1 . Avi Loeb, a scientist, believes that we are not alone in the universe. The belief fits with Loeb’s alien (外星的) spaceship theory that at least one alien spaceship might be flying over the orbit (轨道) of Jupiter, which won the international attention last year.

Astronomers in Hawaii found the first known interstellar (星际的) object in late 2017. It was a bit of light moving so fast past the sun that it could only have come from another star. Almost every astronomer on the planet was trying to figure out how the object, called “Oumuamua” got to our far-away, part of the Milky way galaxy. “One possibility is that ‘Oumuamua’ is debris (碎片) from an advanced technological equipment,” Loeb said. “Technology comes from another solar system just showed up at our door.”

“‘Oumuamua’ is not an alien spaceship,” Paul Sutter, another scientist wrote. He suggested Loeb was seeking publicity. Most scientists think “Oumuamua” is some sort of rock. They think it could be an icy wandering comet.

Loeb says that “Oumuamua’s” behavior, means it can’t be a block of rock shaped like a long photo. He thinks it's more likely an object that’s very long and thin, perhaps like a long pancake or a ship’s sail. Loeb says that if someone shows him evidence that contradicts his beliefs, he will immediately give in.

Loeb believes himself a truth-teller and risk- taker in an age of very safe, too-quiet scientists. “The worst thing that can happen to me is that I would be relieved of my management duties, and that would give me even more time to focus on science,” Loeb says. He said he wouldn’t mind giving up all the titles he had and returning to the Israeli farming village where he grew up.

2 . In recent years, Ethiopia has become a regional leader in solid waste management. Last year, the country transformed the landfill (垃圾填埋场) in Addis Ababa into a new waste-to-energy plant, the first such project on the continent. The plant incinerates up to 1, 400 tonnes of waste every day, about 80 percent of the city's rubbish, supplying the capital with 25 percent of its household electricity needs.

However, despite these important steps, challenges remain in Ethiopia. Although the country has permitted the Basel, Stockholm and Rotterdam conventions, laws and policies for environmentally sound management of hazardous (有害的) wastes are still not effective in pre- venting littering waste illegally.

To help Ethiopia meet these challenges, the Chemicals and Waste Management Program is supporting the country with a three-year project to enhance its capacity for sound management of hazardous wastes.

In the initial stages, a project management unit will be formed, made up of many representatives from government departments and private organizations. This unit will be responsible for reviewing and assessing Ethiopia's current legal system, which, despite numerous advances in recent years, does not specifically target the recycling of hazardous waste. Once legal gaps are identified, the project will seek to update existing policies and strategies.

Many people in Ethiopia are not aware of the possible effect of environmental damage and the need to report such crimes to the police. To resolve this pressing issue, Ethiopia will be conducting a series of capacity-building activities, including creating awareness-raising programs, training trainers and providing equipment.

Ethiopia will also work to establish a national mechanism for chemicals and waste management by engaging government departments and civil society groups. Authorities will also make budgetary provisions (预算拨款) in national, regional and institutional planning to ensure funding for these activities is sustainable even after the project's completion.

3 . A new study has found that animals feign（假装）death for long periods of time in order to escape capture from their predators. How long they are motionless depends on the circumstances, but they can wait out their predators for quite a long time when their lives are in danger.

Animals stay still to avoid capture for different lengths of time. “Most intriguingly, Charles Darwin recorded a beetle that remained motionless for 23 minutes. Antlions, our favorite study creature in this regard, set a record of 61 minutes,” says lead author Nigel R. Franks from the University of Bristol.

Antlions are members of large group of insects. Antlion larvae（幼虫）dig pits in loose soil and then aggressively attack ants and other small insects that fall into the sandy pits. In another study, researchers dug sandpits to understand the physics of how antlion larvae build their pits. As part of their research they needed to weigh the individual larvae. When they put them onto the microbalance scale to weigh them, they noticed that the larvae remained motionless for long periods of time. “This made it ‘piece of cake’ to weigh them but it aroused researchers’ curiosity, ‘What on earth were they playing at?’” Franks says.

The researchers found that the amount of time the antlions remained stationary after being disturbed was unpredictable and was often quite lengthy. In researching other animals, they found that how long they wait to move again can depend on factors such as hunger and temperature, but it always varies.

This unpredictability is absolutely crucial for their survival, Franks says. For example, if a bird visits these antlion pits and the larvae “play dead”. the birds will fly around the antlions to see if they move. “Imagine if antlions always remained immobile for 5 minutes. In such case, the predator could look for alternate prey（猎物）and then return to its original one when the time is up,” he says. “If that happened, it would be a short life for the predictable death-feigner.” But because the time is unpredictable, the birds leave and go find something else to eat. The predators turn their attention from the unmoving prey that no longer catches their eye to something nearby that is a better alternative.

5 . While it's not impossible for birds to fly in the rain, they usually choose not to. You may see birds fly for a few seconds in poor weather, but most of them prefer to stay put on rainy days.

Why does rain make it harder for birds to fly? You might imagine that moving through the air while being pelted by raindrops would be pretty unpleasant. However, it's not the rain itself that makes flying difficult. Instead, birds are influenced by the drop in the air pressure that comes with most rainstorms. When pressure drops, the air is less thick, which makes it harder for birds to fly. Moving through the sky in areas of low air pressure takes a lot of energy.

Most birds need to eat several times a day—rain or no rain. Luckily, most birds' feathers（羽毛）are highly waterproof（防水的）, protecting the skin beneath. Many birds can also make oil that they can spread over their feathers to further protect themselves from the rain. Most birds don't like rain. In fact, in a 2010 study, a team of researchers studied birds living in a Costa Rican rainforest. They found that the birds had higher levels of stress hormone（应激激素）on rainy days. That may not surprise you. After all, many animals feel stressed out during storms. Pet owners often find that rain and thunder make their animals nervous. Some animals are so strongly influenced by nature that they almost seem to forecast the future.

No one really knows how many birds die during a storm or series of storms. But the number is certainly higher than usual. They fly into trees or windows; they get lost over the ocean or a large lake; their food sources are made more difficult to get but, at the same time, they need more food to get warm. However, if rain continues for some time, birds will have to challenge the storm.

6 . Americans are now allowed to get a COVID-19 vaccine （疫苗）. But the process in America is not going as smoothly as some had hoped. Many people are still facing a wait for their first shot. Moreover, the vaccines aren't available to kids under 16 yet. That's because scientists have only tested if the vaccine works in adults.

The good news is that there are two companies, Moderna and Pfizer, making COVID-19 vaccines. They are now running clinical trials（临床实验）to test their vaccines in teens and kids. Volunteers are given a treatment plan and then evaluated after.

Clinical trials are designed with safety in mind and usually done in adults first. They work like this: volunteers get placed into one of two groups. One group receives the vaccine. The other group gets a placebo. This is a shot given in the same way as the vaccine but with no effect. Scientists can compare the effects of the real vaccine against the placebo to see if the vaccine works. Researchers want to know everything that a person experiences when they get the shot, so they can detect any harmful effects. If anything did happen, the trial would stop immediately.

Some teens are eager to volunteer because they want to help people. Maybe you're the right age to be part of a clinical trial for the COVID-19 vaccine. Why not volunteer For A Vaccine Trial? Interested kids should read about the trials because every trial has risks. They should talk to their doctor and weigh the benefits and risks. Every vaccine has rare side effects in a few patients.

If you want to participate in a trial, you can try to sign up online by just clicking here, clinicaltrials gov. which lists every clinical trial in the US, including COVID-19 vaccine trials.