By Morris Jones
Morris Jones, PhD, is an Australia-based journalist and has acted as an advisor on scientific matters to the media. He can be reached at firstname.lastname@example.org.
Multi-messenger astronomy is a hot ticket in science right now. Basically, it means observing the same astronomical target (or event) with different types of instruments. Some phenomena can produce flashes of light (visible with optical telescopes), radio bursts (collected by radio telescopes), and particle emissions (which show up in neutrino detectors and other instruments). Combining simultaneous observations from two or more instruments with different capabilities can help to reveal the true nature of strange things in the universe.
In principle, there’s nothing truly recent about multi-messenger astronomy. Radio astronomers have been contributing to the field for decades, when radio observations were used to supplement the observations of traditional telescopes. But the advent of space-based observatories that observe X-rays and gamma rays has taken multi-messenger astronomy to a new level. Add neutrino observatories and even gravitational wave detectors, and astronomy has never been so capable.
There’s a bright future for astronomers in the years ahead, as they observe things that have never been observed before or explain things that have never previously been explained. But this new age of multi-messenger astronomy could also be a boon for METI.
In the past, astronomers observed strange things in deep space, and sometimes wondered if they were artificial, when they were actually natural objects such as pulsars. Multi-messenger astronomy could help to resolve such matters in the future. Generally, a strange astronomical discovery is more likely to be natural rather than the product of extraterrestrial intelligence. Checking how a new discovery looks to a variety of instruments could help to resolve this question more quickly, and more conclusively.
This won’t help every single case of a suspected extraterrestrial transmission, or the discovery of a potential extraterrestrial artefact. In some cases, it could make the situation even more confusing. How do we really know how an advanced extraterrestrial broadcast is supposed to look to different instruments? Can we really explain every natural phenomenon we are likely to encounter? But there could be some cases where a natural explanation is suspected, but later ruled out. We are getting better at knowing what happens in the cosmos. As our understanding of natural phenomena improves, we will be better at knowing what really doesn’t seem natural.
SETI and METI are products of astronomy. As astronomy has improved, our search for extraterrestrials has grown more capable. Multi-messenger astronomy is certain to continue this trend.