When you look at the map of the Tengger Desert (腾格尔沙漠), you will see a “green wall” in the southwest. It products Wuwei City of Gansu Province from sandstorms.

With an area of over 8,000 mu, the “green wall” was planted by Wang Tianchang and his family. They have done this great job for over 20 years.

In his seventies now, Wang Tianchang is an ordinary farmer from Gansu Province. He and his family live in a small village close to the Tengger Desert. People there once suffered a lot from sandstorms for a long time. They destroyed their farms and houses. To hold back sand, Wang Tianchang decided to do something. In 1999, Wang planted his first plant in the desert and started his life of sand control.

It is never easy to bring life on the desert. In the beginning, Wang had no experience with desert plants. The sand covered the holes he dug very soon. The wind rooted out the seedlings he planted even on the second day he had done. It was challenging, but he never gave up.

His family helped him a lot, especially his son Wang Yinji. To plant more trees, the two of them even lived in the desert for about six years. They found grass to sleep on as their beds.

Thanks to Wang’s “green wall”, Wuwei City sees much fewer sandstorms. Wang has brought back not only green to the desert but also hopes to the people there. He is our hero!

2 . Water makes up 71% of the Earth’s surface, but no one knows how or when such massive quantities of water arrived on the Earth. A new study published in the journal Nature brings scientists one step closer to answering that question.

Led by University of Maryland Assistant Professor of Geology Megan Newcombe, researchers analyzed melted meteorites (熔化的陨石) that had been floating around in space since the solar system’s formation 4.5 billion years ago. They found that these meteorites had extremely low water content — in fact, they were among the driest materials ever measured outside the Earth.

These results, which let researchers rule them out as the primary source of the Earth’s water, could have important information for the search for water — and life — on other planets. It also helps researchers understand the unlikely conditions making the Earth a livable planet.

Researchers wanted to understand how our planet managed to get water because it’s not completely obvious. Getting water and having surface oceans on a planet that is small and relatively near the sun is a challenge.

“We knew that plenty of outer solar system objects were differentiated, but it was sort of secretively assumed that because they were from the outer solar system, they must also contain a lot of water,” said Sune Nielsen, a study co-author and geologist at the Woods Hole Oceanographic Institution. “Our paper shows this is definitely not the case. As soon as meteorites melt, there is no remaining water.”

The findings have applications beyond geology. Scientists of many fields — and especially exoplanet (系外行星) researchers — are interested in the origin of the Earth’s water because of its deep connections with life.

“Water is considered to be a must for life to be able to exist, so as we’re looking out into the universe and finding all of these exoplanets, we’re starting to work out which of those planetary systems could be potential hosts for life,” said Newcombe. “In order to be able to understand these other solar systems, we want to understand our own.”

Yours,

Li Hua

7 . How to Survive a Tsunami on the Beach

The word tsunami is from Japanese. It describes a series of waves that can reach over 100 feet tall and travel at speeds up to 600 miles per hour across the sea. A single wave in a tsunami can be quite long, as much as 60 miles, causing great damage.    1    

Your best chance for surviving a tsunami on a beach is to pay attention to the warning signs, stay away from the shore after an earthquake, and get to high land. Then wait for information from disaster response groups.

    2    With your family, discuss how you’ll reach the evacuation area (紧急疏散区) as soon as possible.

The sooner you know a tsunami is coming the better your chance of making it to higher ground.    3    

·Head for high ground, get at least 100 feet above sea level.

·    4    

·Don’t swim against the current.

As you learn how to survive a tsunami, remember the first wave in a series of waves is the smallest and weakest.    5     If you’re in a boat at the beach, head out into the ocean. You’ll stand a better chance away of survival away from the shoreline.

9 . Every week, Angela looked at her recycling bin, filled with shampoo bottles and plastic containers, with mixed feelings. Sure, it was a lot of plastic, but it was going to be recycled. Or so she thought. Then, her husband sent her some articles revealing that less than 6% of the country’s plastic gets recycled. She was shocked.

Determined to cut back on her plastic consumption, Angela got a starter kit from a company selling refillable household cleaners (家用清洁器). In it were tablets, containing concentrated hand soap as well as glass and bathroom cleaners, and four empty containers. She filled each one with tap water, then dropped in a tablet and watched it dissolve. If she was happy with the cleaners, she would order more tablets but reuse the containers. No new plastic required.

Given plastic’s harmful effects on the environment, nearly three quarters of Americans say they are trying to reduce their reliance on single-use plastic, according to Pew Research Center. Since plastic is everywhere and avoiding it altogether is extraordinarily difficult, some, like Angela, have revived a once-customary practice: refilling containers. Household cleaners seem particularly prepared for a refill revolution, for many can be easily concentrated and reconstituted (with water. If just 10% to 20% of plastic packaging are reused, a report from the World Economic Forum estimates, the amount of plastic waste entering the ocean will be cut in half.

Not everyone is as enthusiastic, though. Jan Dell, a chemical engineer, noted that many cleaning products are packaged in PET or HDPE, two types of plastic with relatively high recycling rates. So she is less concerned about them but far more concerned about the packaging of other products. “What companies should be focusing on is everything else that isn’t recyclable, that is single use and that often becomes plastic pollution,” she said, pointing to plastic bags and cups. “This is just a classic example of big corporations doing something to attract people’s attention over here on something that’s not the main issue to distract from all the single-use plastic they’re pushing out.”