There is lots of junk (垃圾) in space. Some of it is from rockets. In 1996, a rocket broke into about 300,000 small pieces. So far scientists have found many man-made pieces flying around in space. Only a few of them are satellites and space probes (探测器). Astronauts also lose small things while working in space. In 1965, during the first American spacewalk, astronaut Edward H. White lost a glove. For a month, the glove stayed in space, travelling at a speed of 28,000 kilometres per hour. It became the most dangerous piece of clothing for the earth in history.

Things move very fast in space. If they hit one another it can be dangerous. A little piece of paint from a satellite once made a hole in a spacecraft window. Once American spacecraft dropped some bolts (螺栓), and scientists on the earth worried a lot. Luckily the bolts floated (漂浮) away into space. They could not hit the spacecraft.

Taking selfies (自拍) is popular with different ages of people nowadays around the world. There are many things to consider while taking selfies, such as lighting, settings and so on. Sometimes, we may add a second character—a wild animal. However, trying to get too close to wildlife for a photo may cause many problems.

The selfie might harm the animal. For example, when sea turtles come up on the beach to rest or nesting (筑巢), it’s always a big attraction for tourists to take photos. But that kind of attention is extremely harmful to them. The action of selfie may drive them away from the beach, which can possibly make them easier to be attacked or reduce their chance of nesting success. So harm can be caused even without touching the animal.

The selfie might make people get hurt. Even if the animal seems calm and friendly, there is a chance that you will end up in the hospital. Some people think Yellowstone’s famous bison are just big-shouldered cows. Wrong! They are wild animals! In 2015, a 16-year-old tourist was knocked over by a bison as she tried to take a selfie with it.

The selfie might raise moral (道德) problems, too. When you pay to take photos or swim with dolphins, you can get an amazing experience. In fact, the dolphins may be trained many times by cruel methods for this. It also causes the dolphins to lose much needed rest.

     The selfie might cause legal (法律的) trouble. When you post your selfie photos or videos with wildlife online, you might get into trouble with the law. That’s because you are breaking laws on protecting wildlife and endangered animals.

     So, next time when you want to take selfies with wildlife, think twice!