Have you heard of parallel universes? Some scientists believe that there might be other universes right alongside ours. Our universe may be just a part of a tree of universes that are all there at the same time—only in different states of time with different pasts and different futures.

What does this mean? It means there is a different “you” in these parallel universes. You might be a Hollywood star in one of them!

In parallel universes, there may be completely different physical laws (物理法则). World wars might have different results. Really, humans themselves might have become extinct (灭绝的) in certain parallel universes!

The idea of parallel universes dates back to 1954. Hugh Everett Ⅲ, a Princeton University student in the United States, developed the idea that parallel universes—exactly like and related to our universe—are there. However, many physicists and astronomers say that this theory can’t be tested, so it’s not really a theory at all.

But since then, the idea has shown up in comic books, television and movies. Shows like Star Trek and Doctor Who use the idea to develop their stories.

Parallel universes might not only be there in the movies. If their stories are true, some people might have already experienced other realities.

First covered by newspapers in 1952, Cornelio Closa, a schoolboy from the Philippines, kept disappearing right in front of his friends and family. Sometimes disappearing for days, he would somehow disappear from his locked family home and crowded school classroom.

While such stories may sound crazy, even the known universe is far older and larger than we are. So, who’s to say that one day we won’t learn to cross dimensions (维)?

The journey into space is a long and dangerous one, and not many people are able to do it. Lots of training is in need before one gets on the spaceship. But soon, it may be as simple as riding an elevator.

A group of Japanese scientists from Shizuoka University have been working on a “space elevator”, which will allow easy access to space.

On Sept 22nd, 2018, two tiny satellites were sent to the International Space Station（ISS）as a test for the space elevator. The mini elevator has a 10-merer steel cable. It works as a tiny model of a full-size “space elevator”, which might reach from Earth all the way to outer space. “It’s going to be the world’s first experiment to test elevator in space,” the spokesman of Shizuoka University said.

According to Science Daily, the research team hopes to build the elevator by 2050. The space elevator may be able to carry up to 30 people. The trip will be about 36,000 km, which will take around eight days to complete. If it is successful, space elevators will greatly cut the cost of transporting cargo into space from $22,000（154,000 yuan）to $200（1,400 yuan）per kilogram. More importantly, they will produce less pollution during spree travel.

Still, there are many hurdles along the way. According to the official website of the US-based Smithsonian Institution, until now, researchers haven’t found a material strong enough to hold the stress placed on the elevator cable. Even carbon nanotubes, the strongest material they have found so far, would break under the stress.

The challenges facing the space elevator are massive, but they have not stopped Japan from working on it. “Japanese researchers believe the idea of space elevator will be realised. since there are many scientists in the fields of robotics and carbon nanotube technology in the team,” Michelle Z. Donahue, Smithsonian science reporter, wrote in 2016.

China’s Eye In the Sky

July 31 was a big day for China. On that day, China’s first global satellite navigation (satnav) system (全球卫星导航系统), Beidou, started its full-scale (全面的) work. More than 120 countries and regions are now using Beidou services.

Beidou means “Big Dipper (北斗七星)” in Chinese. In old times, when people got lost, they looked up at the Big Dipper for direction (方向). Now, China’s own satellite navigation system, BeiDou, is there to keep us safe and bring us convenience.

With as many as 59 satellites (卫星), Beidou has “sharp eyes”. These satellites fly around the Earth. They can “see” rivers, forests and mountains. They can “see” houses and schools. Of course, they can “see” you, too! From space, they can tell where you are on the ground, with a difference of no more than 10 meters.

A satnav system uses groups of satellites. It sends information to a receiver (接收器), such as a smart phone. The more satellite a system has, the more accurate (精确的) it is.

Beidou is the world’s fourth navigation satellite system. The earliest system is the Global Positioning System (GPS) of the United States. The US has put 24 satellites into space to make sure GPS can locate (定位) a person correctly and globally. Likewise, Russia’s GLONASS and European Union’s Galileo can also work globally.

BeiDou can find you wherever you are. It helps you go faster by finding shortcuts (捷径) and using correct directions. It can look for mines (矿产) in deep mountains. It can give orders to driverless cars. This summer, Chinese people fought the flood in the South. Beidou helped measure (测量) the rise and fall of the flood water.

What’s more, when people are in danger and there is no cell phone signal, they can use Beidou to send a 1,200- word message to ask for help.