You may think that light pollution isn't something extraordinarily important. You may believe that every other type of pollution has a larger impact on the environment that light pollution does. But light pollution is serious.
    Light pollution, or “sky glow”, is the glow you can see at night above cities and towns. Light pollution is a problem that has been accompanying man ever since he started his first fire some 15,000 years ago. Light pollution is the light that comes from streetlights, buildings, parking lots and any other source of light that is reflected or directed into the atmosphere.
    Urban light pollution means that one-fifth of the world's population can no longer see the Milky Way(银河) with the naked eye(肉眼). Many city kids, even if they did look through the orange smog above their heads, would probably see only a handful of stars. We have lost our view of the stars, and we have mucked up our  night-time environment as well. Astronomers are calling for the dark places on Earth to be preserved as national parks.
    Lots of people find the ever-brightening night annoying, and animals that are programmed to prefer the dark may avoid a brightened habitat. Sea turtles can get lost searching for a beach to lay eggs, and their hatchlings(孵化的幼仔)may confuse over-lit beachfront resorts(度假胜地) for the ocean horizon, wasting precious energy needed to find the sea and escape predators(食肉动物). Because their necks aren't yet long enough to see things far away, baby turtles rely on the mirror image of the moon to guide them to the sea, to begin their new life. A car may even hit a particular turtle, which was thinking the light from a nearby city was moonlight reflecting off the ocean waves. Birds that live in and around cities can die because of sky glow, too. The bright lights can blind them, leading to countless collisions with buildings and other tall structures.
    On an individual level, people can help reduce much sky glow by using lighting only when necessary. The stars above us are priceless heritage— for not only for astronomers but for all humans. More of our children should be able to look up at night and see the Milk Way.
    The world consumes hundreds of billions of single-use plastic bags each year. They are difficult to recycle, wasteful and damage the nature. Environmental activists want to ban plastic bags or—as many communities have done —charge a fee for them. But the plastic bag industry defends their use, saying people reuse plastic bags, and industry officials argue recycling is a matter of personal responsibility and should not be forced.
    City officials say New Yorkers use 5.2 billion plastic bags each year. They are offered free with nearly every supermarket, or convenience store purchase. Many people like them, even if they sometimes feel guilty about using them. But what happens to those bags after they've been used in a huge environmental problem. They are found on beaches. They are caught in trees. They are swallowed by marine life.
    Plastic bags are made of petroleum products and natural gas, and do not biodegrade (分解). And they are difficult to recycle. So New York City spends nearly $ 10 million dollars a year to send 100—thousand tons of plastic bags to landfills out of state.
    In Washington, D.C., a five percent charge on all single-use bags led to about a 60 percent reduction and in Los Angeles County in California , a 10 cent charge on single-use bags led to a 95 percent reduction. With a 10 cent charge on bags, customers are much more likely to stop and think about whether they need a bag or not. And that's really all that these laws are doing.
    At the end of every year, Time picks the best 25 inventions that are “making the world better and smarter”. Here we have picked three of this year's inventions that could be a part of your life in the near future.
The levitating(悬浮的) lightbulb
    This special lightbulb was invented by US artist and scientist Simon Morris. He got the idea of making a lightbulb float from hoverboards(悬浮滑板),which he used to dream of having as a kid.
    But the floating is not the most amazing part. The rejection force between the opposite ends of the magnets(磁铁),which were put in the bottom of the bulb and in the wooden base, does the job. What's new here is a technology called induction (电磁感应). It allows the lightbulb to get power from the base even they are not in contact.
Shoes that tie themselves
    They're not what you think-shoelaces that tie themselves in the way we tie them. Instead, the new shoes have small motors that control their laces. When you step in them, your feet will hit a sensor(传感器)in the shoes and the motor will automatically tighten the laces.
    But the shoes weren't just designed for lazy people's needs. They could actually give athletes an advantage during competition. They are also useful for people who cannot move their arms or fingers easily.
The no-touch thermometer
    Taking your body temperature usually means putting a thermometer (体温计) in your armpits (腋窝) and staying still for minutes. It may be easy for you, but it's an impossible task for little kids.
    Now, with the new thermometer, users can simply put it 2.5 centimeters from a patient's forechead and press the button, and it can get the reading in two seconds.
    Through the following four cultural relics, the world has known about Korea's cultural treasures.
