* 1795 – Peter Andreas Hansen, Danish astronomer ( d. 1874 )

* 1546 – Tycho Brahe, Danish astronomer and alchemist ( d. 1601 )

The Danish and German geographical mile ( geografisk mil and geographische Meile or geographische Landmeile, respectively ) is 4 minutes of arc, and was defined as approximately 7421. 5 metres by the astronomer Ole Rømer of Denmark.

The Danish astronomer Theodor Brorsen published the first thorough investigations of the gegenschein in 1854.

In Potsdam in 1906, the Danish astronomer Ejnar Hertzsprung noticed that the reddest stars — classified as K and M in the Harvard scheme — could be divided into two distinct groups.

* 1562 – Christian Sørensen Longomontanus, Danish astronomer ( d. 1647 )

Ole Christensen Rømer (; 25 September 1644, Århus – 19 September 1710, Copenhagen ) was a Danish astronomer who in 1676 made the first quantitative measurements of the speed of light.

The first was begun by Danish astronomer Hans Emil Lau who, after studying the data on the orbit of Uranus from 1690 to 1895, concluded that one trans-Neptunian planet alone could not account for the discrepancies in its orbit, and postulated the position of two planets he believed were responsible.

After disagreements with the new Danish king in 1597, he was invited by the Bohemian king and Holy Roman emperor Rudolph II to Prague, where he became the official imperial astronomer.

* September 25 – Ole Rømer, Danish astronomer ( d. 1710 )

* October 24 – Tycho Brahe, Danish astronomer ( b. 1546 )

* December 14 – Tycho Brahe, Danish astronomer ( d. 1601 )

* September 19 – Ole Rømer, Danish astronomer ( b. 1644 )

* October 8 – Christian Sørensen Longomontanus, Danish astronomer ( b. 1562 )

* October 4 – Christian Sørensen Longomontanus, Danish astronomer ( d. 1647 )

Tycho is a prominent lunar impact crater located in the southern lunar highlands, named after the Danish astronomer Tycho Brahe ( 1546-1601 ).

Ejnar Hertzsprung (, 8 October 1873 – 21 October 1967 ) was a Danish chemist and astronomer.

* Sophia Brahe, Danish astronomer ( born 1556 )

The term was originally coined in 1906 when the Danish astronomer Ejnar Hertzsprung noticed that the reddest stars — classified as K and M in the Harvard scheme — could be divided into two distinct groups.

* Tycho Brahe ( 1546 – 1601 ), Danish nobleman and astronomer

* Peter Andreas Hansen ( 1795 – 1874 ), Danish astronomer

* Hans E. Lau ( 1879 – 1918 ), Danish astronomer

* October 24-Tycho Brahe, Danish astronomer ( b. 1546 )

* Jørgen Christensen-Dalsgaard, Danish astronomer.

* September 19-Ole Rømer, Danish astronomer ( born 1644 )

* 1891 – Ole Kirk Christiansen, Danish carpenter and toy maker, founder of the Lego Group toy company ( d. 1958 )

Three Danish citizens, Niels Jensen, Ole Henriksen, and Mogens Glad, founded Borland Ltd. in August 1981 to develop products like Word Index for the CP / M operating system using an off-the-shelf company.

An early experiment to measure the speed of light was conducted by Ole Rømer, a Danish physicist, in 1676.

* 1959 – Ole Bornedal, Danish actor, director, and producer

* 1588 – Ole Worm, Danish physician ( d. 1654 )

* 1935 – Ole Barndorff-Nielsen, Danish mathematician

The term " stalactite " was coined in the 17th century by the Danish Physician Ole Worm who created the word from the Greek root stalasso, ( σταλάσσω ), " to drip ".

In Scandinavia Thomas Bartholin and Ole Worm, the 17th century Danish scholars and Olaf Rudbeck in Sweden were the first to set the standard for using runic inscriptions and Icelandic Sagas as historical sources.

In Scandinavia, the 17th century Danish scholars Thomas Bartholin and Ole Worm, and the Swede Olof Rudbeck were the first to set the standard for using runic inscriptions and Icelandic sagas as historical sources.

The rise of this legend can be traced to Ole Worm's Runer seu Danica literatura antiquissima ( 1636 ), in which Danish warriors drinking ór bjúgviðum hausa the curved branches of skulls, i. e. from horns were rendered as drinking ex craniis eorum quos ceciderunt the skulls of those whom they had slain.

* March 18 – Ole Barndorff-Nielsen, Danish mathematician

* Danish natural philosopher Ole Worm collects materials that will later be incorporated into his museum in Copenhagen.

* May 13 – Ole Worm, Danish physician and antiquary ( d. 1654 )

* August 31 – Ole Worm, Danish physician and antiquary ( b. 1588 )

The Danish physician Ole Worm determined in 1638 that the alleged alicorns were the tusks of narwhals.

The unicorn horns often found in cabinets of curiosities and other contexts in Medieval and Renaissance Europe, were very often examples of the distinctive straight spiral single tusk of the narwhal ( Monodon monoceros ), an Arctic cetacean, as Danish zoologist Ole Worm established in 1638.

His son in law was the Danish physician and natural historian, Ole Worm, who married Fincke's daughter Dorothea.

Ole Amble, minister in the Danish Lutheran Church.

In 1380, Norway had come under Danish rule, and by literates and artists, like the violinist Ole Bull.

The brilliant contributions to atomic physics of Niels Bohr ( 1885 – 1962 ), the contributions to linguistics by Otto Jespersen ( 1860 – 1943 ), Ludwig A. Colding's ( 1815 – 1888 ) neglected articulation of the principle of conservation of energy, the pioneering work in anatomy and geology by Nicolas Steno ( 1638 – 1686 ), and the astronomical discoveries of Tycho Brahe ( 1546 – 1601 ) and Ole Rømer ( 1644-1710 ) indicate the range of Danish scientific achievement.

Ole Worm ( 13 May 1588 – 31 August 1655 ), who often went by the Latinized form of his name Olaus Wormius, was a Danish physician and antiquary.