The universe is a big place. Most physicists say it is infinite, and estimates of our observable universe fall around 93 billion lightyears across. Fortunately, math and science give us the tools to unravel what we cannot see, such as last week’s breakthrough discovery of the “echo” from the Big Bang.
The Big Bang theory posits the universe burst from a single point some 13.7 billion years ago. In a fraction of a second it underwent staggering expansion, growing exponentially at speeds faster than light. Early phases of the universe contained plasma so “dense” (high-energy) that photons could not escape. About 380,000 years later, the plasma cooled enough to let light push through, giving the universe its first moment of transparency. This theory is widely accepted by the scientific community and explains many properties of our universe, such as cosmic background radiation, large-scale structures, and the large presence of light elements (more on these in future posts).
Another mystery about the universe has to do with its temperature. Wherever we look, space seems thermally uniform. Thirteen billion years is nowhere near enough time for cold and hot spots to have mixed together, suggesting that everything started at the same temperature. The rapid expansion following the Big Bang explains this. Theories predict this inflation would have caused fluctuations in spacetime, gravitational ripples speeding through the fabric of the universe.
Now for the discovery: as explained in MinutePhysics’ video (above), light that escaped from the plasma of the early universe would have bounced one last time before setting out across the cosmos. This impact would have affected the light’s orientation, i.e. its polarization. By looking at the polarization of the cosmic background radiation with the Bicep2 telescope at the South Pole, researchers have been able to paint a picture of what that plasma must have looked like, laying out the distribution of energy in the early universe. While results show most of the light bounced off dense, high-energy locations, about fifteen percent hit areas matching the predicted gravitational waves.
This is huge: not only does it show that gravity is a quantum phenomenon, it allows us to look 380,000 years further into the history of the universe. While the results have yet to be confirmed by other experiments, they could offer a missing link between quantum theory and Einstein’s general relativity. Unifying these two theories remains one of the biggest challenges in modern physics. “Shedding light” on the early stages of the universe can open up new realms of discovery as well. For now, we have to see if these results are validated.
So does this make any sense? I hope so. It’s not every day I get to blog about cosmic inflation. Share your thoughts below. Special thanks to Henry Reich and MinutePhysics for such an awesome and informational video. I’d also recommend checking out the diagram in the New York Times article linked below—it discusses this in terms of something we can all understand: coffee. As always, check me out on Twitter and Facebook, where I talk about science and food and Pokemon. Thanks for reading! Don’t forget to subscribe for new content every Wednesday. IT’S FREE!
Comment question of the week
These findings could support some theories of the multiverse. What is the coolest thing about a space beyond our universe?
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