Do scarecrows really work?
—Trevor Anderson, Oklahoma City, Oklahoma
Not very well, and not for very long. "Birds aren't stupid," says Cornell ornithologist Kevin J. McGowan. "If the same object doesn't move for weeks, they'll eventually figure out that it's not dangerous." An effective scarecrow must make constant motions, get schlepped to a new part of the field every day, and resemble one of the birds' most feared predators, such as a human or an owl. Farmers have recently adopted radical methods of bird-freaking: blasting carbide cannons alongside corn rows, setting up high-frequency electronic signals, and rigging alfalfa fields with inflatable figures that pop up like gunslingers out of Westworld. The Japanese are trying enormous "scary eye" balloons that scowl down at rice paddies, and White House gardeners have been blaring recordings of avian distress calls from outdoor speakers. Agriculturalists across the country have copied the technique, with limited success. The real breakthrough, McGowan argues, will occur when we enter the age of the Robocrow. "The only perfect scarecrow is going to be an android," he says, noting that his proposal for an animatronic owl has yet to be picked up by scarecrow R&D. "It'll take a while."
How far does space go? It can't just stop like a wall.
—Tommy Estes, Tupelo, Mississippi
Even the most dedicated of cosmologists can't answer this maddeningly inexplicable mind-bender, which like all great space enigmas takes us beyond mathematical realities and into the fuzzy realm of metaphysics and theology. But to address at least part of your question, Hubble Telescope findings from May of this year portray an enormous universe that stretches some 30 billion light-years across. Scientists agree that it has been expanding outward in all directions ever since the big bang, 12 to 15 billion years ago. But what is it expanding into? Sadly, we don't know—and we'll never be able to outrace the expansion to find out. "If we could freeze time and travel to the distant reaches of the universe, then we might be able to learn what, if anything, is out there," says Hubble senior project scientist David Leckrone. "Obviously that will never happen." Perhaps the only shred of certainty is that there's no finite end, or wall, to the ever-widening cosmos—at least not one we can fathom, much less measure or observe. "We'll never find an outside," says Leckrone. "The universe is a closed geometry—it's all there is."
Can bees really detect fear?
—B. McCracken, Albuquerque, New Mexico
As far as we know, bees and wasps have no telepathic knack for singling out the paranoid among us, but there is a decided advantage in remaining outwardly calm. Like many insects, they don't have exceptionally sharp vision, so they've evolved other senses to detect threats to the queen and her hive. For starters, they're expert at detecting motion, and if there's one thing that's sure to send a worker into attack mode, it's sudden, jerky movements—exactly the sort of erratic flailing you do to try and swat away a bee. You notice a bee buzzing around you, and you become uneasy: You perspire, your heart beats faster, your breathing quickens, and you may even hyperventilate—at which point the winged critter readies its stinger for attack. "When you're frightened, you exhale more carbon dioxide and your sweat becomes increasingly pungent," explains Justin Schmidt, a U.S. Department of Agriculture research entomologist. "Bees are a thousand times more sensitive to these chemicals than we are, and they use them as cues to zero in on their targets." Once you're stung, however, fear is a wise response: The first bee that nails you plants a pheromone in your skin that acts as a homing device for its stinging compatriots. "At that point," advises Schmidt, "you'll want to channel your panicinto your legs and make a fast exit."
What is a false dawn?
—Simon Hewat, Savannah, Georgia
This is one of nature's great understated luminous spectacles. Zodiacal light, or false dawn as it's known colloquially, is a pale-yellow luminance that appears in the eastern sky two hours before sunrise. The cause: tiny silicate debris left over from the creation of the solar system, and cast off from comets, that orbits our sun in an enormous elliptical disc. The rising sun's light bounces off these grains of space dust, creating an eerie, pyramid-shaped glow that gives the impression of a bright metropolis just over the next hill. But it's a rare and fragile phenomenon, visible only when the sun's rays are in perfect alignment with the orbiting crumbs and when the predawn sky is moonless and black (the faintest twilight of true dawn is enough to kill the effect). To witness it, find a remote spot blessed with zero light pollution, preferably sometime this month: Here in North America, false dawns peak in October.
Illustrations by Jason Schneider P