Slashdot Mirror
Diamond Nanothreads Could Support Space Elevator (space.com)
Taco Cowboy writes with news that Penn State researchers have discovered a way to produce ultra-thin diamond nanothreads that could be ideal for a space elevator. According to the report at Space.com, The team, led by chemistry professor John Badding, applied alternating cycles of pressure to isolated, liquid-state benzene molecules and were amazed to find that rings of carbon atoms assembled into neat and orderly chains. While they were expecting the benzene molecules to react in a disorganized way, they instead created a neat thread 20,000 times smaller than a strand of human hair but perhaps the strongest material ever made. ... Just recently, a team from the Queensland University of Technology in Australia modeled the diamond nanothreads using large-scale molecular dynamics simulations and concluded that the material is far more versatile than previously thought and has great promise for aerospace properties.
How exactly does a space elevator "save" energy for lifting loads to orbit?
The same way using a ladder saves energy over using a jetpack.
systemd is Roko's Basilisk.
The person you heard that from was wrong.
In a rocket,:
- Rockets are quite inefficient, about 16% energy efficient to reach orbit.
- You have to lift your propellant, only to throw it all away
- The rocket not only has to do work against gravitational potential, it also has to provide lateral kinetic energy to reach orbit. The kinetic energy component is huge.
For a space elevator:
- The lifting motors are highly efficient, you just have to keep the power beaming losses reasonable.
- You only have to work against gravitational potential. The tether/earth provides the lateral kinetic energy.
The moon's rotation is tidally locked to the earth (1 rotation/month makes it hard to stay in lunar orbit unless you are really far off & anything orbiting the moon that far off would be gravitationally perturbed by the earth) makes a classical beanstalk impossible. Other solutions like a rotating skyhook are theoretically possible but the mass concentrations make even that iffy.
Posted as anon to conserve mod points.
Unfortunately, for a space elevator, much more important than gravity is the spin speed of the celestial body it's attached to.
It needs to reach beyond the geostationary orbit of that body - meaning orbit of period equal to rotation period of its base body. That way it remains stretched.
Moon, with one spin per month, has no geostationary orbit at all (it's located beyond its Hall Sphere, meaning the Moon's gravity there is too weak to create orbital motion). So - no lunar space elevator, not due to technological limitations but because laws of physics say "no".
Yes, that's why we don't have steel, because it "isn't in the periodic table"; that's why we've discovered all manner of interesting properties in materials that aren't "in the periodic table" but are derived from combinations of the elements, various crystalline and other molecular arrangements of those structures, both those found in nature and those that have arrived courtesy of, you know, science.
The science takeaway -- as opposed to your "man can never fly" mode of reasoning -- is that this is a materials issue, and not one that carries any impossibilities, either.
Here are some quotes for you to contemplate:
"As far as sinking a ship with a bomb is concerned, you just can't do it."
-- Rear Admiral Clark Woodward, 1939
"The energy produced by the breaking down of the atom is a very poor kind of thing. Anyone who expects a source of power from the transformations of these atoms is talking moonshine."
-- Ernest Rutherford, 1930
"There is not the slightest indication that nuclear energy will be obtainable."
-- Albert Einstein, 1932
"Our inventions are wont to be pretty toys which distract our attention from serious things. We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate."
-- Henry David Thoreau
"I must confess that my imagination, in spite even of spurring, refuses to see any sort of submarine doing anything but suffocating its crew and foundering at sea."
-- H. G. Wells, 1901
"What can be more palpably absurd than the prospect held out of locomotives travelling twice the speed of stagecoaches?"
-- Quarterly Review, 1825
"Rail travel at high speed is not possible because passengers, unable to breathe, would die of asphyxia." ...you are a proud member of a very famous group of fools. :)
-- Dr. Dionysus Lardner, 1793-1859