The expansion of the universe is accelerating.

The cosmic microwave background is not uniform.

The abundance of light elements in the universe is higher than expected.

The age of the universe is older than expected.

A constant term in the Einstein field equations that represents the energy density of the vacuum.

A measure of the curvature of spacetime.

A measure of the expansion rate of the universe.

A measure of the density of matter in the universe.

A relation between the pressure and density of dark energy.

A measure of the curvature of spacetime.

A measure of the expansion rate of the universe.

A measure of the density of matter in the universe.

A cosmological constant.

A scalar field.

A modification of gravity.

All of the above.

Dark energy is very difficult to detect.

Dark energy is very weak.

Dark energy is very far away.

All of the above.

Searching for new ways to detect dark energy.

Developing new theories of dark energy.

Using new telescopes to study dark energy.

All of the above.

Dark energy will eventually cause the universe to expand forever.

Dark energy will eventually cause the universe to collapse.

Dark energy will eventually cause the universe to reach a steady state.

The fate of the universe is independent of dark energy.

Dark energy is responsible for the uniformity of the cosmic microwave background.

Dark energy is responsible for the anisotropies in the cosmic microwave background.

Dark energy is responsible for the polarization of the cosmic microwave background.

All of the above.

Dark energy is responsible for the high abundance of light elements in the universe.

Dark energy is responsible for the low abundance of light elements in the universe.

Dark energy has no effect on the abundance of light elements in the universe.

The relationship between dark energy and the abundance of light elements in the universe is unknown.

Dark energy is responsible for the old age of the universe.

Dark energy is responsible for the young age of the universe.

Dark energy has no effect on the age of the universe.

The relationship between dark energy and the age of the universe is unknown.

By measuring the expansion rate of the universe.

By measuring the cosmic microwave background.

By measuring the abundance of light elements in the universe.

By measuring the age of the universe.

All of the above.

By using telescopes to observe distant galaxies.

By using satellites to measure the cosmic microwave background.

By using particle accelerators to search for new particles that could be responsible for dark energy.

All of the above.

By modifying the laws of gravity.

By introducing a new scalar field.

By proposing a multiverse.

All of the above.

By finding a new theory of gravity.

By discovering a new scalar field.

By proving the existence of the multiverse.

All of the above.

The universe will eventually expand forever.

The universe will eventually collapse.

The universe will eventually reach a steady state.

The fate of the universe is unknown.