Ask any question you want about Physics

originally posted by: mbkennel
a reply to: dragonridr

Defying gravity means altering inertia and geodesics of light travel, not floating.

Real warp drive should look weird from the outside---local strong gravitational lensing.

There is no such thing as defying gravity. Either its there or its not. I'll save you time it is very unlikely man will ever build a warp drive. It is much more likely we will build star gates from one location to another. There is huge problems with trying to build a drive to warp space. One we would need a supply of negative energy. We haven't even a clue how you would get that. Then think about this we have a ship that weighs say 100 tons. but we need a ship that can generate a mass several times its own magnitude, but remember objects such as the earth and the sun warps space with very little results.To get the desired results there is a very good likely hood we would create a black hole.

Id say we have much better odds inventing star gates. As a civilization spreads out they build a gate than another and so on.

a reply to: dragonridr
I think even the NASA scientist researching warp drive will admit there's reason for skepticism about whether it will ever work. But our ignorance about dark energy is a double edged sword, meaning you have a point that we don't know how to manipulate negative energy, but our ignorance also means that we don't know enough to say it can't be done. Until we can model somehow the observed value of dark energy to come up with an explanation of the observed value, I'm going to have to say we don't know enough about it.

I'm not surprised by most of your comments, but since you say a warp drive might create a black hole but you don't mention anything about that for the stargate, that infers you think it's more likely to happen with the warp drive.

If you're only creating a warp bubble slightly larger than a spaceship on one hand, and trying to create a 6 light years long worm hole on the other hand with the stargate, isn't it the stargate that's more likely to result in a black hole? A 6 light years long wormhole is about half a trillion times longer than a warp bubble a little under 100 meters.

originally posted by: BASSPLYR
can you explain in more detail the altering geodesic light travel part? sounds intersting.

Dr. White covers that in his "Warp Field Mechanics 101" paper on page 28, though it may not be self-explanatory to a non-physicist. But parts of the rest of the paper might be understood without a background in physics, for example, I'd suggest looking at figure 1 to see the geometries of the warp bubble he considered, with the rightmost geometry sacrificing usable volume inside the warp bubble, for the benefit of reducing the energy density required, to address concerns like dragonridr's that the energy densities required might be too great.

Warp Field Mechanics 101

Still, the concept of manipulating negative energy is discussed in the paper as if we might figure out how to do that, when dragonridr is correct that we have absolutely no idea how to do that. So, it's highly speculative, and Dr. White's rebuttal "yes, but dark energy" is only correct regarding the existence of dark energy. There's no evidence we can manipulate it; we don't even understand it. But, he's trying to collect evidence with his research, so that's a good thing.

originally posted by: Arbitrageur
a reply to: dragonridr
I think even the NASA scientist researching warp drive will admit there's reason for skepticism about whether it will ever work. But our ignorance about dark energy is a double edged sword, meaning you have a point that we don't know how to manipulate negative energy, but our ignorance also means that we don't know enough to say it can't be done. Until we can model somehow the observed value of dark energy to come up with an explanation of the observed value, I'm going to have to say we don't know enough about it.

I'm not surprised by most of your comments, but since you say a warp drive might create a black hole but you don't mention anything about that for the stargate, that infers you think it's more likely to happen with the warp drive.

If you're only creating a warp bubble slightly larger than a spaceship on one hand, and trying to create a 6 light years long worm hole on the other hand with the stargate, isn't it the stargate that's more likely to result in a black hole? A 6 light years long wormhole is about half a trillion times longer than a warp bubble a little under 100 meters.

originally posted by: BASSPLYR
can you explain in more detail the altering geodesic light travel part? sounds intersting.

Dr. White covers that in his "Warp Field Mechanics 101" paper on page 28, though it may not be self-explanatory to a non-physicist. But parts of the rest of the paper might be understood without a background in physics, for example, I'd suggest looking at figure 1 to see the geometries of the warp bubble he considered, with the rightmost geometry sacrificing usable volume inside the warp bubble, for the benefit of reducing the energy density required, to address concerns like dragonridr's that the energy densities required might be too great.

