Protected: Ask Ethan: Could evolving dark energy lead to a Big Crunch?

There is no excerpt because this is a protected post.

by

Ethan Siegel

October 31, 2025

Here in our Universe, there’s long been an argument over our cosmic fate, and whether the expanding Universe will recollapse, expand forever, tear itself apart, or do something even weirder.
With the discovery of dark energy in the late 20th century, we thought we had the answer: it’s destined to expand forever, taking recollapsing scenarios off the table entirely.
But new, recent evidence suggests that dark energy is evolving, and specifically, that it may be weakening. Does that mean a Big Crunch is suddenly possible, or maybe even likely, once again?

This story appears in Starts with a Bang, our special column on astrophysics.

Get our free newsletter on Substack

A theoretical astrophysicist and science writer, host of popular podcast “Starts with a Bang!”

Ethan Siegel Starts with a Bang!

A grid of eight open magazines on display above text inviting viewers to join for access to classes, print issues, community, and more. A yellow “Join Today” button is below.

A middle-aged man with short gray hair and a receding hairline is smiling, wearing a dark t-shirt against a light blue background.

Productivity for Mortals

Oliver Burkeman

Author, “Meditations for Mortals”

A person with glasses and a bald head is looking slightly to the side, centered in a green-tinted square frame.

AI and the Future of Civilization

Yuval Noah Harari

Historian and Philosopher, Hebrew University of Jerusalem, and Best-Selling Author

Abstract geometric design featuring concentric circles, quartered background, and scattered solid and outlined dots in blue, green, and white hues.

The 6 Disciplines of Strategic Thinking

Michael Watkins

Professor of Leadership and Organizational Change, IMD Business School, and Author, “The Six Disciplines of Strategic Thinking”

A woman with long hair and glasses wearing a blazer, posed with her hand under her chin, looks at the camera. The photo is overlaid with a semi-transparent colored square.

Radical Respect at Work

Co-Founder, Radical Candor, and Author, Radical Respect: How to Work Together Better

A middle-aged bald man with light skin and blue eyes, wearing a dark crewneck shirt, looks directly at the camera against a plain background.

No-Nonsense Leadership

Founding Partner, Andreessen Horowitz and Author, The Hard Thing About Hard Things

An older man with short gray hair and glasses, wearing a blue striped shirt and a red sweater, is framed by an orange translucent square overlay.

A Primatologist’s Guide to Human Behavior

C.H. Candler Professor Emeritus at EMORY University, Atlanta, GA

A wall clock is combined with the silhouette of a snail against a textured blue and light blue background.

Slow Productivity

Computer Scientist and Author, Slow Productivity

Related Content

Starts With A Bang

Groupthink in science isn’t a problem; it’s a myth

Scientists are notoriously resistant to new ideas. Are they falling prey to groupthink? Or are our current theories just that successful?

by Ethan Siegel

solar system model

Starts With A Bang

Why aliens might not “speak physics” the same way we do

Physicist Daniel Whiteson challenges the notion that all intelligent species would eventually uncover the same laws of nature. Do you agree?

by Ethan Siegel

ufo lights liverpool

Starts With A Bang

Neutrinos are still the most mysterious particle we know of

Nearly 100 years after being theorized, the strange behavior of the neutrino still mystifies us. They could be even stranger than we know.

by Ethan Siegel

DUNE neutrino detectors

Starts With A Bang

Where does the expanding Universe begin?

The planet, the Solar System, and the galaxy aren't expanding. But the whole Universe is. So where does the dividing line begin?

by Ethan Siegel

An image of El Gordo, a massive galaxy cluster captured by Hubble

Learn from the world's biggest thinkers.

© Copyright 2007-2026 & BIG THINK, BIG THINK PLUS, SMARTER FASTER trademarks owned by Freethink Media, Inc. All rights reserved.