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FIGURE 2‐3 Numerical simulation of a gamma ray burst showing a jet propagating out through a collapsing, massive
star. Many gamma ray bursts are associated with the supernova explosions of massive stars. The powerful bursts of
gamma rays are produced by hot gas moving that move outward through the collapsing star with speed close to that
of light. The most distant discrete source that has been observed thus far in the universe is a gamma ray burst. (Credit
Weiqun Zhang, S.E. Woosley, A. Heger, 2004, ApJ, 608, 365)
Giving Meaning to the Data: Cyber-Discovery
The powerful surveys described above will produce about a Peta-byte (one million Giga-bytes) of
data—roughly as much data as the total that astronomers have ever handled—every week. The data must
be quickly sifted so that interesting phenomena can be identified rapidly for further study at other
wavelengths. Interesting phenomena could also be discovered by cross-correlating surveys at different
wavelengths. Vast numbers of images must be accurately calibrated and stored so they can be easily
accessed to look for motion or unusual behavior on all timescales. As daunting as it sounds, the
technology and software that enables the accessing and searching of these enormous databases is
improving all the time and will enable astronomers to search the sky systematically for rare and
unexpected phenomena. This is a new window on the universe that is opening, thanks to the computer
revolution.
Another way in which computers will enable discovery in the coming decade is through
increasingly sophisticated numerical simulations of the complex physical systems that are at the heart of
much of astrophysics. The merging of two black holes, growth of disks and the planets that form within
them, the origin of large-scale structures that span the cosmos, and the formation of galaxies from the
cosmic web are examples. Such simulations have great potential for discovery because they can
illuminate the unanticipated behavior that can emerge from the interactions of matter and radiation based
on the known physical laws. Through computer modeling, we understand the deep implications of our
very detailed observational data, and formulate new theories to stimulate further observations.
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