GK
THE UNIVERSE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe.
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Dark energy is the most accepted hypothesis to explain the observations since the 1990s indicating that the universe is expanding at an accelerating rate.
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Assuming that the standard model of cosmology is correct, the best current measurements indicate that dark energy contributes 68% of the total energy in the present-day observable universe.
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The density of dark energy is very low ( 7 × 10-30 g/cm3), much less than the density of ordinary matter or dark matter within galaxies.
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Detailed explanation-1: -Dark energy’s density is very low: 6×10−10 J/m3 ( 7×10−30 g/cm3), much less than the density of ordinary matter or dark matter within galaxies. However, it dominates the universe’s mass–energy content because it is uniform across space.
Detailed explanation-2: -The dark matter density near the solar system, from what I could find, sits at around 0.006 solar masses per cubic parsec, which is a set of units that’s not going to make much sense unless you’re a professional astrophysicist. This is extremely low density.
Detailed explanation-3: -We call that mysterious force “dark energy”. Despite the name, dark energy isn’t like dark matter, except that they’re both invisible. Dark matter pulls galaxies together, while dark energy pushes them apart.