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A weird, super-powerful particle that isn’t really a particle could have dominated the universe when it was just a second old, releasing a flood of ripples that permeated all space-time.
Called oscillations, they would have been so energetic that their “ripples” could have triggered so-called gravitational waves – those vibrations in the fabric of space-time that are generated when monster black holes bump into each other. Future experiments to detect these gravitational waves from the beginning of the universe could give us a glimpse of the most extreme conditions the universe has ever encountered.
Related: From the Big Bang to the present: snapshots of our universe through time
Make it big
Physicists believe that when the universe was very young it got much, much bigger in a short period of time. We call this dramatic event “inflation”, and it was perhaps the defining event of the infantile cosmos. At some point in the first fraction of a second of the universe’s existence, something happened (we’re not sure exactly what) that drove the rate of expansion to supercritical levels, inflating the universe at least 10 ^ 52 times (or 1 followed by 52 zeros) greater than before.
After the inflation event, something else happened (again, we’re not sure exactly what) to slow things down and resume a calmer rate of expansion (which continued until nowadays).
Cosmologists are pretty sure that this super-fast balloon happened in the early universe, because today the universe is remarkably uniform on a very large scale. Rapid expansion could have done the trick – smoothing out any wrinkles.
Additionally, astronomers have spotted circumstantial evidence of the inflation event. Inflation has not only made the universe “grow up and go home.” It also triggered another event called reheating. Everything that triggered the inflation eventually died, but as it vanished from the cosmological scene, the mechanism causing the inflation released its remaining pent-up energy, turning this mysterious trigger into a stream of particles that would eventually combine to form protons and neutrons, atoms, molecules, stars, planets and you.
Related: We can finally find out what happened a few moments before the Big Bang
At the same time, as everything in the universe developed during inflation, tiny quantum fluctuations space-time, which extended to macroscopic differences – significant bumps and tremors in the tissue of spacetime; these quantum fluctuations meant that some places in the universe had more gravitational pull than average. In turn, places of stronger gravity collected pieces of material, and those pieces of material grew over billions of years, forming the seeds of all the great structures we see in the cosmos today.
And if inflation was capable of all of this, it could have generated even stranger things.
Give it a shake
As to which spark sparked the inflation event, physicists have several ideas, one of which involves a quantum phenomenon called scalar fields that spans all space and time. A scalar field is basically a fancy way of saying that at every point in the universe, that field has a value or a force, but no particular direction (to help you visualize this, when you see a temperature map on local weather forecast, you’re looking at a scalar field). In the modern universe, scalar fields are essentially bit actors. But the early universe was a very different place, and scalar fields that are rare today could have been in abundance back then. Indeed, some theories of inflation suggest that it was a scalar field that did all the expansion work.
You can think of a scalar field like the surface of the ocean. It stretches all around and across the horizon, and it has various waves going through it. Just like in the ocean, waves in a scalar field can sometimes be calm and steady, and sometimes erratic and violent.
According to a new article published in December 2020 in the Pre-Print Database arXiv, this is exactly what happened in the extremely early universe. Shortly after inflation, as warming began and the universe was flooded with particles, any random scalar fields could have been disturbed, like a hurricane opening over the Atlantic.
This could have generated “oscillations”, which are stable waves that can live for a long time. Oscillations occur in all kinds of situations; for example, a lonely traveling wave is a kind of oscillation. When oscillations form in quantum scalar fields, they also generate their own unique type of particles.
See what’s going on
These oscillations don’t really participate directly in particle interactions, but the oscillations themselves can still affect the universe. The oscillations would have swirled around the young universe, and for a brief moment the energy contained in the oscillations could have been stronger than the energy contained in any other field or family of particles.
With all this sloshing and bustle, interesting things are inevitable. In the case of oscillations, the sloshing could have generated gravitational waves, which are vibrations in the fabric of space-time itself. As the oscillations wave throughout the cosmos, their extreme energies distort space-time, generating gravitational ripples.
Long after the oscillations have disappeared, gravitational waves can remain, rippling throughout the cosmos to the present day. Although we cannot yet observe the gravitational waves of the first universe, future detectors like LISA (the space antenna of the laser interferometer) and BBO (the Big Bang observatory) should be able to do so.
If this oscillating image is correct, it is a potential mechanism for inflation to generate gravitational waves. If we then see these waves, we will have a direct view of the universe while it was under a second.
Originally posted on Live Science.
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