¡¥So, what happened after the Big Bang? How can the stars, planet and the human who manufactured me form? What happened to the radiation left after annihilation?¡¦
¡¥To understand the formation of astronomical objects, we must have a clear concept about the legacy of the Big Bang.¡¦
Let us now examine
one of the more speculative scenarios that could lead to modification of the
standard model. Consider a very chaotic and turbulent early universe. Suppose
this turbulence is driven by gravitational collapse in localized regions. The
primordial motions would eventually dissipate and produce heat, in much the
same way as the airflow around a supersonic missile generates heat. Thus, more
radiation would be generated. The photons produced would be mostly of higher
energy, or frequency, than the average blackbody photon. Consequently, a shift
to the blue, or reduction in wavelength, of the blackbody-radiation spectrum
would occur. Once the radiation spectrum became distorted from its original
distribution, it would subsequently remain bluer relative to the radiation temperature.
At these early eras, the universe would still be highly opaque because of the
many scatterings undergone by the photons. Thus the distorted blackbody radiation
would continue to be scattered. No further distortions of the spectrum would
occur. Once the scattering ceased, a¡§blue
glow¡¨ would he detectable and we would expect to discern a short wavelength
(blue) distortion of the observed blackbody radiation.
To understand why this should be an observable phenomenon, lotus examine the fog analogy a little more closely. Imagine two light sources, one red and one blue, surrounded by fog. An observer would not be able to see the light sources but would see the color of the scattered light. The red light would be seen from a greater distance than the blue light, because red light is of longer wavelength and scatters less than blue light. (This phenomenon explains why the sky is blue and the sun appears to be red when it is near the horizon; the atmosphere scatters more of the blue light and less of the red light.) By examining the scattered blue light, we could draw conclusions about the dust content of the atmosphere and about the nature of the light source, which we could not discern directly. Similarly, we can analyze the cosmic background radiation to determine the conditions in the universe during the radiation era. We should expect to see an excess of ¡§blue¡¨ scattered photons. However, observations of the background radiation yield no definitive evidence for any such distortion; more precisely, they do not provide evidence for a phenomenon at radio wavelengths that is analogous to seeing ¡§blue,¡¨ namely, a preferential enhancement of the intensity of short wavelength photons relative to photons of longer wavelength. The best estimate is that at most 10 percent of the energy in the blackbody spectrum could have been distorted in this fashion. From this evidence we infer that any turbulence or dissipation in the radiation era (from age 6 months to about age I million years) must have been relatively modest.