About astro physics

quintessence is a hypothetical form of dark energy

More precisely a scalar field

Postulated as an explanation of the observation of an accelerating rate of expansion of the universe.The first example of this scenario was proposed by Ratra and Peebles (1988) and Wetterich (1988).The concept was expanded to more general types of time-varying dark energy

And the term quintessence was first introduced in a 1998 paper by Robert R.Caldwell

Rahul Dave and Paul Steinhardt.It has been proposed by some physicists to be a fifth fundamental force.Quintessence differs from the cosmological constant explanation of dark energy in that it is dynamic; that is

Unlike the cosmological constant which

Does not change.Quintessence can be either attractive or repulsive depending on the ratio of its kinetic and potential energy.Those working with this postulate believe that quintessence became repulsive about ten billion years ago

About 3.5 billion years after the Big Bang.