Definition of thorium
: a radioactive metallic element that is obtained especially from monazite and is usually associated with rare earths — see element table
Recent Examples of thorium from the Web
The criminal complaint says those were thorium and americium, both radioactive metals.
The radiation comes from elements like uranium, potassium and thorium - all of which are found in a group of rocky meteorites called chrondites.
While in his bedroom, devices used by police bomb technicians alerted to the presence of radiation sources — thorium and americium.
How bones were dated The bones were dated by measuring the amount of uranium and thorium in calcite stone deposits found on top of the fossils, which were estimated at 226,000 years.
The study uses a total of six methods, including measuring the levels of uranium and thorium in layers of stone that have formed over the fossils.
Next the team reached out to geochronologist James Paces, who retried the now much-improved uranium-thorium dating technique on the bones.
The scientists finally contacted James B. Paces, a research geologist at the United States Geological Survey, who determined how much uranium in the bones had broken down into another element, thorium.
If the US reactor fleet could be converted to LFTRs overnight, existing thorium reserves would power the US for a thousand years.
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Origin and Etymology of thorium
New Latin, from Old Norse Thōrr Thor
First Known Use: 1832See Words from the same year
Learn More about thorium
Britannica.com: Encyclopedia article about thorium
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