World, Writing, Wealth discussion

I'm no scientist, but some of you are. I'm wondering if it's possible to develop an anti-gravity mechanism whereby an object can hover above the earth.

Newton says that for every action there is an opposite and equal reaction.

So, if there is gravity, then there must therefore exist such a force as anti-gravity, whether we can prove it with our feeble minds or not.

I suspect we are not yet in the last paradigm of physics. What the next paradigm has to say about gravity remains to be seen.

Well, there are futurists who believe that perfections in nanotechnology, pictotechnology and femotechnology will allow for the manipulation of matter at the subatomic level. And given that this would definitely parallel growths in our understanding of how all the forces of nature behave (including gravity) it is likely we will be able to simulate gravity.

Graeme wrote: "I suspect we are not yet in the last paradigm of physics. What the next paradigm has to say about gravity remains to be seen."

True. Michio Kaku in his book Parallel Worlds: A Journey Through Creation, Higher Dimensions, and the Future of the Cosmos describes a very speculative type of exotic matter, "negative matter"

... negative matter falls up, so it will float upward in Earth's gravity because it possesses antigravity. It is repelled, not attracted, by ordinary matter, and by other negative matter. This means that it is also quite difficult to find in nature, if it exists at all."

When I see a spacecraft in movies, I imagine that it's able to hover because of anti-gravity. Of course, I know this is in movies, not reality. Could there be another explanation for this ability to hover and move vertically and horizontally?

Yep - engines. :-).

For the record, we are way beyond Newtonian physics when it comes to anti-gravity. At this point, we're into straight up quantum physics and uncertainty principles!

My guess is no. Hovering, of course, is possible, e.g. a helicopter, but there is no evidence whatsoever for antigravity. The problem is, gravity is monopolar. Thus electric charge is dipolar (positive or negative and a pole will repel an identical pole) and what happens is that there is a field (D for those familiar with Maxwell's electromagnetic theory) that starts on charge and ends on the opposite charge. As far as we can work out, nothing whatsoever screens gravity or modifies its force, other than altering the mass or the distance. If nothing screens it, one cannot imagine anything actually repelling mass.

Negative mass implies a negative energy, but energy of an object implies motion, and that implies v^2. To get a negative energy, with one obvious exception, the object would seem to have to be described by a complex number. The exception is gravitational energy - the energy in a gravitational field has to be negative.

As an aside, the Uncertainty Principle arises because you cannot measure anything to within a quantum of action (Planck's constant). The value of that is 6.626 x 10^-34 Joule.second. That is extraordinarily small, and the uncertainty arising from that is not something Hollywood space ships should rely on.

In many sci-fi books, including a few I wrote, the concept of 'directed gravity' is mentioned, where you can make an object 'fall' in the direction you want, contrary to 'anti-gravity', where you reverse gravity. Once we know better the true nature of 'gravity' (other than that mass creates gravity), maybe we will be able to manipulate it one day (but not soon, I suppose).

A directed gravitronic beam emitted from a multi-phase quantum manifold powered by a flux capacitor should do the trick.

Say that again in plain English, please.

Michel wrote: "In many sci-fi books, including a few I wrote, the concept of 'directed gravity' is mentioned, where you can make an object 'fall' in the direction you want, contrary to 'anti-gravity', where you r..."

And haven't we seen breakthroughs in negative mass lately, where objects can be made to behave in exactly that fashion?

If anyone has seen real evidence of negative mass, please give us a clue where.

Michel wrote: "Say that again in plain English, please."

Hehehehehe...

Ian wrote: "If anyone has seen real evidence of negative mass, please give us a clue where."

I have, and here's where:

https://news.wsu.edu/2017/04/10/negat...
https://journals.aps.org/prl/abstract...

Not entirely convinced, Matthew. Note it says some rubidium atoms "behaves as if it has negative mass". They spun a Bose Einstein superfluid up with lasers, and I am not convinced the spin did not have something to do with their odd acceleration 😊 The Phys Rev Lett reference does say negative effective mass. Still, they are certainly interesting references, but I can't see them helping lift a Hollywood space craft off the ground.

The fascinating thing about the reference is the use rubidium - that stuff is not going to be used outside the very special laboratory conditions - it reacts violently with many things.

"Capt'n! The rubidium enclosure is cracking up."
"Dump the core."
"Aye aye, Sir - but we'll lose the anti-grav."
"That's OK - everyone floats down here..."

Graeme wrote: ""Capt'n! The rubidium enclosure is cracking up."
"Dump the core."
"Aye aye, Sir - but we'll lose the anti-grav."
"That's OK - everyone floats down here...""

Hehehehehe

Ian wrote: "Not entirely convinced, Matthew. Note it says some rubidium atoms "behaves as if it has negative mass". They spun a Bose Einstein superfluid up with lasers, and I am not convinced the spin did not ..."

