Noun
dark energy (uncountable)
(astronomy, astrophysics) A hypothetical form of energy which, it is supposed, is spread uniformly throughout space (and time) and has anti-gravitational properties: it represents a possible mechanism for the cosmological constant, and thus is one of the possible explanations for the current accelerating rate of expansion of the universe; and it is estimated to account for about 74% of the mass-energy of the universe.
There is one constant that seems to be fine tuned...and that is dark energy. Steven Weinberg
Dark energy is incredibly strange, but actually it makes sense to me that it went unnoticed, because dark energy has no effect on daily life, or even inside our solar system. Adam Riess
It's everywhere, really. It's between the galaxies. It is in this room. We believe that everywhere that you have space, empty space, that you cannot avoid having some of this dark energy. Adam Riess
Eventually, when the universe expands enough, all that will be left is the dark energy. Leonard Susskind
The dark energy is not exactly zero, but the first 122 decimal points are zero. That's crazy. That is really one of the craziest things we've ever discovered. Leonard Susskind
Dark energy is perhaps the biggest mystery in physics. Steve Allen