Life may have evolved on at least three planets within a newly discovered solar system 39 light years from Earth. Astronomers at the NASA have discovered no less than seven roughly Earth-sized worlds orbiting a dwarf star in the system. Scientists had previously identified a tiny number of "exoplanets", which are believed to have the qualities needed to support life. However, the new system contains an unprecedented(前所未有) number of Earth-sized, probably rocky planets, and is being acknowledged as an "accelerated leap forward" in the search for extraterrestrial (外星球的)life.

    Three of the new planets are said to be particularly promising because there might exist oceans. Thomas Zurbuchen, associate administrator of NASA, told a press conference in Washington: "This gives us a hint that finding a second Earth is not a matter of 'if', but 'when'."

    The planets were discovered using NASA's Spitzer Space Telescope, which was able to track how fast each of the planets crossed the star Trappist-l and completed an orbit. From this the research team calculated how far the planets were from their star, and therefore how likely they are to be habitable.

    NASA's Hubble Space Telescope is already being used to search for atmospheres around the planets. Future telescopes, including the proposed European Extremely Large Telescope and the James Webb Space Telescope, may be powerful enough to discover markers of life, such as oxygen in the atmospheres of exoplanets.

    Astronomers believe there could be as many as 40 billion potentially habitable worlds in our galaxy, the Milky Way. Prof Zurbuchen said that now was a "gold-rush phase" in the search for these exoplanets.

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    The iPhone, the iPad: each of Apple's products sounds cool and has become a fad(一时的风尚). Apple has cleverly taken advantage of the power of the letter “i” --and many other brands are following suit. The BBC's iPlayer--which allows Web users to watch TV programs on the Internet--used the title in 2008. A lovely bear--popular in the US and UK--that plays music and video is called “iTeddy”. A slimmed-down version(简装本) of London's Independent newspaper was started last week under the name “i”.

    In general, single-letter prefixes(前缀) have been popular since the 1990s, when terms such as e-mail and e-commerce(电子商务) first came into use.

    Most “I” products are targeted at(针对) young people and considering the major readers of Independent's “I”, it's no surprise that they've selected this fashionable name.

    But it's hard to see what's so special about the letter “i”. Why not use “a”, “b”, or “c” instead? According to Tony Thorne, head of the Language Center at King's College, London, “i” works because its meaning has become ambiguous. When Apple uses “i”, no one knows whether it means Internet, information, individual or interactive, Thorne told BBC Magazines. “Even when Apple created the iPod, it seems it didn't have one clear definition(定义),” he says.

    “However, thanks to Apple, the term is now connected with portability (轻便).” adds Thorne.

    Clearly the letter “i” also agrees with the idea that the Western World is centered on the individual. Each person believes they have their own needs, and we love personalized products for this reason.

    Along with “Google” and “blog”, readers of BBC Magazines voted “I” as one of the top 20 words that have come to define the last decade(十年).

    But as history shows, people grow tired of fads. From the 1900s to 1990s, products with “2000” in their names became fashionable as the year was connected with all things advanced and modern. However, as we entered the new century, the fashion disappeared.

    Exercise may help to safeguard the mind against depression(沮丧) through previously unknown effects on working muscles, according to a new study involving mice.

    Mental health experts have long been aware that even mild, repeated stress can contribute to the development of depression and other mood disorders in animals and people. Scientists have also known that exercise seems to cushion against depression. But precisely how exercise, a physical activity can reduce someone's risk for depression, a mood state, has been mysterious. So for the new study, researchers at the Karolinska Institute in Stockholm studied the brains and behavior of mice in a complicated and novel fashion.

    We can't ask mice if they are feeling cheerful or in low spirits. Instead, researchers have pictured certain behaviors that indicate depression in mice. If animals lose weight, stop seeking out a sugar solution when it's available — because, probably, they no longer experience normal pleasures — or give up trying to escape from the cold-water zone just freeze in place, they are categorized as depressed. And in the new experiment, after five weeks of frequent but low-level stress, such as being lightly shocked, mice displayed exactly those behaviors. They became depressed.

    The scientists could then have tested whether exercise blunts (延缓) the risk of developing depression after stress by having mice run first. But, frankly, from earlier research, they wanted to know how, so they bred pre-exercised mice. A wealth of earlier research by these scientists and others had shown that aerobic exercise, in both mice and people, increases the production within muscles of an enzyme (酶) called PGC-1alpha. The Karolinska scientists suspected（怀疑） that this enzyme somehow creates conditions within the body that protect the brain against depression. Then, the scientists exposed the animals, which without exercising, were in high levels of PGC-1alpha to five weeks of mild stress. The mice responded with slight symptoms of worry. But they did not develop depression. They continued to seek out sugar and fought to get out of the cold-water zone. Their high levels of PGC-1alpha appeared to make them depression-resistant（抵抗的）. Finally, to ensure that these findings are relevant to people, the researchers had a group of adult volunteers complete three weeks of frequent endurance training, consisting of 40 to 50 minutes of moderate cycling or jogging. The scientists conducted muscle biopsies (活体检查) before and after the program and found that by the end of the three weeks, the volunteers' muscle cells contained substantially more PGC-1alpha than at the study's start.

