Ripples in space-time known as gravitational waves could help reveal the secrets at the dawn of time, just moments after the Big Bang, new research suggests. And physicists say they can learn more about these primeval gravitational waves using nuclear fusion reactors here on Earth.
In a new study, physicists used equations that govern how electromagnetic waves move through plasma inside fusion reactors to create a theoretical model for how gravitational waves and matter interact.
That, in turn, could reveal a better picture of the earliest moments in time.
Moments after the Big Bang, the universe was permeated by a soup of hot, ultradense primordial plasma that sent powerful gravitational waves rippling out into the cosmos.
These ancient gravitational waves would have propagated throughout the universe and should still be present today, so the mutual influence that matter and gravitational waves had on each other in the universe’s infancy would leave observable traces in both. Working backward from those observable traces could reveal a better picture of that early period.
“We can’t see the early universe directly, but maybe we can see it indirectly if we look at how gravitational waves from that time have affected matter and radiation that we can observe today,” said Deepen Garg (opens in new tab), a graduate student in the Princeton Program in Plasma Physics and lead author of the study, in a statement (opens in new tab).
A matter of great gravity
According to Einstein’s theory of general relativity, massive bodies interact gravitationally by deforming space around them, generating ripples in space-time called gravitational waves that travel at the speed of light.
Until now, physicists have used detectors such as the Laser Interferometer Gravitational Wave Observatory (LIGO) to hunt gravitational waves born in the collisions of black holes. These cosmic cataclysms generate the most powerful gravitational waves, and they travel from the collision region to Earth in a vacuum, meaning that to describe them, physicists need only model the physics of these ripples in empty space.
However, when the universe was in its infancy, huge amounts of matter moved around, generating gravitational waves that had to propagate through a primordial plasma, which would have interacted with the waves, altering their shape and trajectory.
To calculate how this…
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