The blue whale (鲸) is the largest animal alive today. And one of these whales has been caught making a big journey through the South Pacific. The whale was first recorded near the Galapagos Islands, west of Costa Rica. Years later, that same whale was photographed off the coast of Chile in South America, a new study reports. The two places are separated by about 5,200 kilometers. That means the whale, nicknamed Isabella, swam farther than the distance between New York and Los Angeles.

Blue whales are found in all the world’s oceans but live in deep waters. So there are few places where they can be found easily. What’s more, they were nearly driven by whaling a century ago. Populations are increasing. But because there are so few of the animals, they are still considered endangered.

One blue whale may look like any other to the untrained eye. But each animal has special spots (斑点). “We use those spots as the fingerprints of blue whales,” Torres Florez says. To make the comparison job easier, scientists focus on the area around a whale’s dorsal fin (鳍), which is on its back. “Comparing those spots we are able to tell if a whale is the same whale we saw in different places or if the same whale is seen during different years in the same place,” he says.

Isabella is probably not the only blue whale to travel so far, the researchers say. Members of her population likely migrate regularly from Chile to the Galapagos. In summer months, Torres Florez notes, waters in the far southern Pacific are loaded with krill, but that food disappears in winter. That’s when the whales travel north to warm, tropical (热带的) waters near the Galapagos. There, instead of feeding, the whales produce babies. Scientists don’t yet know why whales prefer to produce babies in tropical locations. But the ocean there may be warmer and calmer and have fewer killer whales that would feed on baby blue whales, Torres Florez says.

Do you have a mobile phone? Do you send text messages to your friends and family?   

Text messaging or “texting” is becoming very popular. But, scientists have discovered that texting can give us problems with our hands. Be careful! Too much texting can cause swelling（肿胀）in our thumbs（拇指）and wrists（手腕）. Our thumbs are not made for pushing small buttons, over and over. Scientists call this problem RSI.

We spoke to a doctor called Harriet Wilson, who treats many patients with RSI. She said we needed to see how much time we were spending in typing text messages. If we are spending more than 10-15 minutes at once, we could have problems in the future.

We also talked with Dr Harjeet Deepa who treats（治疗）RSI patients. He told us that the youngest patient she had treated was a five-year-old girl. She wasn’t doing well at school, so her parents took her for treatment. It was found that she had such bad RSI in her hands, she couldn’t hold a pencil.

As mobile phones develop, they are getting smaller with buttons closer together. Texting with a smaller phone is worse than using a larger phone with bigger buttons. Using a computer keyboard and playing video games can also cause the same problem. So, more and more people could find themselves with RSI.

Many university students and teenagers have RSI, as they do not know the danger of spending so much time using computers, video games and mobile phones. If we don’t do something about this, too many young people could grow up in terrible pain.

Have you ever poured water onto your shirt right before an important event? Usually, clothes darken in color when they get wet. It would certainly be nice if the water didn’t change the color of the clothes so much. But sadly, this isn’t how things work. So why do clothes often appear darker when they get wet?

Before understanding this question, we should first take a quick look at how we “see” colors. Take a red shirt as an example. When it is hit by the light from the sun, it absorbs (吸收) different wavelengths (波长) of light, except for the red light wavelength. The red light wavelength is reflected to our eyes. That is why the shirt appears red to us.

Now let’s return to the wet shirt. When the light hits a wet shirt, it has to pass through the water on the shirt. The light that should be reflected by the shirt is reabsorbed by the water. This means less light will be sent to our eyes. As a result, the shirt looks “darker”.

But remember, sometimes a wet shirt can seem brighter from some special angles (角度) of observation. The surface of a shirt is usually rough. Adding water to it makes it smoother. A smooth surface reflects light in a different way from a rough surface. So you may see a small and bright reflection of the light from a certain angle. So basically, a wet shirt will be darker than a dry one, but it can also appear more “shiny” at times.

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