An unexpected variety
We’re impressed by the many data sources, tools, and results in a recent paper.
Our astronomer is (he contends) lamentably behind in his reading of the literature, as they call the mass of scientific papers published in the field. It was hard enough back in the days of paper journals, when one had a few thick volumes a month to contend with; now, with electronic publishing and e-prints, he barely has time to scan the titles. But one recent work caught his eye, outstanding for the variety of means it used in several ways. It demonstrates something of how astronomy is done nowadays.
The object of the study is Jupiter, the bright planet visible to the naked eye these evenings. At the moment there’s the NASA spacecraft, Juno, in orbit around it conducting investigations. In support of Juno a number of other instruments has been marshaled to provide complementary data as well as context. As a rule, two bits of data are more than twice as useful as one, when they can be connected in some way. This paper shows that, with a vengeance.
As background, amateur astronomers monitor the planet almost continually. Why? Well, they like to. And with modern instruments and computers they can keep track of features that were out of reach of even the best professionals just a few decades ago. They reported weather disturbances in the cloud-belts of Jupiter, brightenings or darkenings of the belts and zones, in the last months of 2016 and the first of 2017.
The authors of this paper center their report on observations made with ALMA, an array of telescopes in the dry desert of northern Chile. ALMA detects radiation in the millimeter-wavelength range, a sort of no-man’s-land between the far-infrared and the radio. The technology required is sometimes a hybrid of radio and infrared, sometimes something new entirely, so it was developed long after both were well-established.
But they don’t stop there: images from the Hubble Space Telescope (still going strong long after the Space Shuttle has been retired) in all wavelengths from the ultraviolet to the near-infrared add information, along with mid- and near-infrared images and spectra from the very largest of ground-based telescopes; plus supporting data from bona-fide radio telescopes. The authors seem to have used every major astronomical observatory in existence, with the possible exception of gravitational-wave detectors.
Data are only the starting point, of course. To turn them into information they employ a series of spectral-simulation computer programs, tuned to the conditions in the Jovian atmosphere (which is a very strange place in many respects). Then they employ programs most remarkably like the ones that bring you next week’s probability of rain, except that they account for ammonia as well as water condensing out of a convective cell.
What is the result of all this effort? Well, nothing quite as important to science overall as the coordinated observations of a neutron-star collision. Mostly it has to do with the details of how Jupiter’s weather works, something with more implications than is obvious at first glance but hardly Earth-shaking. Our astronomer still marvels at the sheer range of tools employed: observations from the ultraviolet through to the radio, by backyard amateur astronomers all the way to the most sophisticated and expensive installations in astronomy; computers to take the data, interpret the spectra, and, in the end, predict the weather.
