Geraint Francis Lewis,

FLSW The Learned Society of Wales () is a national academy, learned society and Charitable organization, charity that exists to "celebrate, recognise, preserve, protect and encourage excellence in all of the scholarly disciplines", and to serve the W ...

(born 14 March 1969) is a

Welsh Welsh may refer to: Related to Wales * Welsh, of or about Wales * Welsh language, spoken in Wales * Welsh people, an ethnic group native to Wales Places * Welsh, Arkansas, U.S. * Welsh, Louisiana, U.S. * Welsh, Ohio, U.S. * Welsh Basin, during t ...

astrophysicist, best known for his work on

dark energy In physical cosmology and astronomy, dark energy is a proposed form of energy that affects the universe on the largest scales. Its primary effect is to drive the accelerating expansion of the universe. It also slows the rate of structure format ...

gravitational lensing A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

and galactic cannibalism. Lewis is a

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

of astrophysics (teaching and research) at the Sydney Institute for Astronomy, part of the

University of Sydney The University of Sydney (USYD) is a public university, public research university in Sydney, Australia. Founded in 1850, it is the oldest university in both Australia and Oceania. One of Australia's six sandstone universities, it was one of the ...

'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 The Australian Research Council (ARC) is the primary non-medical research funding agency of the Australian Government, distributing more than in grants each year. The Council was established by the ''Australian Research Council Act 2001'', ...

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 The Australian Institute of Physics was established in 1963, when it replaced the Australian Branch of the British Institute of Physics based in London.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 contribut ...

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

Learned Society of Wales The Learned Society of Wales () is a national academy, learned society and Charitable organization, charity that exists to "celebrate, recognise, preserve, protect and encourage excellence in all of the scholarly disciplines", and to serve the W ...

. He is also an elected fellow of the

Royal Society of New South Wales The Royal Society of New South Wales is a learned society based in Sydney, Australia. The Governor of New South Wales is the vice-regal patron of the Society. It is the oldest learned society in the Southern Hemisphere. The Society traces its ...

. Until the end of 2020, Lewis held the position of deputy director of the Sydney Informatics Hub, a Core Research Facility of the

Education

Originally from

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

, Lewis was born in

Neath Neath (; ) is a market town and Community (Wales), community situated in the Neath Port Talbot, Neath Port Talbot County Borough, Wales. The town had a population of 50,658 in 2011. The community of the parish of Neath had a population of 19,2 ...

and raised in Seven Sisters and

Crynant Crynant () 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 and Mynydd y ...

, completing schooling at

Llangatwg Comprehensive Cadoxton (or in full Cadoxton-juxta-Neath) () is a village situated in Neath Port Talbot county borough, Wales. Cadoxton is located just outside the town of Neath and borders the villages of Cilfrew and Bryncoch. The village has 1,684 residen ...

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-nominal letters, post-nominals) is a collegiate university, federal Public university, public research university located in London, England, United Kingdom. The ...

and

PhD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

at the

University of Cambridge The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

's Institute of Astronomy. He has worked in the

State University of New York The State University of New York (SUNY ) is a system of Public education, public colleges and universities in the New York (state), State of New York. It is one of the List of largest universities and university networks by enrollment, larges ...

, the

University of Victoria The University of Victoria (UVic) is a public research university located in the municipalities of Oak Bay, British Columbia, Oak Bay and Saanich, British Columbia, Canada. Established in 1903 as Victoria College, British Columbia, Victoria Col ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, and the

University of Washington The University of Washington (UW and informally U-Dub or U Dub) is a public research university in Seattle, Washington, United States. Founded in 1861, the University of Washington is one of the oldest universities on the West Coast of the Uni ...

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

. After research positions in the US and Canada, 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 the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

and

cosmology Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', with the meaning of "a speaking of the wo ...

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

and

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

on the

evolution Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...

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 evi ...

. 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 the hearts of

quasar A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass rangi ...

s, 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 or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

and

Andromeda Galaxy The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a Galaxy#Isophotal diameter, D25 isop ...

. Using

telescope A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...

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 of Hawaii. Both telescopes have aperture primary mirrors, and, when c ...

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, he has mapped the tell-tale signs of tidal disruption and destruction, providing important clues to how large

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar Sys ...

have grown over time.

Publications

As of August 2020, Lewis has published more than 400

scientific articles Science is a systematic discipline that builds and organises knowledge in the form of testable hypotheses and predictions about the universe. Modern science is typically divided into twoor threemajor branches: the natural sciences, which stu ...

, numerous articles in the popular press, and three popular science books. * ''Where did the Universe come from? And other cosmic questions'' by

Chris Ferrie Chris Ferrie (born 1982) is a Canadian physicist and children's book author. Ferrie studied at the University of Waterloo in Waterloo, Ontario Canada, where he earned a BSc in mathematical physics, a masters in applied mathematics, and a PhD in ...

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, New South Wales, Australia. Objectives and activities The constitutionally adopted objectives of the Society ...

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 ...

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 Fellows of the Learned Society of Wales Welsh astronomers Welsh physicists 20th-century British astronomers 21st-century British astronomers 1969 births Welsh expatriates in Australia