06 Track 6

Review unit 2

fluency practice

review reading 4:

natural mysteries

Page 116

natural mysteries

Advances in science and technology may have helped us solve many natural mysteries, but there are some that still puzzle scientists. Keep reading for three natural events that science has yet to fully explain.

animal migration

Migration has fascinated humans for centuries. Ancient civilizations puzzled over why large numbers of animals would disappear and reappear at certain times of the year.

Many animal species make annual journeys to faraway lands, usually to find food, warmer weather, or places to breed.

Distances traveled are often vast. For example, the monarch butterfly flies between 2,000 to 4,500 kilometers (or more) from the U.S. and Canada to forests in central Mexico.

There, they hibernate and produce the next generation of butterflies that will make the trip back.

How an insect weighing as much as a paper clip can complete such a long journey is one thing. What’s more mystifying is how these animals even managed to get to their locations, especially when they’ve never been taught to do so.

The biologist Rupert Sheldrake noted, “Baby green turtles that have hatched on the beaches of Ascension Island, in the middle of the Atlantic, find their way across the ocean to the ancestral feeding grounds off the Brazilian coast.

Years later, when the time comes for them to lay their eggs, they then make their way back to Ascension Island, only six miles across and over 1,400 miles away, with no land in between.”

The main theory is that these migrating animals navigate using the sun, moon and stars, a magnetic sense, or the sense of smell. But heavenly bodies are not always visible, and the Earth’s magnetic field is known to be very unreliable.

Also, how would an animal smell its destination from such a distance? It seems many of these creatures just know their way by sheer intuition.

Raining Fish and Frogs

In January 2012, residents of the town in Agusandel Sur, the Philippines, got the shock of their lives when it started raining fish. Many thought the world was coming to an end.

But they were just witnesses to a rare phenomenon that has been recorded throughout history and all over the world. People insist there is a simple explanation: strong winds traveling over water may sometimes pick up small items or animals such as fish or frogs before depositing them a few kilometers on.

However, in Depatmento de Yoro of Honduras, it is been raining fish for years and no one has figured out how or why this happens. Every May or June, a heavy rain lasting up to three hours leaves the streets with small fish, many still flapping about.

A National Geographic team, which documented the “rainfall” in the 1970s, determined that the fish were all of the same species but were not found anywhere around the area.

It is also exceptionally rare to have it occur in the same place twice. Since 1998, the city of Yoro has even organized a festival around this called, appropriately, “The Rain Of Fish Festival”!

Ball Lightning

For centuries, people have reported seeing strange glowing balls of light appear during thunderstorms. Called ball lightning, these tennis- or even beach boll-sized spheres typically glow, spin, hiss, balance, and float.

Graham K. Hubler, a physicist who studies ball lightning, describes an encounter when he was 16 years old. “It’s extraordinary − you’re so startled that you remember it for the rest of your life,” he said.

“It drifted along a few feet above the ground, but when it came inside [the pavilion] it dropped down to the ground and skittered along the floor.”

For years, scientists could not explain the phenomenon. But a pair of Brazilian scientists may have finally solved it by creating ball lightning in a lab in 2007. The pair suggested that when lightning strikes the surface, like the Earth’s silica-rich soil, of vapor or gas is formed.

This silicon vapor then combines with oxygen in the air and slowly burns. Energy from this chemical reaction causes the resulting ball of electricity to zoom around.