I've heard quite a few times that a certain percentage (usually claimed 1%) of the noise you see on TV comes from the background radiation of the Big Bang. Is this a myth?

If not, I seems like a reasonably complicated claim to substantiate (interference of other radiation, etc.). But maybe that's just my poor understanding of the mechanics of measuring such a phenomenon.

  • It definitely will be a myth if the big bang theory turns out to be wrong. I wonder, are there any other theories about what could be the cause of this 1% of background radiation? Jul 18 '11 at 5:45
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    The claim is found on CERN and NASA that static is found on TVs as a result of the Big Bang. Not sure about the 1%
    – JoseK
    Jul 18 '11 at 7:57
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    Makes sense, relic radiation frequency is pretty much within frequency ranges of VHF and UHF.
    – vartec
    Jul 18 '11 at 10:25
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    @Randolf Cosmic microwave background radiation has been observed. Even if BBT turns out to be false, this radiation is still there, it will just be very badly named. But that won’t happen. The predictions of the BBT on CBR are among the most precise scientific predictions that have ever been verified. (And this in turn has lead to one of the most famous science comics and most awesome t-shirts.) Jul 18 '11 at 12:19
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    When I turn on my TV I often find a huge amount of noise generated by The Big Bang Theory Jul 19 '11 at 14:05

The static on analog televisions has been attributed to Cosmic Microwave Background (CMB) radiation by a variety of scientific sources such as CERN, NASA and this primer from Douglas Scott ( University of British Columbia)

Can I see the CMB for myself?

In fact you can! If you tune your TV set between channels, a few percent of the "snow" that you see on your screen is noise caused by the background of microwaves.

CMB radiation is in fact considered the best available evidence of the Big Bang Theory. So far from being a myth, this is used to prove the Big Bang happened.

The actual amount of static attributed to BB is debatable. CERN and NASA do not state a number.

The 1% as the amount of static caused by BB is claimed on various other sources with no clear explanation of how it is measured at 1% and whether the other 99% covers all sorts of things, including stuff induced from sparks, lightning, stars.

The claim is found in this presentation by Prof Frank Van Den Bosch from Yale (slide 4) and another on the University of Buffalo, NY, Physics Dept (PPT)

Roughly 1 percent of the static on your TV is CMB!!!

Lots more links to Theory

Now, why did I mention analog earlier? Because with digital signals, you will no longer see leftover radiation from the Big Bang as static on your television screen.

when you are between channels on an analog television, the snow that you see on the screen is made up of interference from background signals that the antenna on your TV is picking up. Some of the “snow” is from other transmissions here on Earth, and some is from other radio emissions from space. Part of that interference – about 1% or less – comes from background radiation leftover from the Big Bang, called the Cosmic Microwave Background (CMB). The same is true for FM radios – when the radio is tuned to a frequency that is between stations, part of the hiss that you hear, called “white noise”, is leftover radiation from the Big Bang some 13.7 billion years ago


Digital signals eliminate the interference while watching a program because instead of broadcasting the picture as a radio wave which communicates to the CRT or plasma screen what to “paint” on the screen by the frequency of the signal, all a digital signal communicates is a 1 or 0, and the digital converter takes care of decoding and sending information as to what the picture and sound on your screen should look like

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    Glad you posted this, JoseK. I was itching to give an actual answer, but wanted to see if you'd turn your comment into one. Good stuff! The only point I'd make, and is maybe worth editing, is that the 1% thing seems to be somewhat ambiguous. I was never able to find a solid source for that figure... I saw it around a few times, just as I'm sure you did, but no one explains where the number actually comes from. One estimate I saw even claims as much as 33%. I think a fairer response would be "1% seems possible, even likely, but no good source was found other than word of mouth."
    – erekalper
    Jul 20 '11 at 12:49
  • + Great answer, but I wonder one thing: Is it the case that the receiver circuit contains automatic gain adjustment, where the lack of signal would cause the gain to max out, and then a good part of the static is just shot noise in the electronics? Sep 9 '13 at 0:47

The noise on an analog TV or FM radio between stations is almost entirely thermal noise and shot noise in the receiver front end. You could put the TV or radio in a shielded box and the noise would still be there. Whether CMB contributes 1% to this is meaningless. You can't measure that amount of additional noise even if it is there.

CMB is very weak, so if you really want to pick up CMB you need a huge dish or radio telescope, and a supercooled amplifier to minimize the thermal noise.

Digital TV is not immune to thermal and shot noise. You can't see or hear the noise because of the digital processing, but if the digital signal is too weak it will be down in the noise, and you just won't see or hear anything.

There could be additional external noise, but that is incidental.

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    Welcome to Skeptics! Please provide some references to support your claims.
    – Oddthinking
    Apr 2 '17 at 15:50
  • You don't need a huge dish. COBE, which mapped the CMB (not just detected it), had a 7.5 inch dish on its main telescope. You just need to be to minimize sources of noise. Given that you can measure the strength of the CMB, and you can figure out the strength of the noise picked up by a TV antenna, you can take a ratio. Something like this ratio isn't meaningless to people would would like to detect the CMB, like say cosmologists.
    – KAI
    Apr 3 '17 at 16:27
  • Where can I get actual technical data on this? What signal strength and frequencies can be expected on an ordinary TV antenna? One graph I saw showed most of the energy is well above 1 GHz, - peaking at 150GHz, which is far outside the TV frequencies. What do you mean by take a ratio? How can then be done without specialized equipment?
    – KLtemp2001
    Apr 4 '17 at 22:12

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