The year 1844 in science and technology involved some significant events, listed below.

Astronomy

• August 10 – German astronomer Friedrich Bessel deduces from the motion of the bright stars Sirius and Procyon that they have dark companions.^[1]

Biology

• June 3 – The last definitely recorded pair of great auks (Pinguinus impennis) are killed on the Icelandic island of Eldey.
• August 1 – Opening of Berlin Zoological Garden.^[2]
• Gabriel Gustav Valentin notes the digestive activity of pancreatic juice.
• George Robert Gray begins publication in London of The Genera of Birds.
• Joseph Dalton Hooker begins publication of The Botany of the Antarctic Voyage of H.M. Discovery Ships Erebus and Terror ... 1839–1843 in London.^[3]

Chemistry

• Karl Klaus discovers ruthenium.
• Professor Gustaf Erik Pasch of Stockholm is granted the privilege of manufacturing a safety match.
• French chemist Adolphe Wurtz reports the first synthesis of copper hydride, a well-known reducing agent and catalyst in organic chemistry.

Earth sciences

• Robert Chambers' anonymous Vestiges of the Natural History of Creation, which paves the way for acceptance of Darwin's The Origin of Species, is published in Britain.

Mathematics

• Joseph Liouville finds the first transcendental number
• Hermann Grassmann studies vectors with more than three dimensions.

Medicine

• Irish physician Francis Rynd utilises a hollow hypodermic needle to make the first recorded subcutaneous injections, specifically of a sedative to treat neuralgia.

Metrology

• Joseph Whitworth introduces the thou.^[4]

Physics

• William Robert Grove publishes The Correlation of Physical Forces, the first comprehensive account of the conservation of energy.

Technology

• January 30 – Charles Goodyear patents the vulcanisation of rubber in the United States.
• May 11 – Samuel Morse sends the first message using Morse code.
• June – Henry Fox Talbot commences publication of the first book illustrated with photographs from a camera, The Pencil of Nature.
• Uriah A. Boyden develops an improved outward-flow water turbine.
• Robert Bunsen invents the grease-spot photometer.
• Thomas and Caleb Pratt design the Pratt truss bridge.
• Dublin iron-founder Richard Turner begins assembling components for the Palm house at Kew Gardens in London, the first large-scale structural use of wrought iron.
• Egide Walschaerts of the Belgian State Railways originates Walschaerts valve gear for the steam locomotive.

Events

• July 27 – Death of English chemist and physicist John Dalton in Manchester where his body lies in honour in the Town Hall and more than 40,000 people file past his coffin.

Awards

• Copley Medal: Carlo Matteucci^[5]
• Wollaston Medal for Geology: William Conybeare

Births

• February 1 – G. Stanley Hall (died 1924), American psychologist.
• February 7 – Alexei Pavlovich Fedchenko (died 1873), Russian naturalist.
• February 20 – Ludwig Boltzmann (died 1906), Austrian physicist famous for the invention of statistical mechanics.
• March 25 – Adolf Engler (died 1930), German botanist.
• June 10 – Carl Hagenbeck (died 1913), German zoologist.
• July 1 – H. Newell Martin (died 1896), British physiologist.
• August 6 – James Henry Greathead (died 1896), South African-born English civil engineer.
• August 13 – Friedrich Miescher (died 1895), Swiss biochemist.
• August 22 – George W. DeLong (died 1881), American Arctic explorer.
• September 11 – Henry Alleyne Nicholson (died 1899), English paleontologist and zoologist.
• October 3 – Patrick Manson (died 1922), Scottish parasitologist, the "father of tropical medicine" .
• October 28 – Mary Katharine Brandegee née Layne (died 1920), American botanist.
• November 25 – Karl Benz (died 1929), German automotive engineer.
• Varvara Rudneva (d. 1899), Russian physician.

Deaths

• June 19 – Étienne Geoffroy Saint-Hilaire (born 1772), French naturalist.
• July 27 – John Dalton (born 1766), English chemist and physicist.
• August 30 – Francis Baily (born 1774), English astronomer.
• December 28 – Thomas Henderson (born 1798), Scottish astronomer.