Scientists voted on Friday to add new prefixes to the SI system of measurement, with ronna- and quetta- becoming the largest units in the system. Following the additions, the Earth can now be said to weigh approximately six ronnagrams.
The measurements were adopted at the 27th General Conference on Weights and Measures, which meets at Versailles Palace in France every four years and determines new additions to the International System of Units (SI).
Just as a kilogram represents 1,000 grams, a ronnagram now represents one gram followed by 27 zeros and a quettagram one followed by 30 zeros. The prefixes can be applied to any of the base units in the SI system. For example, a ronnameter is equal to one meter to the power of 27, and a quettavolt is one volt of electric potential to the power of 30.
The new prefixes were proposed by Dr. Richard Brown of the UK’s National Physical Laboratory, and were driven by the needs of the tech industry, which is already using the previous highest prefixes in data storage (yottabytes and zettabytes).
“In terms of expressing data in yottabytes, which is the highest prefix currently, we’re very close to the limit,” Brown told AFP. He added that the new additions should “future proof the system” for the next 20 to 25 years. The SI system will face a fresh challenge at that point, as with ‘R’ and ‘Q’ taken, there are no more letters in the alphabet that are not already in use for other units.
The new units make it easier to describe extremely large objects. “If we think about mass, instead of distance, the Earth weighs approximately six ronnagrams,” Brown said. “Jupiter, that’s about two quettagrams.”
The conference also voted on two new prefixes to describe the smallest things in the universe. ‘Ronto’ describes one unit to the power of negative 27, while ‘quecto’ describes one unit to the power of negative 30. This means that one quectogram is equal to 0.000000000 000000000000000000001 grams.
Such tiny measurements are “useful for quantum science, particle physics – when you're measuring really, really small things,” Brown explained.