The more we discover what is possible with carbon, the less impossible becomes that Space elevator. We want that in order to haul tonnage into space as we haul tonnage on the Ocean and rail. It obviously matters even if we produce a Magnetic Field Exclusion Vessel or perhaps even if we develop gravity control. Both may simply be too sensitive to mass variation.
A robust cable system sidesteps all that.
What is true today is that we can do it all on the back of an envelope with these new products. We could not when Artur C. Clark wrote about it. Right now i think that it sets us nasty technical problems that still can be solved. It is really going to happen.
Scientists Might Have Accidentally Solved The Hardest Part Of Building Space Elevators
By Ajai Raj | Business Insider – Mon, 13 Oct, 2014 11:50 AM EDT
https://ca.finance.yahoo.com/news/scientists-might-accidentally-solved-hardest-155000475.html
Vincent Crespi Lab/Penn State University Diamond nanothreads are only a
few atoms across, more than 20,000 times thinner than a human hair.
They're also stronger and stiffer than any carbon nanotube or polymer to
date, which could make them an ideal option for a space elevator
tether.
A space elevator is
essentially a cable anchored to the Earth's equator and attached to a
counterweight somewhere way above Earth's atmosphere — much higher than
satellites in orbit. Having one would allow us to send cargo into space
for a fraction of the cost of using rockets
and allow us to harvest vast amounts of solar energy by placing solar
collectors well above the Earth's atmosphere, where the sun never stops
shining.
Finding a material strong enough to serve as a tether is one of the most daunting technical challenges standing in the way.
Earlier this year, however, researchers may have accidentally
discovered the best candidate yet for building a space elevator. A set
of diamond nanothreads created under immense pressures in a lab might
rival or exceed the strength of carbon nanotubes , which are 100 times stronger than steel.
A little bit of luck
J ohn Badding of Penn State University and his team discovered that
liquid benzene, when subjected to extreme pressure (around 200,000 times
the pressure at the surface of the Earth) and then slowly relieved of
that pressure, forms extremely thin, tight rings of carbon that are
structurally identical to diamonds.
In other words, if you could unravel a diamond like you can a piece
of fabric, you'd get these far-out threads. The result is a chain,
thousands of times thinner than a human hair, that has the potential to
be the strongest, stiffest material ever discovered.
The discovery was something of an accident, but far from a hapless
one. The team used a large, high-pressure device called the
Paris-Edinburgh device at Tennessee's Oak Ridge National Laboratory to
compress a 6-millimeter wide quantity of liquid benzene — a huge amount
compared with previous experiments. The volume of liquid benzene,
coupled with the size of the device, forced them to relieve the pressure
more slowly than they would have otherwise.
"It's been known for a long time that if you put benzene under
pressure, it’d make a type of polymer," Badding told Business
Insider. "An Italian team did a similar experiment and found it was
amorphous, disordered, with no pattern to the way material’s held
together, kind of like glass. We were trying to make the same material
everyone else had made, but in larger quantities."
When they released the pressure, "something interesting happened:
the material became ordered," Badding said. The carbon atoms in the
liquid benzene arranged themselves so that each was linked with four
others, in what's called a tetrahedral structure. Structurally, the
threads formed by the liquid benzene are identical to diamond, with each
carbon atom linked with four others. You can see what they look like
below.
It was the breakthrough that Badding had been seeking for 20 years.
"Luck favors the prepared mind," Badding said. "I’d love to be able
to say I predicted this was going to happen for benzene. I don’t think I
can say that. But in a way our studies in benzene were a step in this
larger goal, and we just happened to find that faster than we thought we
would."
Now that Badding and his colleagues have shown that this structure is
possible, the next step is to confirm the precise structure of the
material and look for any imperfections that might exist.
" Theory suggests that if you can make the structures perfect, they
could be as strong or stronger than carbon nanotubes, but we have not
confirmed that experimentally," Badding said.
Going up
Towards the end of his life, science fiction writer Sir
Arthur C. Clarke predicted that a space elevator would be built ten
years after everybody stopped laughing. By the time he died, in 2008,
everybody had.
But it's still too early to say whether these diamond nanothreads
will be up to the task of being strung up in space. Ted Semon, Director
of the International Space Elevator Consortium,
points out that, as with carbon nanotubes, the real challenge will be
scaling the nanothreads to the necessary length — about 60,000 miles.
The longest carbon nanotubes to date are only a few centimeters long.
"In any event, options are good things," Semon noted.
While some observers are doubtful
that a space elevator will ever happen, others, like Clarke, are
confident that it's only a matter of time. Obayashi, a construction
company based in Tokyo, has said that it wants to build one by 2050.
If it comes to fruition, everyone will have stopped laughing for a long time.
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