Lasers, a Martian vista and penguins

Four lasers over Paranal

This week the world's most powerful laser guide star system saw first light.

This spectacular image shows four powerful beams emerging from the new laser guidance system at the European Southern Observatory's Paranal facility in Chile. The system is a crucial component of the optics systems on ESO’s Very Large Telescope.

The Four Laser Guide Star Facility (4LGSF) shines four 22-watt laser beams into the sky, making sodium atoms in the upper atmosphere glow so they look just like real stars. These artificial guide stars are used by the adaptive optics systems to compensate for the blurring caused by the Earth’s atmosphere so the telescope can create sharp images.

Using more than one laser allows the turbulence in the atmosphere to be mapped in greater detail to significantly improve the image quality over a larger field of view.

Full-circle panorama from Mars' Naukluft Plateau

NASA's Curiosity Mars rover has nearly finished crossing a stretch of the most rugged and difficult-to-navigate terrain encountered during the mission's 44 months on Mars.

In doing so, it reached its highest vantage point since its August 2012 landing on the floor of Gale Crater. The rover's Mastcam recorded and combined dozens of images to form a 360-degree panorama of the so-called Naukluft Plateau that includes upper Mount Sharp (right) and part of the rim of Gale Crater.

The plateau's sandstone bedrock has been carved by eons of wind erosion into ridges and knobs and in this image, the foreground and middle distance show a geologic scene dominated by eroded remnants of a finely layered ancient sandstone deposit.

The sandstone within the Naukluft Plateau appears to be dominated by thick layers of windblown sand, suggesting that these deposits formed in a drier era.

The scene released by NASA this week is colour-adjusted to resemble how the rocks and sand would appear under daytime lighting conditions on Earth.

30 years since Chernobyl nuclear disaster

This week marked the 30th anniversary of the Chernobyl nuclear disaster. This photograph was taken this week inside the inner exclusion zone and shows dodgem cars from an abandoned amusement park in the deserted city of Pripyat, Ukraine.

Pripyat lies only a few kilometres from the former Chernobyl nuclear power plant and was built in the 1970s to house the plant's workers and their families. On 26 April 1986, the fourth reactor of the Chernobyl nuclear power plant exploded sending plumes of highly radioactive particles and debris into the atmosphere.

Authorities evacuated 120,000 people from the area, including 43,000 from Pripyat. Today Pripyat is a ghost town, its apartment buildings, shops, restaurants, hospital, schools, cultural centre and sports facilities derelict and its streets overgrown with trees. The city lies in the inner exclusion zone around Chernobyl where hot spots of persistently high levels of radiation make the area uninhabitable for thousands of years to come.

Celebrating world penguin day

This week aquariums and zoos around the world celebrated World Penguin Day to raise awareness to help the future of these beloved species.

This image shows the family bonds between Adelie penguin parents and their chick. It was captured by British wildlife photographer Steve Bloom in Antarctica.

Currently, all 18 of the world’s penguin species are legally protected from hunting and egg collection, but they continue to face threats including the effects of climate change.

World Penguin Day marks the annual northward migration of Adelie penguins who start migrating around 25 April every year to escape the long, dark days of winter in the Antarctic.

Sentinel-1B’s first image

Sentinel-1B – the European Space Agency's mission of land and ocean monitoring for both environmental and humanitarian purposes – launched on 25 April from Europe’s Spaceport in French Guiana.

The first observations were taken on 28 April after Sentinel-1B followed a complicated routine to deploy its 12-metre-long radar and two 10-metre solar wings, as well as passing a series of initial checks.

The first image which shows a 250-kilometre-wide view of the Norwegian Svalbard archipelago, in the Arctic Ocean, with the Austfonna glacier clearly visible.

In the coming months, the satellite will be tested and calibrated before it is declared operational.

When Sentinel-1B reaches its final orbit, it joins its twin Sentinel-1A on the other side of Earth to provide more radar vision for Europe’s environmental Copernicus program.

Each satellite carries an advanced radar that images Earth’s surface through cloud and rain, day and night.