Magazine article The Futurist

Making Waves in the Cosmos: What the Detection of Gravitational Waves Means for Our Understanding of the Universe

Magazine article The Futurist

Making Waves in the Cosmos: What the Detection of Gravitational Waves Means for Our Understanding of the Universe

Article excerpt

Earlier this year, a research team rocked the world of physics when it announced that it had detected gravitational waves. This discovery has huge significance for many areas of study. However, its greatest impact will be on our understanding of the big bang that gave birth to our universe and of the very early stage in its evolution known as inflation.

In order to appreciate the magnitude of this discovery, it helps to know a few things about cosmology.

Cosmology is the study of the origin and evolution of the universe. Our understanding of it has been built on for millennia, from Ptolemy, who placed Earth at its center, to the incrementally more accurate understanding made possible by giants such as Copernicus, Kepler, Galileo, and Newton.

It was subsequent work that really expanded our view--quite literally. In his general theory of relativity, Einstein introduced a cosmological constant in an effort to force a static universe from his equations. Later, he retracted this when the work of Edwin Hubble and others pointed fairly conclusively to an expanding universe.

But what is the universe expanding from? Based on the standard model of physics, it's possible to "reverse engineer" this expansion to within an instant of its outset--the very beginning of the big bang. This indicates everything began from a cosmic singularity, a point of near-infinite density and temperature. When it started to expand (it didn't go "bang"), there was a period during which, according to recent theories, the universe grew far faster than the speed of light. This was the period of inflation, when the universe grew 50 orders of magnitude in a billion trillion trillionth of a second. It's theorized that this was caused by inflatons--high-energy fields similar to dark energy and the Higgs field. After that, the universe shifted to the rate of expansion we see today.

The period of inflation would have flattened out the curvature we'd otherwise expect to see in the universe and smoothed out massive irregularities. Without this, our universe would be very different, and we most certainly wouldn't be here to argue these finer details.

When thinking about the universe, remember that the farther out we search, the further back we're looking in time. The light from a galaxy that appears a billion light-years away left it a billion years ago.

Even when inflation had ended, the universe still remained extremely hot. Only after it had cooled to around 4,000[degrees]C--about 377,000 years after the big bang--did the epoch known as recombination begin. While photons existed prior to this, it was impossible for them to move any distance, due to the universe's high state of ionization, so the cosmos wasn't transparent to light.

This "wall" is the cosmic microwave background (CMB), which registers to us as a nearly uniform field, 2.7[degrees] above absolute zero. It's the farthest we are theoretically able to look back in time and make direct observations of our early universe. Anything earlier has been deemed impossible to detect. Until now.

The second-generation Background Imaging of Cosmic Extragalactic Polarization (BICEP2) is based in Antarctica. Using extremely sensitive equipment, the team managed to extract patterns from the CMB that show a strong indication of being gravitational waves from the inflation epoch of the big bang. …

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