Two physicists say the universe’s expansion has sped up, then slowed down, 7 times since time began.  They describe this oscillation as the universe “ringing.”

Artist’s concept of an oscillating or ‘ringing’ universe. Image via NASA, via University of Southern Mississippi

Two physicists at the University of Southern Mississippi – Lawrence Mead and Harry Ringermacher – announced today (June 26, 2015) that our universe might not only be expanding outward from the Big Bang, but also oscillating or “ringing” at the same time.  The Astronomical Journal published their paper on this topic in April.

As many know, scientists today believe our universe – all space, time and matter – began with the Big Bang some 13 billion years ago.  Since then, the universe has been expanding to the size it is today.  Yet, the universe as a whole has self-gravity, which tries to pull all the matter – all the stars, gas, galaxies, and mysterious dark matter – back together.  This internal gravitational pull slows down the universe’s expansion. Mead said in a statement from Southern Miss: 

• The new finding suggests that the universe has slowed down and speeded up, not just once, but 7 times in the last 13.8 billion years, on average emulating dark matter in the process.
• The ringing has been decaying and is now very small – much like striking a crystal glass and hearing it ring down.

The artist’s illustration at the top of this post illustrates the new finding. According to Ringermacher and Mead, the wave amplitude in this illustration is highly exaggerated, but the frequency is roughly correct according to their study and their understanding of the way in which the universe oscillates or “rings.”

Ringermacher and Mead said they’ve determined that this oscillation is not a wave moving through the universe, such as a gravitational wave, but rather it is a “wave of the universe.” That is the universe as a whole is doing it.

Compare the illustration at top to the artist’s illustration below, which represents the current model of the universe (notice: no oscillation).

Artist’s concept representing the events of the Big Bang from the beginning of time to the present day as described by the current, accepted Big Bang model known as Lambda Cold Dark Matter. The Greek letter Lambda stands for Einstein’s ‘cosmological constant,’ which, in this theory, is responsible for the acceleration of the universe. The outline of the “bell-shaped” universe represents its expanding size. The transition time is the point in time at which the bell shape shifts from going inward to outward from left to right. Image via NASA, via University of Southern Mississippi

Ringermacher said he and Mead made their discovery accidentally when, through their collaboration on dark matter modeling of galaxies, they found a new way of plotting a classic textbook graph describing the scale of the universe against its age (lookback time) that did not depend on one’s prior choice of models of the universe – as was traditional.  He said:

• The standard graph, the Hubble diagram, is constructed by astronomers observing the distances of Type 1A Supernovae that serve as ‘standard candles’ for measuring the expansion of the universe.
• Analyzing this new plot to locate the transition time of the universe, we found there was more than one such time – in fact multiple oscillations with a frequency of about 7 cycles over the lifetime of the universe.
• It is space itself that has been speeding up its expansion followed by slowing down 7 times since creation.

Mead and Ringermacher say this finding must ultimately be verified by independent analyses, preferably of new supernovae data, to confirm its reality. In the meantime, their work into the “ringing” of the universe continues.

To learn more about Ringermacher and Mead’s research, visit Ringermacher’s website.

There’s also more information in the statement from University of Southern Mississippi

Is our universe ringing like a crystal glass? Image via Wikihow

Bottom line:  Two physicists say the universe’s expansion has sped up, then slowed down, 7 times since time began.  They describe this oscillation as the universe “ringing.”

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