1,500 supernovae enable an ultra-precise calculation of the dark universe

In 1998, scientists stumbled upon a surprising cosmic truth. They realized that not only is the universe expanding, but it appears to be acceleration As the years go by, accelerated by a force we cannot see.

This mysterious influence soon became known as dark energy, one of the greatest mysteries in physics.

It would add to the equally if not more confusing aspect of our universe called dark matter, a blanket concept scientists first proved in 1933 to describe whatever makes up the hidden, halo-like barriers that keep galaxies from simply falling apart . (Another power we cannot fathom with human eyes.)

But while we can’t see the elusive nature of dark matter and dark energy, we can measure it with math. And on Wednesday, in a series of articles in the Astrophysical Journal, astrophysicists managed to pin down the most precise bounds yet on the composition and evolution of our universe — including the dark universe.

Using a powerful analysis mechanism called Pantheon+, the team found that the cosmos 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 manifests as dark energy, while the remaining 33.8% is made up of both dark and visible matter.

Even more exciting than the outcome of Pantheon+ might be the amazing way it works. In short, the team used a series of powerful cosmic flashlights to peer into the past and document the contents of the universe as it appeared more than 10 billion years ago.

By “flashlights” I mean Type 1a supernovae.

These stellar explosions are so bright they outshine entire galaxies and can therefore be seen billions of light-years from Earth. They’re like flashlights, but instead of illuminating a long hallway, they illuminate the infinite tunnel of space and time. In fact, they are crucial to the discovery of the dark universe, helping to reveal the existence of dark matter in 1933 and dark energy in 1998.

Pantheon+ took things to the next level. The scientists behind the analysis focused on more than 1,500 supernovae, which together illuminate about three-quarters of the known Universe. Wow indeed.

“This combined Pantheon+ dataset gives us an accurate view of the universe from the time it was dominated by dark matter to the time when the universe was dominated by dark energy,” said Dillon Brout, an astronomer at the Harvard-Smithsonian Center for Astrophysics said in a statement.

“This dataset is a unique opportunity to see how dark energy is turning on and fueling the evolution of the cosmos on the largest scales to the present,” Brout said.

This might settle some scholarly debates

On the other hand, the legacy of Pantheon+ is ready to conquer the dark universe.

As an added bonus, the analysis tool also confirmed that the cosmos is indeed expanding at an ever accelerating pace, and It offered extremely promising evidence in support of a cornerstone of scientific thought: the Standard Model of particle physics.

This framework pretty much outlines how each and every known particle behaves independently and among each other, and even serves as the basis for many leading theories about what the dark universe is really all about.

“We are able to constrain the dynamics and history of the universe to date as precisely as possible,” Brout said. “We’ve combed through the data and now we can say with more confidence than ever before how the universe evolved over the eons and that the current best theories of dark energy and dark matter hold.”

In other words, Pantheon+ might be telling us to summarize some alternative dark matter and dark energy theories independently to the standard model. These theories could be, well, wrong.

Also, we also need to talk about my personal favorite consequence of Pantheon+ datasets. Finally, it could help end a longstanding, rather heated debate among physicists.

We may finally be on our way to deciphering the so-called Hubble constant. Type of.

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

After pooling the Pantheon+ sample with data from another scientific collaboration, a press release from Harvard says we now have what may be the tightest local measurement of the universe’s current rate of expansion. (The keyword here is “local”. That will come later.)

In short, the collaboration found that the Hubble constant is 73.4 kilometers (45.6 miles) per second per megaparsec (km/s/Mpc), which is an astounding value 1.3% uncertainty.

“Put another way, for every megaparsec, or 3.26 million light-years, the analysis estimates that space is expanding at more than 160,000 miles per hour, even in the nearby Universe,” the press release explains. This figure is right in the middle of the 2001 landmark measurement of 72 km/s/Mpc and later reports of 74 km/s/Mpc.

However, it’s a hell of a distance from another leading measurement that suggests a constant 69.8 km/s/Mpc.

OK, yes, there is still a discrepancy. Again, the Pantheon+ constant is based on “local” measurements.

Therefore, the Pantheon+ team emphasizes that “observations from a completely different epoch in the history of the universe predict a different story”. So in a way, there could be a new contrasting Hubble constant Not Resolve Hubble tension but amplify the already tense debate? Like I said, it’s complicated.

“We thought it might be possible to find evidence of a novel solution to these problems in our dataset, but instead we find that our data excludes many of these options and that the profound discrepancies remain as persistent as ever,” said bread .

But at the end of the day, because Pantheon+’s results are so flawless, they might at least clear up where the bones of contention lie in the ongoing Hubble debate.

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

The physics are packed to the brim with complex puzzles and riddles and, frankly, straight roadblocks. But I like to think of these hurdles as motivation to keep the field going and mind turning. For this reason, Pantheon+ was primarily innovated.

And with that mechanism, we’ve made absolute progress in analyzing the truth about the dark side of our universe—at least. Or as Brout puts it: “Pantheon+ gives us our best chance yet to constrain dark energy, its origins and evolution.”