Ripples in Space Are Evidence of Universe’s Early Growth Spurt

By Bill Andrews | March 17, 2014 2:55 pm
Inflations' gravitational waves

When the universe expanded tremendously after the Big Bang, the resulting gravity waves interacted with the cosmic microwave background to produce this characteristic “B-mode” pattern. Credit: BICEP2 Collaboration

Big news in the cosmos today! Researchers from the BICEP2 south pole telescope have found ancient proof that the universe expanded tremendously after the Big Bang, a theory known as inflation. The discovery tells us (albeit indirectly) about an even earlier stage of the universe than we’ve ever before observed, and it provides crucial evidence that inflation did indeed occur. In so doing, it extends our model of the early universe from about one second after the Big Bang right back to less than 10-37 seconds after the event — a stunning leap forward (or backward, as the case may be).

Inflation presentation

To understand this, let’s back up 13.8 billion years or so, to the Big Bang. Also known as the birth of the cosmos and the origins of time and space, this burst of everything set the universe in motion. But a few niggling issues cast some doubts on the Big Bang theory — one of which was the mystery of how the universe came to be so uniformly spread out.

Enter the idea of inflation, in 1980, which suggested that just a few instants after the big moment, the universe suddenly grew enormously. This addition to the cosmic timeline explained why the universe was relatively uniform and it fit nicely with what we already knew about the universe’s earliest moments. However, cosmologists had no direct proof of inflation.

One way to prove inflation occurred, physicists thought, would be to look for gravitational waves created in its wake. These are basically ripples in the “fabric” of space-time — what the universe is made out of. Gravity is a relatively weak force, though, so we could only hope to detect the largest waves out there, caused by huge interactions like black holes colliding. Even though inflation was a relatively huge thing — it literally shaped the whole universe — the gravity waves it produced are now too weak to measure directly.

So instead, researchers were looking for the effect of inflation’s gravity waves on light. And not just any light, but the cosmic microwave background, “echoes” of light leftover from the Big Bang’s energy, created when the universe was just 380,000 years old. When this light interacted with the gravity waves, the theories said, it would have produced a distinctive pattern, called the B mode, in the light’s polarization. Such a pattern would be direct evidence that the gravity waves caused by inflation were real, and thus a key proof of inflation. And today, scientists announced they’d found it.

But that’s not all!

Assuming the finding is confirmed (and that looks likely — the team apparently spent 3 years going over their own data to make sure it was sound before coming forward with it), that’s huge news for cosmology. Direct evidence for inflation has been sought after for decades. Nature quotes Alan Guth, the main “inventor” of inflation, as saying, “This is a totally new, independent piece of cosmological evidence that the inflationary picture fits together,” and adding that the findings are “definitely” Nobel prize-worthy.

But it’s also big news for a couple of other reasons. First, in addition to being the first evidence for inflation, it’s also the first direct evidence for gravitational waves. Even though some observatories have been (and will continue!) looking for these gravitational waves, they’re still incredibly hard to find. The more data we have on these weird, space-time warping ripples, the more we’ll be able to understand the universe itself, and this is a great step in that direction. 

And the other bit of significance to this has to do with understanding gravity in the first place. It’s currently the only one of the four fundamental forces not to play nice with quantum mechanics, which explains how things work on the tiniest scales. At high temperatures (like those found shortly after the Big Bang), the other three even begin to unify into a single super-force. One of the biggest issues in physics today is figuring out how (or if) gravity fits into this picture, and the findings that gravitational waves can result from inflation, a fundamentally quantum phenomenon, suggests that quantum gravity might indeed be possible.

A glimpse into the very first milliseconds of our universe, plus bigger questions ahead — all in all, it’s a pretty good day for science.


CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: big bang, cosmology
  • Buddy199

    it extends our model of the early universe from about one second after the Big Bang right back to less than 10-37 seconds after the event
    Amazing to be able to live in a time to be able to see such things.

    • SixSixSix

      Actually, it was 13.8 billion years ago, plus or minus a few million.

  • EverSubtle

    Congratulations to the BICEP2 team at CalTech !

    Great Job Guys !

  • Ken Oaks

    I’m a natural sceptic, I can’t help but think that evidence of a theoretical event coming from a little understood mechanism just doesn’t qualify as proof…
    The fact that current theory actually PREDICTED the observation is QUITE impressive though.

  • Susan Wright

    This sort of “proof” is similar to that found in the Paul Bunyan stories.

  • bibi

    They are jumping to conclusions in an inadmissible way. How come that no gravity wave detector hasn’t discovered anything yet but they did?. “Beauty is in the eye of the beholder”.

  • RobertSeattle

    I like big bangs and I can not lie
    You other researchers can’t deny…

  • Don’t Even Try It!

    So, what is this going to do “for the children”?

    • Bang Stick

      Might make their taxes go up to fight against evil quantum gravity waves

      • Don’t Even Try It!

        hahaha, good one 😉

  • Reverend Joe Ruyle

    What I find interesting is that they are detecting the evidence of gravity waves from a time when the entire universe was about the size of a baseball after “inflating” from smaller than a single atom in less than a trillionth of a trillionth of a trillionth of a trillionth of a trillionth of a second. (Thank GOD for Plank time!) Anyway…… at that time the universe was still nothing more than a roiling ball of pure energy….. expanding into nothingness at faster than the speed of light….. and yet there was gravity? I realize that energy and matter are interchangeable…. so do this now mean that energy generates a gravitational field like matter does?

  • Boon Tee Tan

    Chinese ancient sage Lao Tzu believed that the universe emerged from a great void, and something eventually came out of nothing. He might be right after all.

    There are many questions that have no answers, especially those related to why.

    First the God particle, now the Holy Grail gravitational wave. Just wonder how near infinite numbers of protons and neutrons could appear from a relatively tiny singularity after the Big Bang.

  • Richadr Levy

    It is correct that from where our sun exits, with measurements back in time the universe we know is about 13.8 billion standard years. However time flows past us as electromagnetic energy from new stars and galaxies flow past us from new cosmic events that are happening right now or in the recent past. From measurements from those galaxies in front of us in time the universe will be measured as much older. we cannot see in front us and only look to the past. We do not exist on the outer limit of the time bubble.

  • Ray

    If our planet is about 4.5 billion yrs old and the universe is estimated to be around 15 billion yrs old how are we able to “see” the universe at it’s earliest stage of creation? Did the universe expand faster than the speed of light? If so, how? Also, is it possible the matter being captured by black holes is what is causing the universe to expand faster? Are black holes creating dark matter?


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