If humans were truly at home under the light of the moon and stars, we would go in darkness happily, the midnight world as visible to us as it is to the vast number of nocturnal (夜间活动的) species on this planet. Instead, we are diurnal creatures, with eyes adapted to living in the sun's light. This is a basic evolutionary fact, even though most of us don't think of ourselves as diurnal beings. Yet it's the only way to explain what we've done to the night: We've engineered it to receive us by filling it with light.
The benefits of this kind of engineering come with consequences — called light pollution — whose effects scientists are only now beginning to study. Light pollution is largely the result of bad lighting design, which allows artificial light to shine outward and upward into the sky. Ill-designed lighting washes out the darkness of night and completely changes the light levels — and light rhythms — to which many forms of life, including ourselves, have adapted. Wherever human light spills into the natural world, some aspect or life is affected. In most cities the sky looks as though it has been emptied of stars, leaving behind a vacant haze (霾) that mirrors our fear of the dark. We've grown so used to this orange haze that the original glory of an unlit night, — dark enough for the planet Venus to throw shadow on Earth — is wholly beyond our experience, beyond memory almost.
We've lit up the night as if it were an unoccupied country, when nothing could be further from the truth. Among mammals alone, the number of nocturnal species is astonishing. Light is a powerful biological force, and on many species it acts as a magnet (磁铁). The effect is so powerful that scientists speak of songbirds and seabirds being "captured" by searchlights on land or by the light from gas flares on marine oil platforms. Migrating at night, birds tend to collide with brightly lit tall buildings.
Frogs living near brightly lit highways suffer nocturnal light levels that are as much as a million times brighter than normal, throwing nearly every aspect of their behavior out of joint, including their nighttime breeding choruses. Humans are no less trapped by light pollution than the frogs. Like most other creatures, we do need darkness. Darkness is as essential to our biological welfare, to our internal clockwork, as light itself. Living in a glare of our own making, we have cut ourselves off from our evolutionary and cultural heritage—the light of the stars and the rhythms of day and night. In a very real sense light pollution causes us to lose sight of our true place in the universe, to forget the scale of our being, which is best measured against the dimensions of a deep night with the Milky Way—the edge of our galaxy-arching overhead.
When most of us think of sand, we immediately think of sunny beaches and summer holidays. But actually it's in pretty much everything that surrounds us in our everyday lives. From the walls of our homes to the glass bottles in our kitchens and even the mobile phones in our hands. Sand is the second most used resource in the world after water: it accounts for more than two-thirds of everything that's being dug out of the ground. But there isn't a limitless supply. In fact, a UN report says we might be running out.
According to the report, we use an estimated 15 billion tons of sand every year in the construction industry alone. That's enough to build a 20m × 20m wall around the equator every year. However, sand can take tens of thousands of years to form: the process starts with rock being eroded(侵蚀) in the mountains and ends, eventually, with sand being in river beds and on the seafloor.
Sand is heavy and difficult to transport, so in developing countries, sand is often mined from the nearest convenient source, and quite often that means a river bed or beach. But beaches and rivers are delicately balanced ecosystems and when a large amount of sand is removed, the balance is upset. The smallest fish, which eat organic matter on the sand in river beds, from the base of the food chain in a river. If this sand is removed, so is the source of food for the bottom feeders. All organisms in a food chain share the joys and the sorrows. Thus, when they disappear, so does the food for the larger fish which would have been caught and eaten, or sold by fishermen.
It is high time we took into consideration the big problem concerning the tiny thing. More and more conservationists are calling for alternatives to sand especially in the construction industry.
If you have difficulty deciding on your book list, the following ideas shared by some great talents might help you out.
Read books from eras past // Albert Einstein
Keeping up with current events and latest books from the bestseller list is a big job, but Albert Einstein thought it was vital to leave some room for older works, too. Otherwise, you'd be "completely dependent on the prejudices and fashions of your times," he wrote in a 1952 journal article.
Don't jump too quickly from book to book // Seneca
Seneca, a first-century Roman Stoic philosopher, believed that reading too wide a variety in too short a time would keep the teachings from leaving a lasting impression on you. "You must spend much time among a limited number of master thinkers, if you would gain ideas which shall win firm hold in your mind," he wrote.
Shop at secondhand bookstores // Virginia Woolf
In her essay Street Haunting, Virginia Woolf described the benefits of shopping in secondhand bookstores, where the works "have come together in vast flocks of various feather, and have a charm which the carefully chosen books of the library lack."According to Woolf, looking through used books gives you the chance to come across something that wouldn't have risen to the attention of librarians and
booksellers, who are often much more selective in building their collections than secondhand bookstore owners.
You can skip outdated science works, but not old literature // Edward Lytton 19th-century British novelist and Parliamentarian Edward Lytton was a firm believer in the value of reading old literature.
"In science, read, by preference, the newest works; in literature, the oldest," he wrote in his 1863 essay collection Caxtoniana. "The classic literature is always modern. New books revive and redecorate old ideas; old books suggest and inspire new ideas."
We may think we're a culture that gets rid of our worn technology at the first sight of something shiny and new, but a new study shows that we keep using our old devices well after they go out of style. That's bad news for the environment and our wallets—as these outdated devices consume much more energy than the newer ones that do the same things.
To figure out how much power these devices are using, Callie Babbitt and her colleagues at the Rochester Institute of Technology in New York tracked the environmental costs for each product throughout its life from when its minerals are mined to when we stop using the device. This method provided a readout for how home energy use has evolved since the early 1990s. Devices were grouped by generation. Desktop computers, basic mobile phones, and box-set TVs defined 1992. Digital cameras arrived on the scene in 1997. And MP3 players, smart phones, and LCD TVs entered homes in 2002, before tablets and e-readers showed up in 2007.
As we accumulated more devices, however, we didn't throw out our old ones. "The living-room television is replaced and gets planted in the kids' room, and suddenly one day, you have a TV in every room of the house," said one researcher. The average number of electronic devices rose from four per household in 1992 to 13 in 2007. We're not just keeping these old devices —we continue to use them. According to the analysis of Babbitt's team, old desktop monitors and box TVs with cathode ray tubes are the worst devices with their energy, consumption and contribution to greenhouse gas emissions more than doubling during the 1992 to 2007 window.
So what's the solution? The team's data only went up to 2007, but the researchers also explored what would happen if consumers replaced old products with new electronics that serve more than one function, such as a tablet for word processing and TV viewing. They found that more on-demand entertainment viewing on tablets instead of TVs and desktop computers could cut energy consumption by 44%.
