Polar bear

Still, keeping cool can be tricky. That’s where a polar bear’s special features come in.

“There are some really interesting adaptations,” says Sladky. “They’re big, but they’re more streamlined, which some people believe is designed for swimming. If you imagine a polar bear head, it’s narrower than a grizzly bear head. Their big wide, thick paws can act like both snowshoes and paddles.”

Perhaps best known — but, surprisingly, not white — is its clear hair, with a dense undercoat and hollow guard hairs outside. It captures air to insulate against frigid water. Few of us get close enough to see the oily black skin underneath; some believe that it may help absorb heat.

Just like humans, polar bears seeking to beat the heat can take advantage of icy pools or air-conditioned indoor areas. Unlike humans, however, the bears also love diving for blocks of ice filled with frozen fish. They also stay busy in and out of the water, chewing not only ice, but also bowling balls and plastic toys.

“The best zoos provide a lot of creature comforts and environmental enrichment,” says Sladky.

Food recalls may well be increasing, partly due to better technology and greater awareness of the possibility for microbial contamination. “We are certainly much better at finding contamination, and there is stepped up surveillance,” says Glass, a microbiologist, but counting recalls does not prove that food is more dangerous.

The deadly bacterium E coli O157, for example, started appearing in hamburger about two decades ago, changes in manufacturing processes have caused it to grow less common in U.S. Department of Agriculture hamburger inspections. “But they are finding the proverbial needle in haystack,” says Glass. “While the rate of contamination has decreased, the number of ground beef recalls has increased from eight in 2006 to 20 in 2007 because more samples are surveyed.”

Yet during the same period, fewer human O157 infections have been confirmed in health laboratories, she adds. “We recall more, but are finding an overall reduced incidence of E coli in ground beef, and are also reducing the rate of lab-confirmed infections. So what interpretation can you make? That the food-safety system is working, even though the number of recalls is rising.”

The universe originated about 13.7 billion years ago with the Big Bang, so light cannot have been traveling for more than 13.7 billion years. “Since we know how old the universe is,” Halzen says, “and the speed of light, we can calculate the size of space we can see.”

Halzen, who directs a giant telescope in Antarctica that is designed to see neutrinos spewed by titanic explosions in the distant universe, says we can theoretically see about 13.7 billion light years in any direction. Because light travels almost 6 trillion miles in a year, it can “only” have traveled about 80 billion trillion miles since the Big Bang.

Practically, astronomers struggle mightily to see objects at these astounding distances. It’s likely that the extremely distant objects that created this ancient light have since blown themselves to bits, but the light from those explosions has not yet reached Earth.

Salmonella, which causes what we sometimes call “food poisoning,” can live more than 400 days in soil. And when dried on a laboratory slide, salmonella survived for almost three years, says Barak, who studies salmonella contamination on leafy greens, a growing cause of gastrointestinal illness.

However, E. coli, another resident of the intestinal tract, tends to die sooner in the environment.

Many bacteria form spores — tough, durable “seeds” that can withstand extreme abuse. Spores of respiratory anthrax, like that used in the 2001 bio-terrorism attacks, can survive for many years.

Environmental also conditions affect survival, Barak adds. For example, the bacterium that causes tuberculosis can be killed by full-spectrum lights, which contain ultraviolet light. In contrast, bacteria that live on plants have pigments that block ultraviolet rays, allowing them to thrive in sunlight.

Finally, bacteria can form communities called “biofilms” that greatly increase their ability to survive adverse conditions. Biofilms can be a major problem on catheters and other medical devices, because measures that kill the outer layers of bacteria may not affect those located deeper inside the biofilm.

It’s in the hundreds of billions, Churchwell says. In contrast, there are but 4 billion stars in our own galaxy, the Milky Way — and the number will keep growing for some time before we run out of galaxies to count.

“To count them all, you have to be able to look far enough back in time or deep enough in space to see when galaxies were formed,” Churchwell says. “We haven’t reached that point yet. It’s not a well-determined number, but at some point we’re going to reach it.”

For the time being, those hundreds of billions in the tally are extrapolated from a picture taken by the Hubble Space Telescope in 2003 and 2004. Pointed at a single piece of space for several months — a spot covering less than one-tenth of one-millionth of the sky — Hubble returned an image of galaxies 13 billion light years away.

“You look at that and say, ‘How many galaxies can I see?’” Churchwell explains. “And that turns out to be a very large number.”

In fact, there are about 10,000 galaxies in the picture, called the Hubble Ultra Deep Field.

“Then you take that number of galaxies from that postage-stamp-sized piece of the sky and multiply it by the number of postage-stamp-sized pieces of sky,” Churchwell says. “And that turns out to be a much larger number.”

Download Hubble Ultra Deep Field images.

Cars warm up in the sun due to the greenhouse effect: Sunlight passing through the windows into the car is mostly absorbed by interior surfaces, then radiated back to the air as heat. That heat does not pass back through the glass, which is an effective insulator for radiation, and the inside temperature can rise above the outside temperature.

