Uranium Is Named After a Planet
Uranium is a heavy radioactive metal. It was named after Uranus, which had itself been discovered only eight years earlier.
Uranium is a dense, weakly radioactive metal, the heaviest element found in significant quantity in nature. Its name is astronomical: Martin Klaproth identified it in 1789 and named it after Uranus, discovered by William Herschel in 1781. Neptunium and plutonium later continued the planetary sequence.
- A heavy radioactive metal. *Enriched uranium.*
- Uranium as a modifier. *Uranium ore.*
- Depleted uranium — uranium with less of the fissile isotope. *Depleted uranium is very dense.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | uranium | Natural uranium. |
| Symbol | U | Element 92, U. |
| Related | enrichment | Uranium enrichment. |
| Related | isotope | The isotope U-235. |
| Related | half-life | A long half-life. |
How it is used in a sentence
- Reactor fuel uses enriched uranium.Raising the proportion of U-235.
- Natural uranium is mostly U-238.About 99.3 per cent.
- Uranium dating measures very long timescales.Geology.
Elements named after planets
- Uranium — Uranus, 1789
- Neptunium — Neptune, 1940
- Plutonium — Pluto, 1940
- Tellurium and selenium — the earth and the moon
- Helium — the sun, where it was detected first
Coined in 1789 by Martin Heinrich Klaproth from the planet Uranus, itself named for the Greek sky god. Radioactivity was not discovered until over a century later.
What is enrichment?
Increasing the proportion of the isotope U-235, which sustains a chain reaction. Reactor fuel needs a few per cent; weapons need far more.
Why is helium named after the sun?
Because it was detected in the sun's spectrum in 1868, before it was found on earth.