Gravity Waves Confirm Universe Ballooned After Big Bang

Great movie that clearly explains how gravitational waves were discovered and their significance to our understanding of the universe

In the beginning there was the Big Bang. A quintillionth of a second later, the universe, teetering in an unstable energy state, suddenly and spectacularly ballooned from smaller than a proton to bigger than anything we can imagine. It hasn’t stopped expanding since.

The sun sets behind BICEP2 (foreground) and the South Pole Telescope. The BICEP2 telescope, located at the south pole, was used to detect the first primordial gravitational waves released nanoseconds after the Big Bang. Credit: Harvard-Smithsonian Center for Astrophysics

That ultra-brief moment of cosmic inflation created gravitational waves or ripples in the fabric of space-time that were finally detected by a team of astronomers led by John Kovac of the Harvard-Smithsonian Center for Astrophysics using a specialized microwave telescope in Antarctica called BICEP-2 or Background Imaging of Cosmic Extragalactic Polarization. Stretched and flattened by billions of years of universal expansion since the Big Bang, the waves bearing the signature of inflation are now a mere whisper in space. It took the team nine years to find them.

Gravitational waves from inflation generate a faint but distinctive twisting pattern in the polarization of the cosmic microwave background, known as a “curl” or B-mode pattern. Credit: BICEP2 Collaboration

Like water waves whose constant lapping of the shoreline leave their imprint as ripples in the sand, gravitational waves left their imprint in the Cosmic Background Radiation (CMB), the relic radiation left over from the Big Bang that warms all of space to 2.7 degrees above absolute zero.

Cosmic inflation theory has always hidden in the shadows of the heavily-publicized Big Bang at least in the public’s eye. Sure, inflation does a great job of explaining our present-day universe, but without evidence it remained an unproven theory. The Big Bang on the other hand has plenty of hard evidence to back it up.

Stanford assistant professor of physics Chao-Lin Kuo delivers the news of today’s breakthrough discovery to Inflation theorist Andrei Linde. Must see!

Inflation was conceived in 1979 by American theoretical physicist Alan Guth and extended by then-Soviet physicist Andrei Linde as a way to explain thorny problems the Big Bang couldn’t fully address. Things like:

* Why the universe appears flat – a line drawn in any direction in space will always remain straight no matter how many light years it extends.

* Why it’s so uniform – look in any direction and the stuff you see is the same as in any other direction.

* How small submicroscopic fluctuations in the Big Bang’s energy field became the seeds for the formation of huge things like stars and galaxies.

Diagram showing the history of the universe at the Big Bang, followed by the headlong acceleration powered by inflation nanoseconds later, and the eventual formation of neutral atoms(around the 300,00o year mark) and finally stars and galaxies. Credit: CERN

Guth and Linde proposed that prior to inflation, when the universe was microscopically small, everything got to mix and mingle before inflation blasted it all to the far corners of the universe. Today we look out through our telescopes and see the same structures and materials no matter what direction we point.

As for flatness, inflation would have taken any curvature present at the start of our universe and flattened it out like a balloon blown so big that no matter where you stood on it, the surface would appear flat as far as you could see.

The image reveals 13.77 billion year old temperature fluctuations (shown as color differences) in the Cosmic Background Radiation that correspond to the seeds that grew to become the galaxies. Credit: NASA/WMAP Science Team

Finally, those sub-microscopic quantum fluctuations (tiny energy fluctuations in empty space), some of which were slightly hotter and denser than others, were magnified to cosmic proportions through inflation. As the universe evolved, they acted as seeds for the formation of everything from dark matter to luminous stars and galaxies.

I know, it all sounds pretty incredible. Sometimes scientists work on a theory for decades before producing experimental proof of the idea. Finding proof of inflation in the imprint of gravitational waves in the CMB is reason for great celebration. I loved watching Andrei Linde’s reaction to the news. Hey – we were on the right track!

Naturally, the team’s results will have to be confirmed. Assuming they are, inflation will stand on its own two feet and join the Big Bang as part of the surprising story of how you and I got here in the first place.

For more on the topic, please check out the team’s technical paper, this New York Times story and a FAQ describing the data.


7 Responses

  1. Bob Crozier

    Please forgive my ignorance, but can you tell me how there can be gravitational waves being formed before there was gravity? From what I read here, it would seem that the particles that have mass (and therefore gravity) did not form even form for many years (300,000?) after the big bang? How can there then be gravitational waves being imprinted on pure energy (that is largely unaffected by gravity anyway) from the first few seconds (or nanoseconds) following creation? How can that happen?

    Live ready!

    1. astrobob

      This is heady stuff for me too. A thorough reading of inflation would show that much of the universe’s matter didn’t form at the moment of the Big Bang. It materialized from a repulsive gravitational force that drove inflation in the first place. The energy of that repulsion – a negative energy – led to the creation of enormous amounts of matter in that instant. Sounds nuts but read more here:

  2. Judy Gibbs

    Thank you Bob for all you do. i just sent this to my dad….don’t know if he still has the capacity to *get it* but he has pondered these things for many years.

    1. astrobob

      Thank you Judy. We’re all still trying to understand these grand events and the forces that led to them.

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