    The finding of these results, in the simplest terms, is that “you reduce the risk of getting depression when you exercise,” said Maria Lindskog, a researcher at the Karolinska Institute.

    After decades of cat-and-mouse between athletes and the word anti-doping agency (WADA), athletes found what they must have believed to be the ultimate (终极的) doping agent: their own blood. To enhance athletic performance with your own blood, you draw your blood and store it in a freezer. Your body compensates by creating more blood. Then, months later, just before a competition, you can re-inject (注射) the old blood for a boost. As the red-blood-cell count goes up, so does an athlete's ability to absorb oxygen. The more oxygen you get with each breath, the more energy your body is able to bum and the better you are able to perform.

    Although the enhancement is small compared to actual drugs, it can be the difference between a gold medal and a silver medal. Best of all, "extra blood" was never something WADA tested for.

    But WADA wasn't going to sit by and be fooled. What it came up with in response might be a solution to stop doping once and for all: an athlete biological passport (ABP). The idea is to record some biological features of an athlete through testing done at regular intervals. The biological passport's partial implementation (实施)—recording blood and steroid levels—began in January 2014.

    When all necessary biological features are finally combined, WADA will no longer need to worry about finding new methods to detect a drug. It will only have to detect (检测) resulting changes in the body. In the case of blood doping, if the athlete's normal red-blood-cell count is, say, 47%, but then is found to be 51% after a competition, cheating may have been involved.

    WADA is confident that the biological passport could even prevent genetic changes—the ultimate, ever-lasting enhancement—which are surely coming next. If an athlete inserts a performance enhancing gene, it will probably leave detectable changes in the body, that would differ from the athlete's feature in the biological passport.

Plants, and the insects which rely on them, are the living foundations of our planet. But these foundations are under stress because we have a tendency to replace fields and forests with decorative trees and shrubs imported from around the world. Adding to the problem, our obsession (痴迷) with perfection leads us to use a lot of pesticides (杀虫剂).

These actions are part of the reason global biodiversity is crashing. There are over three billion fewer wild birds in North America than there were in 1970. Recent research shows that insect numbers, even in nature reserves, have fallen, and 40 percent of all insect species may be extinct within a few decades. This is discouraging news; however, there are actions we can take to help bring at least some species back.

The first step is to redefine our concept of "garden" to include more than just plants. We need to intentionally share our space, and not just with the birds, bees and butterflies that visit our flowers, but also with the little insects that may eat a part (very rarely all) of our plants. Therefore, we must limit pesticide use. It's crucial to support nature's recovery, and it's much better for everyone: no doctor has ever recommended long-term exposure to pesticides.

Many drought-tolerant plants brought in from across the planet are being passed off as ecofriendly. However, mostly they're not. Yes, you're saving water, but these foreign plants can become disasters when they escape our yards. Helping the environment can be about more than saving water. Even in drier areas, like the American West, the selection of attractive native plants to choose from is vast. If dry is your style, there are native wildflowers, flowering bushes and trees that allow you to save water and nature.

Xeriscapes (节水型园艺) leave many gardeners thirsting for green, and there's an important alternative that has been largely ignored. For those disenchanted with dry landscaping, using underappreciated and water-loving native plants to make your garden a real-life oasis (绿洲) could be lifesaving to wildlife. In nature, this unsung group of native plants is limited to riparian zones, the narrow belts of green along water bodies, but if consumers demand them, nurseries will increasingly carry these riparian species, and the presence of such plants in the garden will provide for many animals including not just butterflies and their relatives but also colorful birds.

The ideal garden would offer a combination of drought-tolerant native plants and a few species that need a little more water, providing options for little guests and the bigger ones that will come to eat them. As more creatures stop by to share our yards, we will be making nature, and us all, a little healthier.

Climbing, I once thought, was a very manly activity, but as I found my way into this activity, I came to see that something quite different happens on the rock.

Like wild swimming, rock climbing involves you into the landscape. On the rock, I am fully focused. Eyes pay close attention, ears are alert, and hands move across the surface. Unlike walking, where I could happily wander about absent-mindedly, in climbing, attentive observation is essential.

As an arts student studying English literature, I discovered a new type of reading from outdoor climbing. Going out on to the crags (悬崖), I saw how you could learn to read the rocks and develop a vocabulary of physical movements. Good climbers knew how to adjust their bodies on to the stone. Watching them, I wanted to possess that skillful "language".

My progress happened when I worked for the Caingorms National Park Authority.Guiding my explorations into this strange new landscape was Nan Shepherd, a lady too. Unlike the goal-directed mindset of many mountaineers, she is not concerned with peaks or personal achievement. Shepherd sees the mountain as a total environment and she celebrates the Caingorms as a place alive with plants, rocks, animals and elements. Through her generous spirit and my own curiosity, I saw that rock climbing need not be a process of testing oneself against anything. Rather, the intensity of focus could develop a person into another way of being.

Spending so much time in high and st ony places has transformed my view on the world and our place in it. I have come into physical contact with processes that go way beyond the everyday. Working with gravity, geology (地质学), rhythms of weather and deep time, I gain an actual relationship with the earth. This bond lies at the heart of my passion for rock climbing. I return to the rocks, because this is where I feel in contact with our land.