Sometimes, regions of planet Earth light up with fire. Since fire is the rapid acquisition of oxygen, and since oxygen is a key indicator of life, fire on any planet would be an indicator of life on that planet. Most of the Earth’s land has been scorched by fire at some time in the past. Although causing many a tragedy, for many places on Earth fire is considered part of a natural ecosystem cycle. Large forest fires on Earth are usually caused by lightning and can be visible from orbit. Above, in the year 2000, stunned elk avoid a fire sweeping through Montana's Bitterroot Valley by standing in a river.
Freshwater species survived the comet that killed the dinosaurs
The ability to adapt to a variety of environmental differences likely helped freshwater organisms ride out the destruction.
'Walking shark' discovered in Indonesia
A species of shark that uses its fins to “walk” along the bottom of the ocean floor has been discovered off the coast of Indonesia. The shark, Hemiscyllium halmahera, uses its fins to wiggle along the seabed and forage for small fish and crustaceans, scientists from Conservation International said on Friday.
The shark, which has wide horizontal stripes, grows to a maximum length of just 30in and is harmless to humans.
It was found off the remote eastern island of Halmahera, one of the Maluku islands.
The conservation group said it hoped the discovery would once again demonstrate that most sharks pose no threat to humans.
The find also highlights the extraordinary marine diversity in Indonesia whose chain of islands is home to at least 218 species of sharks and rays, and the country’s recent efforts to protect species under threat of extinction, Conservation International said.
Levitation is not only the domain of swamis and wizards. Science, too, can make objects float, like the electrical fields that levitate frogs or the magnets responsible for the epic phenomoenon known as quantum locking.
Sound, too, can be used to suspend objects in space, via acoustic levitation. We’ve seen this before, in this video, but now it’s been taken to the next level.
Acoustic levitation works because high frequency sound waves will interfere and form standing waves. Small objects can then be suspended at the “nodes” of those waves. Dimos Poulikakos has developed a way to guide those nodes toward each other, letting them initiate floating chemistry without a single human touch.
Here we see the violent reaction between sodium metal and water, captured in levitating glory.
Glide through part of the largest canyon on Mars, Valles Marineris, in this stunning colour movie from ESA’s Mars Express. Valles Marineris is not just the largest canyon on Mars, but at 4000 km long, 200 km wide and 10 km deep it is the largest in the entire Solar System.
The movie focuses on an enclosed 8 km-deep trough in the northern most part of Valles Marineris, called Hebes Chasma. The movie glides over impact craters pockmarking the plains separating the troughs, down cliff faces scarred by landslides, and along the rough valley floor.
In some parts of the valley Mars Express has detected water-bearing minerals, suggesting that significant quantities of water may have once flowed here.
The formation of Hebes Chasma is likely connected to the nearby volcanic Tharsis region, home to the planet’s vast Olympus Mons volcano.
During periods of intense volcanism the whole region stretched upwards, causing tremendous stress in the crust further way. Unable to withstand the strain, the crust ripped open, collapsing into the chasms found in and around Valles Marineris.
Image credit: ESA/DLR/FU Berlin (G. Neukum)