This is because Hg is an abbreviation of the Latin name of the element, which was hydrargium. With this name the Greeks were referring to the fact that mercury is a silvery liquid at room temperature, rather than a solid like other metals.
We've looked at the three types of heat transfer. Conduction and convection rely on temperature differences; radiation does, too, but with radiation the absolute temperature is important.
Circulating air can transfer heat from one side of the room to another; thatâs convection. But out in the vacuum of space, the only way heat can transfer is radiation. Photons of energy get absorbed by an object, warming it up. At the same time, photons are radiating away. If the object is absorbing more photons than it emits, it heats up.