The gallery

Nicolaus Copernicus

1473–1543

Polish astronomer and canon

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In the Observatory

• the wanderersPut the Sun in the middle in 1543, and the planets' backward loops became the Earth overtaking them.
• the orreryHis Sun-centred system is the layout of the orrery.

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Bust after Julien Mairy, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Galileo Galilei

1564–1642

Italian astronomer and physicist

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In the Observatory

• the wanderersSaw Venus wax and wane like the Moon in 1610: it goes round the Sun.

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Bust after voxelstudio3d, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Johannes Kepler

1571–1630

German astronomer and mathematician

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In the Observatory

• the orreryPlanets move on ellipses, fastest near the Sun: the rules the orrery runs on (1609, 1619).
• the wanderersWorked them out from Mars, whose loops had defeated everyone before him.
• the sundialHis fast-near-the-Sun rule is half the equation of time: the Sun falls behind the clock after early January.

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Bust after voxelstudio3d, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Isaac Newton

1643–1727

English mathematician and physicist

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In the Observatory

• the tideExplained the tides in 1687: the Moon and Sun pulling the near and far sides of the Earth unequally.
• the orreryOne law of gravity for an apple and for the planets.

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Bust after voxelstudio3d, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Hendrik Antoon Lorentz

1853–1928

Dutch physicist, Nobel Prize 1902

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In the Observatory

• the clockWrote down in 1904 the equations by which lengths and clocks change with speed, the mathematics of time dilation.
• the speed limitHis factor γ is why pushing harder never quite reaches c.

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Portrait painted after a public-domain original

Thomas Young

1773–1829

English physician and physicist

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In the Observatory

• the double slitShowed in 1803 that light makes interference stripes: it behaves as a wave.

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Portrait painted after a public-domain original

Christian Doppler

1803–1853

Austrian mathematician and physicist

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In the Observatory

• the sirenPredicted in 1842 that motion shifts the pitch of sound and the colour of light.
• the spectroscopeThe motion part of every redshift is his.
• the wobbleHis shift gives away a planet tugging its star.
• the turntableHis shift, one side of a galaxy blue and the other red, is how its turning is measured.

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Portrait painted after a public-domain original

James Clerk Maxwell

1831–1879

Scottish physicist

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In the Observatory

• the speed limitFound in 1865 that light is a wave of electricity and magnetism, travelling at one fixed speed.
• the double slitThe wave that makes Young's stripes is his electromagnetic wave.

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Bust after voxelstudio3d, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Max Planck

1858–1947

German physicist, Nobel Prize 1918

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In the Observatory

• the double slitFound in 1900 that energy is traded in lumps of h f when matter gives off heat and light, the first step to the photon.

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Bust after Julien Mairy, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Albert Einstein

1879–1955

German-born physicist, Nobel Prize 1921

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In the Observatory

• the speed limitTook the speed of light as the same for everyone in 1905, and found E = mc².
• the clockMoving clocks run slow (1905), and clocks deep in gravity too (1915).
• the chirpPredicted waves in space-time in 1916, and doubted anyone would ever measure them.
• the double slitExplained in 1905 that light also travels in lumps, photons: the work of his Nobel prize.

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Bust after Antoine, CC BY 4.0, unaltered, rendered in bronze

Karl Schwarzschild

1873–1916

German astronomer and physicist

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In the Observatory

• the lensFound the black hole in Einstein's equations in 1915, while serving at the Russian front.
• the fallHis radius is where the horizon lies, the line in the fall.

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Portrait painted after a public-domain original

Cecilia Payne-Gaposchkin

1900–1979

British-born American astronomer

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In the Observatory

• the tableShowed in 1925 that the stars are made mostly of hydrogen and helium, the first two squares of the table.
• the SunThe Sun included: three quarters hydrogen by mass.

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Bust after Julien Mairy, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Subrahmanyan Chandrasekhar

1910–1995

Indian-born American astrophysicist, Nobel Prize 1983

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In the Observatory

• the life of a starWorked out in 1930 that a white dwarf cannot weigh more than about 1.4 Suns.
• the lighthouseAbove his limit a dying core falls in further, to a neutron star or a black hole.

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Arthur Eddington

1882–1944

English astronomer

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In the Observatory

• the SunProposed in 1920 that the Sun shines by turning hydrogen into helium.
• the life of a starWorked out how the inside of a star holds itself up against its own weight.

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Portrait painted after a public-domain original

Edwin Hubble

1889–1953

American astronomer

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In the Observatory

• the spectroscopeShowed in 1929 that the further away a galaxy is, the more its light is shifted to the red.
• the speed limitHis expanding universe is the loophole.
• the Hubble flowPut distances next to redshifts in 1929: the further a galaxy, the faster it recedes.

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Bust after Julien Mairy, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Georges Lemaître

1894–1966

Belgian priest and cosmologist

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In the Observatory

• the Hubble flowDerived the expanding universe from Einstein's equations in 1927, two years before Hubble, and later traced it back to a "primeval atom".

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Portrait painted after a public-domain original

Henrietta Swan Leavitt

1868–1921

American astronomer at Harvard

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In the Observatory

• the Hubble flowFound in 1912 that a Cepheid's rhythm gives away its true brightness: the yardstick Hubble measured the galaxies with.

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Maarten Schmidt

1929–2022

Dutch-born astronomer at Caltech

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In the Observatory

• the engineRecognised in 1963 that the "star" 3C 273 was a quasar, billions of light years away: the first known engine.
• the spectroscopeIts hydrogen lines were shifted 16% to the red; that was the clue.

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Portrait painted after a public-domain original

Fritz Zwicky

1898–1974

Swiss astronomer at Caltech

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In the Observatory

• the turntableFound in 1933 that the galaxies of the Coma cluster move far too fast for the light he saw, and called the rest dunkle Materie.

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Vera Rubin

1928–2016

American astronomer

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In the Observatory

• the turntableMeasured with Kent Ford how galaxies turn, from Andromeda in 1970 on: flat, every time.

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Stephen Hawking

1942–2018

English theoretical physicist

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In the Observatory

• the lensShowed in 1974 that black holes are not quite black: they glow faintly and slowly evaporate.

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Bust after Julien Mairy, CC BY-NC-ND 4.0, unaltered, rendered in bronze

Jocelyn Bell Burnell

born 1943

Northern Irish astrophysicist

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In the Observatory

• the lighthouseSpotted the first pulsar in 1967, as a bit of "scruff" on the paper chart of a new radio telescope.

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