Ms. Ye in front of the Sheshan 25-m Radio Telescope, Shanghai, China, 1987. Photo provided by Shanghai Astronomical Observatory.

 

INTRODUCTION

Born in 1927 in Guang Zhou, Ye Shuhua is known for being the first and only female director at the observatory in China. Throughout her active years, she served as the Director at the Shanghai Astronomical Observatory (SHAO), the Vice President at the International Astronomical Union (IAU) and the China Association for Science and Technology (CAST), and many other important positions in the field of science. Her most well-known contributions to astronomy include building the world’s most precise Universal Time systems, invention and implementation of VLBI (Very Long Baseline Interferometry) and SLR (Satellite Laser Ranging) technologies, and the development of astro-geodynamics in China which substantially improved China’s historical accuracy of astronomical measurements.

 

LIFE

Ms. Ye was raised in a poor, kind-hearted Christian pastor’s family. Her father was a carpenter’s apprentice and her mother a silk factory worker. She was the third of six brothers and sisters in the family. Originally planning to pursue a college degree in literature, Ms. Ye was compelled, by her father, to apply to the Department of Mathematics and Astronomy of Sun Yat-sen University in 1945. Unaware of what astronomy is all about, Ms. Ye coincidentally audited a lecture by Professor Yixin Zou and fell in love with the subject, thus switching her path from pure math to science and dedicating her entire life to it. Astronomy, as a major, by that time, was “even less popular than classical literature in China,” according to Ms. Ye’s own account.

 

Graduation Certificate of Ye Shuhua in June 1949: (indicating her School: School of Science [理]; Department: Astronomy [天文])

 

After Ms. Ye’s graduation in 1949, Guangzhou was still not yet liberated. Therefore, Ms. Ye and her husband Mr. Jitai Cheng could not find a job but flew to Hong Kong and taught there as middle school math teachers. 

“Although we had stable jobs and good salaries in Hong Kong, we still wanted to return to the mainland and conduct astronomical research. At that time, we did not know much about the situation in the mainland of China. My husband asked me if I could bear the life of wearing straw sandals and living in a straw house to study in the future, and my immediate answer was ‘no problem’,” recounted Ms. Ye in an interview with Huang Haihua, a journalist working at the Shanghai Observer News. However, the socio-economic development of China at that time was lagging in every aspect compared to other countries in the world. But the couple, with their patriotic hearts and ambitions, were definitive about returning to their motherland to support the country.

In the summer of 1950, Ms. Ye and Mr. Cheng went to the Purple Mountain Observatory (PMO) located in Nanjing, China, but the observatory was only accepting male professionals. Thanks to her youth and vigor, Ms. Ye was not intimidated but wrote a long letter to, Dr. Yuzhe Zhang, the director of PMO, stating the 5 reasons why she is the best fit for the job. Instead of being employed directly by the PMO, Ms. Ye received an offer the following year from Xujiahui Observatory in Shanghai, another important observatory affiliated with the PMO, and later became part of SHAO. It is important to note that she was the first female researcher to work at the observatory. Before her, there were no women employed. From then on, Ms. Ye spent more than 70 years at the Xujiahui Observatory, conducting numerous original research and leading her team to make critical contributions, which laid the foundation of Chinese Astronomy in the 50s-60s.

Ms. Ye is turning a centenarian in 2027.

 

MAJOR CONTRIBUTION

Ms. Ye’s accomplishments in astronomy were recognized internationally. She was honorifically referred to, by other scholars in her field, as “Madame Ye”. More than that, to commemorate her contributions, a main-belt asteroid discovered in August 1994 by the PMO was named after her – 3241 Yeshuhua. You can find more information on the asteroid here.

Orbit viewer of the asteroid “Ye Shuhua”  (at the bottom) by NASA

 

It will be too much to list all of Ms. Ye’s contributions on this website, so let’s look at the most groundbreaking two.

 

1. “MOTHER OF BEIJING TIME”

During the 50s, there was no standard map of China because many provinces had not been accurately measured, which could not be done without the help of astronomical timekeeping. Ms. Ye’s primary task was to “observe stars, reckon sidereal time, and mathematically convert it into Universal Time” on a day-to-day basis. She was then in charge of reporting the measurement results of the Xujiahui Astronomical Observatory – the only time service unit in China – to the Bureau International de l’Heure (BIH). 

In 1954, the Chinese Academy of Sciences (CAS) decided not only to improve time service but also to participate in the ambitious worldwide program – the International Geophysical Year. This double commitment led SHAO to be appointed with the job of improving the measurements. The task was even more daunting than one could expect: while the BIH system is a collaboration of 39 observatories, China has only 2 observatories to use as its database, which makes the country’s time service almost the least accurate compared to all other countries. 

 

Shuhua Ye operating the Danjon astrolabe (from France), one of the many new equipments SHAO bought for better research to be conducted, Shanghai, China, 1964. Photo provided by Shanghai Astronomical Observatory.

 

However, motivated by an unyielding spirit of patriotism and truth-finding, Ms. Ye took the leadership responsibilities to overcome this challenge, thereby conducting numerous trials and modifications to her methods, which eventually overcame the inaccuracy in the calculation system that was caused by “sudden changes of individual instruments”. 

In 1963, with only six instruments from 5 stations, the precision of China’s world time system ranked second in the world with only ±2.0 milliseconds of error thanks to her and her team’s dedication, which even surpassed that of the Soviet Union (with 17 stations). From then, the “Beijing Time” that is seen nowadays in every clock’s setting was born. 

