For Questions That Don't Merit Their Own Thread

[DDE]

On 1/11/2019 at 3:20 PM, ARS said:

Why in land warfare (especially for tanks), a cannon with a caliber 120-150 mm is considered as main gun while in naval warfare a cannon with a caliber 120-150 mm (especially for battleships) considered merely as secondary weapon, with cannons of 300-400 mm caliber taking their place as heavy main gun?

Because battleships are bigger than tanks. Once you look at the actual mass of even a cruiser’s armament system, you’ll realize that no road or bridge would tolerate it.

For example, an AK-130 is a mounted on either end of Sovremenny destroyers. It weighs 89 tons, with those magazines extending several decks under.

And it’s much lighter than, say, the monstrous 203 mm triple autoloaders developed for the Des Moines class cruisers during WWII. For a battleship weapon sustem, we’re counting thousands of tons.

[BillKerman1234]

Say you have a spacecraft that weighs 100 tons, and is cylindrical, 100 meters long and 10 meters wide. Now imagine that spacecraft is instantly ‘teliported’ to a velocity beyond the speed of light. For example, 1.5C, 2C, 5C, 18.367475C.

We know that as a spacecraft approaches the superluminal barrier, the vehicles mass will increase exponentially, and the energy required to keep accelerating will increase exponentially. We also know the length of the spacecraft will decrease exponentially. So the question is: what happens to a spacecraft’s mass & dimensions if it is going faster than the speed of light? 

From what I can tell, there are three possibilities:

1. It’s mass will continue to rise beyond infinity.

2. It’s mass will stay at infinity.

3. It’s mass will start decreasing.

Which one is it? And could we take advantage of it? 

[cubinator]

27 minutes ago, BillKerman1234 said:

Say you have a spacecraft that weighs 100 tons, and is cylindrical, 100 meters long and 10 meters wide. Now imagine that spacecraft is instantly ‘teliported’ to a velocity beyond the speed of light. For example, 1.5C, 2C, 5C, 18.367475C.

We know that as a spacecraft approaches the superluminal barrier, the vehicles mass will increase exponentially, and the energy required to keep accelerating will increase exponentially. We also know the length of the spacecraft will decrease exponentially. So the question is: what happens to a spacecraft’s mass & dimensions if it is going faster than the speed of light? 

From what I can tell, there are three possibilities:

1. It’s mass will continue to rise beyond infinity.

2. It’s mass will stay at infinity.

3. It’s mass will start decreasing.

Which one is it? And could we take advantage of it? 

Its mass stays at infinity, and it doesn't get any faster than 1.0 c. It might just turn into a bigger black hole as you keep putting more energy into it, but other than that it won't actually get any faster than the speed of light. 

[DDE]

52 minutes ago, BillKerman1234 said:

And could we take advantage of it? 

There are many, many better ways to take advantage of a tellyporta.

[kerbiloid]

(Brief answer: nowadays experimentally proven theories are limited with subluminal velocities.)

Edited January 15, 2019 by kerbiloid

[BillKerman1234]

1 hour ago, cubinator said:

Its mass stays at infinity, and it doesn't get any faster than 1.0 c. It might just turn into a bigger black hole as you keep putting more energy into it, but other than that it won't actually get any faster than the speed of light. 

I didn’t say keep accelerating an object to the speed of light and then keep putting more energy into it, I said if all of a sudden the velocity of the craft was superluminal. Think of it as teleporting the ship, but changing the velocity instead of the location.

In other words: what would happen to an object if you forced it (through means I won’t discuss) to various velocity’s faster than the speed of light.

Edited January 15, 2019 by BillKerman1234

[cubinator]

54 minutes ago, BillKerman1234 said:

I didn’t say keep accelerating an object to the speed of light and then keep putting more energy into it, I said if all of a sudden the velocity of the craft was superluminal. Think of it as teleporting the ship, but changing the velocity instead of the location.

In other words: what would happen to an object if you forced it (through means I won’t discuss) to various velocity’s faster than the speed of light.

Unfortunately we can't discuss this because no object goes faster than the speed of light in this universe. There is no model to describe something doing that, so anything I say about what would happen is speculation and not very scientific.

My guess is you would break the fabric of the universe along the ship's path and it would be very destructive.

