5,276 reputation
1329
bio website keith-s-thompson.github.com
location San Diego, CA
age 54
visits member for 2 years, 10 months
seen Aug 8 at 22:05

I'm a programmer and all-around nerd living in San Diego, California and working at JetHead Development Inc.

E-mail: Keith.S.Thompson@gmail.com


Aug
2
comment Is it possible to lift yourself off from the ground?
The question is ambiguous. If you push down against the ground, it's possible. If you try to pull up against your own body, it's not.
Aug
2
comment Is it possible to lift yourself off from the ground?
My father used to tell me about our mythical ancestor Bootstrap Thompson, the only man in the world who could pick himself up by his bootstraps and hold himself out at arm's length.
Aug
1
comment What is the shortest run needed for a “dropped skateboard” rider to reach 160 mph?
If he's skating in a vacuum, will he reach 160 mph before he asphyxiates? Feel free to assume a spherical skateboarder.
Aug
1
comment The theory of moon creation when a Mars size planet hit Earth
@zadane: Only if they're low enough to experience significant atmospheric drag. Manned satellites (the shuttle, ISS, Skylab, Mir, etc.) tend to be launched into as low an orbit as practical, because it's cheaper, and because you need minimal fuel to re-enter and go home; that's worth the expense of an occasional re-boost. GPS satellites orbit at about 20,000 kilometers, and geosynchronous communications satellites are about about 36,000 kilometers; they experience no significant drag, and their orbits are much more stable.
Jul
31
comment The theory of moon creation when a Mars size planet hit Earth
@JohnRennie: Sure, but in the views we've seen of the Enterprise in orbit it's clearly high enough for drag not to be an issue. The ISS is in low orbit so it's easy to get to from the surface; the Enterprise comes into orbit from deep space, so there's no reason for it to be in such a low orbit.
Jul
31
comment The theory of moon creation when a Mars size planet hit Earth
It's possible, but unlikely, that Earth's orbit was eccentric before the collision and nearly circular after.
Jul
30
comment The theory of moon creation when a Mars size planet hit Earth
@ThePopMachine: In the original Star Trek, the ship's orbit around a planet was often portrayed as unstable, requiring power to maintain it. That may actually be part of the reason for the misconception.
Jul
30
comment The theory of moon creation when a Mars size planet hit Earth
Do gravitational interactions with other planets tend to circularize orbits over time?
Jul
28
comment Why are there photographs of nuclear tests?
Yes, the atmosphere absorbs X-rays fairly well; that's why we put X-ray telescopes in orbit.
Jul
25
comment Could cell-phone radiation cause cancer?
And are studies that show a (small) negative correlation less likely to be published, introducing a positive bias?
Jul
16
comment Why do we still not have an exact definition for a kilogram?
But you didn't mention that in your answer. You merely stated that "One kilogram is a mass of a randomly chosen prototype." without saying why (which was the question). And again, I don't understand what you mean by "mass is not directly related to kilograms".
Jul
16
comment Why do we still not have an exact definition for a kilogram?
This doesn't answer the question. And perhaps you could explain what you mean by "mass is not directly related to kilograms".
Jul
10
comment What do spacecraft have in common with atmospheric aeroplanes?
@DmitryBrant: Sure, but the premise of the question was a craft that can operate both in an atmosphere and in deep space. Clearly a deep-space-only craft would likely be much different.
Jul
8
comment What do spacecraft have in common with atmospheric aeroplanes?
@DmitryBrant: True, but a craft that really is capable of operating in deep space and in the atmosphere would likely have a similar look.
Jun
12
comment How many stars within 5 parsecs?
@Electro: I've updated my answer.
Jun
11
comment How many stars within 5 parsecs?
I'm doing some more research on this; I'll update my answer when/if I figure this out.
Jun
11
comment How many stars within 5 parsecs?
It seems to me that a negative parallax doesn't make physical sense. And you're seeing negative parallax values and getting incorrect results; I doubt that this is coincidental. What do the parallax values in the Hipparcos data look like?
Jun
11
comment How many stars within 5 parsecs?
Wouldn't parallax values all be positive?
Jun
8
comment Space station gains enough mass to lose orbit?
But the increase in size causes more atmospheric drag. The ISS has to be boosted periodically to maintain its orbit.
Jun
7
comment Why Higgs particle is the root of all elementary particles?
The popular media tend to claim that the Higgs boson is the source of all mass. If I understand this correctly, it's the Higgs mechanism that's (theoretically) the source of all mass, and the Higgs boson is another consequence of the Higgs mechanism. Is that about right?