Naked Science Forum
General Science => General Science => Topic started by: katieHaylor on 16/02/2018 16:48:28
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Ute asks:
Could a house be searched virtually, like with a radar from a geostationary satellite or other advanced techniques?
What do you think?
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Due to atmospheric dispersion the highest resolution obtainable from a recconosaince satellite is a pixel size of about 15cm which would reveal little detail.
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Due to atmospheric dispersion the highest resolution obtainable from a recconosaince satellite is a pixel size of about 15cm which would reveal little detail.
If multiple satellites were observing the same house, could the combined data from each compensate for the dispersion to attain better resolution?
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There comes a point where it's a lot cheaper to send a housebreaker with a camera.
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So we have established that a satellite can get a fair image of the roof of a house at visible wavelengths.
- Radar could in theory peer through roof tiles, but the wavelength is much longer, and the resolution is lower. And tough luck if it is a metal roof or you have a layer of foil insulation - radar just bounces off.
- So, unless you live in an open maze made out of hedgerows, a satellite can't look into your home.
If spy agencies wanted to see inside your home, they would merely turn on the camera on your smartphone.
- If they wanted to hear inside your home, they would turn on the microphone in your smartphone.
- Why waste hundreds of millions of dollars on a satellite when we will all happily pay hundreds of dollars to purchase and carry around our own spy cameras?
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Why waste hundreds of millions of dollars on a satellite when we will all happily pay hundreds of dollars to purchase and carry around our own spy cameras?
Because the inside of my shirt pocket isn't terribly exciting compared with the dog scratching herself and farting, which is what happens most of the time in this house. We do play some good jazz occasionally, but for a fiver you could have a beer and hear the finished product at a gig instead of listening to hours of tedious rehearsals.
I guess if a spy satellite could follow my keystrokes it might just reveal my plans for world domination by philanthropic intellectuals, but that won't stop people from electing narcissistic morons and compulsive liars to high office, so who cares?
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from a geostationary satellite
The highest resolution imaged don't come from geostationary satellites (about 37,000km away), but from satellites in Low Earth Orbit (LEO), skimming the edge of Earth's atmosphere about 150km up.
The disadvantage of LEO satellites is that they aren't back over the same point on Earth's surface for another few weeks. So if you rearrange your furniture every day, the spy agencies will be completely misled for another couple of weeks.