Why Scientists’ Latest Dark Matter and Dark Energy Estimates Are a Big Deal

Why Scientists' Latest Dark Matter and Dark Energy Estimates Are a Big Deal
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In 1998, scientists encountered a startling cosmic truth. Not only is the universe expanding, they realized, it is visible speeding up over the years, it accelerates with a force we cannot see.

This mysterious effect will soon become known as dark energy, one of the greatest mysteries of physics.

This would be equally, if not more, complementary to the puzzling aspect of our universe called dark matter. first proved in 1933 describing everything that forms the hidden, halo-like barriers that prevent galaxies from simply breaking apart. (Another force we cannot understand with the human eye.)

But even if we don’t realize the difficult nature of it dark matter and dark energy by sight, we can measure it mathematically. And on Wednesday, in A series of articles in the Astrophysical Journalastrophysicists managed to place the most precise limits yet about the composition and evolution of our universe — including the dark universe.

Using a powerful analytical engine called Pantheon+, the team found that the universe is about two-thirds dark energy and one-third matter, mostly in the form of dark matter. More specifically, they suspect that 66.2% of the universe appears as dark energy, with the remaining 33.8% being both dark and visible matter.

More interesting than Pantheon+’s results may be the mind-bending way it works. In short, the team used an array of powerful, cosmic flashlights to peer back in time and document the contents of the universe as it was 10 billion years ago.

By “flashlights” I mean a Type 1a supernova.

These starbursts are so bright that they outshine all galaxies and are therefore visible from distances billions of light years away from Earth. They are like lanterns, but instead of illuminating a long corridor, they illuminate an endless tunnel of space and time. In fact, they were crucial to the discovery of the dark universe, helping to discover the existence of dark matter in 1933 and dark energy in 1998.

Pantheon+ has taken things to the next level. The scientists behind the analysis looked at more than 1,500 supernovae, which together light up about three-quarters of the known universe. Wow, really.


A timeline of the universe.


“With this combined Pantheon+ data set, we get a clear picture of the universe from when it was dominated by dark matter to when the universe was dominated by dark energy,” said Dillon Brout, an astronomer at the Harvard-Smithsonian Center for Astrophysics, in a statement.

“This data set is a unique opportunity to see dark energy turned on and control the evolution of space on the largest scale to date,” said Brout.

This may resolve several scientific controversies

Down the road, the legacy of Pantheon+ is poised to overtake the dark universe.

As an added bonus, the analytical tool also confirmed that space is indeed expanding rapidly, and provided extremely encouraging evidence supporting the cornerstone of scientific thought: The Standard Model of Particle Physics.

This framework describes how almost every known particle behaves with each other as well as independently, and even serves as the basis for many leading theories of what the dark universe actually is.


Image of particles in the Standard Model.


“We are able to put the most precise constraints on the dynamics and history of the universe so far,” Brout said. “We’ve looked at the data and now we can say with more confidence than ever how the universe has evolved over the ages and that the best available theories for dark energy and dark matter are strong.”

In other words, Pantheon+ may be telling us that we need to conclude some alternative theories of dark matter and dark energy. unrelated To the Standard Model. These theories may be wrong.

Additionally, we should also talk about our personal favorite result of the Pantheon+ datasets. Finally, it may help put an end to a long-standing, rather heated debate among physicists.

We may finally be on the way to deciphering what is known as Hubble constant. Kind of.

Basically, we know that the universe is expanding exponentially. We can literally see it happen in real time. But scientists cannot agree on the exact rate of this expansion. The key to the solution is the Hubble constant, but different methods of calculating this constant give different answers.


Arcs and streaks in the Abell 370 galaxy cluster reveal “gravitational lensing,” the distortion of light from distant, background galaxies by the cluster’s gravitational field. The lensing effect helps astronomers measure the distribution of dark matter in galaxy clusters.

NASA, ESA and the Hubble SM4 ERO Team

However, after combining the Pantheon+ sample with data from another scientific collaboration, a Harvard press release says, we may now have the most rigorous local measurement of the universe’s current expansion rate. (The key word here is “native”. This will come into play later.)

In short, the collaboration found the Hubble constant to be 73.4 kilometers (45.6 miles) per second megaparsec (km/s/Mpc). 1.3% uncertainty.

“Put another way, for every megaparsec, or 3.26 million light-years, the analysis estimates, space itself is expanding at a rate of 160,000 miles per hour in the nearby universe,” he said. For context, this figure is from mid-2001 A remarkable size of 72 km/s/Mpc and then 74 km/h/Mp.

However, it is quite far from another leading measurement, which suggests a constant of 69.8 km/s/Mpc.

Well, yes, there is still a discrepancy. And again, the Pantheon+ constant is based on “local” measurements.

Thus, the Pantheon+ team emphasizes that “observations from a completely different period of the universe’s history predict a different story.” So, in a way, there could be a new contrasting Hubble constant no Resolving the Hubble tension, but rather intensifying an already tense debate? Like I said, it’s complicated.

web stream

Simulation of dark matter filaments in the universe.

Zaria Lukic/Lawrence Berkeley National Laboratory

“We thought it would be possible to find clues to new solutions to these problems in our data set, but instead we find that our data rule out many of these options and that the deep inconsistencies are as stubborn as ever,” said Brout.

But at the end of the day, since Pantheon+’s results are so clean, perhaps they could at least clarify where the point of contention lies in the ongoing Hubble debate.

“Many new theories have begun to point to exotic new physics in the very early universe,” Brout said. “However, such unconfirmed theories must withstand the scientific process, and the Hubble tension remains a major challenge.”

Physics is full of complex puzzles and riddles and, frankly, outright obstacles. But I like to think of these obstacles as motivation to keep the field going and to turn the thinking around. That’s why Pantheon+ innovated in the first place.

And with this mechanism, we’re well on our way to exploring the truth about the dark side of our universe—at least. Or, as Brout puts it, “Pantheon+ gives us our best shot at a constraining history of dark energy, its origin, and its evolution.”

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