Think I'll just pack my trunk but then wood that sap all my strength?
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I just read the NASA link posted by Fortran. As I suspected it says:
"There are six landing sites scattered across the Moon. They always face Earth, always in plain view. Surely the Hubble Space Telescope could photograph the rovers and other things astronauts left behind. Right?
Wrong. Not even Hubble can do it. The Moon is 384,400 km away. At that distance, the smallest things Hubble can distinguish are about 60 meters wide. The biggest piece of left-behind Apollo equipment is only 9 meters across and thus smaller than a single pixel in a Hubble image."
So it looks like a footprint is indeed beyond the scope of Hubble's resolving power.
If you have a source of wireless power in your home then how can you be sure that there is nothing around which will be dissipating that power - either by chance or by design, by your thieving neighbour?You do it the normal way. You measure the current drawn, and compare it with the amount used. If there's a significant difference you investigate.
Any leech would have to have a circuit that resonates at a particular frequency; it's not hard to track that down. TV license vans do much the same thing.
The only show stopper that I'm aware for this kind of thing is the frequency- you'd have to operate it at a frequency that wasn't in use.
It's not particularly expensive, it's not outrageously inefficient, it seems to be safe (you can design it within current occupational limits) and it's more convenient. [O8)]
I am not sure I understand "500 feet at 250,000 miles" and why this is okay for seeing footprints.
Does this mean that it can spot something 500 feet across at a distance of 250,000 miles?
How far is Hubble from the moon?
There is no hope that Hubble's resolution could be increased a hundredfold, assuming everything is made perfectly the resolution is determined by the size of the mirror and the frequency of the light it is operating at, Hubble is already at that limit.It seems I remember that the CCD's of the early Hubble had a resolution of 800 by 800 pixels. They must do some tricks with those because the images we see are much more detailed.
I'm not sure what the news cast was claiming was a hundred times better. What ever tricks they use to capture images have probably improved over the last 20 years or so.
Q1. traditional PCs are in metal cases, which act as a Faraday cage, but so-called modded PCs use a whole host of materials; do these ruin the screening properties of the case?
Q2: In theory, would it be possible to make a case out of mesh (or a material with a mesh embedded in it - like the window on a microwave) with zero EM emissions?
Q3: Are PC's unstable if separate parts are not all earthed to a chassis? (ie mainboard, PSU, HDD were just bolted to wood, say). [case designers must have to meet specifications I'm sure, but how problematic would such Heath Robinson systems be, huh?]