WHY BICEP2 PAPER SHOULD BE RETRACTED, PART I
PART I: THE APERTURE FAULT
I.1 Basic fallacies
Bicep2 is a refractor telescope directed at observing the polarization characteristics of the Cosmic Microwave Background Radiation (CMB) at 150 GHz (wavelength 2 mm). It has an aperture diameter 26 cm. Its focal plane is populated by a large number ( ~ 500) of small (physically and electrically) antennas with wide beams. The linearly polarized antennas are alternately at 90 degrees to one another to receive two orthogonal polarizations.
The aperture of the bicep2 telescope has two fatal design faults stemming from:
A. MISUNDERSTANDINGS (of telescope science)
B. MISINFORMATION (about the amount of CMB power available in the sky)
While I cannot speak for others, I myself was most baffled that such a small diameter (about the diameter of a standard dinner plate) telescope could not only receive, but also produce detailed high resolution maps of the very dilute CMB radiation. Remember that the scientists and engineers in the past went to larger and larger collecting aperture from COBE to WMAP to Planck satellites – all directed at observing CMB. The COBE-FIRAS instrument which had a collecting area comparable to BICEP2 was a total failure.
However, the following scientific justification was offered by the bicep2 team for the use of the “novel” use of small aperture:
Small telescopes have an overlooked capability to gather a lot of light with a wide field of view. … it was a novel approach in CMB measurements and gave us an enormous 20 degree field of view. In fact the light gathering power of BICEP is not so different from that of the 10-meter telescope looming over us at the South Pole, but BICEP’s aperture is just 26 centimeters.
While it is not spelled out, this comment refers to an isotropic radiation field (which is what CMB is) where the spectral radiation flux Fν (watts per sq meter, say, integrated over the bandwidth) is the same in all directions.
d = diameter of BICEP2 (= 26 cm)
D = diameter of 10-meter South Pole Telescope (=1000 cm)
A_B = PI*d**2/4, the aperture of BICEP2 telescope
A_SP = PI*D**2 /4, the aperture of South Pole Telescope
Referring to Figure 1, we see that for the BICEP2 Telescope, radiation enters the antenna aperture from all directions within its 20 degree field of view. For the narrow beam South Pole Telescope, radiation enters only in the direction parallel to the telescope axis. This is how it is possible for the same amount of radiation (watts) to enter the aperture of a small telescope and a large telescope. To this extent, the statement from the BICEP2 team is correct.
But it has nothing to do with anything.
What has everything to do with everything is how much radiation P (watts) is received by a single focal plane antenna element. This amount is
P_B = Fν*A_B
P_SP = Fν*A_SP
P_SP/P_B ~ 1500
So everything is in order. An antenna element at the focal plane of a small telescope receives little power, and the same at the focal plane of a large telescope receives great power. This is true in a directed radiation field or an isotropic radiation field. There is no “novel” way to defeat this basic physics.
The above comments pertain to the design of the BICEP2 Telescope. Is there any observational affirmation that the design is defective? It should be noted that Planck Satellite, with vastly larger aperture than BICEP2, reports low power levels difficult to process in the region of the sky that BICEP2 mapped with such clarity. This should rightly be accepted as the observational evidence that BICEP2 Telescope results do not pertain to CMB.
To design a telescope aperture, one needs a design value for the flux available. In this case it is the CMB flux Fν in the sky.
It is a matter of record that the BICEP2 Telescope was designed for a value of Fν corresponding to the ~ 3 K cosmic blackbody radiation discovered by the COBE Satellite.
However, it is an open secret within the scientific establishment that this blackbody does not exist and the actual value of Fν may be two orders of magnitude lower. This information has been available to the BICEP2 team for many years. But the academics have such an inflated collective ego that they would rather design wrong things and report wrong results than to acknowledge that a grave science fraud was committed with their COBE discovery.
The above two faults in BICEP2 design constitute more than enough reason to retract the BICEP2 discovery. However, in Part II I will discuss the BICEP2 imaging technique and associated faults for good measure. I will tell you about how a modern high precision multi-million dollar scientific instrument is periodically given a whirl the way Buddhist prayer wheels are periodically given a whirl.
I do not know yet if BICEP2 is periodically given a whack also, the way the olden days TVs sometimes needed to be given a whack. But I live and learn.