Albert Einstein hypothesized that in the universe there must exist objects of enormous mass, extremely small size, and great gravitational power. His ideas inspired scientists of various schools of thought around the world to theorize about what an object with super-­strong gravity would be like. 

Nothing in the universe, not even light, can escape the gravitational pull of such a “black hole.” The outer­most limit of a black hole is known as the “event horizon,” which marks the boundary of no escape. Begin­ning in 2009, American scientist Sheperd Doele­man brought together colleagues from around the world in the Event Horizon Telescope (EHT) collaboration, to use radio telescopes to observe black holes in hopes of getting clearer images of them. Thanks to scientific advancements, in 2017 astronomers were able to use this global array of telescopes to observe the Messier 87 (M87) galaxy, and from the data they captured they created an image of the black hole at the galaxy’s center. Published in 2019, this first ever image of a black hole is highly compatible with Einstein’s ideas.

The locations of the elements of the Event Horizon Telescope. Those marked with a Taiwan icon are telescopes constructed and operated with Taiwanese participation. 

The Event Horizon Telescope

In 2019, simultaneous press conferences were held at the Academia Sinica in Taipei and in Brussels, San ­Diego, Shanghai, Tokyo, and Washington DC, to release the first image of a black hole in human history.

Eleven EHT sites around the world used millimeter-­wave detectors to observe the M87* black hole, at the center of M87, and the Sagittarius A* (Sgr A*) black hole, at the center of our own galaxy, the Milky Way. The radio telescopes together formed a giant lens with a diameter the size of the Earth, enhancing the imaging resolution. As part of this global project, the Taiwanese team was involved in building and operating four telescopes: the Sub-­Millimeter Array (SMA) and the James Clerk Maxwell Telescope, both in Hawaii; the Atacama Large Millimeter/­submillimeter Array (ALMA) in Chile; and the Greenland Telescope (GLT) in the Arctic.

The construction of the SMA, located 4,000 meters above sea level on Mauna Kea in Hawaii, was a collaborative effort between the Academia Sinica and the US Smithsonian Astrophysical Observatory. Begun before the formal establishment of the Academia Sin­ica’s Institute of Astronomy and Astrophysics (ASIAA), the project was an important opportunity for Taiwan to prove its capabilities in the field of astro­physical observation. Taiwan was responsible for building two of the SMA’s eight antennas. When the Academia Sinica was searching everywhere to source carbon fiber composite material to support the dishes, a suggestion from a German company ­revealed that Taiwan already had companies with the necessary technology.

Chen Ming-tang, ASIAA deputy director for Hawaii operations, recalls that the team later contacted the National Chung-Shan Institute of Science and Technology (NCSIST) and the Aerospace Industrial Development Corporation to launch bilateral ­co­operation.

Chen recalls that when Taiwan worked on the SMA in Hawaii, they at first used carbon fiber tubes made in another country, but these developed cracks because of the dry climate high on the mountain. Thereafter they switched to only using carbon fiber tubes from Taiwan, which is indicative of the capabilities of Taiwan’s materials manufacturing industry.

The Sub-Millimeter Array (SMA) on Mauna Kea, Hawaii.

Taiwan’s ALMA laboratory

The ALMA in Chile was initiated collaboratively by North America, Europe, and Japan, with Taiwan joining in later. Taiwan was also responsible for building the ALMA East-Asia Front End Integration Center (EA-FEIC) in Taiwan, which integrated and tested the ALMA receiver system.

After ASRD director Eric Chi and NCSIST engineer Huang Chi Den spent some time studying in the labora­tory in the US, Asia’s first “ALMA laboratory”—the EA-FEIC—was constructed in Taiwan.

Huang relates that after various subsystems constructed in other countries arrived at the ALMA laboratory, they were tested and assembled into systems. These were then packed up and shipped to Chile, where local experts installed them in the telescopes. This may sound like a straightforward process, but it requires a great deal of precision technology, which is why there are only three FEICs in the world: in the US, the UK, and Taiwan.

