Global warming - an urgent problem requiring radical solution (no politics or religion)
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WilliamAC1230
Sep 4, 2018
0
#7641
Can’t post links for some reason but that’s the article
Here is a brief news release from the researchers at Cambridge,
Needless to say, the tabloid coverage is a tad overhyped, but there is some chance it will turn out to be useful.
At the rate we're going, we'll need need solar powered out houses, just to relieve ourselves from the increasing average temperature. I (reluctantly) used an outhouse over the Labor Day Holiday. It was much too easy to sweat. 
Here's a recent article by Brad DeLong in PS --
https://www.project-syndicate.org/commentary/climate-change-global-implications-by-j--bradford-delong-2018-09
I thought we weren't allowed to post political stuff.
13 years? You would have a lot of trouble getting past Pluto in that time, when the Sun remains far and away the brightest star. The nearest star is about 6600 times as far away as Pluto.
An amusing question is when the TOTAL light from other stars exceeds that from the Sun. The problem is that star light is a lousy source of energy, because it is very, very weak compared to sunlight at a mere 150,000,000 km.
s23bog wrote:
Don't know why, but I thought it was 26. So ... we are looking at a bare minimum of at least two years for the nearest change over to another star's power source. At current rates of travel ..... well .... quite a bit more.
Yes, assuming motion at near light speed is a bit optimistic!
But, I do agree that star light is a lousy source of energy (especially for interstellar travel, or caves. Or caves in an interstellar travelling asteroid, or something. I think I have been fairly consistent in my aims to steer to alternatives to solar power.
Space is nearly empty and nearly black, so it would seem you have to take all your fuel with you.
However there is some hope for a "fusion ram jet" (invented 1960) which gathers hydrogen from interstellar space and fuses it to provide thrust, but physics implies this can "only" reach about 10% of the speed of light as an absolute limit - practical limit surely lower - basically because you get a fixed amount of energy from fusing hydrogen, but the faster you go, the more kinetic energy you lose by gathering it. Note this relies on a fusion device using light hydrogen, which requires way higher temperatures than a hydrogen bomb, and no-one has serious plans for such a device. (The Sun does burn light hydrogen, but very, very slowly).
Even so, as long as you are happy with a faint hope of half a century trip time, this is the only available technology that does anything but take fuel with you.
[The article linked above delves much deeper than I have].
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#7656
s23bog wrote:
Shifting focus, for a moment to something a bit closer to home, how about an adequate power source in deep mines?
Clearly solar is out.
If the mine had sunlight at the surface there are these things called cables! If it is in an area with little sunlight wind turbines might be better. Or perhaps a hydrogen generator.
Wouldn't it be more that people who hadn't learnt about cables would need to do without them?
Long ago, I worked for 2 months as a summer holiday job doing clean room manufacture of fiber optic cables. The stage I worked on produced something about a meter long that was then stretched to 7 km.
s23bog wrote:
I never cared for the fragility of fiber optic, but have never had one break. I just hate having to be careful with it. I very much prefer to work with copper. Nowadays, copper is as fast as fiber for end use.
Not over a long distance. You would need to break it into short lengths and clean up the signal between each two. These days, fiber technology has advanced to where you can have 100 km runs between repeaters, with each fiber carrying terrabits (I believe the current top performance is 10 Tb/s/fiber).
Kasparov is back once again, guys!! Make your predictions here 
https://goo.gl/forms/dWPqaBhgNkRqG2L72
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