INEXPLICABLY regular rings of radio waves have been found in space. The discovery of “Odd Radio Circles” (see “Circles in space made of radio waves are like nothing we’ve ever seen”) has all those ingredients of mystery, intrigue and wonder that make a classic cosmic yarn, speculation of alien involvement included.
But there is much more to this than just a cute story. Odd Radio Circles are a thrilling reminder of how much more there is left to discover out there – and of how much there is to look forward to.
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The find came as part of the Evolutionary Map of the Universe pilot survey, the first stage of a project that aims to increase the number of radio sources we know of in the sky from the current 2.5 million to more than 70 million. It piggybacks on what should eventually become the Square Kilometre Array. This multi-nation project spread over two continents will revolutionise radio astronomy, allowing us to peer back into the “dark ages” of the first billion or so years of the universe’s existence, and so understand better how stars, galaxies and black holes formed.
That’s not all. The Vera C. Rubin Observatory, previously known as the Large Synoptic Survey Telescope, is due to see first light later this year. Its Legacy Survey of Space and Time aims to map 37 billion heavenly objects over 10 years and answer questions ranging from the nature of dark matter and dark energy to how the Milky Way formed and how much stuff there is out there in the solar system – as well as how much of it might be heading Earth’s way. Meanwhile, the LIGO and Virgo gravitational wave observatories are making the detection of ripples in space-time almost routine, opening up a fundamentally new window on the cosmos.
“Odd Radio Circles aren’t just a cute story – they are a thrilling reminder of how much there is left to discover out there”
Gravitational waves, like plenty else out there, are predictions of Einstein’s general theory of relativity. A century on, this remains our best large-scale theory of the universe. As theorist Claudia de Rham reminds us in our cover story (see “What does gravity weigh? The surprise answer that reshapes reality”), the search for even better theories to replace it continues too. So hats off to that, to Odd Radio Circles and to all these journeys of cosmic discovery. The situation on Earth may not be so pretty right now, but in the heavens at least, the wonders never cease.
