High-Stakes Astronomy at Low Frequencies... ...Opening Up a New Wavelength Frontier

Abstract

THE UNIVERSE is an equal-opportunity radio-frequency emitter. Point a dish (or a radio detector array) in any direction and you can find something interesting to study. This is because anything active in the universe gives off a range of wavelengths and frequencies, including low-frequency signals below 400 megahertz (MHz). This includes our Sun, which puts out radio signals across a broad range of frequencies. The planet Jupiter does interesting things that we can study between 15–30 MHz. Exploding stars and the center of the Milky Way Galaxy are also among the millions of sources that astronomers have observed at low frequencies. Yet, until very recently, this range of the radio spectrum remained largely unexplored by astronomers because signals were difficult to detect through all the noise of our technology.