Tuesday, May 6, 2014

Now We Know Cosmic Inflation Occurred – Thanks to Newly Released Results

No photo description available.

According to the Big Bang “sub-theory” of cosmic inflation, the universe rapidly “stretched” in size during its initial expansion phase, and by that we mean the expansion was “faster than light”. We therefore say  the inflation mode is entirely in the realm of 'false vacuum' in which a large and negative valued cosmological constant is assumed. In the context of Einstein's theory of general relativity, the 'false vacuum' may be thought of alternatively as contributing a cosmological constant about 10-100 times larger than it can possibly be today. It is this peculiarity which generates a corresponding 'repulsive' force, causing the universe to inflate on an exponential scale.

Note that this sort of thing (implying velocities of expansion > c) isn't particularly novel. In fact, a number of cosmological models posit that proper distances, i.e. between clusters of galaxies, may increase faster than the speed of light.  To fix ideas here, if the initial size of the universe was 1 fm (Fermi = 10 -15 m or about the size of a proton) then the inflating cosmos would have attained a scale of about eight times the Earth-Sun distance (8 astronomical units) after 90 doubling times, with periods ranging from 10 -43 secs to 10 -36 secs.

 This phenomenon  also explains why the universe is basically uniform.  The problem is that before the BICEP2 (Background Imaging of Cosmic Extragalactic Polarization) results were announced March 17 it was all speculation. The paper on which the results were based has since been submitted to the Journal Nature and should be available soon.

To grasp how significant this is consider this:  No telescope exists – even the Hubble – that can see anything older than the oldest light which comes from 380,000 years after the Bjg Bang or long after inflation ended.

The BICEP2 team discovered that this light, called the CMB or “cosmic microwave background”  has a major defect or “scar” from the cosmos’ early violent expansion. This is by way of polarization or a particular orientation of the light waves emanating from the CMB.  Astrophysicists had predicted that inflation generated gravitational waves that warped space time through which any photons traveled. If in fact this was so, then the CMB ought to have a characteristic “swirling” polarization known as a B-mode. Light is polarized when its electromagnetic waves are preferentially oriented in a particular direction.

Other forms of polarization include:

Linearly or horizontally polarized: I.e. the E- vector is confined to one  (horizontal) plane

---------à E

Vertically polarized: I.e. the E- vector is confined to one  (vertical) plane

^ E


Circular: The E-vector rotates through 360 deg

Elliptic: any polarization not circular or plane.

B-mode polarization is much more complex and illustrated below.

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Here, the E-vector (seen in line of sight) can curl either clockwise or counter-clockwise into spiral patterns. It was precisely this type of pattern that the BICEP 2 detected suggesting that both cosmic inflation and primordial gravitational waves are real (since the latter are the only things known that can give rise to the B-mode polarization)

 The graphic shown above, meanwhile, captures the swirling directions of light within the cosmic microwave background.

Of course, it goes without saying that other independent workers – researchers will now have to confirm these findings if they are to be fully accepted. But to this observer, it should only be a matter of time!


Unknown said...

Technically speaking, the universe is not expanding just because the things in it are flying away from each other.

Copernicus said...

Actually, it IS expanding given the space dimension is actually increase - now nearly 66 b light years in diameter.

The way to visualize what's happening is to use or imagine a balloon with ink spots on it. Each ink spot represents a galaxy cluster. As the balloon is inflated each ink dot moves away from each other AND the balloon increases its dimension (radius) overall.

Our red shift measurements confirm the velocity of recession increases with distance of an object - and hence, yes, this is interpreted as cosmic expansion.