You said you hadn't read or seen anything about it, so I showed what I myself saw. And this was in reference to what Michel said about mass falling in the opposite direction dictated by gravity, which made me think of it. I'm not suggesting this is the answer to the question, just posting it as food for thought.

Graeme wrote: ""Capt'n! The rubidium enclosure is cracking up."
"Dump the core."
"Aye aye, Sir - but we'll lose the anti-grav."
"That's OK - everyone floats down here...""

Everyone floats? Oh dear, is the Captain by any chance named Pennywise?

Indeed...Matthew...

Matthew, part of the reason I was not convinced was that the rubidium atoms were on the bottom of the vessel. How did they sit there if they were repelled by gravity? But, as I said, an interesting reference.

I like to look at the night sky. One night, I was watching a bright object that looked like a planet. Then it moved to the right at great speed and disappeared. It's a real memory for me, but maybe I imagined it. I do have a good imagination.

I'm wondering. If a ship had anti-gravity capability, the ability to hover, what would enable it to move horizontally?

Scout, onsider the possibility of directed gravity rather than simple anti-gravity. If we could learn to manipulate gravity and control it, then space travel will become so much easier. Directed gravity is a concept dear to science-fiction and I hope that it will become a reality one day, along with nuclear fusion generators that would provide us clean, abundant energy.

There are a number UFO sightings that ar difficult to explain, but part of the reasons is that because of the observer difficulties, there is not enough information to rule anything out or in. For what it is worth, Scout, I know a very experienced pilot who saw something a little like what you describe, and from his description it was very difficult to decide what it could have been.

As for moving horizontally, it simply has to develop thrust in the opposite direction. Newton's third law must be obeyed - if you se momentum going in one direction, there must be equal and opposite. Like jumping out of a small boat.

In one of my novels, I described something slightly different that I called 'gravity sails'. Basically the premise (fiction of course) was that gravity waves could be creating by manipulating the force fields of atoms. Then, those gravity waves so created would be projected against a material surface that would react to those gravity waves the same way that ship sails react with the wind to create thrust in one direction. You would then control the direction of your movements by projecting your gravity waves against gravity sails oriented at different angles. I know that it does sound far-fetched, but then most sci-fi novels do.

Ian wrote: "Matthew, part of the reason I was not convinced was that the rubidium atoms were on the bottom of the vessel. How did they sit there if they were repelled by gravity? But, as I said, an interesting..."

Oh, I know where you're coming from. You're a scientist and a critical thinker, and that's why you're so useful to the rest of us! I just feel the need to point out that I'm just the messenger. I hope that such research will produce successful, verifiable results, but I have an obvious agenda. I mentioned anti-gravity in a story I am working on, so if this doesn't work out, I'll either have to stop pretending I write "hard SF" or just change my manuscript :)

Graeme wrote: "Indeed...Matthew..."

Oh, shit! Where did I leave my slingshot and little bits of silver?

This is so interesting. I have another question and don't know where to post it, so I'll ask it here.

It seems to me that motion produces energy - wind, waves, flowing water from dams or streams. We are all in motion every day, as are our dogs when we go for a walk. Is there a way to turn that motion into energy that we can use?

Scout wrote: "This is so interesting. I have another question and don't know where to post it, so I'll ask it here.

It seems to me that motion produces energy - wind, waves, flowing water from dams or streams. ..."

Absolutely, and I'm so glad you asked! The means to turn motion into electricity is known as piezoelectric technology. I'm also impressed you asked because it means you are thinking along the same lines as some of today's top developers. They are all asking "why can't we turn everyday motion into power?"

The answer is that we can! There's already many applications, the only trick is to get it to produce more in the way of electricity. If we can do that, we could generate enough power to sustain ourselves using nothing more than our own daily activities.

Here are some links that could be useful:

http://newatlas.com/self-powered-card...
https://www.cnet.com/news/teeny-tiny-...
http://newatlas.com/vehicle-road-weig...
https://www.treehugger.com/urban-desi...

Scout, motion is effectively kinetic energy, and in thermodynamic terms, it is called work. You can always turn work into another form of work, although of course there is an efficiency problem. Examples include, from your selection, wind power, wave power (to electricity - easily feasible but there is a problem in ensuring the generating capacity is anchored well enough), hydroelectricity, and limited hydropower by putting little turbines in the streams. Most electric is generated this way, one way or another, for example in a coal-fired plant, you generate steam under pressure and then lower the pressure and the motion of the steam turns a turbine. Or it can turn a steam engine. There are some sneaky ways to make electricity without anything moving,m but most of it comes from motion.

One easy, already existing way to transform motion into energy is by putting piezo-electric or pneumatic mini turbine generators in the heels of our shoes. That way, you produce electricity while you walk. There have been studies by the U.S. Army about using that to help recharge things like portable radios, lights, sensors and computers.

Now, that's a cool idea.