Tech UPTechnologyHow much does a kilogram weigh?

How much does a kilogram weigh?

The question seems simple, but it is not. A group of scientists has met this week in London, convened by the prestigious Royal Society , to try to redefine this universal unit of measurement .

The kilogram is the only one of the seven units included in the international system (known as SI for its acronym in English) that is defined based on an object, a cylinder composed of 90% platinum and 10% iridium , manufactured in London in 1879 and kept under a bell jar in the Office of Weights and Measures in Sèvres, near Paris.

However, measurements made over a hundred years ago show that the kilogram has lost weight. Its mass has changed the equivalent of a 0.4 mm diameter grain of sand. Long enough that scientists around the world have decided that the time has come to find a definition that dispenses with the physical object , just as they did with the meter, now defined by the speed of light.

For the kilogram, the scientists suggest using Planck's constant, a value named after the father of quantum physics, Max Planck . To define the relationship between the kilo of life and the Planck constant, experiments are being carried out all over the world. Michael Stock of the Royal Society of London estimates that the change could be approved "reasonably" at the next conference on weights and measures, to be held in Paris in 2015.

A simple ray of light, a jet of photons, is capable of giving us information about the temperature, composition, speed and distance of the star that emitted it.

The legacy of Albert Einstein: the Theory of Relativity

On this day Albert Einstein was born in Germany, author of the theory of relativity, who determined that the laws of physics are the same for all non-accelerating observers.

An asteroid that was going to hit Earth in 2023 turns out to be...

For a few days in January, asteroid 2022 AE1 became the most dangerous asteroid observed in more than a decade.

This is theory that says what was there before the Big Bang

One of the problems with physics is that its two great theories, general relativity and quantum theory, get along like a cat and a dog. Although we have been searching for a quantum theory of gravity for more than half a century, the truth is that the results are quite disappointing.

Is there only one time?

Time is a concept that we use daily throughout our lives. However, what is it? Time, we say, is what the clock ticks. But that is not saying much. If we reflect a little more we will see that no matter how hard we try to find an answer, none will completely satisfy us. Time is an elusive concept and it is surprising that something so familiar is so difficult to define.