[kerbiloid]

https://en.wikipedia.org/wiki/Tachyon

[p1t1o]

5 hours ago, BillKerman1234 said:

Say you have a spacecraft that weighs 100 tons, and is cylindrical, 100 meters long and 10 meters wide. Now imagine that spacecraft is instantly ‘teliported’ to a velocity beyond the speed of light. For example, 1.5C, 2C, 5C, 18.367475C.

We know that as a spacecraft approaches the superluminal barrier, the vehicles mass will increase exponentially, and the energy required to keep accelerating will increase exponentially. We also know the length of the spacecraft will decrease exponentially. So the question is: what happens to a spacecraft’s mass & dimensions if it is going faster than the speed of light? 

From what I can tell, there are three possibilities:

1. It’s mass will continue to rise beyond infinity.

2. It’s mass will stay at infinity.

3. It’s mass will start decreasing.

Which one is it? And could we take advantage of it? 

You can extrapolate from what happens up to 1c, or speculate/hypothesise, but the long and short of it is....within the bounds of known science, the question does not make sense. The words "beyond infinity" literally cannot translate to any meaning, like "less than purple".

It is the same as asking "what happens if the spacecraft turns into a crocodile?"

Within the bounds of the totality of human knowledge, it is not possible to exceed c, it is also not possible for a ship to spontaneously turn into a crocodile. The two possibilities are equivalent.

It sounds like Im making fun, but Im not, it is a fascinating subject to discuss - but in this case, it is a dead end.

To make guesses about what happens when you accelerate beyond c, means that you discount all of known science - which means that the answer does not have to conform to known science either. Therefore, if the answer "it is unknowable/impossible/non-sensical" is not satisfying enough, the only alternative is "literally anything could happen". It could create a universe, destroy this one, turn into strawberry icing or anything else in between.

The best answer we have, disappointingly, then is that you just could not pass c.

Not everything you can imagine, is possible in reality. I think that might even be proven, Im not sure. We are getting dangerously close to philosophy here.

 

 

(In case anybody is thinking along the lines of "Ugh, dead end? How do you think progress was made if people stopped at "
dead ends"? I'd say, sure, we can examine what happens beyond c, but first all you have to do is make a paradigm-shifting discovery that realigns the virtual entirely of known science, whilst still explaining everything  else just as well as we can now. Its a big ask, but do that and we can talk superluminal. I'll wait )

 

Edited January 15, 2019 by p1t1o

[ARS]

Can anyone can identify the name these aircrafts?

[Mad Rocket Scientist]

1 hour ago, ARS said:

Can anyone can identify the name these aircrafts?

The first two are a mystery, the third is probably a Zero, one of the models with the square wingtips, and I'm very confident that the last one is a Zero version with the rounded wingtips.

[DDE]

4 hours ago, ARS said:

Can anyone can identify the name these aircrafts?

Bottom two are Zeroes, the amount of canopy framing is a dead giveaway. Upper two... not Army Zeroes, not Lavochkins, radial engine so not British, synchronized guns so not American, and it’s not a Focke-Wulf either.

[Ho Lam Kerman]

What the actual...

Now there's a lot of weird things going on here.

1. Why is Cassini connected to the DSN? Cassini, of all spacecraft?!

Is the DSN doing some decommissioning work for Cassini, or is it a glitch?

2. VGR stands for "Voyager", but why isn't it VGR1 or VGR2? When I click on it, the target is labelled "Testing".

[SuperFastJellyfish]

Strange.  Maybe they were doing maintenance.  It's marked VGR1 for me:

 

[p1t1o]

4 hours ago, DDE said:

Bottom two are Zeroes, the amount of canopy framing is a dead giveaway. Upper two... not Army Zeroes, not Lavochkins, radial engine so not British, synchronized guns so not American, and it’s not a Focke-Wulf either.

Very likely just down to inaccurate modelling, probably all Zeros. Or a made-up hodge-podge.

But they look instantly Japanese hey?

[Gargamel]

The fourth one is definitely a Zero, and I would say the same for the third, but the wingtips don't match exactly.   That's the problem with a lot of artists renditions. 

[Mad Rocket Scientist]

8 minutes ago, Gargamel said:

The fourth one is definitely a Zero, and I would say the same for the third, but the wingtips don't match exactly.   That's the problem with a lot of artists renditions. 

