What is an open closed and flat universe?

What is an open closed and flat universe?

If the sum of the kinetic and potential energy is negative (smaller than zero), the universe will be closed. If it is zero the universe is flat, and if it is larger than zero, the universe is open. In the case of a flat universe, where the total energy is zero, the mass density is called the critical density .

What happens if the universe is closed?

Also, if the universe is closed, this theory would predict that once this universe collapses it will spawn another universe in an event similar to the Big Bang after a universal singularity is reached or a repulsive quantum force causes re-expansion.

What are the three possible outcomes for the universe?

The three possible outcomes include: an open universe, in which the expansion will never stop; a closed universe, in which the expansion will stop and turn into a contraction; and a flat universe, in which the expansion will slow to a halt in time—but it will never contract.

Is the universe flat open or closed?

The exact shape is still a matter of debate in physical cosmology, but experimental data from various independent sources (WMAP, BOOMERanG, and Planck for example) confirm that the universe is flat with only a 0.4% margin of error.

Why is the universe flat?

The usual explanation of the universe’s formation includes a period just after the big bang called inflation, when the universe rapidly expanded. Our current models of inflation naturally lead to a flat universe, so if the universe is actually closed, they would have to change.

What are the theories for the end of the universe?

If the Universe holds enough matter, including dark matter, the combined gravitational attraction of everything will gradually halt this expansion and precipitate the ultimate collapse. Over time, galaxies, then individual stars, will smash into each other more frequently, killing off any life on nearby planets.

What is the big freeze theory?

This term comes from the theory that, in the Universe and other isolated systems, entropy will increase until it reaches a “maximum value”. During this Big Freeze, the Universe would, in theory, become so vast that supplies of gas would be spread so thin that no new stars can form.

Which is the closed model of the universe?

The closed model of the universe predicts that the expanding universe will begin to contract matter back into a Big Bang state, something called the ‘Big Crunch.’ Another model of the universe is known as the open universe. This is a model of an infinite universe involving curved space-time, which does not curve back on itself.

When does the expansion of the universe stop?

If space is flat, there is exactly enough mass to cause the expansion to stop, but only after an infinite amount of time- the universe has no bounds and will also expand forever, but the rate of expansion will gradually approach zero after an infinite amount of time.

Why is the shape of the universe flat?

But if the universe is flat and the density of matter is low — including visible matter, invisible matter, and ordinary energy (which is equivalent to matter) — something must provide the missing density. That something is the cosmological constant, or some other form of dark energy.

What is the critical density of a closed universe?

(In a closed universe gravity eventually stops the expansion of the universe, after which it starts to contract) For a closed Universe, the total energy density (mass+energy)* in the Universe has to be greater than the value that gives a flat Universe, called the critical density * excludes vacuum energy from cosmological constant