Galactic gravitational lensing, ALMA-HST image. Composite image of a galaxy observed by gravitational lensing, combining millimetre wavelength light and optical data from the Atacama Large Millimeter Array (ALMA) and the Hubble Space Telescope (HST). The orange ring is millimetre wavelength light from the galaxy SDP.81 (12 billion light years distant), gravitationally lensed around a closer galaxy (4 billion light years distant), seen in optical wavelengths (blue) by Hubble. The millimetre wavelength light is emitted by dust (bright orange ring) and carbon monoxide (CO, fainter orange areas) in the distant galaxy. These galaxies are in the constellation of Hydra. The observations were made in 2014.