Media alt text:
3D render of old tv set with animated static on its screen, as if tuned to a dead channel.
This is a very non scientific answer, but when I was a kid (good 40 years ago) I remember having a science book that called TV static “an echo of the big bang”. I guess that would mean just randomly scattered energy bouncing around on all bands?..
I could probably Google it and give you an answer, but I’ll just wait for someone with a more convincingly and authoritatively written reply.
but I’ll just wait for someone with a more convincingly and authoritatively written reply.
Pfft sprayed my drink lol
Probably because of how accurate it is
Now that you mention it, I remember something similar! I may have to follow up on that to see (but I’m also curious of others’ responses, hence asking).
Well apparently now astrophysicists are saying maybe the Big Bang didn’t happen. ¯_(ツ)_/¯
That’s false. Most of them still agree that Big Bang happened, it is just that the first extra small fraction of a second of Big Bang can’t be explained with our current understanding of physics, and there is still a lot of some unanswered questions about it.
But it is still the result of background radiation, which is caused by something.
The TV will try and amplify and display any signal. Without a station, it will end up amplifying random radio noise and tiny fluctuations in the amplifier circuits themselves.
The momentary signal strength is interpreted as brightness of a spot which is rapidly scanned over the display. In this case the signal is random so every spot on the screen will be a random brightness, changing every frame.
Modern digital TVs won’t do this, because with compressed video recognizable data is needed to even attempt displaying a picture.
As for the sources of the radio noise, most of it is from electrons being jostled by heat, some from space. (Including the cosmic microwave background others have mentioned)
The electron jostling (thermal noise) is the reason the receivers on radio telescope as cooled to insanely low temperatures often with liquid helium.
This is the closest to the correct explanation. The reason televisions based on AM radio reception showed static is because of a circuit called the AGC (Automatic Gain Control) which worked like a robotic volume control. Its job is to keep the recovered video signal within a certain amplification range. As long as there was a carrier (the TV station was “on the air”), you’d see whatever the station broadcast. But when they turned off their transmitter, the signal strength would fall and the AGC would increase the amplification until what you see is white noise, mostly due to the random motion of electrons in the electronic components. We can minimize that by cooling, but it can’t be totally eliminated. Audio amplifiers often come with a “hiss” specification that tells you how much of this kind of noise you can expect at normal operating temperature.
BTW, modern digital TVs -will- show a noise picture if they lack a video muting function when no carrier is detected. I have an LG bought in 2019 that does this, and it’s hella annoying when I accidentally hit the input selection button on the remote, switching from HDMI to TV reception.
“The sky above the port was the color of television, tuned to a dead channel.” W. Gibson.
It’s wild that this makes no, or little at most, sense to entire generations now.
Ha I remember that. I also recall someone in the 80s there was a pop song popular in Poland, entitled “Glass Weather”. It was about these rainy autumn evenings when there’s nothing better to do than sit in front of your (black and white) TV. The lyrics were mentioning “apartment window blue from the TV glow”.
Waves are everywhere. The TV picks up whatever waves it can. Some of those waves are signals meant to transmit an image (eg from a broadcast tower), others are just random noise in our environment.
Not an expert, but that was my understanding
It’s been awhile since I’ve messed about with this, so I don’t remember (and you may not either, so this is an open question), but wouldn’t it produce the effect even if disconnected from an antenna?
If so…Would the same principle be in play of it picking up on general EM waves to cause the effect?
Yeah, the same way a radio tuned to a station could be static until you plug in an antenna.
You could also get hums and interference from other sufficiently strong EMF sources, like how AM radios can pick up the sound of transmission lines
Your mom (or dad) using an electric knife to cut a turkey on thanksgiving would do the same. It was wild.
AM car radio can pick up the waves from your cars electrical alternator as well, which can cause the static to rise and fall in pitch as you speed up and slow down.
By tv static, I mean like this btw:
There’s always more or less random noise, and that’s what you see and hear in analog systems. Random noise. As for why it isn’t in color, see: https://dsp.stackexchange.com/questions/46401/why-is-tv-static-noise-always-black-and-white
Ah luminance subcarrier signals . Makes sense.
It’s the echo that sings “I want my M-T-Vvvvvvvvvvv” right before the guitar riff kicks in.
I remember putting my finger near the CRT display of these televisions during the animated static and noticing the weird electrical tingle in my finger. I even did this with my hair. It was so fun… and also potentially dangerous.
Now that’s something I can’t replicate anymore with my modern telly.
Its just static electricity. Not dangerous at all and not exclusive to the scramble screen.
Copied from an old reddit post:
Old cathode ray tube (CRT) televisions have an electron gun which fires electrons at the back of the screen. And the screen is coated with phosphorus phosphors which emit light whenever struck by an electron. The side-effect of this process is that each electron increases the static charge of the screen, and over time as the image on the TV changes it increases the charge. Meanwhile, rubbing your hand, which has a slight negative charge, across the screen will remove some of this built-up static.
Good to know
It’s not static. It’s the ant attack.
I’m glad I’m not the only one. I remember people calling it “the ant race” when I was little (very early 90s), but no one seems to recall this.
and what happens if you broadcast static, like point it at a car thats blasting some shitty radio station, and you are transmitting that same frequency? the distortion will destroy their speakers.
John Wayne in a Blizzard. So said my dad.