A study by scientists confirms that Albert Einstein may have been right and the end of the universe may come with the Big Crunch.
In a new study, scientists shared data from a special observatory that led them to suggest that dark energy may be weakening. All of this data comes from the first year of observations from the Dark Energy Spectroscopic Instrument (DESI), a collection of 5,000 robots that worked together to map the cosmos in more detail than ever before.
Although we don’t yet fully understand dark energy, a shift in our understanding of the concept—from thinking of it as constant to thinking of it as decaying—could impact all of physics and influence the end of our universe.
When discussing the history of the modern Universe, scientists use a paradigm called the cold lambda dark matter model (ΛCDM), a mathematical equation that works in harmony with our current understanding of the Big Bang origins of the Universe. And an important part of it is the cosmological constant lambda, which dates back to Albert Einstein, but has changed in its purpose over time. The constancy of lambda is important to our understanding of the ΛCDM model and is closely related to dark energy, which was also assumed to be constant.
Celticbird Telescope 80 mm Aperture 600 mm
However, after a year of observations at DESI in Arizona, dark energy is not behaving quite as expected. “We see some potentially interesting differences that may indicate that dark energy is evolving over time,” said director Michael Levy on the DESI blog.
Discussing this discovery last week, Popular Mechanic’s Darren Orff explained to scientists the importance of this discovery, especially since this is supposed to be just the beginning of what DESI is about to discover. It is important to note that these data represent only one year of the five planned for the DESI project, and that observations may change or lead to different conclusions as more data is collected.
But it is also, by far, the most precise set of measurements of the entire cosmos ever assembled. With its 5,000 graphic robots, DESI can go back a billion years and create seven slices, each capturing a snapshot of history from 3 to 11 billion years ago. Robotic observers have sophisticated abilities to separate layers of light and darkness to gain information about the ancient reaches of space. In particular, the piece of data covering the oldest cosmos is by far the most accurate.
So if DESI isn’t completely wrong, what does weakening dark energy mean? Well, dark energy pushed the Universe apart, while the residual energy from the Big Bang holds everything together. Writing for Space.com, Robert E. Lee makes the analogy of someone being pushed on a seesaw: The Big Bang is the push that naturally stops, while dark energy is the mysterious, constant extra push that keeps the swing moving . no one expects this.
If dark energy is not constant after all, any change in it will affect the rate of expansion or contraction of the Universe. Mathematically transform the ΛCDM equation with x number of variables into one with x+1. If you delve into algebra, you’ll realize that this means that lambda can no longer be used to relate between different versions of the same equation. You will join the ranks of things that are constantly changing and require solutions. And without a deeper understanding of what dark energy means and is right now, it won’t be easy.
Without the dark energy constant, Albert Einstein’s original fear might be true: gravity would pull the Universe inward, causing a Big Crunch that would reverse or cancel the Big Bang.
While there is of course no comfortable version of the end of our Universe in billions of years, it might be nicer to imagine a symmetrical end to events than to imagine the slow, drifting expansion and death of another theory: the Great Cooling. In any case, DESI maintains its original plans to deepen and enrich our knowledge of space. Our current models are no more than 25 years old since the Universe was discovered to be expanding rapidly. The DESI team published a series of preprints (not yet peer-reviewed) of the first year’s data, as well as a lengthy press release from Lawrence Berkeley National Laboratory, which is overseeing the project.
What you discover over the next few years of work will undoubtedly be promising.
Caroline Delbert is a writer, avid reader, and contributing editor for Pop Mech magazine. She is also an enthusiast of almost everything. Her favorite topics are nuclear energy, cosmology, the mathematics of everyday things and the philosophy of it all.