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For Questions That Don't Merit Their Own Thread

Skyler4856

By Skyler4856
in Science & Spaceflight

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p1t1o

p1t1o

Posted
Posted
1 hour ago, DDE said:

We have to stop this man before he scares our benevolent experimenters so much they pull a Ctrl-Alt-Del on our little simulation.

You dont think the current reality could use a little debugging?

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p1t1o

p1t1o

Posted
Posted (edited)
1 hour ago, mikegarrison said:

My answer to that depends on whether I am considered a bug or a feature.

What if we are not a part of the program, what if we are part of the substrate the program is running on?

Then you couldnt be a bug ;)

Edited by p1t1o
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K^2

K^2

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Posted
On 4/14/2020 at 8:47 AM, tater said:

https://writings.stephenwolfram.com/2020/04/finally-we-may-have-a-path-to-the-fundamental-theory-of-physics-and-its-beautiful/

Livestream in a couple hours:

https://www.wolframphysics.org/

 

I'll have to do a deeper dive, but so far, I'm not seeing anything that's going to solve the actual problem. We already know equations that describe everything derived from same principles as all the rest of physics - Gauge Theory. We have a combined "theory of everything" master equation that should describe everything we can observe. Problem is that we can't solve it. Worse, if somebody just gave us a result that is a particular solution to particular initial conditions, we wouldn't be able to even verify it. It's infinite sums over infinities divided by more infinities that must be canceling somewhere, because universe exists, but we don't know how - in general. We have some narrow, approximate special cases solved. For example, if we consider that gravity isn't a factor, we get Standard Model of particle physics, where there are still infinities divided by infinities, but we have math tricks to cancel them out and get nice numerical results that match experiment. (Mostly - mass of vacuum is a bit of a problem.) Likewise, if we throw away interactions due to intrinsic degrees of freedom (electromagnetism, nuclear forces, etc.) we get General Relativity. We can even do fancy things like particle physics inside a neutron star, where both quantum and space-time curvature are factors, but on different scales, so we can treat equations as if they were separable, and this does give us predictions about neutron stars that we wouldn't get from either theory alone. So there's a very good chance that Gauge Theory is fundamentally correct on all levels. It just happens to be mathematically useless when we try to load it with absolutely every known degree of freedom at the same time.

What I've gathered from published Wolfram work is that it manages to reproduce features of Standard Model and General Relativity. Which screams at me that it is probably equivalent to Gauge Theory via some mathematical transformation. And that itself isn't terribly surprising, because both are playing off concepts in topology. Moreover, anything that has a chance of working as theory everything kind of has to have this equivalence, at least in limiting cases, because it has to have theory that we already know works. What isn't clear, and in fact, I don't see any attempt to verify this one way or another, is whether this new approach lets you work around any of the divergences we get in Gauge Theory when we are dealing with curved space-time. And if not, which seems more likely barring evidence to contrary, then it's still going to have the same bumps with Quantum Gravity that exist in Gauge Theory. It is possible that with the new formalism, we will see new mathematical methods develop that let us work around these problems. That's always the hope. But this isn't the first time somebody tried to introduce a new formalism, and so far, nothing got us closer to a working model. So I'm very curious to see where theoretical physicists can take this, but I wouldn't pop the champagne just yet.

tl;dr - Very exciting mathematics, TBD if it helps at all in theoretical physics - unless I missed something huge in all of this.

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Spacescifi

Spacescifi

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Posted (edited)

I only made this thread here so I don't hog the spaceflight thread, since KSP is not ONLY about me and what I want, and I respect that. Other posts matter.

Question: Are inflatable chemical rocket boosters possible?

If not now I think they are worth researching.

Why? Weight. Also reusuabilty

My idea of an inflatable rocket booster would be a donut shaped ring hugging the rocket ship until it ran out of fuel and was dropped off.

If some of it was still inflated it could survive the fall.

The rocket nozzles per modern tech would have to be hard, but if future tech allows for inflatable fabrics that are as heat and pressure resistant as solids... it's game on I say.

Even better.... an inflatable rocket nozzle could be designed to expand for altitude compensation, which a solid booster cannot do.

The other plus is if the entire booster is inflatable, you could store several in small spaces, which makes it easy to just fill the booster up with water and and whatever antimatter or nuclear tech on hand to boost off an Earth rated planet relatively quickly.

Faster than actually building a booster from scratch.

What do you think?

Edited by Spacescifi
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K^2

K^2

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Posted

Unlike liquid fuel rockets, the most complex and expensive part of SRB is the fuel. There are parts worth recovering, but these can already be recovered by parachuting the boosters down. And because boosters are inherently non-structural to the rocket, and solid fuel helps support its own weight, there is absolutely no benefit to pressurizing them like the liquid fuel tanks. Anything you could gain by making the structure inflatable you simply don't need, so it'd only be making the booster more expensive.