Pulguksa Temple
    Pulguksa Temple plays an important part in the history of Korean temples. The building of Pulguksa Temple began in 751. In the year 774 the large temple was finished, becoming an important center for Korean national-protection Buddhism(佛教). The way used to create the store structure gave the temple a look of beauty. The building thus represents the excellent Korean sculpting(雕刻).
Sokkuram Cave
    Sokkuram Cave is a man-made cave, which has been sculpted from white stone in special sculpting ways. In the cave, a seated Buddha is the main statue. On the walls around him are found 38 other statues and the Four Heavenly Kings. This stone cave is one of Korea's greatest places, built when Shilla's religion, science and sculpture were at the height. It shows Shilla's knowledge of math, physics and art.
Haeinsa Temple
    Haeinsa Temple's Changgyong Panjon (藏经板库) is a world-class cultural treasure. It has 81,340 wooden blocks. Millions of Chinese characters were caved on the blocks. In addition to its artistic value, it is famous as the oldest Buddhist canon(教义)in the world today. The building is beautiful. What's more important is that its design allows for natural wind as well as temperature control. Each book is 69.5cm in width and 23.9cm in height. There are 23 lines on each of the blocks and each line contains fourteen characters.
Changdokkung palace
    Changdokkung palace, one of the five places of the Chosen Dynasty, was built in 1405. The oldest structure is Tonhwammun Gate. Other ancient buildings include Injongjon hall, Sonjongjon Hall and Taejojon Hall. The back garden for kings remains a great example of the ancient Korean scenery.
    A ground-based system that uses much stronger signals than GPS can find your location in cities and indoors. It is a new positioning system that could compete with GPS to make sure you never lose your directions again.
    Instead of satellites, Locata uses ground-based equipment to send a radio signal over a localized area that is a million times stronger on arrival than GPS. It can work indoors as well as outdoors, and the makers claim that the receivers can be shrunk(缩小) to fit inside a regular cell phone. Even the US armies, which invented GPS technology, signed a file last month agreeing to a test of Locata at the White Sands Missile Range in New Mexico.
    “This is one of the most important technology developments for the future of the positioning industry,” says Nunzio Gambale, CEO and co-founder of the firm Locata, based in Griffith, Australia.
    As for the Locata's correctness, Christopher Morin of the US Air Force tested it recently at White Sands, and it worked to within 18cm along any axis(轴). Morin said it should be possible to get the exactitude down to 5cm.
    The tests were performed in an open desert where GPS also worked beautifully, but its signal was weak—like a car headlight from 20,000 kilometers away—and easily cut off by solid objects(实心的物体). Locata's signal was far stronger, though not guaranteed to work in a complex urban environment, said David, speaker of the UK' s General Lighthouse Authorities.
    Locata's technology will face competition in the race to transform indoor navigation. But it could shine in specific areas, Gambale said. Robots with Locata could easily navigate inside buildings without the complex optical(视觉的) systems they need at the moment. And the process that handles correct location data could not only guide you around a mall, railway station or airport, but also take you to the exact shelf in a shop for the product you want. It would be small and cheap enough for smart phones and it should be available within five years—a similar path to the one GPS took on its way towards the world, he said.
    Whether in the home or the workplace, social robots are going to become a lot more common in the next few years. Social robots are about to bring technology to the everyday world in a more humanized way, said Cynthia Breazeal, chief scientist at the robot company Jibo.
    While household robots today do the normal housework, social robots will be much more like companions than mere tools. For example, these robots will be able to distinguish when someone is happy or sad. This allows them to respond more appropriately to the user.
    The Jibo robot, arranged to ship later this year, is designed to be a personalized assistant. You can talk to the robot, ask it questions, and make requests for it to perform different tasks. The robot doesn't just deliver general answers to questions; it responds based on what it learns about each individual in the household. It can do things such as reminding an elderly family member to take medicine or taking family photos.
    Social robots are not just finding their way into the home. They have potential applications in everything from education to health care and are already finding their way into some of these spaces.
    Fellow Robots is one company bringing social robots to the market. The company's “Oshbot” robot is built to assist customers in a store, which can help the customers find items and help guide them to the product's location in the store. It can also speak different languages and make recommendations for different items based on what the customer is shopping for.
    The more interaction the robot has with humans, the more it learns. But Oshbot, like other social robots, is not intended to replace workers, but to work alongside other employees. “We have technologies to train social robots to do things not for us, but with us,” said Breazeal.