FOR a $10 billion instrument, the James Webb Space Telescope (JWST) spends a lot of its time staring at nothing. The shots of deep space this produces are remarkably beautiful, transforming an apparently empty sky into a field flecked with thousands of distant galaxies, some seen as they were just a few hundred million years after the big bang.
The first results of these surveys of the early universe have surprised astronomers, as the galaxies seem brighter than had been expected, with more star formation and larger black holes. Yet maybe we shouldn鈥檛 have been too startled to find the universe surprising us: it has been doing so since we first peered into the cosmic darkness.
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The most famous image of the early universe is the , captured over a week or so in 1995. Yet this shot was almost never taken. Time on the Hubble Space Telescope (and on JWST) is precious and astronomers spend months preparing proposals to try to get even a few hours鈥� worth of access. The process is a bit odd 鈥� often requiring researchers to argue simultaneously that the proposed observations would transform astronomy, but also that we know exactly what they will show 鈥� and competition is fierce.
There are normally seven or eight times as many proposals as can be accepted, so risky observations have trouble getting through. Back in the 1990s, many eminent astronomers argued that directing Hubble at deep space was pointless, betting that the space telescope wouldn鈥檛 find a single new galaxy. This pessimistic outlook was based on assuming that the galaxies we see around us today are representative of those throughout the past 14 billion years or so, an idea we now know is badly wrong. The Hubble Deep Field was only rescued by the personal intervention of Robert Williams, then the director of the Space Telescope Science Institute, who used his personal access to Hubble to make it happen.
Finding the early universe lit up with firework displays of star formation was a serendipitous discovery. But once you start looking, you will find that astronomical history is filled with discoveries made by accident, or while scientists were looking for something else entirely.
When radio engineers first detected 鈥渟tar noise鈥� coming from the cosmos in the 1930s and 1940s, they were ignored by astronomers who didn鈥檛 understand the technology being used. Jocelyn Bell Burnell was supposed to be investigating the distance of what we now know are quasars when she spotted 鈥渟cruff鈥� in her data 鈥� the rapidly repeating signal that indicated the presence of the first pulsars to be detected.
The team behind NASA鈥檚 Cassini probe was focused on its mission to explore Saturn鈥檚 famous rings and its mysterious moon Titan when a chance encounter with the tiny moon Enceladus revealed fountains of water coming from its south pole. It is now perhaps the most likely place for us to find life beyond Earth. If aliens were to be found swimming under its icy surface, it would have profound implications across the cosmos.
These discoveries are all a long way from how science is taught, where careful experiment and testing of hypotheses lead to progress. Surprise is fun, so maybe we should embrace serendipity a little more. Several of the astronomers involved in sorting through this year鈥檚 bumper crop of JWST observations have suggested it would be fairer, and easier, to allocate time on the telescope via a lottery, acknowledging that with so many good ideas floating around, we can鈥檛 possibly choose between them. But whether it is staring into deep space or exploring the solar system, experience has taught us that preparing to be surprised by the universe is the best way to make new discoveries.
Chris Lintott is professor of astrophysics at the University of Oxford and聽author of
