For Questions That Don't Merit Their Own Thread

[YNM]

Does anyone know an alternative to R-squared for polynomial regression ?

Also, could they be calculated for a formula derived through different means (ie. not through direct regression) against a set of data ?

[Racescort666]

@KG3 just don’t ask what the difference is between a bolt and a screw 

My question is related to astronomy: when people (scientists is suppose) discuss interesting celestial objects like hyper giant stars, brown dwarfs, failed stars, contact binaries, and the like, are these objects limited to the Milky Way?

I assume that there are other things like this in other galaxies but are we observing them? Or is most of the weird stuff that we’re observing limited to our own galaxy?

[KG3]

1 hour ago, Racescort666 said:

@KG3 just don’t ask what the difference is between a bolt and a screw 

My question is related to astronomy: when people (scientists is suppose) discuss interesting celestial objects like hyper giant stars, brown dwarfs, failed stars, contact binaries, and the like, are these objects limited to the Milky Way?

I assume that there are other things like this in other galaxies but are we observing them? Or is most of the weird stuff that we’re observing limited to our own galaxy?

There is nothing particularly special or different about our galaxy compared to the rest of the universe.  If it's in this galaxy it's also in other galaxies.  It's difficult to see individual stars in other galaxies because of the distance involved.  

[p1t1o]

17 hours ago, Racescort666 said:

@KG3 just don’t ask what the difference is between a bolt and a screw 

 A bolt is something you fire from a crossbow and a screw is what boats push themselves with, what's the big deal?

[Racescort666]

10 hours ago, p1t1o said:

 A bolt is something you fire from a crossbow and a screw is what boats push themselves with, what's the big deal?

This is what I like about this forum.

[tater]

For no particular reason, except it's cool:

 

[peadar1987]

22 hours ago, p1t1o said:

 A bolt is something you fire from a crossbow and a screw is what boats push themselves with, what's the big deal?

Lotsa screws in this picture :p

[monophonic]

2 hours ago, peadar1987 said:

Lotsa screws in this picture :p

Sure. Every boat in it has at least one. But that nearest ship's boat sure is an eyesore. A bright orange RIB on a tall ship, ugh. Certainly very practical as a utility boat though.

[kerbiloid]

1. Do they believe that putting trapezoids and triangles perpendicular to the surface makes water flow faster?

2. Do those small holes along the board decrease air drag?

3. Are those vertical sticks with geometrical figures telescopic?

Edited April 26, 2018 by kerbiloid

[Kernel Kraken]

On 4/26/2018 at 1:10 PM, kerbiloid said:

1. Do they believe that putting trapezoids and triangles perpendicular to the surface makes water flow faster?

2. Do those small holes along the board decrease air drag?

3. Are those vertical sticks with geometrical figures telescopic?

1. Possibly, it sounds like it makes sense in theory.

2. I think they're windows on a boat (portholes)

3. Generally no, but that's an excellent idea.

Why isn't the sky violet?

 

On 4/25/2018 at 9:41 PM, Racescort666 said:

This is what I like about this forum.

The general mindset of mild to heavy sarcasm mixed with childlike wonder and general friendliness, while at the same time retaining a love of explosions and BadSery similar to the mindset of one Jebediah Kerman? Yup, this forum is awesome. 

EDIT: My question was 'Why isn't the sky Violet?'.

Edited May 6, 2018 by Kernel Kraken

[NSEP]

Can we use hydraulic fluids (water) to dampen G-forces on the human body, when, aerobraking/acceleration at high speeds?

[Racescort666]

1 hour ago, NSEP said:

Can we use hydraulic fluids (water) to dampen G-forces on the human body, when, aerobraking/acceleration at high speeds?

fluids... dampen... lol...

I suspect yes but I'm not the right person to answer, I just wanted to make a joke about fluids dampening.

[p1t1o]

14 hours ago, NSEP said:

Can we use hydraulic fluids (water) to dampen G-forces on the human body, when, aerobraking/acceleration at high speeds?

Yup, in theory.

If floating in a fluid, the changes in pressure under G loads exactly balance out the forces on the fluids in the body, in essence giving you a "perfect" g-suit, allowing one to withstand high g-loads without experiencing any ill effects.

In reality however, the human body is not a uniform density, and contains air spaces which are compressible. This is a problem as g-forces would act to compress these spaces as the acceleration rises.

The answer is to fill the lungs with fluid, oxygenated so that breathing still works. If this is done properly then it could be used to protect humans from much higher g-forces (current limit is 9gs with a conventional g-suit. There are some advanced suit designs including forces breathing which can keep you awake up to 12-13gs) although naturally there are some drawbacks involved with having to plumb yourself into a tank and fill your lungs with fluid.

There have been some positive results with liquid breathing, but we're not quite there yet.

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

There would still be an upper limit on g-forces, as pressure will rise proportional to G load and funny things happen to things in solution as pressure changes. Similar limits would be imposed to those experienced when diving. In fact, fluid breathing I think was first conceived for very deep dives.

***edit***

@NSEP Extra-FunFact!: Remember that movie "The Abyss"? Fluid breathing for deep dives is featured, and there is a scene where they submerge a rat in the breathing fluid, the rat "drowns" and then successfully breathes the fluid and is revived afterwards. This scene was supervised by the scientists who pioneered the technique and it was shot using real breathing fluid and the rat was actually submerged in it, and survived breathing it. 

Edited May 8, 2018 by p1t1o
avoid double-post

[kerbiloid]

5 hours ago, p1t1o said:

In reality however, the human body is not a uniform density, and contains air spaces which are compressible. This is a problem as g-forces would act to compress these spaces as the acceleration rises.

