Plus: Meteorites’ Role in Life on Earth, the Cheetah-Bot, Blown-up Rivers and Rocks Melted with Light.

Canadians Dynamite their Rivers
Each winter, explosives experts lay down dynamite across the Rideau River in Ottawa, Canada and set it off in a startling display of hydro-violence. This activity isn’t fueled by anger, but is actually a traditional feat of engineering inventiveness.

Without this explosive intervention, the Rideau River runs a high risk of flooding at the end of winter when water becomes backed up behind trapped ice and threatens to spill over the banks. To prevent this from happening, engineers use buzz saws and amphibious ice breakers to cut channels through the frozen portions of the river, drill holes in the ice, pack the holes with explosives and detonate the charges to blow apart sheets of ice.

“The process costs the city $460,000 a year, mitigating the risk of water damaging hundreds of nearby buildings,” Canada’s Globe and Mail reports. “With a mix of delicate prep work, a tractor-boat hybrid called an Amphibex that helps smash and dash the ice — as well as teeming eruptions — the team works to stop blocks from forming a frozen, impenetrable wall at the foot of the electrical dam that towers above the falls.”

This method of clearing ice jams has been used in Ottawa since the 1880s, and today attracts crowds that consider the explosions a sign of spring’s approach. However, there is a downside to using dynamite to clear out river ice, and the explosive approach to the problem may not be around for much longer.

“The river does remain open in fast moving reaches, so the fish stay in the deep pools and the water remains oxygenated by exchange with the atmosphere in rapids,” Bruce Reid, of the Rideau Valley Conservation Authority, which works on ice clearance, told BBC News. “Harm to them during ice removal has been a concern, hence the increasing use of an amphibious excavator instead of explosives.”

Building a Replacement for Hubble
The Hubble Space Telescope has had a long and storied history of obtaining astronomical images and data. But after operating for more than 20 years, it will soon be due for retirement. While it may signal the end of an era, Hubble’s replacement is designed to exceed the accomplishments of its predecessor.

When NASA’s James Webb Space Telescope is launched to replace the Hubble Telescope in 2014, it will feature 18 hexagonal reflectors, more than any other space telescope in the past, which will combine to form an enormous mirror seven times larger than that of Hubble. This reflector array will allow it to collect more light and observe more distant objects in the universe.

The new space telescope’s mission goals include finding the earliest galaxies or luminous objects formed after the Big Bang, gathering data on star and planetary system formation, determining how galaxies evolved from their early stages and measuring the physical and chemical properties of planetary systems to investigate the potential for life outside Earth.

“It may look more like a perplexing work of avant-garde sculpture than it does a telescope, but make no mistake about it — the golden snowflake on a surfboard that is the James Webb Space Telescope will be the premier eye in the sky of the next decade,” Discover Magazine explains. “With the assistance of the Webb, astronomers hope to take a giant leap forward in understanding the origins of the cosmos.”

id="451" class="mt-enclosure mt-enclosure-image" style="display: inline;" rel="lightbox[16155]" title="Light Friday: Building a Replacement for Hubble">

Click image for larger view
Image Credit: NASA

Meteorites May Have Brought Life to Earth
Exploring the cosmos may be more important than ever before, as new evidence suggests that life on Earth could have been kick-started by ingredients brought from outer space. A meteorite discovered in Antarctica was found to contain an abundance of ammonia and nitrogen, key components of the basic building-blocks of life.

“Asteroids and comets have long been suspected of helping nudge Earth toward life. The interplanetary interlopers have struck Earth since the beginning, delivering carbon, water, and sometimes organic compounds such as amino acids,” Scientific American explains. “By providing key chemicals or even pre-formed biological building blocks, as well as the heat and energy generated by a meteorite impact, space rocks may have played an important role in getting the biological ball rolling.”

A team of researchers from Arizona State University subjected the Antarctic meteorite, known as Graves Nunataks (GRA) 95229, to high pressure and temperatures of 300 degrees Celsius, simulating conditions on its parent asteroid. The tests yielded ammonia, an important source of nitrogen, which is a key ingredient in DNA and amino acids. According to the team’s findings, recently published in the Proceedings of the National Academy of Sciences, these meteorite chemicals are important because “their delivery to the early Earth could have fostered prebiotic molecular evolution.”

Although meteorites broken off from asteroids may have delivered crucial elements that spurred the development of life, scientists are unclear on the specifics of this process. Some hypotheses contend that the materials may have interacted with volcanic environments or tidal pools to generate more complex molecular compounds.

“You find these extraterrestrial materials (in meteorites) which have what you need, but on the how and when, in which environments and by what means – really, we don’t know,” Professor Sandra Pizzarello, head of the Arizona State research team, told BBC News. “You can only say that yes, it seems that the extraterrestrial environments could have had the good stuff.”

Cheetah-Bot Designed to Hunt
Boston Dynamics’ earlier inventions include an eerily lifelike running robot and a “robotic packhorse,” so it’s little surprise that the U.S. military has now commissioned the robotics company to develop an animal-like robot capable of chasing down a human being.

As its name suggests, the Cheetah robot will be a four-legged machine with a flexible spine, an articulated head and the ability to outrun the fastest human. Apart from moving at high speeds, the robot’s developers also intend the Cheetah to be agile, allowing it to make tight turns while chasing and evading targets, as well as being capable of stopping on a dime.

“There’s no fundamental reason why it can’t go as fast as the animals (60 to 70 mph), but it will take a while to get there,” Marc Raibert, lead investigator of the Cheetah program and Boston Dynamics’ president, told the Boston Herald. The developers’ initial goal is to produce a prototype that can reach speeds up to 30 mph within the next 20 months.

The new robot was commissioned by the U.S. military’s Defense Advanced Research Projects Agency’s (DARPA) Maximum Mobility and Manipulation program. In addition to the Cheetah, DARPA has also ordered development on a humanoid robot known as Atlas, which might be even more frightening.

“Atlas is supposed to look more or less like the T-800 series of Terminators, minus the head. Its designers say it’ll be able to walk like a human over rough terrain, crawling on its hands and knees when necessary and turning itself sideways to slip through any narrow passages it encounters,” Wired.com’s Danger Room blog explains. “Headless, with a torso and two arms, it’s a step up from Boston Dynamics’ other biped, the lower-body-bot Petman.”

Melting a Rock with Sunshine
Never underestimate the power of sunshine. In an episode of the British science TV series Bang Goes the Theory, Jem Stansfield traveled to the Solar Furnace Research Facility in Southern France and experienced the incredible heat generated by sunlight focused between specialized mirrors. This enormous magnifying glass is capable of melting steel, rock — you name it.

Have a great weekend, folks.