Given Australia's size and the fact that early settlements were far apart, Australian society is remarkably homogeneous (同种的). The way of life in the major cities and towns is much the same, however many miles divide them. It takes a sharp ear to tell the differences between regional accents.

    However, there is some difference in lifestyle between people in the city and those in the countryside. Almost 90 per cent of the population lives in the fast-paced cities along the coast and has little more than a passing familiarity with the desert. The major cities keep some colonial (殖民的) heritage, but the overall impression is modern, with new buildings reflecting the country's youth. By comparison, the rural communities tend to be slow-moving. For many years, Australia was said to have “ridden on the sheep's back”, a reference to wool being the country's main money-earner. However, the wool industry is no longer dominant. Much of Australia's economy is now achieved from natural coal and wheat, and by being the largest diamond producer in the world. Newer industries such as tourism and wine making are also increasingly important. Australians are generally friendly and relaxed, with a self-deprecating sense of humor. On the whole, Australia is a society without hierarchies (等级制度), an attitude generally held to stem from its prisoner beginnings.

    Yet, contrary to popular belief, very few Australians have true prisoner origins. Within only one generation of the arrival of the First Fleet in 1788, Australia had become a nation of immigrants. Originally coming almost entirely from the British Isles, today one in three Australians comes from elsewhere. Australia's liberal postwar immigration policies (政策) led to a growing number of survivors from war-torn Europe, most notably Greeks, Italians, Poles and Germans.

    The emphasis has changed in recent years and today most of the new immigrants are from Southeast Asia. Today Australia is a ‘blend of nations' and although some racial (种族的) problems exist, it has generally been a successful experiment and the country is proud to have one of the most harmonious multicultural communities in the world.

    If you thought pilots dimmed（调暗）the lights before takeoff to give you some shuteye, think again. Believe it or not, the dim lighting could actually help save your life in case of a plane emergency.

    The dimmed lights before taking off the runway and landing are a flight precaution used to help passengers' eyes adjust quicker during an emergency escape. “Going from a brightly lit environment to one that's completely dark would require some time for our eyes to focus and see the escape slide,” Alice Theriault, service director for Air Canada wrote in a press statement. “Since we need to have all the seconds on our side in the event of an emergency, dimming the lights is one of many steps we take to ensure the safety of our customers.”

    The phenomenon that your eyes see those strange speckles (小斑点) as your sight adjusts to a dark place after being in a light place is called dark adaptation. It normally takes our eyes about 20 to 30 minutes to see best in a dark room. The brighter the lights, the longer it takes for our eyes to adjust, which is why dimming the plane lights could shorten your “dark adaptation” time since you haven't been sitting under fluorescent bulbs (荧光灯) all flight.

    Not only does dimming lights add valuable time to the escape process, it reduces the tension on your eyes if you need to look outside, or see the emergency lighting along the passage. “It helps keep you in the right direction.” Patrick Smith, an airline pilot and author of Cockpit Confidential told The Telegraph. “It also makes it easier for flight attendants to assess any outside risks, such as fire or debris, that might affect an escape.” So next time a pilot dims the lights, just know it's for your safety, even though it creates a gentle atmosphere for your takeoff into the sky.

    Social media is one of the fastest growing industries in today's world. A study conducted by the US Pew Research Center showed that 92 percent of teenagers go online daily. The wide spread of social media has changed nearly all parts of teenagers' lives.

    Changing relationships

    High school student Elly Cooper from Illinois said social media often reduces face- to-face communication. “It makes in-person relationships harder because of people's attention given to their phones instead of their boyfriends or girlfriends,” Cooper said.

    Yet, some people believe social media has made it easier to start relationships with anyone from anywhere. Beth Kaplan from Illinois met her long-distance friend through social media. He currently lives in Scotland, but they're still able to frequently communicate with each other. “I can feel close to someone that I'm talking to via FaceTime,” Kaplan said.

    Wanting to be “liked”

    The rise of social media has changed the way teenagers see themselves. The 19- year-old Essena O'Neill announced on the social networking service Instagram that she was quitting social media because it made her unable to stop thinking about appearing perfect online. Negative comments also can do great damage to a teenager's self-esteem. Teenagers who get negative comments can't help but feel hurt.

    Opening new doors

    However, Armin Korsos, a student from Illinois, takes advantage of the comments he receives over social media to improve his videos on the social networking site YouTube. “Social media can help people show themselves and their talents to the world in a way that has never been possible before,” Korsos said.

    A new study shows that rising levels of planet-warming gases may reduce important nutrients in food crops.

