The geometrical definition for a perfect sphere is the set of all those points in a three-dimensional plane that are at exactly equal distance from a particular point. An ideal sphere has a base of exactly one point, which is nearly impossible to be realized in real world scenario. However, a team of Australian scientists and optical engineers are working hard to create an object that beholds to the definition of an ideal sphere to the highest possible level of precision. If successful, this silicon ball will redefine the standard kilogram. At present, the prototype that represents the standard weight of 1 kg is a right circular cylinder made up of an alloy of 90% platinum and 10% iridium that measures exactly 39mm in height and diameter, it is kept at Paris, France.
This weight has been used as a standard under the SI unit of standards since 1889. But the problem with this mass is that it has lost about 50 micrograms in the past century, the exact reasons for which are unknown. The Australian team has so far achieved success to attain a precision of 35 nanometers – meaning the ball’s diameter alters by an average of 35 nanometers at the maximum fault, thus making it the roundest solid object in the world so far.
Redefining the standard kilogram depends on several parameters for which the exact causes of the alteration of the current mass need to be known. If it was due to change in it’s physical properties, new standard could just work fine; however, if was due to change in earth’s gravitational field over time, high chances are that the new standard too could go obsolete some day.
Source: Switched
