Gravity Creation Idea (don't assume troll)

"Matthew Hagston" wrote:

:There's an idea that's been going through my head dealing with creating
:artificial gravity, before you think troll just stay with me here. It deals
:with two of Einstein's papers; the first stating as an object speed
:accelerates closer towards the speed of light, it's mass increases, the
:second states mass is directly related to gravity. So Take an object like a
:large super-conductive disk, inside a vacuum to reduce friction, and spin
:it. If you can make it spin fast enough (up towards the speed of light) you
:should be able to create gravity with out having the real mass required.
:Creating a sort of virtual mass so to speak.
:
:I realize there must be something wrong with my logic because this seems
:like such a simple solution, so I invite some criticism here.

What holds it up?

"Matthew Hagston" wrote in message
nk.net...
There's an idea that's been going through my head dealing with creating
artificial gravity, before you think troll just stay with me here. It
deals
with two of Einstein's papers; the first stating as an object speed
accelerates closer towards the speed of light, it's mass increases, the
second states mass is directly related to gravity. So Take an object like
a
large super-conductive disk, inside a vacuum to reduce friction, and spin
it. If you can make it spin fast enough (up towards the speed of light)
you
should be able to create gravity with out having the real mass required.
Creating a sort of virtual mass so to speak.

I realize there must be something wrong with my logic because this seems
like such a simple solution, so I invite some criticism here.

As others have pointed out, the chemical bounds of the molecules are
overcome well before you get to this point.


But also, my understanding is that what one could more properly call the
"apparant" mass of the system increase. But outside the system you haven't
changed the total amount of mass and so there's no gravitional change
outside the system.



--
Matthew Hagston
Hungates Creative Toys and Hobbies
........ http://www.hungates.com

Henry Spencer wrote:
Remember, the whole point of the question that started this particular
thread is (essentially) that "mass" and "matter" are not the same thing.
Energy too has mass, and the mass of the hypothetical disk with the
relativistic spin is dominated by its energy content, not its matter
content. That is, its density at rest is basically irrelevant.

What *is* relevant, alas, is the impossibly high structural strength it
requires. With the strongest materials we've got, flywheel energy storage
struggles to be competitive with batteries. This falls many orders of
magnitude short of what's needed to store significant *masses* of energy.
There is room for improvement in the materials, notably with the nanotube
composites that many people are trying to make, but that's about one order
of magnitude, which is nowhere near enough.

Plus, as others have pointed out, transporting such vast amounts of energy
is much harder than transporting equivalent amounts of matter. The entire
energy output of the Sun is only about four million tons per second.

Quite so. I have tried to be careful not to address the
flywheel issue too seriously as it really isn't serious
in any meaningful sense. Those orders of magnitude are
something like *eleven* orders of magnitude. Which, as
you know, is no small thing.

OK, so let's get more serious (which is really more of a
testament to the improbability of the subject at hand
than anything else) and talk about how much matter you
would need if you had very high density material
available, such as neutronium. So, assuming a density
of 3e14 g/cm^3 and a desired gravity of 9.8 m/s^2, I
come up with the rather nonsensical figure for an
uncompressed sphere of about 240 nanometers in diameter
with a mass of 2 grams. This would work well if humans
were significantly smaller than 240 nanometers.
Obviously, this result means that neutronium is more
than dense enough for these purposes, though the basic
scaling needs might cause problems regardless of the
density of matter available. For example, if we
assume a setup with a very dense mass at a distance of
several tens of meters (to avoid serious tidal
problems), we end up with a mass of trillions of kg,
similar to your previous estimate. Which is probably
still too much to be practical. Rotation is still
definitely the prefered method of manufacturing
gravity like effects.

In article ,
Greg D. Moore \(Strider\) wrote:
But also, my understanding is that what one could more properly call the
"apparant" mass of the system increase. But outside the system you haven't
changed the total amount of mass and so there's no gravitional change
outside the system.

No, there's nothing "apparent" about it. Energy has mass. Real mass,
just as real as the mass of matter, although a bit more thinly spread. :-)
Store a very large amount of energy in a system, and its mass -- both
inertial and gravitational -- increases detectably.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Larger wheel in space, with superconducting wires wrapped around it.
Normally the speed of propagation of electricity is only a significant
fraction of the speed of light.

But if the disk could be spun fast enough, you might be able to get the
electricity cramming the speed limit, possibly "generating" a gravity
field.

Just some old musing I had a year or two ago.

Wish I had the math and physics to really figure it out.

In article et,
Matthew Hagston wrote:
There's an idea that's been going through my head dealing with creating
artificial gravity, before you think troll just stay with me here.

Both of the models of relativity offered by Einstein, special and
general relativity, are self-consistent and have conservation laws.
If you can create gravity within the realm of Einsten's theories -- and
there are ways to do it -- then there is nothing "artificial" about it.
The tone of your question sounds like you want a way to somehow cheat
mathematical theorems about Einstein's laws using Einsten's laws.
Creating "artificial" gravity in this way would be like creating gold
just by buying and selling it.

