Those here who dispute Robitaille have revealed that they have not understood his work or have not bothered to study his papers before uttering their comments. It is irrefutable that water absorbs and emits in microwave. In the liquid phase it does so in a continuous spectrum. In the gas phase it does so only in narrow bands. The glass of water in a microwave oven attests to absorption by water of microwaves. Similarly, radio communications in microwave is not used for submarines because under water microwaves are readily absorbed by the surrounding water. That which is a good absorber is also a good emitter, in the same frequencies. A good reflector is a poor absorber and hence a poor emitter.
The so-called CMB mean temperature (~3K) is resident in what is termed the monopole signal. The so-called anisotropies are in micro K. No monopole signal has ever been detected beyond Earth influence. COBE was in obrit at an altitude of ~950 km. WMAP and Planck were at L2, some 1.5 million km from Earth. WMAP was a differential instrument and therefore incapable of monopole detection. Plank's Low Frequency Instrument (LFI) had both absolute and differential capability. No monopole signal at L2 has been detected. The galactic foreground is in milli K. Thus, the alleged anisotropies are ~1000 times weaker than the noise. Laboratory experience attests that it is impossible to extract such a weak signal from such a large surrounding noise unless the experimenter has at his disposal at least one of two options: (1) a priori knowledge of the nature of the signal source, (2) the ability to manipulate the signal source. Neither option was available to any anisotropy probe. All talk of CMB and CMB anisotropies without a monopole signal beyond Earth influence is baseless. COBE DMR, WMAP, Planck etc; none can separate noise from signal. COBE FIRAS had tremendous signal to noise. It detected microwave emission from the oceans, but the COBE team erroneously assigned it to the Cosmos, because they wanted a Cosmic signal. Penzias and Wilson observed from the ground. They did not take account of microwave emission from the oceans. The finding by Penzias and Wilson was immediately assigned to the Cosmos by Dicke, Wilkinson, Peebles, and Roll, without knowledge of microwave emission from the oceans, and in ignorance of the nature of the hydrogen bond.
About 70% of Earth's surface is covered by water. The oceans are not microwave silent. Microwaves emitted by the oceans are scattered by the atmosphere. The conditions are steady-state. COBE's shield could not protect it from microwave emissions from below.
The species by which water emits in microwave is the hydrogen bond, at an apparent temperature of ~3K as a blackbody source. It is known that an atomic explosion over water causes the water in near vicinity to turn black for a short time, recovering its normal appearance after the shock wave has passed. This is plain evidence that water then acts as a blackbody in the visible bands. The black appearance is due to compression of the water lattice by the shock wave. Water has a hexagonal planar lattice, like graphite.
Here are Robitaille's papers on the COBE and WMAP:
Robitaille P.-M.
WMAP: A Radiological Analysis
http://www.ptep-online.com/index_files/2007/PP-08-01.PDF
Robitaille P.-M.
COBE: A Radiological Analysis
http://www.ptep-online.com/index_files/2009/PP-19-03.PDF
Robitaille has adduced a wealth of observational data that proves that the Sun is not a gas ball but is condensed matter. He proposes a liquid metallic hydrogen form for the Sun. I will not lengthen this post by further comment on the Sun. Robitaille's paper on the sun is also freely available at the website of the journal Progress in Physics.