Paving the way for the redefinition of the unit of temperature

At present, the kelvin is literally based on no more than water—on the triple point of water, to be more precise. The base unit of temperature is therefore dependent on a material whose properties may vary. But this is ...

The most accurate optical single-ion clock worldwide

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically ...

Hubble finds birth certificate of oldest known star

( —A team of astronomers using NASA's Hubble Space Telescope has taken an important step closer to finding the birth certificate of a star that's been around for a very long time.

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