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or without a mixture of majorons (assuming the majorons exist). Otherwise,
the electron and positron are so far apart from each other at the time that
they can hardly meet and annihilate. Instead, they will form an analog of the
hydrogen atom, called the positronium, and then slowly spiral towards each
other to annihilate [34].
All these will lead to what is generally called the “heat death” of the universe,
where there is no transfer of energy from one system to another. This idea was
initiated by Lord Kelvin in 1851. Kelvin wrote:
The result would inevitably be a state of universal rest and death, if the universe
were finite and left to obey existing laws. But it is impossible to conceive
a limit to the extent of matter in the universe; and therefore science points
rather to an endless progress, through an endless space, of action involving the
transformation of potential energy into palpable motion and hence into heat,
than to a single finite mechanism, running down like a clock, and stopping for
ever.