It deals with two of Einstein's papers; the first stating as an object
speed accelerates closer towards the speed of light, it's mass increases,
the second states mass is directly related to gravity. So Take an object
like a large super-conductive disk, inside a vacuum to reduce friction,
and spin it. If you can make it spin fast enough ...

It is true that a disk spinning at a relativitistic velocity is heavier
than one that is not spinning. But there are two problems with your
description: First, in relativity all energy has mass. However you
obtained the energy to spin up the disk, it would weigh just as much
as the extra weight of the disk. In relativity, mass is conserved,
so the mass has to come from somewhere.

Second, relativistic velocities and energies are extreme. For example,
if a 4-gram bullet travelling fast enough to exactly double its mass
(i.e. sqrt(3)/2 = 86% of the speed of light) crashed into the ground
from space, it would make a 90-kiloton explosion, like an atomic bomb.
The forces involved in relativistic rotation go way, way beyond what
is possible with ordinary chemistry. There are observed objects in the
universe that have some extra mass because they spin, but they are neutron
stars, not titanium disks. For example, the neutron star IGR J00291+5934
rotates at 600 hertz, and people estimate its surface velocity at 10%
of the speed of light:

http://www.universetoday.com/am/publ...ng_pulsar.html

If this estimate is correct, then the equator of the neutron star is
2% heavier because it spins; the neutron star as a whole could be 0.2%
heavier or so for the same reason. (This depends on how the star's mass
is distributed.)

--
/\ Greg Kuperberg (UC Davis)
/ \ Home page: http://www.math.ucdavis.edu/~greg/
\ / Visit the Math ArXiv Front at http://front.math.ucdavis.edu/
\/ * All the math that's fit to e-print *

In article ,
Greg D. Moore \(Strider\) wrote:
But also, my understanding is that what one could more properly call the
"apparant" mass of the system increase. But outside the system you haven't
changed the total amount of mass and so there's no gravitional change
outside the system.

The correct statement is that the functional mass of an object depends
on your reference frame. As Henry Spencers says, it is not in any
sense an illusion. It is a lot like considering whether the "height"
of a 100-foot rod is 100 feet or 80 feet if the rod is 37 degrees from
vertical. The rod has an intristic length of 100 feet, but that is only
its functional height when it is exactly vertical.

Likewise the instrinsic mass of an object - its rest mass - is what its
mass would be if it were stationary. Its functional mass when it moves
is more. If it moves in a straight line, that is like a tilted rod.
It is a little more complicated for a rotating disk, which is more like
a rod which is shortened by coiling. In any case a rotating disk is
heavier than a stationary one.

--
/\ Greg Kuperberg (UC Davis)
/ \ Home page: http://www.math.ucdavis.edu/~greg/
\ / Visit the Math ArXiv Front at http://front.math.ucdavis.edu/
\/ * All the math that's fit to e-print *

Matthew Hagston wrote:
There's an idea that's been going through my head dealing with creating
artificial gravity, before you think troll just stay with me here. It deals
with two of Einstein's papers; the first stating as an object speed
accelerates closer towards the speed of light, it's mass increases, the
second states mass is directly related to gravity. So Take an object like a
large super-conductive disk, inside a vacuum to reduce friction, and spin
it. If you can make it spin fast enough (up towards the speed of light) you
should be able to create gravity with out having the real mass required.
Creating a sort of virtual mass so to speak.

I realize there must be something wrong with my logic because this seems
like such a simple solution, so I invite some criticism here.

Remember that as you approach the speed of light, it takes
nearly-infinite energy to get to up there. Same with your spinning
object. So much energy crammed into a spinning material object will
simply tear it apart as its speed gets to a point where it cannot stay
together. Even molecular bonds will fail given the speeds and forces
required.

--
Cheers,
Bama Brian
Libertarian

Henry Spencer wrote:



No, there's nothing "apparent" about it. Energy has
mass. Real mass, just as real as the mass of matter,
although a bit more thinly spread. :-)

Store a very large amount of energy in a system, and
its mass -- both inertial and gravitational -- increases
detectably.

Clinton
It all dependes on what "apparent" is.
/Clinton

The source of gravity in GTR is the stress-energy-momentum
tensor, which can be sliced and diced in various ways. What
you ultimately get is gravity, and if you think of it as
originating purely in mass, well, that's one way to think of
it. OTOH, you can equally well think of it as originating purely
in energy. It all depends on the 3D+T angle from which you view
it.

Massenergy distorts spacetime in tensor form we have the EINSTEIN
TENSOR (see page 40 and 41 in Misner Thorne and Wheeler's GRAVITATION;

Einstein = G_ = 8 * pi * T_

where the _ denotes a boldface type, which denotes a tensor.

Tensors are lists of vectors. Vectors are lists of numbers. So,
tensors are also tables of numbers.

The Einstein tensor is a geometric object that generates a table of
numbers known as a Riemann tensor (R00) that describes precisely how
space distorts in four dimensions in the presence of massenergy.
Massenergy in the equation is represented by T_ which is the
stress-energy tensor. Being tensors they don't need coordinates to
describe them, and they're always equal (given the factor 8pi between
them)

So, you are correct - mass and energy both can distort spacetime to
create a gravity field.

