Astronomers see 'warm' glow of Uranus's rings

By Robert Sanders

Image: UC Berkeley image by Edward Molter and Imke de Pater

Composite image of Uranus’s atmosphere and rings at radio wavelengths, taken with the ALMA array in December 2017. The image shows thermal emission, or heat, from the rings of Uranus for the first time, enabling scientists to determine their temperature: a frigid 77 Kelvin (-320 F). Dark bands in Uranus’s atmosphere at these wavelengths show the presence of molecules that absorb radio waves, in particular hydrogen sulfide gas. Bright regions like the north polar spot (yellow spot at right, because Uranus is tipped on its side) contain very few of these molecules.

The rings of Uranus are invisible to all but the largest telescopes—they weren't even discovered until 1977—but they're surprisingly bright in new heat images of the planet taken by two large telescopes in the high deserts of Chile.

More at Phys.org