The answer is to fill the lungs with fluid

Spoiler

The Abyss, 1989

and not to eat beans before the flight. There are not only lungs, not only air...

And take out dentures and dental fillings. Otherwise one can inhale them.

[p1t1o]

2 hours ago, kerbiloid said:

  Reveal hidden contents

The Abyss, 1989

and not to eat beans before the flight. There are not only lungs, not only air...

omg this is too perfect...

...whilst checking the facts about the rat experiment featured in "The Abyss", I also read this little gem:

(from the imdb "trivia" page on "The Abyss")

During filming Ed Harris demanded cabbage as a snack/meal as he was on a strict diet. This however became almost unbearable for him and indeed the rest of the crew as he was constantly farting and giving himself and the other crew members the dry boak. In one underwater scene where Harris was in his diver suit, he farted and the smell was so intoxicating that he actually vomited inside the suit. The scene was obviously cut and it took hours for Harris to resurface, clean the suit, submerge and re-shoot the scene. James Cameron was reportedly furious with Harris for this and took action by placing air fresheners in all the actors and crew members suits to help ensure that there was no repeat of the incident. Harris also got pink eye during filming and had to wear contact lenses for a week.

 

[kerbiloid]

4 minutes ago, p1t1o said:

..whilst checking the facts about the rat experiment featured in "The Abyss"

Caution! Shocking content.
(Though no animal has been harmed.)
 

Spoiler

No, seriously, caution.
 

Spoiler

 

 

 

[wumpus]

On 5/7/2018 at 5:49 PM, NSEP said:

Can we use hydraulic fluids (water) to dampen G-forces on the human body, when, aerobraking/acceleration at high speeds?

If a conventional G-suit can handle 6-7 gees of acceleration, why do you want to subject humans to more?  Perhaps an air launch at such force might make sense, but very few rockets (all of which were solid based) have used anywhere near such accelerations.  Typically by the time you are beyond the atmosphere, your gravity losses are declining anyway, reducing the need for such acceleration.

Humans aren't the only weak points in a rocket.  For decellerating, such speeds imply leaning heavily on the heat shield, although since the heat shield isn't involved with decellerating the rocket (the velocity energy is turned into adiabatic heating, which mostly passes around the spacecraft) it might make more sense (if you have the tech, why are you abusing the passengers so much).  This sounds more like "crimes against kerbals", like when I send Jeb to Duna in a MkI capsule.

- I remember seeing the g meter buried in pre-release during a "don't bother aerobraking, just impact the planet" Mun return.  The souposphere would still slow down the spacecraft (and it didn't care about reentry heating), so I think this qualified as an exploit.

[NSEP]

1 hour ago, wumpus said:

If a conventional G-suit can handle 6-7 gees of acceleration, why do you want to subject humans to more?

Aerobraking at Gas Gaints, launching on magnetic force space cannons, things like that.

Its for a Sci-Fi!

[magnemoe]

On 5/14/2018 at 7:12 PM, NSEP said:

Aerobraking at Gas Gaints, launching on magnetic force space cannons, things like that.

Its for a Sci-Fi!

Humans can take more than 7 g if lying down and is not supposed to be functional during the event, launch abort is the obvious one. 
Think you can use compressed air over water, lighter for one. 
And emergency systems don't have to be totally safe, just safer than the alternative 

[StrandedonEarth]

On 5/7/2018 at 2:49 PM, NSEP said:

Can we use hydraulic fluids (water) to dampen G-forces on the human body, when, aerobraking/acceleration at high speeds?

Rama II used fluid baths to allow humans to endure high gees (don't recall the exact number) for extended periods...

[p1t1o]

16 hours ago, magnemoe said:

Think you can use compressed air over water, lighter for one. 

It wont have the same effect. Humans are roughly the same density as water, so the "floating" is what supports your body. We sink in air, so does blood, so there needs to be a pressure differential, which is uncomfortable and limited by the pressure difference the body can handle between feet and head, and the pressure needs to be adjusted with changes in G - this is exactly how modern G-suits work, and pressure-breathing prototypes. In water, the pressure differential is caused by the mass of the water and corresponding pressure, and exactly (ish) matches similar pressure changes within the body, meaning the blood "floats" where it is and doesnt pool in your feet (or wherever). A fluid bath also does not require any active pressure management and cannot fail under load (unless gross structural failure of the tank).

Note that a compressed air system requires heavy tankage, plumbing, pumps etc. which offset the weight advantage against a simple fluid filled pod which might only require a mass of a couple hundred kilos of fluid.

If you're accelerating at 10-plus G's, it seems like saving a few kilos here and there might not have been a primary design requirement.

Edited May 16, 2018 by p1t1o

[Not Sure]

On 2/14/2018 at 4:09 PM, cubinator said:

Anyone know what happened to Iridium 911? I saw it rotating pretty fast the other day, like once every 3 or 4 seconds, and wanted to know how it got going like that.

Saw it the other day too. Blinking every 4 or so seconds. Hope it has a backup.

[cubinator]

What do the Venera probes look like today? I can't imagine decades under that acid oven of an atmosphere would leave them in any sort of decent state.

[Lisias]

What's the difference between merging an craft into the current editing one, or merging a subassembly?

There's some difference on the internal data structures if I choose one or another?

Edited May 17, 2018 by Lisias

[Cunjo Carl]

16 hours ago, Lisias said:

What's the difference between merging an craft into the current editing one, or merging a subassembly?

There's some difference on the internal data structures if I choose one or another?

I was a bit curious too, so I tried it both ways and ran a comparison on the files, and they seem identical as far as the data structure and the links between the parts are concerned.

If you'd like a response from someone more in the know though, try asking the same question over in the Gameplay Questions and Tutorials forum. There's a ton of folks with good knowledge about KSP mechanics active over there.