Discussion in 'Politics' started by Gordon Gekko, Feb 2, 2003.
Quote from marketsurfer:
1. a rocket travels horizontally 5 feet off the ground from malibu, CA across the ocean. the rocket is traveling faster than 25,000 MPH ( escape velocity ). will it miss the curvature of the earth and careen into space ??
nice question! like ArchAngel said, i think it would eventually exit the earth's atmosphere, but starting horizontally off the ground only 5 feet, is a wee bit low.
2. if you were born on a completely stationary space station and were transported to earth after 20 years of being stationary, would you feel the earth rotate ??
i think it would basically be the opposite of how it is for us today. presently, we're used to the earth's gravity. when we go in space, we find the weightlessness odd.
if you were born in space on a non accelerated platform (if that's what you meant), zero gravity is what you'd be used to. if you then came to earth, the earth's gravity would feel strange to you. also, you probably couldn't even function on earth because your body's muscles wouldn't be prepared for the gravity on earth. i think i've heard that astronauts that spend long periods of time in zero g space, when they come back to earth, they are put on a stretcher/wheelchair upon leaving the spacecraft.
as far as feeling the earth rotate, i don't think we feel much of it on earth now. much of the feeling we have is from gravity, not because the earth is spinning. we don't feel much of it because everything, including the atmosphere, moves with us. also, we are tiny beings on a large object, which makes it pretty unnoticeable for us.
here's something to keep in mind if this stuff interests you. einstein came to the conclusion that gravity and accelerated motion have the exact same feeling to a person. for example, if we put you inside an elevator in zero g space and accelerated you "up" equal to the force of earth's gravity, you would not be able to tell the difference between that and standing on earth.
one more cool thing. all objects have gravity. the presense of an object in space is what creates gravity. the more mass something has, the bigger the distortion of space, and the greater the gravitational pull. that's why the earth has more gravity than the moon, because the earth has more mass. even you and i, and a pencil on your desk have gravity. however, the amount is so miniscule, it doesn't really matter much to us. if we could build a giant marble with the mass equal to that of the moon and send it into space, it would have gravity much like the moon does.
I'm sure someone has thought about this before, but:
Since the earth with it's gravitational pull is sort of like a giant magnet, would it be too far fetched to engineer a device to repel earth, by using the same gravitational powers that be, and turning it upsidedown ? Much the same way magnets can both attract and repulse each other? Somehow if we could harness this action on a large scale. I've always thought if UFO's really existed, this would be their means of propulsion. Or in this case re-pulsion.
gravity exists because of the very PRESENSE of an object in space. in order for earth's gravity to go away or change, its mass would have to change. it's not really at all like magnetic force.
interesting note: gravity "moves" the same speed as light. it takes light from the sun about 8 minutes to reach earth. therefore, if the sun suddenly disappeared, we wouldn't see OR feel a difference for 8 minutes afterward.
another interesting concept: most people already know this one, but every time you look at something, you are seeing it in the past. even something right in front of you -- your own reflection in a mirror. the farther something is away from you, the farther back in time you are looking. with a telescope you could take a picture of something RIGHT NOW that is thousands of light years away. however, as soon as you took the picture, what you took a picture of is how it was thousands of years ago. you could take pictures of things that don't EXIST anymore. YOU COULD EVEN LOOK AT SOMETHING THAT HASN'T EXISTED SINCE BEFORE YOU WERE BORN! pretty amazing....
I don't profess the ability to assess the merits of particular NASA studies, initiatives, and programs, and I suspect that "space elevator" projects will remain beyond our technical capabilities for a long time to come, but it may be worth remembering that the concept that was eventually adopted for the voyage to the Moon was initially dismissed as completely impractical, and was deepsixed until other supposedly more likely alternatives were found to be hopeless. Somewhat less visionary, though still ambitious concepts - "sky hook," "space tether," and so on - may turn out to be first steps toward an eventual "space elevator" or to some currently unenvisioned or forgotten alternative to putting a few tiny organisms on top of an immense explosion, then sending them through an inferno while dropping them back to the ground.
Yeah, I was using magnets more for description than anything else. However I still believe that something such as gravity can be turned against itself... how, I don't know. Was it Newton who said for every action there is an equally opposite reaction? Hard to tell, being as I barely made it through high school. I did get strate A's in speling thoe.
You may like to visit the following web page:
The title is:
Repulsive Gravity & the Cosmological Constant
Thanks for the link. Kremminy, I never thought someone actually broke it down to a working theory. It's just something (repulsion) that's been in my head since I was a kid. Very interesting, guess I'll start surfing the web for more of the same.
From the link:
now, suppose you have a piston full of "false vacuum" matter
you don't need to squeeze it because the negative pressure will cause it to squeeze itself
the "false vacuum" can produce energy - it will pull you with the piston if you are holding on
the "false vacuum's" mass energy is proportional to its volume (i.e. through E=mc2)
it is 100% efficient at convering mass to energy (compared to < 1% for nuclear reactions)
Why is it called false vacuum?
vacuum means essentially nothing
a false vacuum is like a vacuum (i.e. no oridinary matter or radiation)
but, it has this extra energy density
if space was filled with a false vacuum we couldn't easily tell
energy only comes out if we convert the false vacuum to something else
There are so many problems with the so-called space elevator - the sheer technical absurdity of stringing a cable from ground to synch orbit, inadequate tensile strength of any substance (including the carbon nanotubes mentioned in the report - which can neither be constructed in sufficient quantity nor for any reasonable cost), the significant problem of electrical potential differential, connecting the ionosphere to ground, etc. - then you still have to employ a very large mass mover mechanism (and sufficient mass to make the whole endeavor worthwhile) to move large mass from ground to orbit.
Since sci-fi gadgets like electrogravitational propulsion, hyperdimensional transport, and negative spatial warps aren't likely to pop out of a lab any time soon, the most sensible approach seems to me to be three-fold:
1. Reinvigorate the conventional rocket launching vehicles for cargo like satellites and other bulk material and supplies. The cost per ton vs. any technology foreseeable in the next few decades is much better. This would serve as the primary bulk lifter for sending devices and bulk material into orbit.
2. Build a multi-propulsive lifting body that can be flown using conventional air breathing engines to an altitude where ramjets can be kicked in to push the vehicle basically into a sub-orbital or just extra-atmospheric orbital path and complete the final orbital injection using high efficiency rocket engines. The vehicle could also be flown back under its own power rather than being a man-made meteor. The payload to vehicle profile should be better than the shuttle, be cheaper to build and operate, have dual operating capability as a high speed global transport in necessary, and be in the reach of existing technologic and engineering capabilities.
3. Extra-atmospheric transits (moon, Mars, etc.) should then use a third space-only vehicle optimized for that and not having to deal with first getting off the ground.
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