How does one go about measuring the mass of an object? Mass is defined as the amount of matter an object contains. This is very different from weight, of course, as the mass of our object would remain ...

A high-tech version of a balance scale has just brought scientists a critical step closer toward a new and improved definition of the kilogram. The scale, called the NIST-4 watt balance, has conducted ...

Astronomers have used the sharp vision of NASA’s Hubble Space Telescope to repeat a century-old test of Einstein’s general theory of relativity. The Hubble team measured the mass of a white dwarf, the ...

Determining the size of an Earth-size exoplanet by the amount of starlight it blocks hundreds of light-years away once was the realm of science fiction. Measuring the mass of such a small planet based ...