[thedoc (OP)]

Agate Auzāne  asked the Naked Scientists:
   
Hi!

Several times I have heared that placing cacti around a computer can protect you from radiation comming out of it. So is that just a myth or are they really able to absorbe some radiation?

Waiting forward to your reply,
Agatha

What do you think?

[BioChemSFC]

If you are worried about computer radiation then just move it further away because intensity is inverse radius squared. This means by moving it away you exponentially reduce radiation. I don't think cati will help you and I also think you are much too worried about the risk. There is no reason cacti would be better than any other water based blockage. So if it did work then so would anything that was mostly water.  From a computer the electromagnetic radiation is minimal, the WiFi microwave radiation is much less that your cell phone (so if you're worried take that out of your front pocket) and there is negligible decay associated radiation. If you use a 4G network through a wireless card the microwave radiation is higher than during normal computer operation. But if you stick your cell phone next to you head then this radiation is not your main concern.

[evan_au]

Regulations were imposed many years ago that reduced "accidental" radiation from computers.
You can test this by taking a battery-powered portable AM radio (if you can find one), tune it between stations and turn up the volume so you get a loud "hiss".
Then closely approach your computer, and you should hear various pulsing and buzzing noises (especially if you try it with the case open).

Place some cacti around, and I don't expect it to affect the noise level at all (unless you spike yourself).

That leaves "intentional" radiators, such as a WiFi antenna. Maximum power here is regulated by the wireless standards.
The problem with placing radiation absorbers around your computer is that the computer has to transmit at higher power (or maximum power for longer) to reliably transmit a signal through the absorbing barrier.

If you are still worried about this unmeasurable risk, perhaps the best solution is to use a wired Ethernet connection to your computer, rather than wireless...

[CliffordK]

Water is good at absorbing a lot of stuff.  So, if a cactus has a high water content, it would be a good protector, in the areas blocked by the cactus.  A fish tank might be better, although for some reason electronics seem to do better around dry things than wet.

However, there are different types of "radiation".

Nuclear radiation (alpha, beta, gamma), is generally NOT produced by your computer.
X-Rays are also not produced by your computer, although CRTs can emit a small amount of ionizing radiation. 
Light?  Perhaps too many LEDs, but the light from the screen is what you desire, and certainly not dangerous.
IR is pretty ubiquitous.  Your body in fact generates IR.

The primary concern falls down in the spectrum of radio waves.  Your computer will be using power at 50 or 60 HZ (in the power supply), and will have oscillators running at up to a few GHZ, all putting you in the middle of the radio wave spectrum.  And the energy per photon is much less than the X-Rays and Gamma.

Nothing has ever been proven for human biological damage from low energy radio waves, although it could disrupt your radios.

So, what to do?
Locate your computer tower and UPS a little farther from where you sit.
Replace the CRT with a LCD.