View our new "On this day" sections for July.


1 July 

  • 1770 Lexell’s Comet makes a closer approach to Earth than any other comet in recorded history, passing at a distance of just 0.015 astronomical units

2 July 

  • 1897 Guglielmo Marconi receives a patent for his invention of the radio
  • 1862 Birth of William Henry Bragg, who shared the 1915 Nobel Prize with his son William Lawrence Bragg for their invention of the x-ray spectrometer and subsequent work on x-ray crystallography
  • 1906 Birth of Hans Bethe, the theoretical physicist who made contributions to nuclear physics, quantum electrodynamics and astrophysics, headed the Theoretical Division of the Los Alamos National Laboratory, which created the first atomic weapons, and who was awarded the 1967 Nobel Prize for his work on stellar nucleosynthesis
  • 1914 Birth of Mário Schenberg, known for his theory of the nuclear processes in the formation of supernovae

3 July 

  • 1886 The world’s first motor car, the Benz Patent Motorwagen, is unveiled by Karl Benz the engineer and founder of the Mercedes-Benz motor company

4 July 

  • 2012 CERN tentatively announces the discovery of the Higgs boson, the particle thought to be responsible for the existence of mass
  • 1054 A supernova 6500 lightyears away in the constellation Taurus becomes visible from Earth; its remnants now form the Crab Nebula

  • 1934 The chain-reaction design of the atomic bomb is patented by Leó Szilárd, who later assigns the rights to the British Admiralty to ensure its secrecy. Szilárd also held the patent for the nuclear reactor, jointly with Enrico Fermi
  • 2005 NASA’s Deep Impact spaceprobe is crash-landed onto the comet Tempel 1 with a mission to study its composition
  • 1868 Birth of Henrietta Swan Leavitt, who discovered the relationship between the luminosity of Cepheid variable stars and the period of the oscillations in that luminosity; her discovery was later used by Edwin Hubble to show that “spiral nebulae” were actually separate galaxies at huge distances from our own

5 July 

  • 1687 Isaac Newton publishes Philosophiae Naturalis Principia Mathematica (“Mathematical principles of natural philosophy”) setting out the foundations of classical mechanics and his law of gravitation
  • 1951 William Shockley announces his invention of the bipolar junction transistor
  • 1820 Birth of William John Macquorn Rankine, one of the founders of thermodynamics
  • 1946 Birth of Gerard ‘t Hooft, who shared the 1999 Nobel Prize with his former thesis supervisor Martinus J G Veltman "for elucidating the quantum structure of electroweak interactions in physics"

6 July 

  • 1962 A nuclear test is carried under the Nevada desert as part of a programme aimed at investigating possible civilian uses of nuclear explosions, such as mining. The resulting Sedan Crater is the largest artificial crater in the US

7 July 

  • 1959 Venus occults Regulus, the brightest star in the constellation Leo, allowing an accurate determination of the planet’s diameter and of the composition of its atmosphere

8 July 

  • 1947 A UFO is claimed to have crash-landed near Roswell, New Mexico

  • 2011 The final mission of NASA’s space shuttle programme gets underway with the launch of Atlantis
  • 1894 Birth of Pyotr Leonidovich Kapitsa, awarded a share of the 1978 Nobel Prize for his work in low-temperature physics
  • 1895 Birth of Igor Tamm, who, along with Pavel Cherenkov and Ilya Frank, discovered what is now known as Cherenkov radiation; the trio were awarded the Nobel Prize in 1958

9 July 

  • 1955 Albert Einstein and Bertrand Russell launch their joint manifesto highlighting the danger posed by nuclear weapons
  • 1911 Birth of John Archibald Wheeler, a leading early expert in, and proponent of, Einstein’s general theory of relativity
  • 1926 Birth of Ben Roy Mottelson, winner of the 1975 Nobel Prize along with Aage Bohr and James Rainwater "for the discovery of the connection between collective motion and particle motion in atomic nuclei and the development of the theory of the structure of the atomic nucleus based on this connection"

10 July 

  • 1962 The first ever communications satellite, Telstar, is launched
  • 1832 Birth of Alvan Graham Clark, the first person to observe Sirius B, the first known white dwarf star
  • 1920 Birth of Owen Chamberlain, awarded the 1959 Nobel Prize jointly with Emilio Segrè for their discovery of the antiproton

11 July 

  • 1735 Pluto moves inside the orbit of Neptune, according to orbital calculations

  • 1962 Communications satellites are used to broadcast a television transmission across the Atlantic for the first time
  • 1979 The first US space station, Skylab, re-enters the Earth’s atmosphere due to greater drag than predicted, and burns up over the Indian Ocean
  • 1916 Birth of Alexander Prokhorov, winner of the 1964 Nobel Prize along with Charles Hard Townes and Nikolay Basov for work on the development of the laser and maser
  • 1924 Birth of César Lattes, who discovered the pion – a particle made up of a quark and an antiquark – along with Cecil Powell and Guiseppe Occhialini
  • 1931 Birth of Tullio Regge, known for his theory of strong interactions at high energies and for his approximations of spacetime geometries in general relativity – now known as Regge theory and Regge calculus respectively

12 July 

  • 1863 Birth of Paul Drude, known for his eponymous model of electrical conduction

