Artist impression of a fast radio burst. Credit: Danielle Futselaar
Despite everything astronomers have learned about the nature and structure of galaxies, there are still mysteries about the Milky Way. The reason for this is simple: since we are embedded in the Milky Way’s disk, we have difficulty mapping it and observing it as a whole. It’s also very challenging to observe the center of the galaxy, what lies beyond it, and features in the disk itself because of all the gas and dust between stars- the Interstellar Medium (ISM). However, by observing the Milky Way in the non-visible spectrum (radio, x-ray, gamma-ray, etc.), astronomers can see more of what’s out there.
There’s also the spectral line that corresponds to the emission frequency (1420 MHz) of cold neutral hydrogen gas (HI), which makes up the majority of the ISM. Using the Five-hundred-meter Aperture Spherical Telescope (FAST) – the most powerful radio telescope in the world near Guizhou, China – a team of scientists located more than 500 new faint pulsars. During the survey, the team simultaneously recorded the spectral line data with high spectral and spatial resolution, making it an extremely valuable resource for studying the structure of the Milky Way Galaxy and the life cycle of its stars.
One of the most challenging questions to answer when confronting the Fermi Paradox is why exponentially scaling technologies haven’t taken over the universe by now. Commonly known as von Neumann probes, the idea of a self-replicating swarm of extraterrestrial robots has been a staple of science fiction for decades. But so far, there has never been any evidence of their existence outside the realm of fiction. That might be because we haven’t spent a lot of time looking for them – and that could potentially change with the new Five-hundred-meter Aperture Spherical Radio Telescope (FAST). According to some recent calculations, the massive new observational platform might be able to detect swarms of von Neumann probes relatively far away from the sun.
The Five-hundred-metre Aperture Spherical Telescope (FAST) has just finished construction in the southwestern province of Guizhou. Credit: FAST
In 2016, China’s Five-hundred-meter Aperture Spherical radio Telescope – the largest single-aperture radio telescope in the world – gathered its first light. Since then, the telescope has undergone extensive testing and commissioning and officially went online in Jan of 2020. In all that time, it has also been responsible for multiple discoveries, including close to one hundred new pulsars.
According to a recent study by an international team of scientists and led by the Chinese Academy of Sciences (CAS) suggests that FAST might have another use as well: the search for extraterrestrial intelligence (SETI)! Building on their collaboration with the non-profit science organization Breakthrough Initiatives, the authors of the study highlight the ways in which FAST could allow for some novel SETI observations.
The Five-hundred-metre Aperture Spherical Telescope (FAST) has just finished construction in the southwestern province of Guizhou. Credit: FAST
Relax, its not a space station! And according to the Chinese government, it’s for entirely peaceful purposes. It’s known as the Five-hundred-meter Aperture Spherical Telescope (FAST), a massive array that just finished construction in the southerwestern province of Guizhou, China. Equivalent in size to over 20 football fields joined end to end, it is the world’s largest radio telescope – thus ending the Arecibo Observatory’s 53 year reign.
As part of China’s growing commitment to space exploration, the FAST telescope will spend the coming decades exploring space and assisting in the hunt for extraterrestrial life. And once it commences operations this coming September, the Chinese expect it will remain the global leader in radio astronomy for the next ten or twenty years.
In addition to being larger than the Arecibo Observatory (which measures 305 meters in diameter), the telescope is reportedly 10 times more sensitive than its closest competitor – the steerable 100-meter telescope near Bonn, Germany. What’s more, unlike Arecibo (which has a fixed spherical curvature), FAST is capable of forming a parabolic mirror. That will allow researchers a greater degree of flexibility.
The Chinese Academy of Sciences (CAS) has spent the past five years building the telesccope, to the tune of 1.2-billion-yuan (180 million U.S. dollars). As the deputy head of the National Astronomical Observation, which is overseen by the CAS, Zheng Xiaonian was present at the celebrations marking the completion of the massive telescope.
As he was paraphrased as saying by the Xinhua News Agency: “The project has the potential to search for more strange objects to better understand the origin of the universe and boost the global hunt for extraterrestrial life.” Zheng was also quoted as saying that he expects FAST to be the global leader in radio astronomy for the next 10 to 20 years.
The construction of this array has also been a source of controversy. To protect the telescope from radio interference, Chinese authorities built FAST in Guizhou province’s isolated Dawodang depression, directly into the mountainside. However, to ensure that no magnetic disruptions are nearby, roughly 9,000 people are being removed from their homes and rehoused in the neighboring counties of Pingtang and Luodian.
Li Yuecheng is the secretary-general of the Guizhou Provincial Committee, which is part of the Chinese People’s Political Consultative Conference (CPPCC). As he was quoted as saying by the Xinhua News Agency, the move comes with compensation:
“The proposal asked the government to relocate residents within 5 kilometers of the Five-hundred-meter Aperture Spherical Telescope, or FAST, to create a sound electromagnetic wave environment… Each of the involved residents will get 12,000 yuan (1,838 U.S. dollars) subsidy from the provincial reservoir and eco-migration bureau, and each involved ethnic minority household with housing difficulties will get 10,000 yuan subsidy from the provincial ethnic and religious committee.”
China’s recent forays into space include the Chang’e-3 moon lander, seen here by the Yutu moon rover. Credit: CNSA/SASTIND/Xinhua/Marco Di Lorenzo/Ken Kremer
In addition, the construction of this telescope is seen by some as part of a growing desire on behalf of China to press its interests in the geopolitical realm. For instance, in their 2016 Annual Report to Congress, the Department of Defense indicated that China is looking to develop its space capabilities to prevent adversaries from being able to use space-based assets in a crisis. As the report states:
“In parallel with its space program, China continues to develop a variety of counterspace capabilities designed to limit or to prevent the use of space-based assets by the [Peoples’ Liberation Army’s] adversaries during a crisis or conflict… Although China continues to advocate the peaceful use of outer space, the report also noted China would ‘secure its space assets to serve its national economic and social development, and maintain outer space security.'”
However, for others, FAST is merely the latest step in China’s effort to become a superpower in the all-important domain of space exploration and research. Their other ambitions include mounting a crewed mission to the Moon by 2036 and building a space station (for which work has already begun). In addition, FAST will enable China to take part in another major area of space research, which is the search for extra-terrestrial life.
For decades, countries like the United States have leading this search through efforts like the SETI Institute and the Nexus for Exoplanet System Science (NExSS). But with the completion of this array, China now has the opportunity to make significant contributions in the hunt for alien intelligence.
In the meantime, the CAS’ scientists will be debugging the telescope and conducting trials in preparation for its activation, come September. Once it is operational, it will assist in other areas of research as well, which will include conducting surveys of neutral hydrogen in the Milky Way and other galaxies, as well as detecting pulsars and gravitational waves.
