Photons (quanta of light) are believed to have zero rest mass, and so would qualify as the lightest objects.
The current experimental upper bound for the mass of a photon is 10-18 eV/c2, or (in S.I. units) about 10-54 kg.
The opposite of lightest is heaviest.
The superlative for "light" is "lightest."
Hydrogen is the lightest gas found in air.
Hydrogen gas has the lightest density of any liquid.
lighter, lightest
the aerogel
The opposite of lightest is heaviest.
the lightest elements are gases and the lightest of these are hydrogen and helium.
The lightest metal is lithium.
The superlative form of the adjective 'light' is lightest.
Hydrogen is the lightest element. The isotope protium is the lightest kind of hydrogen atom.
ANSWER:The ant is the lightest animal in the world.
No hydrogen is the lightest element.
gas is the lightest in weight
Hydrogen was, and is, the lightest gas
Iron 56 is the lightest
The superlative for "light" is "lightest."