Warp Field Mechanics 101

Still, the concept of manipulating negative energy is discussed in the paper as if we might figure out how to do that, when dragonridr is correct that we have absolutely no idea how to do that. So, it's highly speculative, and Dr. White's rebuttal "yes, but dark energy" is only correct regarding the existence of dark energy. There's no evidence we can manipulate it; we don't even understand it. But, he's trying to collect evidence with his research, so that's a good thing.

My main concern is energy densities required to shrink space in front of the craft. I'd say yes throw momentum in and you have enough energy to create a black hole in your path.

As far as a 6 light year work hole you confused me the worm hold doesn't actually stretch to your location it avoided all the space between. It connects to points directly to each other this isn't like the movies no tunnel you would step through and be there. We may find no matter the distance the worm holes will always be the same. But the biggest reason is with those all we need is energy granted a huge amount but exotic matter isn't required. But both possibilities are so far out right now who knows what will find in the next thousand years.

I see you guys still devising warp drive. Cool. But I think 'warp' is huge scientific misconception that came out of loose math.

to counter gravity of Earth to lift a vessel one needs to create an immediate gravity 'cone' for it to fall into, imo


D0.

a reply to: darkorange

Never heard the carrot analogy using a sheep before. Nice.

a reply to: darkorange

As to the gravity cone, it is exceeding unlikely that a ship attempting to create a warp field would do so on earth. And in all likelihood, it would be well past the immediate gravity well of the planet, and would probably be assembled in space.

a reply to: pfishy

Honestly, it seems unlikely that even any test that develops an actual field to propel anything would be conducted on earth. The potential for disaster would be astronomical

if the Sun is like a big nuclear reactor where does the magnetism come from and why are sunspots black and not bright?

a reply to: Arbitrageur

a reply to: bottleslingguy

The Sun[a] is the star at the center of the Solar System and is by far the most important source of energy for life on Earth. It is a nearly perfect spherical ball of hot plasma,[12][13] with internal convective motion that generates a magnetic field via a dynamo process.[14] Its diameter is about 109 times that of Earth, and it has a mass about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System.[15] Chemically, about three quarters of the Sun's mass consists of hydrogen; the rest is mostly helium, with much smaller quantities of heavier elements, including oxygen, carbon, neon and iron.[16]

en.wikipedia.org...

Magnetism is the key to understanding the Sun. Magnetic fields are produced in the Sun by the flow of electrically charged ions and electrons. Sunspots are places where very intense magnetic lines of force break through the Sun's surface. The sunspot cycle results from the recycling of magnetic fields by the flow of material in the interior. The prominences seen floating above the surface of the Sun are supported, and threaded through, with magnetic fields. The streamers and loops seen in the corona are shaped by magnetic fields. Magnetic fields are at the root of virtually all of the features we see on and above the Sun. Without magnetic fields the Sun would be a rather boring star.

solarscience.msfc.nasa.gov...

Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They correspond to concentrations of magnetic field that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere. Sunspots usually appear as pairs, with each spot having the opposite magnetic polarity of the other.[2]

Although they are at temperatures of roughly 3,000–4,500 K (2,700–4,200 °C), the contrast with the surrounding material at about 5,780 K (5,500 °C) leaves them clearly visible as dark spots. This is because the luminance (which is essentially "brightness" in visible light) of a heated black body (closely approximated by the photosphere) at these temperatures varies extremely with temperature - considerably more so than the (temperature to the fourth power) variation in the total black-body radiation at all wavelengths (see Stefan–Boltzmann law). If the sunspot were isolated from the surrounding photosphere it would be brighter than the Moon.[3] Sunspots expand and contract as they move across the surface of the Sun and can be as small as 16 kilometers (10 mi)[4] and as large as 160,000 kilometers (100,000 mi)[5] in diameter, making the larger ones visible from Earth without the aid of a telescope.[6] They may also travel at relative speeds ("proper motions") of a few hundred meters per second when they first emerge onto the solar photosphere.

