Oliver Wendell Holmes famously once wrote, "A mind that is stretched by a new experience can never go back to its old dimensions." My mind, and assuredly those of countless others, never did after pondering some of the key concepts of the mathematician Benoit Mandelbrot, who died last week at the age of 85.

Mandelbrot invented the term fractal to describe the "roughness" he saw all around him in nature -- the jagged shape of a cloud, the rugged indentations of a coastline. Classical Euclidean mathematics, the kind we learn in school, serves well for the human-made world of straight lines, circles, and squares. But nature's non-linear shapes were generally considered unmeasurable -- until Mandelbrot developed fractal geometry.

"In the whole of science, the whole of mathematics, smoothness was everything," Mandelbrot says in "Hunting the Hidden Dimension." "What I did was open up roughness for investigation."

Suddenly, something as ragged as a coastline could come under mathematical scrutiny. While he couldn't actually measure a coastline, Mandelbrot found, he could measure its roughness. It required rethinking one of the basic concepts in math -- dimension.

The other day I had the honor of speaking with Buzz Aldrin, the first man on the moon along with Neil Armstrong.

I was interviewing Aldrin for an article I'm writing for the NOVA website on whether we should consider a one-way manned mission to Mars -- one in which pioneer astronauts remained on the Red Planet to launch a colony that would later grow into permanent settlement. (Initial shock aside, most experts agree we could do a manned mission a lot sooner and a lot cheaper if it wasn't round-trip.)

With the 50th anniversary of President Kennedy's famous go-to-the-moon speech approaching in 2012, I asked Aldrin if he thought we should, to paraphrase Kennedy, go to Mars in this decade.


"No, it's probably going to take three decades," Aldrin said, and went on to outline his proposal for securing a lasting human presence on Mars.

My son Nick is autistic. My wife and I first began noticing something was off when Nick was 18 months old, but our pediatrician said not to worry, he's just developing slowly, let's see where he is in six months. When the pediatrician repeated that wait-and-see advice six months later, we ignored it and got Nick diagnosed at Children's Hospital Boston (and got another pediatrician).

Nick is now 13 and lives full-time in a residential facility dedicated to kids with autism -- his challenges are that severe. To this day, we wonder how much further along Nick would be today if it had been as clear to his doctor as it was to us that something was seriously wrong, and we had gotten him diagnosed at 18 months rather than at two and a half. With autism, the earlier the intervention, the greater the chances for lessening the often devastating impact of this little-understood disorder.

Now, as scientists report in a new study published online in the Proceedings of the National Academy of Sciences on July 19, a new technology that analyzes vocalizations in very young children offers hope of early screening of kids like Nick for autism, as well as for typical children who suffer from a language delay.

Even before Tenzing Norgay summited Mt. Everest with Edmund Hillary in 1953, it was widely known that his people, the Sherpas, had something that the rest of us did not.

On May 22 of this year, Apa Sherpa made a record 20th ascent of Mt. Everest, further driving home the obvious -- that these eastern Nepalese of Tibetan stock are superbly adapted to their lofty Himayalan home, which has about 40 percent less oxygen in its air than we lowlanders enjoy at sea level.

Sherpa climbing near Mt. Everest. Image © Bartosz Hadyniak/iStockphoto

Now scientists have found evidence that, over the thousands of years that Tibetans have lived on the Tibetan Plateau, natural selection has been working on their genes, causing evolutionary changes that enable Tibetan peoples not only to survive but to thrive at altitudes of 13,000 feet or more.

Three independent studies published in recent weeks have identified strong positive selection among Tibetans in genes that are involved in dealing with hypoxia, a deficiency of oxygen reaching the body's tissues.

One study, led by Xin Yi of the Beijing Genomics Institute in China, compared the genomes of 50 Tibetans living at 14,000 feet with those of 40 Han Chinese living in Beijing (altitude <200 feet). The team discovered about 30 genes that differ significantly between the two groups, even though the two groups split only 3,000 years ago, the team says. (As Nicholas Wade reports in a Times article, other experts dispute that figure, arguing that the split occurred thousands of years earlier.)

