The Moon's oxygen isotopic ratios are essentially identical to those of Earth.

The researchers measure the isotopic ratios at different locations and times to infer information about the physical processes of the ocean.

This results from differences in isotopic ratios of sediments and rocks within the different oceans.

These samples do have different isotopic ratios, but this is hard to see when they only differ after the decimal point.

No, somebody, the builder, made sure the osmium ball had a different isotopic ratio from normal.

When the gas is analyzed, it turns out to have exactly the same chemical composition and isotopic ratios as the air on Mars.

"The isotopic ratios are very close, but they're not identical."

As with all compounds of uranium it is radioactive to a degree dependent on its isotopic ratios.

"One more scan, and I'll have the current isotopic ratios of the dilithium crystals."

Only with continual monitoring can we see exactly how the isotopic ratios of air samples change over time.