Manifesting intense magnetic activity, sunspots host secondary phenomena such as coronal loops (prominences) and reconnection events. Most solar flares and coronal mass ejections originate in magnetically active regions around visible sunspot groupings. Similar phenomena indirectly observed on stars other than the sun are commonly called starspots and both light and dark spots have been measured.[7]

en.wikipedia.org...

a reply to: bottleslingguy

Sunspots are caused by perturbation in the magnetic field. And actually, if you were looking at just a sunspot, somehow isolated from the sun, it would be fairly bright. But because it is a good deal cooler than the surrounding material it appears darker. The localized disruption in the magnetic field partially impedes the flow of energy to the surface where the sunspot is located.

originally posted by: pfishy
a reply to: darkorange

As to the gravity cone, it is exceeding unlikely that a ship attempting to create a warp field would do so on earth. And in all likelihood, it would be well past the immediate gravity well of the planet, and would probably be assembled in space.

what's the purpose of anti gravity concept then if you are away from gravity source around you to begin with?

thanks


D0.

a reply to: darkorange

Which particular concept are you referring to. Warp drive isn't necessarily an anti gravity tech.

GR in particular. Why?



D0.

according to it, mass causes space-time distorted to a degree. I meant to say if to move a vessel off the ground you would need to counter Earth overall gravity rate by creating even greater rate gravity 'well' immediately in front of the vessel. Meaning the vessel should fall into locally more abrupt gravity well that would go in front of it to create propulsion, no?)))


D0.

a reply to: darkorange

Buy nobody is saying that the technology is intended to lift the craft from a stationary position on the surface of the planet. We already have the capability to move objects into space, and will likely have far better methods by the time the warp field theory can even be tested in a practical manner.

originally posted by: bottleslingguy
if the Sun is like a big nuclear reactor where does the magnetism come from and why are sunspots black and not bright?

a reply to: Arbitrageur

Well the sun really isn't a nuclear reactor that is a fision process. The sun because of plasma densities actually performs fusion.Every second, 600 million tons of hydrogen is being converted into helium. This fusion we call a proton proton chain here's a very basic description.

1.Two pairs of protons fuse, forming two deuterons

2. Each deuteron fuses with an additional proton to form helium-3

3. Two helium-3 nuclei fuse to create beryllium-6, but this is unstable and disintegrates into two protons and a helium-4

4. The reaction also releases two neutrinos, two positrons and gamma rays.

This final step gives us most of its energy and heat. And interestingly the reason we know fusion is occurring is because of the neutrinos. Figured id throw this in there since I've seen people argue fusion isn't occuring.

Interesting side note because we don't have the mass of the sun to create a fusion reaction on earth we need temperatures of 100 million Kelvin, over 6 times the suns core temp.we can create temperatures of a couple billion degrees but sustaining them is very difficult. Now sun spots as far as why there dark simple the area around them is brighter. It's like having a Chem light in front of spot light. The Chem light will look like it's not creating any light.

originally posted by: pfishy
a reply to: darkorange

Buy nobody is saying that the technology is intended to lift the craft from a stationary position on the surface of the planet. We already have the capability to move objects into space, and will likely have far better methods by the time the warp field theory can even be tested in a practical manner.

yes, I understand the difference. 'Warp', imo, essentially this, a gravity well conduit in front of the ship), no?


D0.

a reply to: darkorange

No. Not really. It is the compression and expansion of spacetime.

a reply to: pfishy

Gravity alone could not accelerate an object beyond the speed of light. It propogates at the speed of light.

originally posted by: pfishy
a reply to: darkorange

No. Not really. It is the compression and expansion of spacetime.

yep.

But how do you contract a space-time?


D0.