events
French astronomer Pierre Janssen discovers helium.
Related Wikipedia articles
Astronomer
Scientist in the field of astronomy
An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, moons, comets and galaxies – in either observational or theoretical astronomy.…Source: Wikipedia (CC BY-SA)
Pierre Janssen
French astronomer (1824–1907)
Pierre Jules César Janssen, usually known as Jules Janssen, was a French astronomer who, along with English scientist Joseph Norman Lockyer, is credited with discovering the gaseous nature of the solar chromosphere, but there is no justification for the conclusion that he…Source: Wikipedia (CC BY-SA)
Discovery of chemical elements
List of history of chemical elements
The discoveries of the 118 chemical elements known to exist as of 2025 are presented here in chronological order. The elements are listed generally in the order in which each was first defined as the pure element, as the exact date of discovery of most elements cannot be…Source: Wikipedia (CC BY-SA)
Helium
Chemical element with atomic number 2 (He)
Helium is a chemical element; it has symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements, and it does not have a melting…Source: Wikipedia (CC BY-SA)