While most people believe the universe will continue expanding forever, a team of scientists has proposed a bold new hypothesis that turns this idea upside down — suggesting that the universe will eventually collapse in on itself in a “reverse big bang” that could occur in less than 20 billion years.
According to a new study published in the Journal of Cosmology and Astroparticle Physics, the universe — currently about 13.8 billion years old — will keep expanding for roughly another 11 billion years before reaching its maximum size, about 1.7 times its current scale. After that, it will gradually begin to contract under the pull of cosmic gravity.
As reported by ScienceAlert, this collapse will ultimately cause the universe to shrink back into an extremely dense point — a mirror image of the original Big Bang.
A Shift in Cosmic Understanding
Lead researcher Henry Tye from Cornell University explained that this scenario is based on new evidence suggesting that dark energy — the mysterious force driving the universe’s expansion — may not be constant as once believed, but actually decreasing.
Tye said:
“For over twenty years, we assumed the universe would expand forever. But recent data suggest the opposite. If these results are confirmed, the universe will have a definite end — just as it once had a beginning.”
Dark Energy and the Cosmological Constant
The model is based on Einstein’s cosmological constant, introduced in his theory of general relativity. If the constant is positive, it pushes the universe to expand indefinitely; but if it’s negative, it acts as a gravitational pull that slows expansion and eventually reverses it.
The study proposes that dark energy may result from extremely light, hypothetical particles known as axions, which initially drive cosmic expansion but gradually lose their strength until gravity takes over.
A Faster Collapse Than the Beginning
Researchers compared this process to riding a bicycle uphill with a tailwind that slowly fades — the climb slows at the top, then the descent begins rapidly.
Their calculations indicate that the collapse phase will be faster than the expansion phase, as the kinetic energy of axions accelerates the contraction until the universe reaches a final “reverse big bang,” where galaxies, stars, and planets compress into a single, hot, dense point — a reversed reflection of the beginning of time itself.
A Hypothesis, Not a Prophecy
Despite the dramatic implications, scientists emphasize that this scenario is not a prophecy, but a scientific hypothesis based on observations that remain unconfirmed. The true nature of dark energy is still one of the greatest mysteries in cosmology.
The Universe at Midlife
If this theory is correct, humanity currently exists at about the midpoint of the universe’s life. Though the end lies roughly 20 billion years ahead, it raises a profound question:
“Is the universe an open system expanding forever… or a closed loop endlessly repeating itself in an eternal cycle of explosion and collapse?” 🌌
