Context: Recently, Scientists have suggested using Calcium-41 for Radiometric Dating as an alternative to Carbon-14 for determining the age of fossilized bones and rocks.

• They have suggested a technique called Atom-Trap Trace Analysis (ATTA) as a solution, because ATTA is sensitive enough to spot Calcium-41, which is a rare isotope.

Limitation of carbon dating

• Carbon Dating was invented in 1947.

• It is used to estimate the age of organic material based on how much carbon-14 it contains.

• However, carbon-14 has a half-life of 5,700 years.

• It means the technique cannot determine the age of objects older than 50,000 years.

Calcium-41

• In 1979, scientists suggested using calcium-41, with a half-life of 99,400 years.

• Calcium-41 is produced when cosmic rays from space smash into calcium atoms in the soil.

• It is found in the earth’s crust, opening the door to dating fossilised bones and rock.

• But several problems need to be overcome before it can be used to reliably date objects.

How researchers can use Calcium-41?

• When an organic entity is alive, its body keeps absorbing and losing carbon-14 atoms.

• When it dies, this process stops and the extant carbon-14 starts to decay away.

• Using the difference between the relative abundance of these atoms in the body and the number that should have been there, researchers can estimate when the entity died.

What is the benefit of using Calcium-41 instead of carbon dating?

• Carbon dating detects carbon-14 atoms, which occur once in around 10^12 carbon atoms.

• Calcium-41 is rarer, occurring once in around 10^15 calcium atoms.

Atom-trap trace analysis (ATTA)

• ATTA is sensitive enough to spot these atoms.

• It is specific enough to not confuse them for other similar atoms and fits on a tabletop.

• In ATTA, a laser’s frequency is tuned such that it imparts the same energy as required for an electron transition in calcium-41.

• The electrons absorb and release this energy, revealing the presence of their atoms.

• ATTA also avoids potassium-41 atoms, which are similar to calcium-41 atoms but lack the same electron transition.