When astronaut Chris Hadfield was asked last week what his favorite photo taken during the first three weeks of a stint on the International Space Station was, he answered simply.
"I love the beautiful pictures of the world," Hadfield said, "but for
me, the one that was most significant was looking at the noctilucent clouds.
These are clouds that you can barely see from the surface of the Earth.
They're the highest clouds that exist—tiny ice particles way up in
the mesosphere. And yet from orbit, as the sun rises, the light bounces
off of those clouds, directly into our eyes—and we can see a part of
the Earth's atmosphere that's basically invisible to people on the
surface. To me, that's both beautiful—because of the colors and
textures and ripples of it—but it's also really significant. It's a
way to understand the changes in our atmosphere, and a way to understand
exactly how our atmosphere interacts with the universe beyond."
What exactly did Hadfield mean by that last sentence, in which he says that the clouds can help us understand changes in our atmosphere and our relationship to the universe? I set off in search of the science behind noctilucent clouds for the answer.
Scientists previously thought that the
smooth, hairless surfaces of fingers and toes wrinkled up like raisins after
they got wet because water passed into the outermost layer of skin, causing it
to swell. But recent studies have shown that the wrinkling is not a result of osmosis, but rather an autonomic nervous system reaction: placing hands or feet in water causes a
constriction in blood vessels which reduces the pulp in digits. The loss of internal pressure causes ridges and valleys to form on glabrous skin. The question, of course, is why?
A new study published by three
scientists in the journal Biology Letters suggests the physical change may have
developed as a way to improve grip on wet objects. In other words, prune-like fingers and toes that form during long surfing and kayaking sessions may actually help you hold on to your board or paddle.
Last year was the hottest year on record for the contiguous United States since record-keeping began in 1895, according to a Tuesday announcement from the National Oceanic and Atmospheric Administration (NOAA). Here's a breakdown of the 2012 measurements, by the numbers.
55.3: Average temperature, in degrees Fahrenheit, for 2012. The record is 3.2 degrees higher than the 20th-century average and a full degree higher than the previous record, which was set in 1998. NOAA
26.57: Annual precipitation, in inches, for 2012. The number is 2.57 below the average, making 2012 the 15th driest year on record. NOAA
11: Number of disasters that reached the $1 billion threshold in losses. The events are believed to have caused 349 deaths. The U.S. Climate Extremes Index indicated that 2012 was the second most extreme year on record for the nation. NOAA
On Wednesday January 2, 42-year-old Irish adventurer Ian McKeever was leading a group of more than 20 people through the lunar landscape section of Mount Kilimanjaro when he was struck by lightning and killed instantly. The Telegraph reported that fellow climber Jack O'Donahue, 60, was hiking just three feet away from McKeever when the bolt knocked him off his feet. Donahue survived. At least six other people on the expedition were treated for injuries, including McKeever's fiance, whom he planned to wed in September 2013.
The Irish Times reported that friends were surprised that McKeever would die from a lightning strike on Kilimanjaro, as he had climbed much more difficult and dangerous terrain. In 2007, he set the speed record for climbing the seven summits, achieving the feat in 156 days. (Vern Tejas now holds the record—he climbed all of the peaks in 136 days.) "I am absolutely shocked to hear about the death of my friend Ian. It was a freak accident and a complete fluke," Irish explorer Pat Falvey told the Independent. "I have lost two friends in lightning strikes, including one on the Himalayas—but they are very rare on Kilimanjaro."
Incidence of lightning strikes (click on image for full size). Photo: NOAA
Death caused by a lightning strike is an incredibly rare event, but there are some areas in the world where it occurs at a higher rate than others. Central Africa has a greater incidence of lightning strikes than any other large region. (See the large black area in the map above, which is to the west of Kilimanjaro.) Moist airflow from the Atlantic Ocean couples with mountainous terrain and leads to year-round thunderstorms in a location where much of the population is rural, few advanced warning systems exist, medical facilities are often sub-standard, and most buildings are rudimentary. Though there is no definitive overall set of statistics for the region, there is not a shortage of reported strikes. In 2011, 18 children and a teacher were killed in a primary school in Uganda when it was hit by lightning.
FalconGuides just announced the first 12
titles in a new line of interactive outdoor guides the company developed in
partnership with Inkling, a platform for interactive learning.
For the price of the download, readers get
expert content optimized for iPhone, iPad, and Web, with features that bridge
the gap between apps and ebooks: slideshows with high-res images not found in
the print editions, guided visual tours, hyperlinks, and smart search that makes
it quick and easy to get to the information you need, from a list of dog-friendly
hikes to a river name. Hiking guide
users can give tips to other readers and share trail notes on washed out bridges, best photo ops, bees nests to watch out for, or anything else. An animal tracks feature lets you click through a series of questions that narrows down which animal tracks you’ve spotted based on pattern, shape, and size. Rock climbing instructional guides have stop-motion animation
illustrating specific techniques.