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Astronomy

Why Is Dark Energy Accelerating the Universe's Expansion?

Quick fact

Dark energy was discovered in 1998 when two independent teams found that distant Type Ia supernovae were fainter than expected, indicating they were farther away than a slowing expansion would allow—revealing an accelerating universe.

Why this is interesting

You know the universe is expanding, but did you know that since the 1990s, astronomers have discovered the expansion is actually speeding up—like a car accelerating instead of braking. What could possibly be pushing everything apart?