Cosmic Background

On the last three decades, several space experiments with parts at very low temperatures have been flown. Among these, we mention IRAS (Infrared Astronomical Satellite) launched in 1983 (see Fig. 14.1), COBE (Cosmic Background Explorer) launched in 1989, ISO (Infrared Space Observatory) launched in 1995 and Astro-E (X-ray Observatory), launched in 2000 with instrumentation at 65 mK [35], Some cryogenic space missions are in the preparation or in final phase in Europe, USA and Japan. For example, ESA is going to fly Planck (for the mapping of the cosmic background radiation) and Herschel (called before FIRST Far Infrared and Submillimetre Telescope ) [36], These missions will carry experiments at 0.1 and 0.3 K respectively. 

The development of new low-temperature detection technology and the launch of the Cosmic Background Explorer (COBE) satellite by NASA in 1989 helped to resolve this problem. The results from these observations were amazing - an almost perfect black body curve (Figure 2.3) with a black body temperature of 2.725 0.002 K and a maximum wavelength of the radiation at kmax = 1.05 mm. 

Figure 2.3 An almost-perfect black body spectrum for the cosmic background radiation. Figure courtesy of NASA/COBE Science Team...

Keywords fluxon gas in thermalized Josefson systems the criteria of degeneracy of the relativistic ideal gas absolute minimum realization of the most probable state in the equilibrium system temperature of the primary microwave cosmic background primary quantum magnetic flow. 

As follows from the previous analysis for quasi and ordinary particles gases there exists a critical value of parameters a and b for which the least value of the distribution function for observable frequencies is observed. From the physical point of view this is in agreement with the absolute minimal realization of the most probable state. As in any equilibrium distribution, there is an unique most probable state which the system tends to achieve. In consequence we conclude that the observable temperature of the relic radiation corresponds to this state. Or, what is the same, the temperature of such radiation correspond to the temperature originated in the primary microwave cosmic background and the primitive quantum magnetic flow. 

Universe, tell me how old you are, and 1 will tell you the colour of your radiation background and the energy of each of your photons. Today, the cosmic background radiation is red, very red. It is so red and cold (about 3 K) that it cannot be seen. Its chilled voice quivers in the great ears of our radiotelescopes. Solar emissions, on the other hand, can be compared with the radiation from an incandescent body at a temperature of around 5700 K. Temperatures vary across the Universe, from 2.73 K for the cosmic background to 100 billion K when a neutron star has just emerged. 

The neutrino Sun never sets. Sixty billion neutrinos blasted out from the Sun s core eight minutes ago fly through every square centimetre of our body each second. We feel absolutely nothing and neither do they. They are the height of discretion. The night is not absolutely dark because, not only are we forever bathed in the cosmic background radiation at microwave wavelengths, but we... 

It is therefore a Euclidean universe which lies at the meeting point between data from remote supernova studies and observations of the cosmic background radiation. Such a universe contains just enough matter and energy to keep the geometry Euclidean. In fact the Euclidean cosmology fits our Universe like a glove. 

For most astronomers, the solution to these cosmological problems resides in a combination of various methods. The luminosity-redshift test must be combined with independent techniques, such as anisotropies in the cosmic background radiation and statistical study of gravitational lenses. 

J. Schafer and W. Meyer. Collision induced dipole radiation of normal hydrogen gas in frequency range of the cosmic background. In J. Eichler, I. V. Hertel, and N. Stolterfoht, eds., Electronic and Atomic Collisions,... 

In the spirit of Lorentz [45], de Broglie, and Vigier, let us postulate the existence of a preferred frame E. Operationally, E may be identified with the frame of cosmic background radiation (CBR), whose isotropic thermal nature was established by measurements during the COBE-FIRAS project [46]. Then, the principle of relativity simply states that all frames that are not accelerated relative to E, are equivalent to it. 

For the connection between the CN-predic-tion and the cosmic background radiation, see Kragh, Cosmology and Controversy, 134-135, 345-347. 

An important application of cosmic background radiation is to provide a test of the reality of the expansion if we are able to measure the temperature of the background at higher redshift it should scale accordingly to ... 

The most accurate measurements of the CMB spectrum to date have come from the Far InfraRed Absolute Spectrophotometer (FIRAS) on the COsmic Background Explorer (COBE) (Boggess et al., 1992). In contradiction to its name, FIRAS was a fully differential spectrograph that only measured the difference between the sky and an internal reference source that was very nearly a blackbody. Figure 9.2 shows the interferograms observed by FIRAS for the sky and for the external calibrator (XC) at three different temperatures, all taken with the internal calibrator (IC) at 2.759 K. Data from the entire FIRAS dataset show that the rms deviation from a blackbody is only 50 parts per million of the peak Iv of the blackbody (Fixsen et al., 1996) and a recalibration of the thermometers on the external calibrator yield a blackbody temperature of... 

We cannot help but notice that temperature fluctuations in the cosmic background radiation have a typical fractional magnitude of J7 as 10 5 [70,71]. The observed and measured value T k, 10 5 [70,71] is obviously far more certain than the speculated value / 10 5 hence the distinction between the fs symbol as opposed to the symbol. Although it is unlikely that there is a connection between T k, 10 5 [70,71] and / 10 5, it doesn t seem to hurt if we at least mention this numerical concurrence — just in case there might be a connection. 

Observations with the Cosmic Background Explorer (COBE) have shown that, to a precision of better than 10 , the cosmic microwave background (CMB) is thermal, with a temperature of 2.73 K (Mather et al., 1994). 

For results from CODE (Cosmic Background Explorer), see http //lambda.gsfc.nasa.gov/product/cobe/. 

The anisotropy of the microwave cosmic background radiation is being measured by the Wilkinson Microwave... 

This temperature is that of the cosmic background radiation. The species have reasonably large electric dipole moments for CH and CN, measurement gives... 

---