No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.

     “Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.

    People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.

    The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.

    Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

    However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.

    So he tried it.

    He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.

    They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.

    West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

    Jack was born without eyes. He's very lucky with his timing. He grew up having other kittens to play and socialize with, and was used to people from the moment he was born since there are always kids hanging around the barn. He was a favorite amongst the students at the barn. However, when it came time to find the kittens homes, no one knew where Jack would end up. That's when I got an e-mail from my friend. All she asked was “Do you still want one of the kittens? There's one here with no eyes and no one can take him.” Without thinking I told her that I did want the kitten.

    When we first brought him home Jack stayed mostly in my room. He walked cautiously around, sniffing everything. After about a day he had no issues running around, jumping onto my bed and climbing on everything. He went through a time where he could climb the stairs, but couldn't get down. He would sit at the top and cry until someone came and got him. Every now and then when he gets disoriented he'll stop and cry. But we just call his name and talk to him and it isn't long before he finds his way back to us.

    Also, a few weeks after getting Jack, we got a new barn cat named Bear. I always take Jack outside at that time for some fresh air and exercise. He loves to run (at top speed!) around the back yard and gardens. Bear and Jack have become best friends. It doesn't matter that he can't see, Jack always knows when Bear is around. He'll run across the yard straight to Bear and wrap his front legs around his neck in a big hug. They chase each other around and wrestle, and when they're tired they'll lie down in the grass together.

    Jack is truly an inspiration. I've owned a lot of kittens in my life, but Jack is the happiest, most playful of them all. He doesn't feel sorry for himself. Heck, for all he knows, all cats are just like him. People who know Jack don't feel sorry for him. They cherish him for the treasure that he is. I have talked to a few people who haven't met him personally who tend to pity him, but they just don't understand. Jack doesn't need pity. I think Jean (who has Gumbo the eyeless ginger) said it best when she told me that cats don't have disabilities, they have adaptabilities.

    After opening the world's first commercial Direct Air Capture plant（直接空气捕集工厂）designed to pull CO₂ out of the air, Swiss company Climeworks is now trying to create the world's first “negative emission（负排放）” power plant.

    An international team of scientists has been working on a way to turn captured CO₂ into minerals. The project is called CarFix. Experts capture the gas, put it into water and send it to more than 700 meters underground. There the CO₂ on contact with a special kind of rock forms into a mineral.

    “Our results show that between 95 and 98 percent of the CO₂, sent underground was mineralized over the period of less than two years, which is amazingly fast,” says lead author of the CarFix project, Dr. Juerg Matter. Before this discovery it was thought that this mineralization could take hundreds to thousands of years.

    The DAC technology can collect CO₂ from the atmosphere and then store it underground or sell it to business needing the gas. For example, customers can use it in drinks. And the first plant in Zurich is supplying the captured CO₂ to a nearby greenhouse to “feed” vegetables. By using the company's CO₂ the customers can reduce their carbon mission as well as lower their dependence on energy.

    A 2015 study suggested that before the CarFix project, experts could collect CO₂, but they didn't have a large-scale（大规模的）method to safely treat it.

    Combining Climeworks' DAC technology with the CarFix mineralization process they will be able to create a system. This system doesn't put additional carbon back into the atmosphere. Actually it is carbon negative.

    “The economic cost of applying this kind of carbon capture technology on a large-scale is not particularly practical now, but for the first time we are seeing a realistic and effective system,” says Christoph Gebald CEO of Climeworks.

    You don't have to be a superhero to help the environment. Even small, simple actions can add up to big change. People around the world will celebrate Earth Day on April 22. But anyone – including kids – can work to help the earth at any time. TFK (Time for Kids) talked to a few kids about how they are protecting the planet. Let them inspire you!

    Mari, 10, lives in Flint, Michigan, where people have been without clean drinking water since 2014. That is when the water became polluted with lead（铅）. Children in Flint have suffered from health problems due to lead poisoning. Mari has worked hard to spread awareness of Flint's water crisis by organizing fundraisers and other events.

