Multiplexed astronomy
An example of answering several questions at once, by doing several kinds of observation at once.
There may still exist the idea of astronomers as lone scientists, peering through telescopes through the wee hours of the night. A recent event, extremely important to astronomers and even mentioned in the mainstream media, showed how inaccurate that picture has become.
A pair of neutron stars in a distant galaxy collided. The event was first detected through gravitational radiation, a prediction of General Relativity that has only recently been directly proven. Within two seconds an orbiting telescope picked up the accompanying burst of gamma radiation. Soon telescopes on the ground discovered the visible-light signal. Within a couple of weeks, X-Ray and radio waves had been picked up.
Our astronomer points out that this series of observations has only recently become possible. Detectors of gravitational radiation are new, of course, with their first detection just a couple of years ago. But gamma rays and X-Rays have to be sought from above the Earth’s atmosphere, and so their observatories are products of the Space Age. Less visible, but just as important, are the capabilities to alert observers quickly enough to a transient event, and then to be able to search a large patch of sky for a faint object. Even leaving out gravitational waves, coordinating all the other observations would have been impossible a decade or two ago.
The scientific return on this multiplexed event has been considerable. First, it explains the origin of a type of gamma-ray burst. They’ve been seen before, and thought to come from neutron-star mergers, but proof was hard to come by. Second, it’s an example of a theorized “kilonova,” an explosion intermediate in size between a nova and a supernova, hypothesized to explain the origin of a number of elements not made in normal stars. (Carbon and sulfur, for example, come from fusion reactions in massive stars, but elements like gold aren’t made that way.) Third, the short delay between the gravitational waves and the gamma rays puts severe contstraints on certain kinds of theories of gravity that extend General Relativity. They predict that gravity waves and light waves should have a different speed; but that’s hard to manage if they arrive, after tens of millions of years of travel, within two seconds of each other. That’s just the beginning; a whole issue of a major journal has been devoted to this one event.
The science and technology highlighted by this multiplexed set of observations are impressive. But our astronomer points out a social aspect. It’s been estimated that roughly one-third of all professional astronomers have been involved. It appears the science is headed for an age in which a large fraction of the workers in the field have a share in any major accomplishment. We will have to change the way in which competition for grant money, jobs and everything is conducted. How?
