Birkeland married Ida Charlotte Hammer in May 1905.

The results of the Norwegian Polar Expedition conducted from 1899 to 1900 contained the first determination of the global pattern of electric currents in the polar region from ground magnetic field measurements.

Birkeland proposed in 1908 in his book The Norwegian Aurora Polaris Expedition 1902–1903 that polar electric currents, today referred to as auroral electrojets, were connected to a system of currents that flowed along geomagnetic field lines into and away from the polar region.

Birkeland's theory of the aurora continued to be dismissed by mainstream astrophysicists after his death in 1917.

Proof of Birkeland's theory of the aurora only came in 1967 after a probe was sent into space.

The crucial results were obtained from U.S. Navy satellite 1963-38C, launched in 1963 and carrying a magnetometer above the ionosphere.

Therefore, in the 1910s and 1920s, it was gradually replaced in Norway by a combination of the Haber process and the Ostwald process.

In 1913, Birkeland may have been the first to predict that plasma was ubiquitous in space.

The 299 members of the society included, by 1922, people like prime minister Gunnar Knudsen, as well as a wide range of doctors, professors and shipowners.

In 1912 it was the alleged medium Etta Wriedt from Detroit, famous for her "spirit trumpet", who was exposed as a fraud.

In 2017, Yara International ordered the Yara Birkeland, which will be the world's first autonomous ship and is named after Birkeland.

It will enter service in 2018 and be fully autonomous by 2020.