Astrophysicists regularly use high-powered computers in their work, with a growing number of astrophysics departments now featuring study groups strictly dedicated to 'computational astrophysics'. These research initiatives are driven by state-of-the-art supercomputers and cutting-edge software.
In August 2015, the International Astronomical Union inaugurated a new commission on computational astrophysics. The move was seen as official recognition of the importance of computer-driven astronomical research.
Computational astronomy is a relatively new discipline that seeks to describe the universe using mathematical and physical laws. Prior to this, astronomy was predominantly observational, using telescopes and early theoretical physics. Thanks to recent advancements in computational technology, astronomical models that replicate celestial bodies, phenomena and even the universe on a grand scale have led to the rise of this third pillar of astronomy. Some important research initiatives include those run by the US Department of Energy and the international Virgo Consortium.
Supercomputers essentially function as telescopes for objects and occurrences we otherwise wouldn't be capable of seeing. Telescopes are used to view electromagnetic radiation, and as such, there are many things we cannot see, even with the most high-powered and sophisticated telescopes. Rather than trying to investigate the universe through observation, supercomputers use highly-complex calculations to uncover phenomena that are otherwise hidden due to issues of time and space.
Astronomy involves dealing with mass, energy and time on massive scales. As supercomputers have become more powerful, we've become capable of modelling key astronomical processes - like those involving fluid dynamics and radiative transfer - to perform meaningful investigations of astronomical objects and scenarios. Scientists can even perform a wide range of trials by simply shifting a few parameters within their simulations.
Modelling may be used to test hypotheses, but it can also be utilized to investigate new worlds, even those beyond our current understanding. Computational astronomers may get outcomes from a model that they didn't expect, and this can be the first step to making revolutionary discoveries and establishing new theories.
For example, in the conventional scenario of planet formation, small solid bodies referred to as 'planetisimals' interact with each other and this leads to the evolution of their orbits around a star. Collisions between these bodies result in the creation of rocky planets like the Earth. To better comprehend this sequence of events, it requires extremely complex large-scale calculations involving a large multitude of factors.
A Massive Japanese Supercomputer Comes Online
In June 2018, the National Astronomical Observatory of Japan (NAOJ) announced it had begun operating the world’s fastest supercomputer dedicated to astronomy.
Cray XC50, nicknamed NS-05 “ATERUI II”, is an enormous parallel supercomputer that is a fifth-generation NAOJ system with triple the speed of the past three ATERUI supercomputers.
A high-speed network makes it possible for scientists to access ATERUI II and its 40,000 processing cores from their respective institutes around the world. In this year, about 150 scientists will use ATERUI II to investigate various issues too challenging for other supercomputers.
“A new ‘telescope’ for theoretical astronomy has opened its eyes,” said Eiichiro Kokubo, a project director. “I expect that ATERUI II will explore the Universe through more realistic simulations.”
One project, for instance, is investigating supernovae using extremely high-resolution 3D models to gain more understanding into these massive explosions. A different project is using ATERUI to investigate the distribution of galaxies across the universe.
Since it came online, ATERUI, it's been regularly used at more than 90 percent of its capacity, in terms of the quantity of CPUs operating at any moment.
In addition to ATERUI, NAOJ research also use the high-powered K computer. While high-end supercomputers like the ones in Japan are capable of making astounding discoveries, it’s important to realize that middle-class supercomputers are essentially the ‘workhorses’ of computational astronomy.