What do these groups of animals -- parrots, hummingbirds, songbirds, bats, elephants, cetaceans (whales and dolphins), and possibly some lions -- have in common with us humans? Hint: think what parrots are famously good at.

Right, parroting. These seven animal groups - and no others known so far -- can imitate sounds they've heard. Other creatures may understand the meaning of sounds, but they can't mimic them. A dog knows what "sit" means but can't, well, parrot that sound. A chimp can ape, but not vocally. All they can do is produce sounds they were born with.

Why? The reason, as Erich Jarvis of Duke University and other neurobiologists have found in birds and humans, have evolved a special neural connection that makes this possible. It's a direct link from the forebrain to motor neurons in the brainstem that are responsible for vocalization. It's this link that enables our speech.


Jarvis and colleagues are just beginning to uncover the physical basis of that neural hook-up -- one of many recent advances that are forcing a radical revision in how we think about animal smarts.


Erich Jarvis © NOVA/WGBH Educational Foundation

Today marks the one-year anniversary of the loss of Air France Flight 447 over the Atlantic Ocean, and investigators are no closer to resolving the mystery of why the plane crashed. The flight, from Rio de Janeiro to Paris, disappeared on June 1, 2009 after entering a zone of severe thunderstorms, killing all 228 people on board.

Last week, the French Bureau of Accident Inquiry, known by its French acronym BEA, called off its third attempt to locate the plane's flight recorders. (Soon after the accident, searchers did recover 50 bodies as well as scattered pieces of the plane, including part of the tail section seen here.) The BEA, which has issued two draft reports about the accident but has drawn no conclusions as to the cause, has not said whether it will conduct a fourth search.

What little is known comes from automated messages that the plane sent to Air France just before the plane vanished. The so-called pitot tubes, external ports that measure airspeed, apparently failed by becoming clogged with ice or water. The aircraft's autopilot, which needs to know the airspeed to function properly, switched off. The plane may then have gone into a stall, from which the pilots were unable to recover.

With the 20th anniversary of the launching of the Hubble Space Telescope coming up this Saturday, April 24th, we thought it was worth noting, for all those Hubble enthusiasts out there, the various Hubble-related programs and web features we've created in recent years.


Hubble image of the Eagle Nebula, aka the Pillars of Creation, Courtesy Jeff Hester

Last August, we aired a segment on NOVA scienceNOW about the repair mission of May 2009. This fix, the final one Hubble will get, followed on four others -- in 12/93, 2/97, 12/99, and 2/02, respectively. We found the story of the 2009 repair such rich drama that we aired a full one-hour NOVA on it, Hubble's Amazing Rescue, in October.

The director of both programs, Rush DeNooyer, wrote a series of behind-the-scenes blog posts about the 2009 repair. He began on launch day, May 11, and last posted on September 9, when the first images from the new, improved Hubble came through. (They were stunning.) Watch for a new blog post from Rush this Saturday, on the anniversary.

Its name doesn't exactly roll off the tongue: ununseptium (oon-oon-SEP-tee-um). But like many things in science, what it loses in pizzazz it gains in accuracy. In Latin, ununseptium means "117," and it refers in this case to a new element scientists have just added to the Periodic Table.

I was in touch yesterday with Ken Moody, one of the scientists involved in the find. Ken is a research chemist at Lawrence Livermore National Laboratory; his collaborators on this project come from two U.S. universities, the Oak Ridge National Laboratory, and the Joint Institute for Nuclear Research in Dubna, Russia. Altogether Ken has helped uncover six new chemical elements, numbers 113 through 118.

I asked Ken, whose group's discovery of element 114 (ununquadium) we chronicled in a 2006 NOVA scienceNOW video segment, what it felt like when he and his team "saw" that first atom of 117. He said they weren't sure at first and so remained cautious.

"Sorry, no shouts of 'Eureka!', no joyous dancing in the halls, and no victorious toasting," Ken told me in an email. But a few weeks later the team detected a second tell-tale occurrence. "It was consistent with the previous event in most particulars," Ken wrote, "and while random events can always bite you when you have only one of something, if you have two and they look alike, the assignment is pretty definite." In the end, the team detected six atoms of the stuff, enough to secure ununseptium a place on the Periodic Table.