Liquid helium of liquid water. Helium was first liquefied on July 10, 1908, by the Dutch physicist Heike Kamerlingh Onnes at the University of Leiden in the Netherlands. At that time, helium-3 was unknown because the mass spectrometer had not yet been invented. In more recent decades, liquid helium has been used as a cryogenic refrigerant, and liquid helium is produced commercially for use in superconducting magnets such as those used in magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), Magnetoencephalography (MEG), and experiments in physics, such as low temperature Mössbauer spectroscopy. The temperature required to produce liquid helium is low because
1732 Heike November 1977 (). 1732 Heike 1732 Heike, provisional designation , is a stony Eoan asteroid from the outer region of the asteroid belt, approximately 24 kilometers in diameter. It was discovered on 9 March 1943, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after Heike Neckel, the granddaughter of astronomer Alfred Bohrmann. The S-type asteroid is a member of the Eos family. It orbits the Sun in the outer main-belt at a distance of 2.7–3.3 AU once every 5 years and 3 months (1,911 days). Its orbit has an eccentricity of 0.11 and an inclination