The hum of the Universe is shifting space-time

The astrophysics community has been buzzing for weeks with rumors of a big announcement with a promise of discoveries 15 years in the making. This week, their findings were released.?

What they found is important, but what this means for the future of astrophysics and theoretical physics could be even more important, particularly in how we can record the “hum” of the universe, the hunt for the theory of everything, and understanding how the universe came to be.?

It’s mind-blowingly complicated, so we’ll try to break it down into a few bullet points:?

The researchers, as part of North American Nanohertz Observatory for Gravitational Waves (NANOGrav) and others around the world, found clear evidence of a background of cosmic gravitational waves rippling through the Universe, creating a “hum” that can now be recorded and researched?

• They found strong evidence that these waves originate from supermassive black holes (SMBHs), more specifically supermassive black hole binaries (SMBHBs) —more on that later — and they ripple the fabric of space and time, changing how time progresses and can be perceived
• It is a key step, researchers believe, in understanding how galaxies are created and evolve?
• Results seem to confirm (well… researchers never say “confirm”) as yet unevidenced assertions from Albert Einstein’s general theory of relativity that space is not “empty” but full of things we don’t yet fully understand??

“We have found evidence for a stochastic background of gravitational waves, which we suspect is coming from the largest binaries of the largest black holes in the universe,” lead researcher Xavier Siemens, a co-director of NANOGrav, tells Newsweek. “These are a billion solar mass black holes that are in orbit around one another. They form when galaxies merge.”

“[The waves are] passing through our galaxy, they're stretching it, and they're squeezing the galaxy as they're going through it, but they're doing so over this time scale of about ten years.”

The theory goes that when supermassive black holes, each weighing anything up to a billion of our solar system’s Suns or more each, begin orbiting each other, they will eventually merge — becoming an SMBHB —and release huge amounts of energy, enough to change the shape of the universe. This research shows that is likely.?

Despite that, no SMBHBs have been observed, so their existence is not categorically proven, even though candidates have been seen. This research will allow in future —potentially —one to be found and measured. The idea is that the closer ones (around one billion light years away) will rise above the hum and can be recorded separately. Right now, “they're just producing a din, and we can't distinguish one from another,” Siemens says. But it has the chance to change how space-time is measured.????

?“What we measure is the Earth kind of moving in this sea,” astrophysicist Michael Lam, of the SETI Institute and NANOGrav member, told the Washington Post. “It’s bobbing around — and it’s not just bobbing up and down, it's bobbing in all directions.”?

It’s a huge discovery and changes the next steps of astrophysics but doesn’t fundamentally change the building blocks of theoretical physics— primarily Einstein’s theory of general relativity and quantum mechanics… yet.?

There was a lot of talk about this announcement shepherding in new ways toward a theory of everything, something Professor Stephen Hawking spent his life searching for. He contended that black holes held a lot of the secrets. The theory of everything would unify quantum mechanics and classical physics, with one definition that could explain every law of the universe. In simple terms, a single framework that would work for everything. Still with me? So does this better understanding of black holes mean we’re a step closer??

"We might get gravitational waves from the first seconds after the Big Bang" - Hank Green

“I wouldn't characterize it that way, unless we discover evidence for new physics, like cosmic strings or something like that, something very exotic,” Siemens tells Newsweek. “Another possibility is that we discover evidence that Einstein's gravity theory is not right through some modifications to it, but we don't make any such claims at all. That is not what we're really doing.

“We’re asking how often do galaxies merge? How big are they? How big are the black holes that they host? Those kinds of questions. So it's really more about structure assembly through cosmic time, which is sort of more an astrophysics question than a fundamental physics theory of everything question.”

The experts that I’ve spoken to say clearly that this is the start, not the end, of this work after this breakthrough. Academic papers are expected about theories of what the hum could mean and where it originates from. But, perhaps most excitingly, what it opens up the door to is more fundamental questions about the formation of the Universe.?

“We have this standard model of physics that’s lining up very well in a lot of ways but has a couple of things that don’t work perfectly,” science communicator Hank Green said. “Beyond the standard models of physics, we don’t have good ways to test them yet. But this is going to be a way where we can say whether or not they are right.?

“Right now, we have light that’s from 400,000 years after the Big Bang, but we might get gravitational waves from the first seconds after the Big Bang.”

The questions we still don’t have answers to after researching this article: (all musings/questions/opinions welcome to [email protected] if you think you know the answers)?

1. What happens when we know for certain that a Supermassive Black Hole Binary does exist? Science moves in decades rather than days, but this would underpin a lot of future work?
2. How has Einstein’s theory managed to hold up so strongly for so long? E=mc^2 mght be the world's most famous equation, but "energy equals mass times the speed of light squared” is still the foundation of how we see the Universe.?
3. How does quantum gravity play into this, if at all? Nobody knows fully how gravity influences sub-atomic particles nor if/when this will be better understood. If we can observe waves from the Big Bang, that means we’re viewing an infinitely powerful wave from an infinitely small point. Is that quantum physics, or does it still fall under Einstein??