Why would we expect the rate of expansion of the universe to be slowing down?

The density of matter decreases as the universe expands because the volume of space increases. Currently the density of dark energy is higher than that of matter, but in the distant past the density of matter should have been greater, so the expansion should have been slowing down then.

What force would slow the expansion of the universe?

gravity
Back then, gravity was the major force that influenced the structure of the universe. It slowed the rate of expansion and made it possible for matter to coalesce. Eventually, the first stars appeared about 400 million years after the Big Bang.

How do we know the universe is expanding faster?

Yet the prediction falls short: When cosmologists observe astronomical objects such as pulsating stars and exploding supernovas, they see a universe that’s expanding faster, with a larger Hubble constant. The discrepancy, known as the Hubble tension, has persisted even as all the measurements have grown more precise.

Will the Universe continue to expand?

The universe won’t ever stop expanding, but will spread out over trillions of years, stretching all matter and energy to such an extreme that our one universe will be separated into multiple universes. Inside these universes, the mysterious dark energy will materialize into normal matter and radiation.

Is the expansion of the universe slowing down or speeding up?

The discovery of accelerating rather than decelerating expansion has apparently revealed the presence of such an energy form, referred to as dark energy. Whether or not the expansion is slowing down or speeding up depends on a battle between two titans: the attractive gravitational pull of matter and the repulsive gravitational push of dark energy.

Is the universe flat or bent?

The universe has all sorts of deformations in space-time where it varies from the perfectly flat. Any place where there’s mass or energy, there’s a corresponding bending of space-time — that’s General Relativity 101.

Does the density of dark energy change as the universe expands?

Although little is known about dark energy, its density is expected to change slowly or not at all as the universe expands. Currently the density of dark energy is higher than that of matter, but in the distant past the density of matter should have been greater, so the expansion should have been slowing down then.

How does gravity affect the expansion of the universe?

In Einstein’s theory, the notion of gravity as an attractive force still holds for all known forms of matter and energy, even on the cosmic scale. Therefore, general relativity predicts that the expansion of the universe should slow down at a rate determined by the density of matter and energy within it.