horse). Facing us partially edge-on, the galaxy showcases it’s beautiful arms which swirl like a whirlpool around its bright central region.
Astronomers took this image using Hubble’s Wide Field Camera 3 (WFC3), as they were observing an extraordinary exploding star — a supernova — which can still be faintly seen as a tiny red dot near the galaxy’s central yellow core. Named SN2014C, it rapidly evolved from a supernova containing very little Hydrogen to one that is Hydrogen-rich — in just one year. This rarely observed metamorphosis was luminous at high energies and provides unique insight into the poorly understood final phases of massive stars.
NGC 7331 is similar in size, shape, and mass to the Milky Way. It also has a comparable star formation rate, hosts a similar number of stars, has a central supermassive black hole and comparable spiral arms. The primary difference between our galaxies is that NGC 7331 is an unbarred spiral galaxy — it lacks a “bar” of stars, gas and dust cutting through its nucleus, as we see in the Milky Way. Its central bulge also displays a quirky and unusual rotation pattern, spinning in the opposite direction to the galactic disc itself.
By studying similar galaxies we hold a scientific mirror up to our own, allowing us to build a better understanding of our galactic environment which we cannot always observe, and of galactic behaviour and evolution as a whole.
The year: 2007. The place: Cape Canaveral. The Columbus module, built in Italy and shipped from Germany, is undergoing tests at NASA’s Kennedy Space Center in Florida.
This unique interior view features some of the hardware that makes Columbus a world-class laboratory. Resembling airline galley storage units, the ‘racks’ are highly compact facilities for research in various scientific disciplines.
Each rack is the size of a telephone booth and can host autonomous and independent laboratories, complete with power and cooling systems. Video and data links send results back to researchers on Earth.
From left to right are the European Drawer Rack, a flexible experiment carrier; the European Physiology Modules for experiments focusing on the human body; Biolab for life sciences experiments; and the Fluid Science Lab for studying fluids in microgravity.
The four are seen here in their launch configuration. The racks were later relocated inside Columbus once in orbit.
Thanks to these and other facilities in Columbus, researchers have been able to conduct multidisciplinary research in microgravity over the past decade.
From studying immune cells to understand how they function to developing technology that finds its way to Earth, Columbus and its suite of research equipment have hosted more than 225 experiments and generated countless scientific papers.
On 7 February, ESA is celebrating 10 years of Europe’s gateway to space research at our technical heart in the Netherlands. The event is a unique opportunity to re-live some exciting milestones, connect live to the Station and look into space exploration plans.
The larger Columbus family of planners, builders, scientists, support teams and astronauts will gather to celebrate the past, present and future of Europe’s major contributions to the Station.
Just as the Sun drives weather on Earth, solar activity is responsible for disturbances in our space environment, which scientists have dubbed ‘space weather’.
This gives rise to auroras, which are produced by electrically charged atomic particles streaming from the Sun colliding with charged particles in our atmosphere.
UK-based photographer Ollie Taylor is in Iceland this week, and he captured a beautiful landscape image combining a lake, a waterfall, a rainbow and a green auroral streak, all bathed in moonlight.
He notes: “I hunted for a clear sky patch in Iceland eager to shoot a ‘moon bow’. We drove some 600 km north to get the clear skies in the Lake Mývatn area, and the Godafoss Waterfall. I had to keep changing the angle to be able to see the lunar rainbow.
“Eventually, after hours of shooting, you could see full colour in the rainbow, luckily at an angle that also allowed the capture of the aurora when it gave us a display!”
Numerous areas of Europe’s economy can be affected by space weather. These range from space-based telecommunications, broadcasting, weather services and navigation, through to power distribution and terrestrial communications, especially at northern latitudes.
One significant influence of solar activity is seen in disturbances in satellite navigation services, like Galileo, due to space weather effects on the upper atmosphere. This in turn can affect aviation, road transport, shipping and any activities that depend on precise positioning.
On Earth, commercial airlines may also experience damage to aircraft electronics and increased radiation doses to crews (at long-haul aircraft altitudes) during large space weather events. Space weather effects on the ground can include damage and disruption to power distribution networks, increased pipeline corrosion and degradation of radio communications.
See more of Ollie Taylor's photos via
This Copernicus Sentinel-2 image features Tunisia’s capital Tunis, in North Africa, and highlights some of the country’s important wetlands.
Captured on 15 December 2017, the image shows part of the Mediterranean’s Gulf of Tunis, which provides natural protection for this ancient city and busy port. The area has seen a series of settlements over the last 3000 years, but arguably the most famous is Carthage, which now forms a suburb to the northeast of the centre of Tunis.
While the image offers sharp contrast between the city’s urban environment and surrounding hills and agricultural fields, it also depicts several bodies of water, which are protected under the Ramsar Convention on Wetlands.
World Wetlands Day is celebrated every year on 2 February, and with this year’s theme being Wetlands for a Sustainable Urban Future, this image of Tunis highlights how important these wetlands are to the city.
There are seven Ramsar sites around Tunis, five of which are visible in the image. Lake Tunis can be seen close to the coast and features a causeway. It is a brackish lagoon surrounded by intertidal marshes. It offers good nesting grounds for several species of bird and wintering grounds for species such as the Greater Flamingo. Mammals include rodents and bats, and it is an important source of food, a spawning ground and a nursery for several fish species. The main human activity carried out is fishing, regulated according to its protected status.
The shallow lake of Sebkhet Sejoumi is west of Lake Tunis and is one of the largest water reservoirs protecting the capital from floods. Unlike other sebkhets – or salt lakes – in the area, Sejoumi retains some water all year and is therefore particularly important for wildlife in the summer when other sebkhets dry up.
The smaller protected lakes of Ghdir El Golla and Barrage Mornaguia can be seen further west on the outskirts of the city. To the north of the city, lies Sebkhet Ariana which loses much of its water in the summer.
Through its GlobWetland Africa project, ESA works in partnership with the Ramsar Secretariat to use information from satellites to help conserve and manage vulnerable wetlands such as these.
This image is featured on the Earth from Space video programme.
The Copernicus Sentinel-3B satellite at Thales Alenia Space’s premises in Cannes, France. Carrying a suite of cutting-edge instruments, the Sentinel-3 satellites have been designed to measure Earth’s oceans, land, ice and atmosphere to monitor and understand large-scale global dynamics. The mission also provides essential information in near-real time for ocean and weather forecasting.
Week In Images
29 January - 2 February 2018