Big Rip

Lore & Background

The Big Rip hypothesis depends on the type of dark energy present in the universe. If the dark energy is phantom energy, with an equation of state parameter w less than −1, its density increases as the universe expands. This causes the expansion of the universe to accelerate at an ever-increasing rate, shrinking the observable universe and the cosmological event horizon. When the horizon becomes smaller than any bound structure, no fundamental force can hold that structure together, and it is ripped apart.

Reader's Guide

The Big Rip represents a dramatic alternative to the standard cosmological model, which predicts a constant expansion and heat death. However, uncertainties remain too large to discriminate among w < −1, w = −1, and w > −1. The closer w is to −1, the further the Big Rip is in the future; if w were exactly −1, the Big Rip could not happen. Because statistical fluctuations make it nearly impossible to measure w exactly at −1, the Big Rip is very difficult to completely rule out.

Did You Know?

• The Big Rip is only possible if the universe contains phantom energy, a hypothetical form of dark energy with implausible physical properties.
• If w were exactly −1, the Big Rip could not happen.
• Because statistical fluctuations make it nearly impossible to measure w exactly at −1, the Big Rip is very difficult to completely rule out.