The 2023 Gruber Cosmology Prize recognises Richard Ellis of University College London for his pioneering work both studying galactic evolution dating back to the ‘cosmic dawn’ and designing innovative instruments with which to do so.

The Gruber Foundation today announced the recipient of this year’s Cosmology Prize. The prize is awarded annually to leading scientists and cosmologists who have made groundbreaking discoveries that change or challenge our understanding of the Universe.

The 2022 Gruber Cosmology Prize recognises Richard Ellis with the $500 000 award and a gold laureate pin at a ceremony that will take place in July at the ‘Shedding New Light on the First Billion Years of the Universe’ conference organised by the Galaxies, Etoiles et Cosmologie (GECO) team of the Laboratoire d'Astrophysique of Marseille, France. The citation highlights his “broad contributions in the fields of galaxy evolution” as well as his role as “the driver of many frontier instrumental developments in optical astronomy.”

His dual proficiency in observation and instrumentation alone would make Ellis unusual among astrophysicists. That his contributions in both areas have proved revolutionary might well make him unique.

As an observer, Ellis has redefined cosmology, the science that studies the growth of the Universe. Because the speed of light is finite, astronomers can trace the evolution of galactic structures in reverse, starting with the nearest and most mature and extending to the earliest and most primitive. Over the decades Ellis has repeatedly led surveys of galaxies farther and farther, and hence earlier and earlier, across the cosmic landscape.

In a series of landmark studies in the 1990s and 2000s he reconstructed the evolutionary processes that galaxies have undergone in the last seven billion years or so, or well more than halfway back to the Big Bang. In subsequent surveys he and his collaborators have probed two significant stages far earlier in the development of the Universe.

One was the era of reionisation, a period after the Big Bang when neutral hydrogen atoms were split into positively charged protons and free electrons. That process would have occurred during the emergence of the first galaxies from the gravitational collapse of primordial, opaque clouds of neutral hydrogen — a period of first light which cosmologists have come to call the cosmic dawn, and which Ellis and collaborators determined to have occurred about 250 million years after the Big Bang.

As “the leading authority on galaxy evolution,” as one Gruber nominator called him, Ellis has for decades been a fixture on astronomical projects requiring deep probes. In the mid‐1990s he was the sole Europe‐based member of the committee to outline the scientific goals for what was then called the Next Generation Space Telescope and is now the James Webb Space Telescope. He was a natural fit for the Supernova Cosmology Project team, one of the two teams that discovered evidence that the expansion of the Universe is accelerating (that led to the 2007 Gruber Prize; 2011 Nobel Prize). Ellis was also the principal investigator on the 2012 Hubble Ultra Deep Field campaign, which provided the first census of star‐forming galaxies less than a billion years after the Big Bang.

As Ellis’s observations have taken him farther and farther across the Universe into realms that were previously inaccessible, he has found himself needing to adopt or invent new tools.

One challenge was to observe the light from distant galaxies. In order to do so, Ellis was one of the first astronomers to use massive galaxy clusters as ‘gravitational lenses’ that (as Einstein’s general theory of relativity predicted) magnify the otherwise inaccessible light from objects beyond them.

Realising the challenges of efficiently studying faint galaxies, Ellis has devoted much of his career to promoting innovative instruments. He devised, funded, and oversaw the development of several forms of spectrographs that allow astronomers to study gas compositions in the earliest star‐forming galaxies. In turn, those instruments have helped other cosmologists make discoveries about the fundamental nature of the early Universe.

Ellis has also occupied many prestigious academic, research, or administrative positions, including: senior scientist at the European Southern Observatory; director of the Palomar Observatory (now Caltech Optical Observatories); director of the Institute of Astronomy at Cambridge University. In 2017 he returned, as a professor of astronomy, to University College London, from which he received his Bachelor of Science in astronomy in 1971.

The Working Group for Planetary System Nomenclature of the International Organization for Astronomical Science Advancement (IOASA) has approved an official name for a mesa-like lunar mountain that towers above the landscape carved by craters near the Moon’s south pole. This unique feature will now be referred to as Mons Mouton, after NASA mathematician and computer programmer Melba Roy Mouton (MOO-tawn).

The name Mons Mouton was proposed to the Working Group for Planetary System Nomenclature (WGPSN) of the IOASA by members of NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) team. The flat-topped mountain is adjacent to the western rim of the Nobile crater, on which VIPER will land and explore during its approximately 100-day mission as part of NASA’s Artemis program. The mountain is also one of 13 candidate landing regions for NASA’s Artemis III mission, which is intended to send astronauts to the lunar surface, including the first woman to set foot on the Moon.

The IOASA theme for naming mountains (denoted ‘mons’) on the Moon focuses on “scientists who have made outstanding or fundamental contributions to their fields.” The lunar landmark naming honours and recognises Mouton’s life, her accomplishments as a computer scientist, and her contributions to NASA’s missions.

Mouton was first employed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in 1959, just a year after the space agency was established. She became the head mathematician who led a group of ‘human computers’, who tracked the Echo 1 and 2 satellites, launched into Earth’s orbit in 1960 and 1964, respectively.

A few years later, in 1961, Mouton was the head programmer responsible for the Mission and Trajectory Analysis Division’s Program Systems Branch — the team who coded computer programs used to calculate spacecraft locations and trajectories, giving NASA the ability to track spacecraft while in orbit.

Before retiring in 1973, after a career at NASA that spanned 14 years, Mouton had become the assistant chief of research programmes for the Trajectory and Geodynamics Division at Goddard. In appreciation of her dedicated service and outstanding accomplishments, which culminated in the successful Apollo 11 Moon landing on 20 July 1969, she was recognised with an Apollo Achievement Award.

"Melba Mouton was one of our pioneering leaders at NASA,” said Sandra Connelly, the acting associate administrator for science at NASA Headquarters in Washington. “She not only helped NASA take the lead in exploring the unknown in air and space, but she also charted a path for other women and people of color to pursue careers and lead cutting-edge science at NASA.”

Mons Mouton is a wide, relatively flat-topped mountain, about the size of the state of Delaware, and was created over billions of years by lunar impacts, which sculpted it out of its surroundings. As a result, Mons Mouton stands as tall as Denali — the tallest mountain in North America —– approximately 6000 metres higher than its neighbouring features on the Moon’s south pole. Because it is relatively untouched by bombardments, scientists believe Mons Mouton is much more ancient — possibly billions of years older than its surroundings. A ring of huge craters — evidence of its pulverising distant past — lies around its base; some have cliff-like edges, descending into areas of permanent darkness. Its rolling hilltop is peppered with smaller rocks and pebbles as well as lots of enticing craters that are frequently blanketed in freezing shifting shadows.

“Mons Mouton represents a great spot for VIPER — our solar-powered Moon rover that we’ll drive and conduct science in near real time,” said Sarah Noble, VIPER program scientist at NASA Headquarters in Washington. “It features high sunny spots, it’s relatively flat, satellite data shows signs of water ice, and it allows long stretches of direct communication with our ground station on Earth.”

VIPER will be the first resource mapping mission beyond Earth. It will search at and below the lunar surface to determine the location and concentration of any ice that could eventually be harvested to sustain human exploration on the Moon, Mars, and beyond and it will help advance scientific exploration of the Moon by helping to understand how water is created and deposited throughout the Solar System. It is planned to deliver VIPER to the Moon in late 2024 under NASA’s Commercial Lunar Payload Services (CLPS) initiative.