By Xinhua writers Yu Fei, Han Song and Hu Zhe

BEIJING, Dec. 30 (Xinhua) -- When China started in 1931 to build the Purple Mountain Observatory (PMO), its first modern observatory, shortage of funds was the biggest problem.

That year also saw the Japanese invading northeast China and serious floods in south China. The construction of the observatory was completed three years later.

Its earliest astronomical instruments are still preserved on the picturesque peak of the Purple Mountain in Nanjing, east China's Jiangsu Province, but they are mainly used to promote science, attracting many visitors every year.

Although the observatory is still named after the Purple Mountain, its observation stations are distributed more widely: from eastern Shandong to northwestern Qinghai, from northeastern Heilongjiang to southwestern Yunnan, and even in Antarctica.

SYMBOL OF MODERN HISTORY

The observatory has become one of the most influential institutions in China's daily life.

It provides the exact time of the sun rising and setting every day and the 24 solar terms, the seasonal division points in the traditional Chinese calendar.

One of the original purposes of establishing the observatory was to promulgate the country's own calendar.

Ships from the world's second largest economy sail the globe using the nautical almanac compiled by the PMO. The observatory also offers the basis for setting the time to raise the national flag in Tian'anmen Square in Beijing.

Its astronomers have intensified the monitoring of space debris.

"We can make an accurate early warning of falling space debris," said Zhan Jinwei, assistant researcher at the PMO department of applied astromechanics and space debris.

It also provides collision avoidance advice for growing numbers of Chinese spacecraft.

All this is possible only with advanced observatory equipment, which was rarely available to previous generations of Chinese astronomers.

The International Astronomical Union invited China to join the measurement of earth's longitude and latitude in the 1930s. But Chinese astronomers failed to participate as they couldn't prepare the instruments in time.

In order to observe the total solar eclipse in 1941, Chinese astronomers overcame many difficulties to raise money to buy a telescope from the United States, but it was blown up by Japanese aircraft after it was shipped to Hong Kong.

Now the PMO has developed an advanced satellite, Dark Matter Particle Explorer (DAMPE), under cooperation with other research institutes and universities with an investment of about 700 million yuan (about 100 million U.S. dollars).

The observatory is constructing another satellite, expected to be launched around 2022, to study the sun.

Together with other organizations, the PMO is also pushing forward construction of an observatory in Antarctica with an estimated investment of over 1 billion yuan.

The study of astronomy was once regarded as the domain of the nobility. Its significant increase in funding in recent years is a result of the growing comprehensive strength of China, said Wu Xuefeng, deputy dean of the PMO academy of astronomy and space science.

The biggest change was brought about by the reform and opening up inaugurated in 1978. At that time, China's economic aggregate accounted for less than 2 percent of the world's total, compared with 15 percent today.

To achieve innovation-driven development, both applied science and basic science have received more investment.

"The PMO is a symbol of China's modern history," said Wu.

CHINESE ANSWERS

Chinese astronomers today do many things their predecessors could only dream of.

During wartime in the 1940s, the PMO was moved to the southwestern Yunnan Province, and it was impossible for the astronomers to conduct any observation. They could only study old data, and achieved limited results.

"We are now carrying out a project to paint a portrait of the Milky Way by using a millimeter-wave telescope in Delingha, Qinghai Province. We aim to probe the distribution, structure and physical properties of molecular clouds to get a relatively complete picture of the structure of the Milky Way," said Mao Ruiqing, deputy director of the PMO.

Nearly 70 percent of the ambitious project is completed, he said.

Chen Dengyi, 30, is working on the detector of the second-generation dark matter satellite in the new PMO laboratory.

When China's first dark matter satellite, DAMPE, was launched in 2015, Chen was monitoring the data at the Jiuquan Satellite Launch Center. "I cried with excitement when I got the news that the solar panels of the satellite had unfolded successfully," said Chen.

Fan Yizhong, deputy chief engineer of the application system of DAMPE, was born in a rural area in 1977. He would not have gone to college without the financial support of his brother who went to work in Shenzhen, the city that pioneered China's reform and opening-up.

Fan first majored in engineering, which he believed would earn more money. But he later decided to follow his interest and he went to Nanjing University to study astronomy.

"I was influenced by Stephen Hawking," said Fan.

"How was the universe born? Why does intelligent life exist? How is consciousness generated? Are there other universes? Chinese also want to answer these questions," said Wu.

The Chinese telescopes on the Antarctic ice sheet might help find some answers. Since 2007, two survey telescopes have been installed at an automatic observation station at Dome A and the third is planned for 2019.

With these telescopes, Chinese astronomers have received optical signals relevant to the gravitational wave generated by the merging of two neutron stars, which was discovered for the first time in 2017. They also found more than 100 candidates for extra-solar planets.

SHARED FUTURE

"Openness and cooperation are very important for astronomical research," said Shi Shengcai, director of the PMO department of Antarctic astronomy and radio astronomy.

The PMO joined the International Asteroid Warning Network under the United Nations Committee on the Peaceful Uses of Outer Space in 2018.

Since 2006, astronomers have used a PMO telescope in Xuyi, east China's Jiangsu Province, to search for near-earth asteroids.

"An early warning system for near-earth asteroids with potential threat is one of the contributions made by the PMO to the shared future of humanity," said Ji Jianghui, a researcher at the PMO department of planetary science and deep space exploration.

The PMO telescopes in Antarctica complement monitoring systems in Europe and the United States.

"Since 2000, about a third of our students have been able to study aboard. Astronomers from other countries came to our observatory to conduct joint research," said Wu.

Some PMO astronomers also participated in the European Space Agency's Rosetta mission to explore a comet in 2014.

"The solar system might be hard to inhabit in future, and we have to search for earth-like planets," Wu said. "We found a habitable planet several hundred light years away. The development of science and technology might one day help humans migrate there."

(Wang Juebin contributed to this story.)