Colourful Mars, weightwatching meerkats and an ice-scoured Caspian Sea
Our top five science-related pictures of the week.
Mars shows its true colours
The Nili Fossae region, located on the northwest rim of Isidis impact basin, is one of the most colourful regions of Mars.
The region is ancient and has had a complicated geologic history, leading to interesting structures like layered bedrock, as well as other compositions.
Elsewhere on Mars, the colour tends to be the uniform red we think of in relation to the planet, because the surface is covered with a layer of dust, soil, broken rock, and other similar materials. But in the Nili Fossae the bedrock is exposed, except where there are sand dunes.
That allows the colour of rocks with diverse compositions to shine through in HiRISE infrared-red-blue colour images such as the one above taken by NASA's Mars Reconnaissance Orbiter.
Size matters to a meerkat
Meerkats watch each others' weight to make sure they are not left behind, a study by Cambridge University zoologists has shown.
In the meerkat world, only the biggest animals have offspring and so it is important to be among the weightiest. That makes the animals highly competitive. While studying wild meerkats in the Kalahari Desert, the researchers fed the animals boiled eggs to build up their body mass and they found that other meerkats grew faster in response.
“Size really does matter,” co-author Tim Clutton-Brock told reporters. “It is important to stay on top.”
Caspian Sea ice sculpture
An apparently abstract piece of art is, in fact, a natural-colour image of the Caspian Sea around the Tyuleniy Archipelago taken by the Operational Land Imager (OLI) on NASA's Landsat 8 satellite. Shallow waters surrounding the Tyuleniy Archipelago allow you to see the dark green vegetation on the sea bottom.
Ocean scientist Norman Kuring of NASA’s Goddard Space Flight Center was puzzled by the lines crisscrossing the bottom and what could possibly have caused them.
At first, he thought the marks may a human origin – maybe due to trawling by fishermen. But further study of the scientific literature and an earlier satellite image from January suggested to Kuring that a majority of the marks were gouged by ice.
In January, blocks of ice stand at the leading end of many lines, most notably in the northeast corner of the image. By April, ice has melted and only the scour marks persist.
Ice that forms here in wintertime is usually about 0.5 metres thick, so most of it never touches the seafloor. But the ice tends to be “warm” and thin, which gives rise to relatively weak ice cover that is easily deformed by wind and currents. When pieces of ice are pushed together, some ice is forced upward and downward into so-called “hummocks”. The keels of hummocks, frozen into the ice fields, can reach the seafloor and scour the bed as the ice moves.
Cruising an undersea forest
Today, 27 May, is the last day for entries in the 2016 National Geographic Travel Photographer of the Year contest. And to whet our appetites Nat Geo released some of the images, including this other-worldly shot of a seven-gill shark gliding through a kelp forest just off the shore of Simonstown near Cape Town.
The grand-prize award winner will earn the prestigious title and also receive a seven-day Polar Bear Photo Safari for two at Churchill Wild–Seal River Heritage Lodge, a National Geographic Unique Lodge of the World.
Eligible contestants can visit natgeo.com/travelphotocontest to submit photographs in any or all of three categories: Nature, People and Cities.
You can see some more preview pictures here.
Latest Galileo satellite launch into orbit
Europe took another step towards creating its own navigation satellite constellation with the launch of the 13th and 14th Galileo satellites at 08:48 UTC on 24 May. The satellites were launched from Europe’s Spaceport in French Guiana on top of a Soyuz rocket.
The first three stages took the Galileo satellites and their Fregat upper stage into low orbit in just less than nine minutes.
Then the re-ignitable Fregat will undergo two burns to lift the satellites for release in opposite directions at their target 22,522 kilometres-altitude orbit, three hours and 48 minutes after launch.