The big question is so what?

Energy and mass are the same, related by the constant - c^2 - the speed
of light squared.

In a practical sense this means that you need lots and lots of energy
to equate to trifiling amounts of mass. Also, when spinning something
at high rates of speeds, you accelerate them. Accelerating a mass
generates gravity waves, just as accelerating charges generates
electromagnetic waves. So, the energy you put into to your disk will
constantly need to be replenished as the energy of the gravity waves is
radiated away into space.

What are you trying to achieve here? Strong gravity fields. There's an
easy way to achieve that. Make black holes.

How do you do that? Pile matter together in sufficient quantities. How
much is needed for a black hole? Well, if you start with normal matter
you have many things to consider.

The first is the nature of matter. Things like hydrogen when they get
piled on top of each other heat up and convert to helium and release
energy - the fusion process. This process powers the stars ahd hydrogen
bombs. Things like uranium when put together in big quantites absorb
each other's neutrons and start a process called fission. This process
powers the core of the Earth, nuclear reactors, and atomic bombs.

In fact, all matter heavier than an isotope of Iron called Iron 56, has
a tendency to fission under high pressures. All matter lighter than
this isotope of iron hasa tendency to fusion when pressurized.

But, when you have a ball of Iron 56 - no energy is released when it is
pressed together. So, by this consideration this is the material of
choice if you are engineering the creation of a black hole.

So, now that we've addressed the issue of what material to make our
black holes out of, we now address how the material compresses when
piled together. For this you need an equation of state for matter.
This is given by the Harrison Wheeler equation of state for cold matter
first developed in 1958;
rho + p dp
gamma = --------- -------
p drho

Where rho is density and p is pressure.

For densities below nuclear densities - this is rho 3e13 g/cc things
are pretty clear. At densities above this, things get interesting
because of nuclear interactions.

At zero pressure a ball of pure cold Iron 56 has a density of 7.86
g/cc. As the sample is compressed normal solid-state forces provide
internal pressure. But the electrons don't feel the nuclei as much as
they are compressed out of their shells. So, at about 1e5 g/cc valence
forces are completely negligible. So, gamma drops from 3 to about 5/3
with most of the pressure coming from electrons acting as a Fermi gas -
with the electrons moving at non-relativistic speeds.

Compressing the sphere even more increases the speed of the electrons
and the Fermi gas becomes relativistic. So, gamma approaches 4/3.

Above rho=1.4e7 g/cc the rest of the iron nuclei with their
relativistic electrons is greater than the rest mass of Nickel nuclei
with fewer electrons. So, even with Iron 56, when you compress things
above 1.4e7 g/cc, a nuclear reaction takes place one that converts Iron
56 to Nickel 62

As compression continues the electrons move with greater and greater
energy. These energetic electrons cause new nuclear reactions.
Everything becomes neutron rich. This changes the material structure
again. At 3e11 g/cc the nuclei have so many neutrons that they start
dripping neutrons off of them.

At this point matter becomes highly compressible until about 4e11 g/cc
is reached. At that point there are so many neutrons that the pressure
between them is bigger than the pressure exerted by the electrons.
This raises gamma.

Compression beyond 1e13 g/cc disintegrates the remaining nuclei and the
sample becomes almost a pure fermi gas consisting of neutrons. Here
gamma rises to 5/3.

So, we can see that the motion of things at the atomic level can be
affected by very strong compressions.

The simplest way to create black holes is to pile matter up to about
the mass of the sun and let it collapse. This results in big black
holes and is not particularly easy.

Another way to create blackholes is to collide shaped matter into one
another and focus the resulting shock waves centrally. Here
compression energy is provided by the kinetic energy of the colliding
parts relative to one another. Basically if you collide matter together
at 1/3 the speed of light or more, you can compress matter to black
hole densities with sufficiently accurate compression waves.

Colliding stuff together can obtain miniature black holes. Collections
of black holes can be charged up and accelerated by electromagnetic
fields to generate gravity waves and other cool stuff.

Eric Chomko wrote:
Matthew Hagston ) wrote:
: There's an idea that's been going through my head dealing with
creating
: artificial gravity, before you think troll just stay with me here.
It deals
: with two of Einstein's papers; the first stating as an object speed
: accelerates closer towards the speed of light, it's mass increases,
the
: second states mass is directly related to gravity. So Take an
object like a
: large super-conductive disk, inside a vacuum to reduce friction,
and spin
: it. If you can make it spin fast enough (up towards the speed of
light) you
: should be able to create gravity with out having the real mass
required.
: Creating a sort of virtual mass so to speak.

: I realize there must be something wrong with my logic because this
seems
: like such a simple solution, so I invite some criticism here.

I'm no physicist, but don't molecules have trouble staying together
in
cyclotron-like environments? IOW, everything to date that we can
manage
accelerate is of a sub-molecular level. What good is creating gravity
for
elements with no way of retaining any molecular form?

And your object, the super-conductive disk; where can I buy one?

Eric

: --
: Matthew Hagston
: Hungates Creative Toys and Hobbies
: ........ http://www.hungates.com