Our sun is a star, and nine worlds (天体) move round it. Worlds like these are planets. But here are other stars, other suns, not only thousands of them, but millions of them. Do different stars have planets? We can see the planets round our own sun. But we haven't been anymore. The stars are too far away from us. Stars give out light, but the planets don't have any light of their own. So we can't see them. They are too far, and too dark. Still, we can tell that some stars have planets. While a big planet goes round, it pulls its star to one side. And sometimes we can see this. Then we know that the star has a planet. For example, Barnard's Star is a small red star. And it is the quickest star in the universe. But sometimes it moves slower, and then quicker again. We have known Bernard''s Star for many years, and now we are sure it has a planet.

    Garbage(垃圾) Island

    You can't see it from the air. It's almost impossible to see from a ship. But somewhere in the North Pacific is a huge island of garbage, just below the water surface.

    What is the island made of?

    The garbage island is not an island, but a collection of millions of plastic and other objects. The water movements of Pacific Ocean bring the objects together and cause them to go around in a big circle.

    Charles Moore found it in 1997 and named it “the Great Pacific Garbage Patch” .

    Where does all the plastic come from?

    Much of the garbage comes from everyday objects, such as shopping bags and water bottles. Some of these objects finally reach the ocean. Garbage from the western coast of North America takes about six years to reach it. Objects from East Asia take about a year. Other garbage comes from ships passing through the area.

    Is the Garbage Patch dangerous?

    The larger pieces of garbage are a problem for wildlife. For example, sea turtles（海龟）and seabirds often think the plastic is their food. They eat the plastic and die.

    In addition, the plastic stops sunlight from reaching deeper water. Without sunlight, very small sea animals die. Then, there is less food for larger fish to eat.

    What can we do to help stop it?

    Cleaning up the island isn't easy. But we can make people realize the problem. One environmentalist(环保主义者), David de Rothschild, is sailing around the world in boat made of plastic bottles to teach people about the problem of garbage in the sea.

    Another idea is that we can recycle the plastic garbage. Environmental engineer Cesar Harada is building a robot that collects pieces of plastic. Harada hopes to use his robot in the Pacific. Harada also has a website for reporting environmental problems. He says, “I hope everybody can become an environmental activist.”

    Many of us enjoy watching animals in the world. But do you know they can teach us?

    Geese(雁), for example, teach a very good lesson about 1. In the fall, Canada geese fly to the warm south to 2 Canada's cold winter. They lift off in no order. Yet 3 they form a V shape, with one bird leading the group.

    This V shape allows geese to 4 energy. When the front bird moves its wings up and down, the resulting force of the air lifts the next one. This continues down the line. The bird 5 has the hardest job. When it gets6 , it moves behind, and another bird moves into the lead. By sharing the role, the group can travel great distances. Geese flying in a V shape can fly 70 per cent farther without 7 than birds flying alone. During the long flying journey, geese communicate with one another. They honk(鸣叫) to 8 the birds up front to keep up the speed. They also cheer each other up 9 working toward a common goal.

    What have we learned from the lovely geese's experience and skills?

    10 together! Whether it is our personal lives or our jobs, we need other people. We need the spirit of teamwork!

    Our eyes may be playing tricks on us.  New research shows that sometimes people physically see what they want to see. Cornell University social psychologist(心理学家) David

    Dunning carried out experiments to test whether wishful thinking can actually affect what we see.

    “It's well proved from what is experienced in everyday life, and from the laboratory as well, that people think what they want to think," he says. "We're taking this a step further.

    We're asking if strong wishes and fears can actually affect what people physically see."

    Dunning and his assistants told volunteers that a computer game would show them either a letter or number to decide whether they would drink orange juice or fruit syrup(果子露).

    As they wrote in the Journal of Personality and Social Psychology, the computer would flash an ambiguous picture, which could be seen as the letter "B" or the number "13". Volunteers who were told that a letter would get them orange juice most often reported seeing "B". Those who were told that a number would get them orange juice most often saw "13".

    The researchers also used a hidden camera to track volunteers' eye movements, particularly the first eye movement. "We don't control them," Dunning says, "and they don't even know that we are watching them, so it honestly shows what a person is seeing."

    "This research suggests that the brain is doing a lot of work between the eye and the conscious awareness to affect what we think," Dunning concludes (得出结论). "Before we even see the world, our brain has decided to keep what we want to see and avoid what we don't want to see."

    Do you think laughter can help you deal with pain? Scientists from Britain did two experiments(实验). The first was done in a lab. People wore special wristbands(腕带). Some of them were asked to watch comedies while others watched serious programs. Then the scientists tightened(勒紧)the wristbands to see how much pain the people could feel.

    The other test was done at an art festival. Some people watched a comedy show and others watched a drama(戏剧). At the same time, they had to put their backs against the wall and keep their legs bent(弯曲的)just like sitting on a chair. They did this before and after the show.

Scientists found that just 15 minutes of laughter improves people's ability to stand pain by 10%. However, the serious programs and the drama didn't make a difference to pain at all.

    The study found that the magic power of laughter comes from endorphins(内啡肽). These are chemicals(化学物质). They are produced by the human body. They make you feel less pain and can make people feel happier. Exercise can produce endorphins. Your muscles(肌肉)move in and out when you are laughing. Scientists believe that this makes your muscles tiring, so we start to produce endorphins.

    Scientists also found that the only real and relaxing laughter works not just polite laughter.

    Next time you have a headache, get together with a group of Mends, watch a funny movie and laugh. You will soon feel a lot better because laughter is the best medicine.

    Scientists think that there has been life on earth for millions of years. However, we haven't found life on other planets yet. The earth is a planet and it goes around the sun. And there are seven other planets that also go around the sun. The sun and its planets are called the solar system. The solar system is a small part of the universe.

    Scientists have launched many spaceships to explore other planets in the solar system. Some spaceships have gone beyond the solar system. However, no one has discovered any life in space yet.

    Why has no one from other planets sent us a message? Have they tried to send information to us? With so many stars in space, are we alone, or is there life on other planets in space?