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Spacescifi

Spacescifi

Posted
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21 minutes ago, K^2 said:

Unlike liquid fuel rockets, the most complex and expensive part of SRB is the fuel. There are parts worth recovering, but these can already be recovered by parachuting the boosters down. And because boosters are inherently non-structural to the rocket, and solid fuel helps support its own weight, there is absolutely no benefit to pressurizing them like the liquid fuel tanks. Anything you could gain by making the structure inflatable you simply don't need, so it'd only be making the booster more expensive.

 

I was referring to using inflatable liquid fuel boosters.

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K^2

K^2

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6 hours ago, Spacescifi said:

I was referring to using inflatable liquid fuel boosters.

Tank pressure is often required for liquid fuel rockets to maintain structural integrity. That's not really anything new. In fact, you can see one of the Starship prototypes collapsing due to loss of pressure in lower tank during testing. It has enough rigidity to support its weight while empty, but it can't support weight of the filled upper tank without pressure in the lower tank.

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magnemoe

magnemoe

Posted
Posted
4 hours ago, K^2 said:

Tank pressure is often required for liquid fuel rockets to maintain structural integrity. That's not really anything new. In fact, you can see one of the Starship prototypes collapsing due to loss of pressure in lower tank during testing. It has enough rigidity to support its weight while empty, but it can't support weight of the filled upper tank without pressure in the lower tank.

Think all orbital rockets need pressure to maintain structural integrity fully fueled. Might be exceptions but fully fueling it and not pressurize the lowest tank don't sound good. 
The deal about the Atlas was that it could not support itself empty unless pressurized  

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ARS

ARS

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Posted

Firing bullet underwater makes the bullet travel less due to underwater drag and significantly reduces its effective range. If say, there are 2 people swimming underwater, and they are at sufficient distance, is it possible for people to A fire a (non-underwater designed) bullet into person B, in such a distance that the bullet simply slows to a crawl just inches away from people B's face that the people B can clearly see the bullet before it drops down and sink underwater?

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Spacescifi

Spacescifi

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5 hours ago, ARS said:

Firing bullet underwater makes the bullet travel less due to underwater drag and significantly reduces its effective range. If say, there are 2 people swimming underwater, and they are at sufficient distance, is it possible for people to A fire a (non-underwater designed) bullet into person B, in such a distance that the bullet simply slows to a crawl just inches away from people B's face that the people B can clearly see the bullet before it drops down and sink underwater?

 

No.

Gravity curves the fall.

If you launch a rocket and reverse thrust to slow it's orbit... will it fall straight down?

No.  Not unless you have thrust to slow it's descent and orbital momentum at the same time.. before falling again, but straight.

With the underwater bullet, as it slows it will begin curving downward.

The only way for it to stop in front of the other person's face would be if they swam toward it, since by the time it has slowed that much it will no longer be level with the person where they originally were.

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Spacescifi

Spacescifi

Posted
Posted
3 minutes ago, ARS said:

What's the advantage and disadvantage between SLBM missile tubes behind the conning tower versus in front of conning tower on submarines?

?????

The questions asked thus far that I have seen that you have brought up seem basic.

So basic that you may not even need us to find the answer.

What I want to know is the why.... are you writing submarine miltary fiction?

Since that is just an educated guess based off the last poat plus this one?

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ARS

ARS

Posted
Posted
4 hours ago, Spacescifi said:

What I want to know is the why.... are you writing submarine miltary fiction?

Well you find it out, huh? Yeah, I'm writing a submarine science fiction

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kerbiloid

kerbiloid

Posted
Posted (edited)

Afaik the only one with front tubes was Typhoon / Akula, and the only reason for it was that its SLBM was too long to fit a usual hull, so they made a catamaran and placed the tubes between its highest widest diametrest parts, and that was just one variant of suggested.

Also its bulky hull allowed to pass through the shallow water next to the Northern bases, if empty the cysterns, and to crash the polar ice with Archimedes force.

On other subs they probably not put the tubes behind the habitat, but the habitat on the opposite end from the engines and reactors and close to the navigation equipment.

Edited by kerbiloid
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Spacescifi

Spacescifi

Posted
Posted
3 hours ago, ARS said:

Well you find it out, huh? Yeah, I'm writing a submarine science fiction

 

Well... interesting.

I will say that is not the usual, I mean I can count the underwater scifi movies (most I have not seen) on one hand).

Also FYI, if you actually want to shoot anything with a bullet in the water then you want a harpoon gun.

Slender profile but heavy enough to cut through enough water to actually hit that guy and even stuff farther out.

Google will tell you the max range of an underwater harpoon gun.

Second, with submarines, one torpedo hit should be a definite kill.

But is not always.

It depends on several factors.

https://www.quora.com/Can-modern-submarines-survive-a-torpedo-hit

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