The Mystery Accelerating the Universe

The universe is expanding, but something unexpected is happening: that expansion is accelerating.

Scientists use the term dark energy to describe the unknown component associated with this accelerated expansion. It appears to make up most of the universe’s total energy content.

As the universe expands, distant galaxies become increasingly separated as space itself expands between them.

Observations indicate that this expansion has been speeding up rather than slowing down under the influence of gravity. Dark energy is the name given to whatever is driving this cosmic acceleration, but its true nature remains unknown.

Dark energy appears to determine how the universe evolves on the largest scales and could ultimately influence its long-term fate.

Understanding it is one of the biggest unsolved problems in modern physics and cosmology—and could reveal that our current understanding of the universe is incomplete.

You discovered that most of the universe may be dominated by something we still don't understand: dark energy.