Following the stars

The U.S. Naval Academy in Annapolis, Md., is once again teaching midshipmen the ancient art of celestial navigation, almost 20 years after scuttling the subject.

The constellation of Global Positioning System (GPS) satellites we’ve come to rely on to navigate our cars was originally launched in the early 1990s to support military operations. But satellites and GPS are vulnerable to cyberattacks. Sextants, nautical charts, and chronometers are not.

“We went away from celestial navigation because computers are great,” Lt. Cmdr. Ryan Rogers, deputy chairman of the Naval Academy’s department of seamanship and navigation, told the Capital Gazette. “The problem is there’s no backup.”

Although difficult to do and far less precise than GPS, navigating by the sun and stars can still provide position accuracy to within 1.5 miles, which might be good enough if the high-tech system has been knocked out.

“Knowledge of celestial navigation in the GPS era provides a solid backup form of navigation in the event GPS becomes unreliable for whatever reason,” said Capt. Timothy Tisch, an instructor at the U.S. Merchant Marine Academy, which never stopped teaching celestial navigation. “It is also good professional practice to use one navigational system to verify the accuracy of another.”

The Naval Academy is offering a three-hour introductory course this year, and the class of 2017 will be the first to graduate with the reinstated instruction, according to the Capital Gazette.

Crystal clear-eyed

It’s likely many of you reading this page right now are using reading glasses. Wouldn’t it be nice if a simple operation could restore your near vision? Some promising new research may lead to reading glasses becoming obsolete.

Devesh Mistry, a doctoral student at the University of Leeds, is developing an implantable eye lens made of liquid crystal—the same material found in LCD screens—that may be able to cure presbyopia, a condition common in people over 45 in which eye lenses lose flexibility.

“As we get older, the lens in our eye stiffens, [and] when the muscles in the eye contract they can no longer shape the lens to bring close objects into focus,” said Mistry, a graduate student at the university’s School of Physics and Astronomy. “Using liquid crystals, which we probably know better as the material used in the screens of TVs and smartphones, lenses would adjust and focus automatically, depending on the eye muscles’ movement.”

Surgeons could implant future liquid crystal artificial lenses in a simple procedure not unlike common cataract surgery. A small incision is made in the cornea, and ultrasound is used to break down the old lens. The liquid crystal lens would then be inserted to replace the diseased lens.

The first commercial liquid crystal lenses could be available in six to 10 years, according to the University of Leeds. —M.C.

Weed terminator

Weeding by hand is tedious, and herbicides are bad for the environment. But a new, autonomous farm robot may be able to eliminate both.

BoniRob, developed by Bosch’s Deepfield Robotics, uses artificial intelligence to learn the difference between good and bad plants, according to a recent report in Popular Science. The robot’s weeding mechanism, called a “ramming death rod,” structurally destroys weeds so that desired plants have a growth advantage.

The death stick was more than 90 percent effective in carrot cultivation trials, according to Deepfield’s Birgit Schulz. —M.C.