The Aeronautical Systems Research Division of the National Chung-Shan Institute of Science and Technology assists the Academia Sinica with building astronomical telescopes and other instruments. (photo by Lin Min-hsuan)

Northward to Greenland

In 2010, the US National Science Foundation asked participants in the ALMA project to submit ideas for repurposing an ALMA-NA prototype antenna, ­located in the desert in New Mexico, that had been idle for many years. ASIAA hoped to get the opportunity to operate this radio telescope to enhance its leadership in astronomical observation. To this end, Kei­ichi Asada, an associate research fellow at the Academia Sinica, led a team to begin searching for a suitable ­location for this telescope: a place with a dry climate at a high latitude, where the antenna could form an array with the SMA in Hawaii and the ALMA in Chile. Eventually the team chose the northernmost land on earth: Greenland.

Chen Ming-tang, who is in charge of the Greenland Telescope Project, recalls that when foreign scientists heard about this plan, they thought the Taiwan team were “crazy.” But as a result of cooperation between the Academia Sinica and the NCSIST, as well as assistance from technicians from a variety of countries, they ultimately completed this “mission impossible.”

NCSIST engineer Hsia Chieh-peng, who took part in the project, recalls that just going to Greenland to work was an adventure. He had to climb up on the telescope, which is three to four stories high, to install equipment. “After working for a while, you had to put your hands in your pockets to warm them up.” In an environment where resources were not easily accessible, the Taiwanese engineers constantly had to make use of locally avialable materials to adjust or repair the equipment, demonstrating their skills at improvisation.

Engineers from the ASIAA have been responsible for maintenance work on the Greenland Telescope. Over the past couple of years maintenance work had been postponed because of the Covid-19 pandemic, but if the telescope’s “cold head” were not switched out the quality of the black hole observations would have been adversely affected. This is why engineer Joshua Chang had to go to Greenland in winter, during the “polar night.” He says that when he was working there, everybody helped each other out. The local Danish team in particular were able to conjure up some gear “out of nowhere” and helped the Taiwan team overcome its shortage of materials.

The Greenland Telescope was originally built as a North American prototype for ALMA. A team from Taiwan moved it from New Mexico in the US and installed it in Greenland.

The next image of a black hole

Keiichi Asada says that some data collected in 2018 that the team has recently been processing was a product of the Greenland Telescope. The two images previously made public of the M87* and the Sgr A* black holes were somewhat fuzzy, but after adding in the data from the Greenland Telescope the resolution will be greatly enhanced and we will be able to see these black holes much more clearly.

“We’ve spent a lot of time on the Sgr A* black hole, so it is only now that we are getting around to processing the M87* data collected in 2018,” says support scientist Chih-wei Locutus Huang. Pointing at Asada, he says: “The Sgr A* black hole changes very quickly. It’s so difficult to get a handle on that he says he doesn’t want to have anything to do with it ever again.” Asada responds with a laugh: “It’s a nightmare!”

Through these projects, Taiwan has continually been able to demonstrate its capabilities in the field of astronomy. ASRD director Eric Chi says that the projects that the Academia Sinica has entrusted to the NCSIST have been quite innovative even at the international level. The team often had to work out operating procedures themselves, yet ultimately the final product frequently won praise from countries around the world, who also invited the Taiwanese team to assist them. For example, in the late stages of the ALMA project, work fell behind schedule at the European FEIC, so they asked Taiwan to help out. The NCSIST immediately opened another production line to support Europe, and completed 20% of its production needs. 

Engineer Huang Chi Den notes that in the past, specialists from Taiwan had to learn technology from the US. But when Taiwan later developed the Band-1 ­receiver cartridge (which is used to detect planet forma­tion) for ALMA, the Academia Sinica and the ­NCSIST did all their own R&D and manufacturing. When the receiver cartridges were delivered to Chile and installed two years ago, an American scientist who saw the opera­tions report declared to the Taiwan team: “You have graduated!”—meaning that Taiwan’s astro­nomical R&D and manufacturing capabilities have reached inter­national standards.

Astronomical observation teams are like a little United Nations. Over the past 20 years, Taiwan has found its own place and has built collaborative models with numerous nations. Whether on a mountaintop in Hawaii, a plateau in Chile, or an ice field in Greenland, everyone has the same objective: not to compete, but to work together to unravel the mysteries of the universe. 

Keiichi Asada (right) and Chih-wei Locutus Huang (left) of the ASIAA remotely operating the Greenland Telescope. (photo by Lin Min-hsuan)

The second ever image of a black hole: Sgr A*, at the center of the Milky Way galaxy. (courtesy of ASIAA)