“The visible radiation that we see is transparent to the glass but thermal radiation is not and gets trapped by the glass,” Klein says. “As a consequence, the inside of the car will warm because radiation is coming in but not much is going back out.”

The interior color may make a small difference in internal temperature, he says, because darker internal surfaces will absorb slightly more solar energy than light ones do.

Tinted glass will have an even more pronounced effect, he says, by reducing how much solar radiation enters the vehicle in the first place.

There are plenty of cats that love water, according to Sandi Sawchuk, a clinical instructor at the School of Veterinary Medicine.

Big, wild cats, especially those that live in hot, arid areas, often love to swim. An Asian species known as the fishing cat uses webbed paws to dive for fish, frogs and crayfish.

Among domestic breeds, the Turkish Van is known for swimming. But most house cats shy away from water.

“Because cats groom themselves, we as owners tend not to introduce them to bathing like we do our dogs,” Sawchuk says. “Ask somebody who has show cats, which have to be bathed regularly and have been in the water since they were young. Those cats will tolerate it. There’s no fight at all.”

The spray-bottle method of controlling cat behavior — giving them a squirt between the eyes when they jump up on the counter — would make just about anyone wary.

“What’s the cat going to think about water then, when it’s only used for punishment?” says Sawchuk, who has three cats at home.

It’s not uncommon for the owners of Sawchuk’s feline patients to describe their cats sitting on the edge of the bathtub, batting at the stream of water from the faucet or showerhead.

“When they have the ability to control how much they can get near the water and how much exposure they have, they don’t seem to mind at all,” Sawchuk says.

Goldman explains that one compartment inside onion cells contains an enzyme, called allinase, while another compartment holds the enzyme’s substrate: a suite of sulfur compounds known as ACSO for short. Because sulfur is an essential nutrient, the onion stores sulfur from the soil as ACSO for later use.

When onion cells rupture – whether through an insect’s nibble or a knife’s cut – allinase and ACSO mix together and react, producing another set of sulfur compounds called thiosulfinates. In addition to giving onions their familiar taste and odor, thiosulfinates repel pests that attack onion bulbs underground.

They aren’t the chemicals that cause tears to well, however. Before the thiosulfinates are produced, the reaction of allinase and ACSO releases a volatile chemical that wafts into the air and reacts with the water in our eyes. “Basically it produces something like sulfuric acid in your eye,” says Goldman.

The mild acid irritates the eye’s nerve cells, stimulating tears that help wash it away. Chilling onions before chopping can reduce the crying, says Goldman, because “this is an enzyme-mediated process, and low temperatures slow enzymes down.”

Sweet onion varieties, like Vidalia, grown in the low-sulfur soils of Georgia and Texas also show less of this activity and are less pungent, he adds.

“If you go to any park or golf course in Madison, you have to watch where you step for all the goose poop,” Temple said.

You might want to watch where you point your jet engine, too, Temple says, lest it end up inhaling a goose.

Geese in Wisconsin are divided into two populations headed in different directions. The flocks of geese that breed in Canada and migrate through Wisconsin are not getting larger. In fact, their numbers have dwindled slightly in recent years.

It’s the geese that live and breed in Wisconsin year-round that are booming — up to 148,293, a 27 percent jump over 2008, according to the Department of Natural Resources.

The local geese have bounced back remarkably from historically low numbers that were held down — in part — by an early fall goose hunting season.

“It ended up putting a disproportionate amount of the hunting pressure on the locally breeding geese who spent all of the hunting season in state,” Temple says.

A successful effort by fans of the giant Canada goose (the species most often settling in Wisconsin year-round) to push back the hunting calendar turned shotguns on the migrating geese when they are far more active over Wisconsin than their local brethren.

An abundance of food has worked for the local geese, too. Modern no-till farming leaves waste grain above ground through the winter, and during the milder months geese are drawn to some of the same spots people enjoy.

“Turf farms and golf courses and parks are very welcoming places for geese,” Temple says.

And those attractive locations are generally near urban and suburban areas, where population control through hunting is not particularly welcome.

Some plants, notably catnip, make cats feel good, Sawchuk says. “If I eat this, I am going to get spacy, and I like that feeling.” Some cats also like spider plants, which contain compounds related to opium. “Or cats learn that certain plants will act as a purgative, causing them to vomit if they have an upset stomach,” Sawchuk says.

But plants can also be poisonous. Asiatic lilies, including Easter lilies, are a key cause of concern. “Ingesting even a tiny amount can put a cat into kidney failure,” Sawchuk says.

Owners should separate cats from toxic plants, but also deal with the many cats that like plants. Owners may want to offer their cats edible sprouts, chopped lettuce, or the “kitty grass” sold in pet stores. Sawchuk recommends that cat owners check reputable web sites for lists of toxic and nontoxic plants, and make sure to place any toxic plants well beyond reach.

Reader beware: The ASPCA says aloe vera causes vomiting, depression, diarrhea and other symptoms among cats.