    Researchers studied the effects of one such gas—carbon dioxide—on rice. The researchers grew rice plants in a controlled environment. They set carbon dioxide levels to what scientists are predicting for our planet by the end of the century. They found that the resulting rice crops had lower than normal levels of vitamins, minerals and protein. The researchers said the effects of planet-warming gases would be most severe for the poorest citizens in some of the least developed countries. These people generally eat the most rice and have the least complex diets, they noted.

    In the experiment, scientists grew 18 kinds of rice in fields in China and Japan. They pumped carbon dioxide gas over the plants in an effort to create the atmosphere of the future. Rice grown under high carbon dioxide conditions had, on average, 13 to 30 percent lower levels of four B vitamins and 10 percent less protein. The crops also had 8 percent less iron and 5 percent less zinc（锌）an rice grown under normal conditions. However, vitamin E levels increased by about 13 percent on average.

    The results are bad news, “especially for the nutrition of the poorer population in less-developed countries,” said the University of Tokyo's Kazuhiko Kobayashi, who helped to write the report. That includes about 600 million people in Indonesia, Cambodia, Myanmar, Bangladesh, Laos and other nations, mainly in Southeast Asia, the report said.

    One of the scientists is Sam Myers of Harvard University in the American state of Massachusetts. He said that findings like this are an example of the surprises climate change create. “My concern is there are many more surprises to come,” he said.

    Myers noted that pollution, loss of some species, destruction of forests, and other human activities are likely to produce unexpected problems. He said that you cannot completely change all the natural systems that living organisms have grown to depend on over millions of years without having effects come back to affect our own health.

    The new study suggests a way to lower the nutritional harm of climate change. One way, Kobayashi said, is grow different forms of rice that have shown to be more resistant to higher carbon dioxide levels.

Do you continue to be healthy in social isolation? NASA is looking for people to spend 8 months locked in a Russian lab for a new experiment.

When humans go to the moon and travel to Mars, they will need to be prepared for long-term space travel and even longer stays on these far-off destinations. Currently, NASA's Artemis program aims to land humans on the moon for the first time since NASA's Apollo 17 mission landed in 1972.

While the moon is the main goal of NASA's Artemis program, the agency's larger goal is to send people to Mars. But long-term space travel and habitation won't be easy. Such missions will present both physical and mental challenges as astronauts work to not only survive, but perform important scientific research in uniquely difficult environments.

In the upcoming NASA-Russia experiment, a group of people will live in a closed facility at Russia's Institute for Biomedical Problems, which is in Moscow. This habitat facility was used in2011 for notable series of Russian mock (模拟的) Mars missions known as Mars 500. During these missions, groups of people spent 520 and 105 days on two separate missions in the facility.

The facility, according to the statement, will have "environmental factors similar to those astronauts are expected to experience on future missions to Mars". The group of people will spend 8 months living together in isolation and working on scientific research.

By living and working in this Mars-like environment, participants in this study will help NASA researchers better understand the psychological and physiological (心理和生理的) effects of isolation. These missions help researchers not only perform relevant science experiments but also see how people might get on under strange conditions for long periods of time.

So, if you're finding that living in social isolation works for you, you might be particularly well-suited for living in a Mars-like environment and this could be for you. But first, you have to qualify. NASA is looking for "highly motivated" Americans between the ages of 30-55, who must speak both Russian and English fluently and have a Master of Science, Doctor of Philosophy, Doctor of Medicine, or military officer training. Applicants with other related experience may also be considered. Those who are chosen to be a part of this group will be paid for their work.

A rainy day can be a chance to recharge. While you relax on the sofa with a movie, the raindrops falling on your windows might one day provide the power for your TV. This is the idea behind an invention that harvests energy from water. 

The technology is based on the triboelectric (摩擦电的) effect. An engineer at the University of Hawaii, David Ma knew that it was possible to generate electricity by rubbing two things together. So, he thought, "Why don't we use water?"

A drop of water sliding across a surface coated with two different materials would generate enough friction(摩擦) to create an electrical charge. By placing metal wires that the drop of water touched as it moved, it should be possible to harvest electricity, he reasoned. 

It worked. In fact, the researchers lit up 15 LED bulbs with a single moving water drop. 

This is not the first time that scientists have got electricity from water-generated friction. Earlier experiments, though, harvested the charge produced in a surface by a sliding drop of water. There, the surface had acted as an electrode(电极). This is different. The energy of friction is being harvested from the water itself. 

"The technology could someday power phones, sensors or other small electronics," says Christopher Oshman, an engineer at the Colorado School of Mines. "This work is a step towards harvesting the energy of moving objects all around us, including ourselves, to power the electronic devices we use every day," he says. 

"Ma has shown that the technology can work in a lab," Oshman says. Next, the Colorado researcher would like to see it tried on a larger scale, such as on an umbrella.