Astronomers have constructed the first map of the Universe based on the positions of supermassive black holes.
The map precisely measures the expansion history of the Universe back to when the Universe was less than three billion years old.
The map was created by scientists from the Sloan Digital Sky Survey (SDSS), an international collaboration including astronomers from the University of Portsmouth.
As part of the SDSS Extended Baryon Oscillation Spectroscopic Survey (eBOSS), scientists measured the positions of quasars — extremely bright discs of matter swirling around supermassive black holes at the centres of distant galaxies.
To make the map, scientists used the Sloan telescope to observe more than 147,000 quasars.
But to use the map to understand the expansion history of the Universe, astronomers had to go a step further and measure the imprint of sound waves, known as baryon acoustic oscillations (BAOs), travelling in the early Universe.
The eBOSS experiment continues using the Sloan Telescope, at Apache Point Observatory in New Mexico, USA, observing more quasars and nearer galaxies, increasing the size of the map produced.
After it is complete, a new generation of sky surveys will begin, including the Dark Energy Spectroscopic Instrument (DESI) and the European Space Agency Euclid satellite mission.