elements · 55 / 118 · All 118

Caesium

Z: 55
Mass: 132.905
Lifeforce: Fire

Soft as butter, explosive in water. And of all metals, this is the one that measures time itself: the second is defined by its hyperfine transitions, and every atomic clock on Earth runs on it.

A smith's hands strike sparks from glowing embers; the sparks become tiny glowing runners. — Plate · Fire Fire never waits. It *ignites* whatever it touches.

Caesium. Element fifty-five. Defines time itself: the second is measured by its hyperfine transitions. Soft as butter, explosive in water. Every atomic clock on Earth runs on it.

Lab note · Element fifty-five; the second is measured by its hyperfine transitions. Reacts explosively with water.

Tool · Cosmic origin

Where your atoms come from

Cs · Supernova

Born in supernova explosions, the death of massive stars scattering their innards across the galaxy.

65 of the 118 elements share this origin.

Choose a stage: click, or arrow keys. · Cosmic nucleosynthesis · current standard model

Tool · Periodic table

Your place in the system

H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og

Fire
Water
Air
Earth
Source

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