Whether rich or poor, parents who have books in the home increase the level of education their children will attain, according to a 20-year study led by Mariah Evans.

    For years, educators have thought the strongest predictor of attaining high levels of education was having parents who were highly educated. But, the study showed that the difference between being raised in a bookless home compared to being raised in a home with a 500-book library has as great an effect on the level of education a child will attain as the difference between having parents who are barely literate (有文化的) and having parents who have a university education.

    Being a sociologist, Evans was particularly interested to find that children of lesser-educated parents benefit the most from having books in the home. What kinds of investments should we make to help these kids get ahead? The results of this study indicate that getting some books into their homes is an inexpensive way that we can help these children succeed. Evans said, "Even a little bit goes a long way. Having as few as 20 books in the home still has a significant impact on motivating a child to a higher level of education, and the more books you add, the greater benefit the children get.”

    The researchers were struck by the strong effect having books in the home had on children's educational attainment even above and beyond such factors as education level of the parents, the father's occupation or the economic level of the country.

    Having books in the home is twice as important as the father's education level, and more important than whether a child was brought up in a developing country or a developed country. Surprisingly, the difference in educational attainment for children born in developed country and children born in developing country was just 2 years, less than two-thirds of the effect that having 500 or more books in the home had on children.

    Following news of the potential for life on the recently-discovered TRAPPIST-1 system, there may be another competitor ready to take its place.

    With the help of the Cassini spacecraft, NASA (National Aeronautics and Space Administration) scientists have picked up the first evidence that chemical reactions are taking place deep below the surface of Enceladus, Saturn's (土星的) sixth-largest moon. This means that there could be life in Enceladus' warm underground seas.

    An early study found that liquid oceans exist miles below Enceladus' surface. But to reveal what is happening down there, scientists must rely on the plumes (股) of water that spray (喷射) through cracks in Enceladus' icy surface. In October 2015, NASA sent Cassini into a deep dive into one of the plumes.

    Cassini's findings, published on April 13 in the journal Science, showed that hydrogen (氢) not only exists on Enceladus, but is also responsible for a chemical reaction between hot rocks and water in the ocean beneath its surface.

    This same process on Earth provides energy for entire ecosystems around volcanic vents (火山口). There, tiny creatures are able to survive without sunlight, using hydrogen and carbon dioxide as fuel in a process known as “methanogenesis (甲烷生成)”.

    The discovery of this chemical energy source on Enceladus means it could be a very good candidate to host life.

    “Confirmation (确认) that the chemical energy for life exists within the ocean of a small moon of Saturn is an important milestone (里程碑) in our search for habitable (可居住的) worlds beyond Earth,” Linda Spilker, Cassini project scientist at NASA, told the Daily Mail.

    Alien life was once only thought possible on habitable planets within the “Goldilocks zone” – far enough from our sun not to be a fireball, but not so far as to be freezing.

    Research on Enceladus is still in its early stages, but the recent findings have important meanings for future exploration.

    “At present, we know of only one genesis (诞生) of life, the one that led to us,” David Rothery, professor of planetary geosciences (行星与地球科学) from the Open University in the UK, told The Telegraph.

    “If we knew that life had started independently in two places in our solar system, then we could be pretty confident that life also got started on some of the tens of billions of planets and moons around other stars in our galaxy,” he said.

    Have you eaten too much over the holidays? You should try fidgeting for a while. Those around you might not like it, but scratching (moving your nails (指甲) against a part of your body) and twitching (moving suddenly and quickly when you don't want to) is an important way of burning up calories (卡路里).

    American researchers have found that some people's squirming (continuously turn your body when nervous) and wigging (move in small movements, especially from side to side) equals (等于) several miles of slow running each day.

    The scientists, based at the National Institute of Health's laboratory in Phenix, Arizona, are studying why some people get fat and other stay slim.

    In one study 177 people each spent 24 hours in a room in the institute where the amount (量) of energy is measured by their oxygen and carbon dioxide (二氧化碳) levels. By the end of the day, some people had burned up 800 calories in toe-tapping, (moving the front part of your foot up and down) finger-drumming (hitting your fingers continuously and lightly against something hard) and other nervous habits. However, others had burned up only 100 calories.

    The researchers found that slim（苗条的）women fidget more than fat women, but there was no significant difference in men. Heavy people burn up more energy when they fidget than do thin people.

Imagine turning on the GPS and seeing an image of your car from above. As the car drives, the map follows along in real time, informing you of any traffic, pedestrians, animals or other things nearby. Routes and names of road appear over the live stream. It's like the map has come to life.

This type of map isn't available yet. But it could be very soon. In 2014, the WorldView-3 satellite was sent into space. Even though it orbits Earth at more than 370 miles (600km) away, it can take images of objects on Earth that are just 10 inches (25cm) across. Looking all the way from outer space, it can make out a smart phone held in your hand. It can tell what types of cars are travelling down a road. But it can't identify your face or read the cars' license plate numbers.

According to some reports, this satellite and other US satellites have the technology to take even sharper images, with a resolution of up to around 4 inches (10cm). But US law forbids making these super-sharp pictures public. But the idea that anybody might be able to spy on the entire Earth in such detail may seem scary. Live, high-detail satellite mapping could be used to keep tabs on anybody at any time, without the person's knowledge. Ray Purdy of University College London told CNN that he couldn't imagine what this could mean for privacy. "Most satellites are commercially owned, so if you have money, you can have that imagery. It means anyone can spy on anyone." he said.

At the same time, live, detailed maps of the Earth's surface could aid humanity in amazing ways. Satellite images can help experts track storms as they form and chart their paths. At high detail, live maps of a disaster area could quickly reveal people in need of rescue as well as the safest routes in or out. Satellites images are already helping the police catch illegal fishing operations. Higher detail may make it possible to catch other criminals in the act. The images could also make it easier for farmers to watch over their crops or for scientists to find minerals. Also, these images play a very important role in monitoring the health of forests and other landscapes.

What do you think? Would you like to see everyone accessing high-detail live maps of the Earth's surface? Please share your idea with us on the website.

Las Vegas can offer a lot more than you expect. Here are the best guided tours to help visitors make the most of their Sin City getaway.

Big Bus Las Vegas—Open Top Night Tour

Admire the glittering lights downtown on this evening double-decker bus tour. Along the drive, you'll pass well-known buildings before hopping off to enjoy the free light shows on Fremont Street. Tour-takers praise the guides for their informative, friendly account.

Passengers can board the buses at the LINQ Promenade starting at 7 p.m. each evening.

Cowboy Trail Rides—Red Rock Canyon Sunset Horseback Ride

When you need a break from the city life, put on a cowboy hat and boots for a sunset trail ride through Red Rock Canyon. On the ride, you'll follow a guide through the picturesque desert landscape, watching for wildlife. Travelers warn that it can get chilly on the ride, so they advise wearing warm layers.

Trail Rides are offered Tuesday through Sunday.

Papillon Grand Canyon Helicopters—Grand Celebration Tour

Papillon Grand Canyon Helicopters' Grand Celebration tour offers bird's-eye views of sought-after sights, like Eagle Point and Lake Mead. The tour also includes a Champagne picnic. The pilots and staff earn praise for their friendliness and professionalism.

There are several daily departure options.

Secret Food Tours—Las Vegas Strip

Every day Secret Food Tours take groups of 10 participants to five-star restaurants on the Strip to sample a variety of cooking delights, including pizza, chocolates and lobster. During the walking tour, highly praised guides teach tourgoers about the city's food and culture. Travelers say the food on the tour is plentiful and tasty, but they warn that you'll be doing a lot of walking.

Tickets include all food tastings.