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| Centimeter Wavelengths |
 Title text: Yes, the cosmic microwave background is great, but what about the earthly microwave foreground? |
Explanation
Cosmic microwave background radiation is microwave radiation which permeates throughout the entire observable universe. It originated from light released during proton-electron recombination shortly after the Big Bang, which has since grown less energetic due to cosmological redshift, becoming background microwave radiation which we see today. This radiation is not visible to the naked eye, but can be detected using specific radio instruments, including centimeter wavelength antennas, which are antennas designed to detect signals in the 1~10 cm wavelength range (from 30GHz down to 3GHz); the core range of the wider microwave band of radio waves.
In 1978, American astronomers and physicists Arno Allan Penzias and Robert Woodrow Wilson were awarded the Nobel Prize in Physics "for their discovery of cosmic microwave background radiation". During routine experiments with the Holmdel Horn Antenna, a centimeter wavelength antenna, Penzias and Wilson discovered that they were detecting a static background noise that they could not explain. After "debugging" the antenna and removing all potential sources of noise, including the 'removal' of nesting pigeons and their droppings, they found that this background noise was still present. This led to their accidental discovery of the cosmic microwave background radiation, and thus provided a key confirmation of the Big Bang hypothesis itself. (In the world of xkcd, this could explain this phenomenon.)
Wi-Fi networks also transmit their signals using electromagnetic waves at similar wavelengths. The common frequency bands currently used are 2.4 GHz and 5 GHz, and 6 GHz is seeing more use recently. The three ranges would roughly correspond to wavelengths of 12.5cm (4.92in), 6cm (2.36in), and 5cm (1.97in) respectively. Many other sources (notably microwave ovens) can also produce emissions in the same wavelengths, which can interfere with those signals, they can interfere with each other, and intervening structures, etc., can obstruct signals (or create spurious ones), all of which can cause annoying loss of function necessitating investigation and intervention to stabilise the signals. Less technically capable workers may need extra support to properly setup up their networks, while too capable ones could also risk breaking things in more profound ways...
Randall is bemoaning the fact that none of the efforts of people working in the IT sector, who may be spending even more time troubleshooting issues related to Wi-Fi connectivity on their site, have been recognised in the way that Penzias and Wilson have been.
This comic is something of an inverse of the sentiment expressed in 3154: Physics Insight.
The title text may be a reference to Perytons, a signal first seen by astronomers in the early 2000s. Perytons looked similar to fast radio bursts, which are very energetic astronomical signals, the origin of which is still not understood. Perytons, on the other hand, were found to be the result of opening the door of a microwave oven in the radio observatory, which let out a short burst of microwave radiation as the magnetron in the oven turned off.
Transcript
- [A scatter plot graph with the Y axis of "time spent debugging centimeter-wavelength antennas" and X axis of "Nobel prizes awarded as a result". The X axis has the numbers 0 and 1 marked, while the Y axis has no numbers marked. Many dots arranged vertically appear at 0 on the X axis (zero Nobel prizes), collectively labeled as "I.T. people troubleshooting WiFi issues". A single dot appears at 1 on the X axis, vertically about 1/3 of the height of the graph up, labeled "Penzias & Wilson".]
- [Caption below the panel:]
- I just think the other people working in the field deserve at least a little recognition.
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