    At age 3, Ryan went with his dad to recycling center near his home, in Orange County, California. The next day, Ryan began collecting recyclables from neighbors. Soon, Ryan's Recycling Company was born. “Recycling keeps bottles and cans out of the ocean,” Ryan, now 8, told TFK, “so animals don't get sick from them and die.” So far, Ryan has helped customers recycle 320,000 bottles and cans. He has also donated nearly $6,000 to the Pacific Marine Mammal Center.

    Joris, 11, has always loved cheetahs. When he learned that the big cats might disappear in his lifetime, he set out to help protect them. Joris began raising money. So far, Joris has raised more than $14,000. The money goes to a wildlife sanctuary（避难所）in Namibia, a country in Africa. This helps prevent the animals from being killed. Jorin has spent three summers volunteering at the sanctuary.

Iman, the last Sumatran rhino(犀牛) in Malaysia, died in 2019 — bringing the endangered species one step closer to extinction. Now, Malaysian scientists are hoping to use tissues and cells from Iman and other dead rhinos to bring the population back.

"Before the three rhinos (the last survivors in Malaysia) died, we got their cells, and the cells are still alive — which is why I'm quite confident," Dr. Lokman said. "If we don't have any cells, or have just tissue that isn't living anymore, we wouldn't be able to do anything. But now we have a living thing that we can use. "

The cells came from the rhinos'hearts, lungs and brains. What is the most important is that the team collected stem cells (干细胞). One possible approach is to develop these stem cells into an egg (卵子) and sperm (精子), to create an embryo (胚胎) that will be placed into a surrogate mother (代孕母亲). She will likely be another rhino, either a Sumatran rhino from another country or another species. The other method is to take the egg of a surrogate animal, remove the nucleus (细胞核), and join it with a Sumatran rhino's body cell. This technique was famously used to clone Dolly the sheep in 1996. Dr. Lokman and his colleagues are trying both ways. The team is still in the early stages; next, they need to find a suitable surrogate female.

Sumatran rhinos are listed as critically endangered by the World Wildlife Fund. There are less than 80 alive in Indonesia and Thailand. The fall in the population was first caused by hunting. Later, the situation was worsened by the loss of habitats and human activity. Unfortunately, there are now only five remaining rhino species worldwide, and all are threatened. Some sub-species have already died out; the western black rhino was declared extinct in 2013. And it is a pity that the last male northern white rhino died in 2019.

After months of expectation and secrecy, the official mascot (吉祥物) of the 2022 Winter Olympic Games－a giant panda-inspired cartoon character－made its first public debut with cheers at Beijing's Shougang Ice Hockey Arena.

The panda is named “Bing Dwen Dwen” in Chinese. Bing means “ice” in Chinese, while Dwen Dwen suggests “health and cleverness”－characteristics also shared by pandas. Pandas are perhaps the most recognized animal species in China, organizers said.

“Pandas combine China's traditional culture and its modern appearance together with winter sports elements in a fascinating image (形象) that shows our great expectations for the Games and shows that we welcome the world,” said Beijing Mayor Chen Jining, who also serves as an executive president on the organizing committee.

“I have already seen the mascot and from what I've seen, it's a wonderful choice,” IOC President Thomas Bach said before introducing the character.” “The mascot really takes in the best elements and characteristics of China and the Chinese people. It will be a great ambassador (大使) for the country and the 24th Winter Olympics.”

The ring of light surrounding the mascot's face is suggestive of ice and snow tracks, as well as the flowing “ribbons” of the National Speed Skating Oval. The oval is one of two new competition sites in downtown Beijing expected to become a landmark of the Games, according to its chief designer Cao Xue.

The introduction of the mascots marks the key point of a journey that began in August 2018, when Beijing organizers started a global design competition for the mascots. A total of 5,816 designs were received from 35 countries, and were reviewed by Chinese and international experts in a comprehensive evaluation and selection process.

The new mascot will serve as spirited symbol of the Games that will take place in the three zones of downtown Beijing, the suburban district of Yanqing and co-host city Zhangjiakou in surrounding Hebei province.