It is said that Thomas Edison used to chase the twilight (追求模糊状态) moments between wakefulness and sleep. Supposedly. he used to fall asleep in a chair. holding two balls in his hands. As he nodded off, the balls fell down. The resulting noise woke him up. Then, he could write down his inventive ideas before he fell into a deep sleep and forgot them. This inspired a new study.

Researchers tested Edison's method of encouraging creativity with 103 healthy people. Volunteers came to the lab to solve a number problem. They were asked to change some numbers into a shorter sequence (序列). They were told to follow two simple rules. However, what the volunteers weren’t told was that there was an easy trick to finish this task. The second number in the sequence would always be the correct final number.

After doing this task 60 times, volunteers got a 20 - minute break. Volunteers held the similar balls that Edison used as “alarm clocks”. The researchers told them to rest or sleep if they wanted to. All the while. their brain waves were kept track of (跟踪) . More than half of the volunteers stayed awake. Twenty- four fell asleep and stayed in the stage (阶段) of sleep called N1. Fourteen others progressed to N2, a deeper stage of sleep.

After their rest. volunteers returned to their number problem. People who reached the N1 stage of sleep were 2.7 times as likely to discover the hidden trick as people who stayed awake and were 5. 8 times as likely to discover the trick as people who fell into a deeper sleep stage.

“Such obvious (明显的) differences in such experiments arc not common,” said Delphine Oudiette, a scientist. “We were quite surprised at the results, and more work is needed to show the connection between N1 and creativity.” Interestingly, according to the result of the experiment, people may be able to lean to take advantage of that twilight stage of sleep. Undoubtedly. Edison is such a great person, but there is no need to pay too much attention to Edison's habit. He is also said to have considered sleep “a total waste of time”.

During the outbreak, many people study and work at home. Online classrooms and cloud offices are developing rapidly in China.

According to China Daily, at least 600,000 teachers from schools all over China have been providing online classes during the epidemic. On DingTalk. Alibaba's cloud office platform, more than 50 million students had been taking online courses by mid-February.

Many after-school tutoring institutions（辅导机构）are also taking action. Over 80 education companies, including Zuoyebang and VIPKid, have been offering free online courses. They are trying to attract more long-term users. "The epidemic has made online education companies save advertisement fees of nearly 240 billion yuan in China, as it takes around 1,000 yuan to move a student from offline study to online," said Chen Xiangdong, founder of online education firm Genshuixue.

For employees（员工）, online office software is making it possible to work from home. According to China Daily. DingTalk has served more than 10 million companies. Tencent Meeting. another similar platform, has added more than 100. 000 cloud servers to increase its computing capacity（能力）. It can now allow over 300 people to have video meetings online together.

“In the long run, online offices and education will be better developed. We should not underestimate（低估）the rise of new users on different platforms during the epidemic. The users' new habits might influence the future," Zheng Anqi from the China Academy of Information and Communications Technology told Guangming Daily.

How much do you know about Earth-the planet that we live on? Our knowledge of Earth has been developing since ancient times. However, many puzzles (谜) about Earth remain unsolved. Live Science has published a list of the eight biggest mysteries about Earth. Let’s look at some of them.

Where did water come from?

When it first came into being 4.5 billion years ago, Earth was a dry rock. So where did all of our water come from? Scientists think that it might have arrived in the form of ice by an asteroid (小行星) from outer space that hit our planet. But this idea has not been confirmed (证明) because there is very little related evidence (相关证据) to be studied.

What’s in the core (地核)?

Scientists used to study meteorites (陨石) as small examples of Earth, believing that Earth’s core was made of iron and nickel (镍). However, a later study in the 1950s proved this way to be wrong because it found that Earth would be too light to provide gravity (引力) if its core contained only iron and nickel. Today, scientists continue to bring forward different ideas, but none have been confirmed.

How was the moon born?

Scientists have found that the chemical compositions (成分) of Earth and the Moon are very similar. That suggests that the Moon actually came from Earth. For example, it could be a piece of Earth that separated when Earth hit another planet. It is also possible that when Earth first came into being, it spun (旋转) very fast and threw off enough molten (熔化的) rock to later form the Moon.