People also ask
How much of the universe is dark matter and energy?
By fitting a theoretical model of the composition of the universe to the combined set of cosmological observations, scientists have come up with the composition that we described above, ~68% dark energy, ~27% dark matter, ~5% normal matter. What is dark matter? We are much more certain what dark matter is not than we are what it is.
How do we know how much dark energy there is?
We know how much dark energy there is because we know how it affects the universe’s expansion. Other than that, it is a complete mystery. But it is an important mystery. It turns out that roughly 68% of the universe is dark energy.
How does dark energy affect the expansion of the universe?
Probing dark energy, the energy in empty space causing the expanding universe to accelerate, calls for accurately measuring how that expansion rate is increasing with time. Dark energy is thought to drive space apart. The diagram at right shows the changes in the rate of expansion since the universe’s birth 15 billion years ago.
Is dark energy Einstein’s cosmological constant?
Hubble observations suggest the dark energy may be Einstein’s cosmological constant, an energy percolating out of the vacuum of the space between galaxies. The energy of the universe is dominated by empty space emitting a repulsive form of gravity that is pushing the universe apart.