 

2. Very Long Baseline Interferometry (VLBI) & Satellite Laser Ranging (SLR)

During the ’60s, Ms. Ye came to know the new technology called the Very Long Baseline Interferometry in books and was hooked by its 10 times higher resolution than traditional instruments. VLBI is, by definition, a space-geodetic technique used to determine precise coordinates on Earth, monitor Earth’s rotation and orientation, and derive various Earth system parameters. It also plays a crucial role in astronomy by providing accurate coordinates of extragalactic radio sources and contributing to relativistic and cosmological models (for more explanation, click here). The technique, according to Ms. Ye, is “in short, to unite several small radio telescopes to achieve the observation effect of one large telescope in terms of angular resolution.”

 

A diagram explaining how VLBI technology works. Picture provided by a research Ms. Ye was part of.

Because of the novelty of the technology, only a few developed countries decided to adopt it, let alone China. There was a limited amount of funding available in the department for Ms. Ye’s project, but, envisioning the bright application prospects of VLBI, Ms. Ye continuously sought chances for her aspiration to be realized. The project finally caught the attention of CAS and, in 1975, Ms. Ye led a research team and started “the construction of an experimental VLBI system with 6-m radio telescopes”.

The successful experiment in 1981 led to the official approval and launch of the project in the early ‘80s. By then, Ms. Ye further suggested that one of China’s three VLBI stations should be built in Urumqi – a city in the northwest of China with only a very small and underdeveloped observatory – to better prepare for potential collaboration with European countries in the future. Her “recklessly” bold idea was once again proved right in 1988 when The IAU and the International Institute of Geodesy announced the comprehensive adoption of the VLBI technology and abolished the traditional method of measurement.

 

Ms. Ye Shuhua proposing the establishment of three VLBI stations in China in the 1980s.

During the first campaign of the Asian-Pacific Space Geodynamics (APSG) program in October 1997, two VLBI experiments were carried out with six stations’ participation, including Seshan and Urumqi stations of China (the third proposed station was not built due to a lack of funding):

Here is part of the collected data:

Some major conclusions drawn from this experiment include but not limited to:

“1 ) The mean accuracy of the baseline length measurements of the six VLBI stations in the Asian-Pacific region is about 1.3 × 10^-9, which is consistent with the repeatability of baseline length measurement for other VLBI stations in the world.

2) The detected eastward motion of Seshan station and the north by northeast motion of Urumqi station are of importance to the study of the modern crustal movement of China, which directly indicates the effect of the northward movement of the Indian plate on the rising Tibetan Plateau and on the motion of the Tianshan mountain area in the northwest part of China as well as on the eastern part of China.” 

—— Measurements of the VLBI experiments during the first campaign of the Asian-Pacific space geodynamics (APSG) program

 

Moreover, the adoption of VLBI technology in China later helped China to conduct truck measurements by Chang’e 1 (嫦娥一号), a Chinese lunar-orbiting spacecraft launched in 2007, to be within 6 minutes and that of Chang’e 4 (嫦娥四号) and Tianwen 1 (天问一号) within 1 minute.

 

Ms. Ye during a recent interview with a journalist from Jiefang Daily. Photo provided by Shanghai Observer News. (Photographer: Wang Qingbin)

 

🪐 “If you only have 40% confidence in doing something and you stop there and do nothing, it will slowly become 20% and finally become zero. But if you work hard, you can turn it into 60%, 70%, and finally get it done.” – Ye Shuhua

🪐 “A career in astronomy is my lifelong romance,” – Ye Shuhua

 

BIBLIOGRAPHY

1) An, Tao, Xiaoyu Hong, Weimin Zheng, Shuhua Ye, Zhihan Qian, Li Fu, Quan Guo, et al. “Space Very Long Baseline Interferometry in China.” arXiv, June 3, 2019. https://doi.org/10.48550/arXiv.1901.07796.

2) Huang, Haihua, and Shuhua Ye. “92岁院士叶叔华：哪怕穿草鞋住草房，也要回到祖国去_解放网，上观新闻.” 上观新闻 Shanghai Observer. Accessed September 25, 2024. https://www.jfdaily.com/staticsg/res/html/web/newsDetail.html?id=125279.

3) Jie, Ke. “叶叔华：壮心不已的中国首位女天文台台长_杂志论文_今日科苑杂志.” 今日科苑 Modern Science, May 22, 2021. https://web.archive.org/web/20210522104035/https://www.zz-news.com/com/jinrikeyuan/news/itemid-305800.html.

4) Schuh, H., and D. Behrend. “VLBI: A Fascinating Technique for Geodesy and Astrometry.” Journal of Geodynamics 61 (October 1, 2012): 68–80. https://doi.org/10.1016/j.jog.2012.07.007.

5) Wang, Guangli, Shuhua Ye, Zhihan Qian, Jinling Li, Chopo Ma, Jim Ryan, David Gordon, et al. “Measurements of the VLBI Experiments during the First Campaign of the Asian-Pacific Space Geodynamics (APSG) Program.” Science in China Series A: Mathematics 44, no. 2 (February 1, 2001): 259–64. https://doi.org/10.1007/BF02874429.

6) Ye, Shuhua. “A Walk in Time and Space: My Journey as a Strategic Scientist.” Annual Review of Astronomy and Astrophysics 61 (2023).