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.

For the first time ever, plants from Earth are growing on the moon. The China National Space Administration (中国国家航天局) showed photos of cotton plants. The administration said the cotton plants were among several plants that were “growing well”. Other plants that are now growing on the moon are vegetables.

The plants are part of a project to the far side of the moon. Project leader Liu Hanlong says the cotton seeds were the first to come up. He said the plants were chosen because they were small, strong and could grow in the difficult conditions on the moon’s surface.

Professor Hanlong said the project’s aim was to understand more about how plants grow outside of Earth. The long-term aim is to develop plants that can grow not only on the moon but also on the Mars (火星).

The professor said: “We have considered the future survival live in space. Learning about these plants growing in a low-gravity (低重力) environment would allow us to know that in the future humans may live in the space.”

Mars is the fourth planet from the Sun and the second smallest planet of the Solar System.

It is around two times smaller than Earth with a diameter of 6,779 km. If you stand on Mars and look at the Sun, it will appear about half the size we see it on Earth. Mars is widely known as the red planet. Its red appearance is caused by the rusty iron in the ground.

In many ways, Mars can be considered Earth’s brother. On Mar’s surface, we have discovered the biggest mountain in the Solar System. It is named Olympus Mons, and it is three times bigger than the largest mountain on Earth. A day on Mars is also a little longer than a day on Earth. It lasts about 24.6 hours. A year on Mars, however, or the time that takes for the red planet to circle our Sun, lasts about 687 Earth days. That is almost twice as long as a year on Earth !

In the 19th century, it was believed that life on Mars existed. An astronomer said that he “found” straight lines on Mars’s surface. Many people believed that those were the work of clever life as the straight lines were most likely to be canals for irrigation.

However, as more advanced telescopes were built, it was found that the straight lines were an optical illusion.

To this day, humans are still trying to find out whether there was life on Mars!