There were Zeros with squared off wingtips. I used airplane ID charts from WWII to find the planes, see the difference between "Zeke" and "Hap" in this chart:

 

[Ho Lam Kerman]

13 hours ago, SuperFastJellyfish said:

It's marked VGR1 for me:

It's usually marked VGR1 or VGR2 for me as well, but this time it just appears as VGR. It's gone back to being VGR1 and VGR2, so I believe it was maintenance.

[lrd.Helmet]

On 1/16/2019 at 6:41 AM, ARS said:

Can anyone can identify the name these aircrafts?

*snip*

Ki-43 Hayabusa perhaps? Canopy and tail look similar.

[Cunjo Carl]

@ARS

I'm probably the internet's slowest surfer at the moment, so it was by some wild serendipity that I think I found your planes! They seem to be from an upcoming Bandai-Namco game called Kotobuki (full name: Kouya no Kotobuki-Hikoutai or Kotobuki Squadron from the Wastelands). Here's the links I found associated (web pages in Japanese):

https://kotobuki-game.bn-ent.net/aircraft/

https://kotobuki-anime.com/aircraft/

The planes in your pictures seem to be:

Photo 1: Ki-43 "Hayabusa" ('Oscar' or 'Army Zero')
Photo 2: N1K1-J "Shiden" ('George')
Photo 3: A6M3 "Zero" ('Hap', 'Zero' or 'Zeke 32')
Photo 4: A6M2b "Zero" ('Zero', or 'Zeke')

Plane 5: Ki-44 "Shouki" ('Tojo')

There was a 5th plane shown on the web page as well, so I went ahead and added it to the list. Within my abilities, I'm happy to translate anything on the pages. The tag line for the game seems to be "So many skies, so many of our stories to tell." and it has a planned release in winter 2019. Neat!

Edited January 18, 2019 by Cunjo Carl

[ARS]

3 hours ago, Cunjo Carl said:

Photo 1: Ki-43 "Hayabusa" ('Oscar' or 'Army Zero')
Photo 2: N1K1-J "Shiden" ('George')
Photo 3: A6M3 "Zero" ('Hap', 'Zero' or 'Zeke 32')
Photo 4: A6M2b "Zero" ('Zero', or 'Zeke')

Plane 5: Ki-44 "Shouki" ('Tojo')

Many thanks! Someone gave me that pics of aircrafts and I'm as interested as him to know what's the name of these. I'm looking forward for this series, looks interesting!

[Cunjo Carl]

Does anyone know of an electronic device (ideally an IC or a combination of discrete components of some sort) which can block reverse current without imposing a forward voltage drop? Relays and reed switches are a bit too slow for my application, unfortunately. I'll probably be working in the 10s-100s of us time scale. I'm above signal level, but ultimately still looking at low-ish currents (250mA) and voltages (20V) for starters though. Also, I'll unfortunately specifically need to block reverse current not bypass it like in a crowbar circuit.

I've heard of symmetric JFETs does anyone have experience with those maybe? Not sure if they do what I'm thinking of.

Thanks in advance!

[GDJ]

4 minutes ago, Cunjo Carl said:

Does anyone know of an electronic device (ideally an IC or a combination of discrete components of some sort) which can block reverse current without imposing a forward voltage drop? Relays and reed switches are a bit too slow for my application, unfortunately. I'll probably be working in the 10s-100s of us time scale. I'm above signal level, but ultimately still looking at low-ish currents (250mA) and voltages (20V) for starters though. Also, I'll unfortunately specifically need to block reverse current not bypass it like in a crowbar circuit.

I've heard of symmetric JFETs does anyone have experience with those maybe? Not sure if they do what I'm thinking of.

Thanks in advance!

A Schottky Diode has a very small forward voltage loss. Would that work for you?

[Cunjo Carl]

15 minutes ago, GDJ said:

A Schottky Diode has a very small forward voltage loss. Would that work for you?

It's a good idea, and I should have specified. Unfortunately, the ~.25V drop of a schottky will be too much. I'm hoping for a forward drop in the .01V range, (equivalent to an RDSon of 40mOhm). I realize this may be impossible of course!

[DDE]

Let’s revisit the old “shoot gas tank for car explosion” trope. Justs how impossible is it?

And what happens if we use an actual gas (propane)?