  • 1913 Birth of Willis Lamb, winner of the 1955 Nobel Prize along with Polycarp Kusch for “discoveries concerning the fine structure of the hydrogen spectrum". He lends his name to the Lamb shift – the difference in energy between two of the energy levels in a hydrogen atom, which were predicted by Paul Dirac to have the same energy and which are caused by the interaction of the atom’s electron with the vacuum

13 July 

  • 1919 The first return airship journey across the Atlantic is completed when the vessel R34, nicknamed “Tiny”, lands. Its journey from Pulham, Norfolk to Mineola, Long Island and back again took 182 hours

14 July 

  • 1965 The Mariner 4 spacecraft takes the first close-up photos of another planet as it flies by Mars

15 July 

  • 1918 Birth of Bertram Brockhouse, who shared the 1994 Nobel Prize with Clifford Shull for work on using neutron scattering to investigate condensed matter

  • 1922 Birth of Leon M Lederman, winner of the 1988 Nobel Prize jointly with Melvin Schwartz and Jack Steinberger for their work on neutrinos, including their discovery of the muon

16 July 

  • 1746 Birth of Giuseppe Piazzi, discoverer of the dwarf planet Ceres
  • 1945 The “Trinity” test – the first ever detonation of a nuclear weapon – takes place in the New Mexico desert
  • 1969 Apollo 11, the first manned mission to land on the Moon launches
  • 1994 The comet Shoemaker-Levy 9 collides with Jupiter
  • 1888 Birth of Frits Zernike, winner of the 1953 Nobel Prize for his invention of the phase contrast microscope

17 July 

  • 1920 Birth of Gordon Gould, one of the inventors of the laser and the physicist who first coined that term for the device

18 July 

  • 1853 Birth of Hendrik Lorentz, winner of the 1902 Nobel Prize along with Pieter Zeeman for their discovery and explanation of the Zeeman effect – the splitting of spectral lines in the presence of a magnetic field. Lorentz also lends his name to the coordinate transformation formula used by Albert Einstein in formulating his special theory of relativity

19 July 

  • 1983 The journal Radiology publishes a paper by Michael W Vannier and others describing the first three-dimensional reconstruction of a human head built up from individual CT-scan slices
  • 1921 Birth of Rosalyn Sussman Yalov, the medical physicist who won the 1977 Nobel Prize in Physiology or Medicine, along with Roger Guillemin and Andrew Schally, for their development of the radioimmunoassay – a technique that uses radioactive materials to determine levels of antigens

20 July 

  • 1969 Apollo 11 touches down in the Sea of Tranquility in the first ever landing of a manned mission to the Moon

  • 1947 Birth of Gerd Binnig, who shared half of the 1986 Nobel Prize with Heinrich Rohrer for their design of the scanning tunneling microscope

21 July 

  • 1969 Neil Armstrong and Buzz Aldrin step out of Apollo 11’s lunar module and become the first humans to set foot on the Moon
  • 2011 NASA’s shuttle programme ends with the landing of Atlantis

22 July 

  • 1784 Birth of Friedrich Bessel, who first used measurements of parallax in calculating the distance to a star and after whom Bessel functions in mathematics are named
  • 1887 Birth of Gustav Ludwig Hertz, winner of the 1925 Nobel Prize along with James Franck for their experiments on inelastic collisions of electrons in gases, which lent support to the Niels Bohr’s atomic model

23 July 

  • 1995 Alan Hale and Thomas Bopp independently discover the comet now named after both of them
  • 1775 Birth of Étienne-Louis Malus, known for Malus’ law relating the intensity of polarized light to the angle of incidence with the polarizer
  • 1886 Birth of Walter H Schottky, known for his theories of electron and ion emissions and for his development of semiconductor devices
  • 1928 Birth of Vera Rubin, known for her work on galaxy rotation rates

24 July 

  • 1969 Apollo 11 lands in the Pacific Ocean, completing the first manned mission to land on the Moon

25 July 

  • 1837 The electric telegraph is used commercially for the first time, transmitting between Euston and Camden Town in London

26 July 

  • 1971 Apollo 15 is launched on the first Moon mission to use a Lunar Rover

27 July 

  • 1733 Birth of Jeremiah Dixon, the astronomer whose survey undertaken along with Charles Mason established the Mason-Dixon line – resolving a border dispute between four British colonies in North America and later symbolically serving as the border between northern and southern US states
  • 1848 Birth of Loránd Eötvös, known for his work on gravity and on surface tension

28 July 

  • 1915 Birth of Charles Hard Townes, who invented the maser along with Nikolay Basov and Alexander Prokhorov, for which the three were awarded the 1964 Nobel Prize

29 July 

  • 1957 The International Atomic Energy Agency is established, aimed at promoting the peaceful use of nuclear power and restricting the use of nuclear weapons
  • 2005 The discoveries of the dwarf planets Eris and Makemake are announced; this ultimately leads to Pluto being redesignated as a dwarf planet
  • 1898 Birth of Isidor Isaac Rabi, winner of the 1944 Nobel Prize for his discovery of nuclear magnetic resonance

30 July 

  • 1971 Apollo 15 lands on the Moon with the first Lunar Rover to be deployed there

31 July 

  • 1718 Birth of John Canton, who came up with a way of making artificial magnets