Life and Nature ~ Page 2 din 11

In a pitch black cave underground, cats would see what we see — that is, total darkness. Can cats see in total darkness? For all animals, sight requires light. You can see only when light strikes an object — and bounces from the object into your eye. The light hits special receptors, which trigger nerve impulses — which your brain converts to a picture of the …

A scientist talks about a new tool for space exploration — a robot that thinks like a geologist. When a space probe sends data from Mars, the radio signal can take up to 20 minutes to travel back to Earth. And if mission controllers send a command back to the probe, it might take another 20 minutes to reach Mars. This delay makes it tough to …

When it’s any hotter out than about 98 degrees Fahrenheit, it’s pretty tough for the body to cool down. And that’s when we really start to sweat. Our body temperature is 98.6 degrees Fahrenheit. But when it’s 98 degrees outside we’re not comfortable. We think the temperature is nice at about 75 degrees. Why is this? The reason has to do with how humans have …

To learn how brains think, we need to know more about neurons, or nerve cells in the brain. A scientist talks about new techniques to make movies of neurons growing inside the brains of living mice Neurons are the nerve cells in the brain and spine that pass information back and forth. If neurobiologists fully understood how neurons grow and change, it might help them …

Bacteria that invade our bodies can do some surprising things — they form complex communities and talk to each other with chemical signals. Today — a scientist who’s using that information to develop new ways to fight back. Bacteria cause many chronic illnesses in humans — from children’s earaches to cystic fibrosis. New kinds of microscopes have revealed that a bacterium cell can change its …

Jellyfish are among the most primitive animals alive today. Like their close relatives, sea anemones and corals, jellyfish have no head, no heart and no skeleton. But do jellyfish have a brain? Do jellyfish have a brain? Renaissance scholars thought jellyfish were plants. It wasn’t until the 18th century that they were recognized as animals. And, no, jellyfish don’t have brains — because their bodies …

Red blood cells make up nearly half our body’s blood volume. A healthy human produces about 2 million new red blood cells every minute. But red blood cells aren’t true cells, which we talk about. Of all the cells in the body, red blood cells have not DNA. Why? When red blood cells are developing — in the marrow of your bones — they do have …

Wasps like yellow-jackets and hornets can sting over and over again. But bees can only sting once. We answer a listener’s question about bee stings. Why do bees die when they sting you? A bee’s stinger is made of two shafts, lined with barbs like fishhooks. When a bee stings, it can’t pull the barbed stinger back out. It leaves behind not only the stinger, …

In the U.S., most of us can read. But still very little is known about how our brains actually do it. Up next — a scientist who studies what’s going on in our brains when we read. Dr. Guinevere Eden is Director of Georgetown University’s Center for the Study of Learning. She’s in the third year of a five-year study that’s looking at what parts …

If you spread out your brain’s cerebral cortex, it’d be the size of a large pizza. It fits in your skull because it’s crumpled up. And your brain’s pattern of folds is more individual than your fingerprints. The main structure of your brain is called your cerebral cortex . . . And you use different areas of it for different mental jobs — from solving …

It was long thought that language was a uniquely human trait — a dividing line that separates humans from other primates. But does it? We talk with one researcher who is studying how chimps talk. Speaking with Sally Boysen, a psychologist at Ohio State University. Dr. Boysen worked with chimpanzees for nearly 30 years. In the 1970s, she taught chimps to communicate, first using American Sign …

Scientists who search for life beyond Earth would love to analyze samples from distant planets and moons in the lab. They can’t do that yet — so they’re using light to hunt for life. Europa is one of Jupiter’s largest moons. Its surface is solid ice. But below the icy crust of Europa, there might be a warmer liquid ocean. And scientists wonder if life …