Geraint Francis Lewis (born 14 March 1969) is a

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peop ...

astrophysicist, who is best known for his work on

dark energy In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovas, which showed that the univ ...

gravitational lensing A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known ...

and

galactic cannibalism Interacting galaxies (''colliding galaxies'') are galaxy, galaxies whose gravity, gravitational fields result in a disturbance of one another. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. A ...

. Lewis is a

Professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...

of Astrophysics (Teaching and Research) at the Sydney Institute for Astronomy, part of the

University of Sydney The University of Sydney (USYD), also known as Sydney University, or informally Sydney Uni, is a public research university located in Sydney, Australia. Founded in 1850, it is the oldest university in Australia and is one of the country's si ...

's School of Physics. He is head of the Gravitational Astrophysics Group. He was previously the Associate Head for Research at the School of Physics, and held an Australian Research Council Future Fellowship between 2011 and 2015. Lewis won the 2016

Walter Boas Medal The Walter Boas Medal is awarded by the Australian Institute of Physics for research in Physics in Australia. It is named in memory of is named in memory of Walter Boas (1904-1982) — an eminent scientist and metallurgist who worked on the physic ...

in recognition of excellence in research in Physics. In 2021, he was awarded the David Allen Prize of the

Astronomical Society of Australia The Astronomical Society of Australia (ASA) is the professional body representing astronomers in Australia. Established in 1966, it is incorporated in the Australian Capital Territory. Membership of the ASA is open to people "capable of contributi ...

for exceptional achievement in astronomy communication. In April 2020, Geraint was elected as a Fellow of the

Learned Society of Wales The Learned Society of Wales ( Welsh: Cymdeithas Ddysgedig Cymru) is a learned society and charity that exists to "celebrate, recognise, preserve, protect and encourage excellence in all of the scholarly disciplines", and to serve the Welsh natio ...

. He is also an elected fellow of the Royal Society of New South Wales. Until the end of 2020, he held the position of Deputy Director of the Sydney Informatics Hub, a Core Research Facility of the

Education

Originally from

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

, Lewis was born in Neath and raised in Seven Sisters and

Crynant Crynant ( cy, Y Creunant) is a village and community in the Dulais Valley in Wales. It lies 7¾ miles north-east from the town of Neath in Neath Port Talbot, situated between the mountains of Mynydd Marchywel to the west, Hirfynydd to the east ...

, completing schooling at Llangatwg Comprehensive and Neath Tertiary College. He completed his first degree at the

University of London The University of London (UoL; abbreviated as Lond or more rarely Londin in post-nominals) is a federal public research university located in London, England, United Kingdom. The university was established by royal charter in 1836 as a degree ...

and PhD at the

University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

's Institute of Astronomy. He has worked in the State University of New York, the

University of Victoria The University of Victoria (UVic or Victoria) is a public research university located in the municipalities of Oak Bay and Saanich, British Columbia, Canada. The university traces its roots to Victoria College, the first post-secondary insti ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, and the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

. After research positions in the US and

, he then became a Research Astronomer at the

Anglo-Australian Observatory The Australian Astronomical Observatory (AAO), formerly the Anglo-Australian Observatory, was an optical and near-infrared astronomy observatory with its headquarters in North Ryde in suburban Sydney, Australia. Originally funded jointly by the U ...

in 2000. In 2002, Lewis joined the University of Sydney where he is currently the head of the Gravitational Astrophysics Group.

Research fields

Lewis undertakes a broad spectrum of research in

astronomy Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, g ...

and

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

. On the largest scales, his program involves looking at the influence of

and

dark matter Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not a ...

on the

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

and

ultimate fate of the universe The ultimate fate of the universe is a topic in physical cosmology, whose theoretical restrictions allow possible scenarios for the evolution and ultimate fate of the universe to be described and evaluated. Based on available observational e ...

. Another aspect of Lewis's research uses the phenomenon of gravitational lensing to probe the nature and distribution of the pervasive dark matter, and employing individual stars to

magnify Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a calculated number also called "magnification". When this number is less than one, it refers to a reduction in siz ...

the hearts of quasars, the most luminous objects in the universe. Closer to home, Lewis's research focuses upon galactic cannibalism, where small

dwarf galaxies A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is so ...

are torn apart by the much more massive

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

and

Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gal ...

. Using

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observ ...

s from around the world, including the 10-m

Keck telescope The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state In the United States, a state is a constituent political entit ...

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

, he has mapped the tell-tale signs of tidal disruption and destruction, providing important clues to how large galaxies have grown over time.

Publications

As of August 2020, Lewis has published more than 400

scientific articles : ''For a broader class of literature, see Academic publishing.'' Scientific literature comprises scholarly publications that report original empirical and theoretical work in the natural and social sciences. Within an academic field, scient ...

, numerous articles in the popular press, and three popular science books. * ''Where did the Universe come from? And other cosmic questions'' by Chris Ferrie and Geraint F. Lewis, SourceBooks (Chicago), (Sept 2021,) * ''The Cosmic Revolutionary's Handbook: or how to beat the Big Bang'' by Luke A. Barnes and Geraint F. Lewis, Cambridge University Press (Feb 2020, ) * ''A Fortunate Universe: Life in a finely tuned cosmos'' by Geraint F. Lewis and Luke A. Barnes, Cambridge University Press (Oct 2016, ) *''Dark Matter in Astroparticle and Particle Physics - Proceedings of the 6th International Heidelberg Conference'', World Scientific Publishing Company, Australia, 2007,

Public outreach

Lewis is noted for his public speaking about astronomy on radio and at public events. He was appointed Patron of

Macarthur Astronomical Society Macarthur Astronomical Society is an organisation of amateur astronomers, based in the Macarthur Region of outer South Western Sydney, NSW, Australia, including the local government areas of the City of Campbelltown, Camden Council, Wollo ...

in February 2020. With his colleague, Luke Barnes, he regularly discusses astronomy, cosmology and physics at his YouTube channel Alas Lewis & Barnes.

Related lists

List of astronomers The following is a list of astronomers, astrophysicists and other notable people who have made contributions to the field of astronomy. They may have won major prizes or awards, developed or invented widely used techniques or technologies within as ...

References

External links

Geraint F. Lewis's Personal PageSchool of Physics, University of SydneyDirectory link at IAU
{{DEFAULTSORT:Lewis, Geraint F. Living people People from Seven Sisters, Neath Port Talbot Academic staff of the University of Sydney Alumni of Queen Mary University of London Alumni of the University of Cambridge Welsh astronomers Welsh physicists 20th-century British astronomers 21st-century British astronomers 1969 births