Mysterious green UFO spotted on Jupiter from NASA image, sparks debate

Started by WAS, October 29, 2018, 05:03:55 PM

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WAS

The Real Solar System mod isn't compatible with the latest version of Kerbal Space Program so I'll need to downgrade to use it, but I'll try and make video if my system can handle it (game sucks up RAM).

Matt

This is the version where you plug in distance and it outputs time and end velocity:

https://keisan.casio.com/exec/system/1224852055

You can't use this for Felix's jump because he was inside the atmosphere. The calculator assumes no air resistance. That's why it gave you a higher top speed than Felix's real jump.

I only used it to calculate the speed you would reach *before* reaching any substantial atmosphere. I picked 400 km to 100 km altitude - there is some atmosphere at 100 km, but not enough to matter in these calculations. Felix was much lower in the atmosphere so it will give the wrong number.
Just because milk is white doesn't mean that clouds are made of milk.

Matt

Quote from: WASasquatch on November 02, 2018, 12:47:20 AM
However I'll point out the ISS isn't in freefall, it is effectively ballistic flight

Yes, it's in ballistic flight. Ballistic flight is freefall.

Quote
at a speeds which defeats the SOI + pull. That speed slowly slows and once it's too slow for the SOI begins to "actually" fall towards the center of mass, which is when they do orbital correction burns.

True. The gradual slowdown is caused by minute amounts of air resistance, even at 400 km. (I don't know the term SOI though - what's that?).
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Oh duh! That makes sense. Though like I was saying I don't think you'd heat up. Think of the SpaceX boosters. They fall from at least half of ISS orbital distances, and don't even heat enough to create vapor.

The Shuttle reaches a maximum of about about 1,650 C with a re-entry of Mach M or Mach ~25 (7823.2mp/s) (And even at this speed it's a gradual inclination to the atmosphere, not a steep fall).

Also, I'm unsure those falling characteristics are still that accurate when you consider mass of on object which place a significant role in gravitational pull. For example, it takes more delta v to lift said mass into orbit, it also plays a roll in descent.

It'd be weird for a person to gain the speed you suggest (2400mps), as it suggests if it were able to continue falling, you would gain orbit (7666mps equatorial), or break orbit from Earth which just wouldn't make sense.

Ballistic Flight is not free-falling, it is defeating gravitation influence without aerodynamics. Flying is lift via aerodynamics, Spaceflight is lift via delta v, or acceleration only. Saying it's freefalling means all flight is freefalling which is just silly. Freefalling is freefalling, from a fixed position under gravitational influence without thrust. For example you could be using spaceflight for ascension, which would be the opposite of falling towards the gravitational influence until you break the SOI.

Matt

In the absense of atmosphere, feathers fall at the same speed as cars.

Re. freefall/orbital physics, I suggest you read an article on the subject if you're really interested in understanding this stuff.
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Quote from: Matt on November 02, 2018, 06:13:25 AM
In the absense of atmosphere, feathers fall at the same speed as cars.

Re. freefall/orbital physics, I suggest you read an article on the subject if you're really interested in understanding this stuff.

Falling is falling. As I edited in my last post, you could be using your delta v for ascension until you break SOI. Even my teacher corrected a student citing that immediately as "urban legend". Even spaceflight wiki doesn't mention anything about technical freefall, or even Google Scholar.

And even than, still not answering the point where that speed is just simply too fast. Objects being flicked from a finger from a fixed position could gain orbital speeds. It's just not adding up.

Matt

Just because milk is white doesn't mean that clouds are made of milk.

WAS

What did I say that wasn't true? I said that speed doesn't add up from your calculations and the calculator you used. The speeds accumulated are already near break-away speeds for leaving the atmosphere, close to gaining orbit. And at speeds much greater than that things don't even burn up completely like larger celestial objects, like most meteorites. Most space-junk is reduced only to 10-15%, and these are just basic material satellites, thin aluminum you can melt through with a lighter (foil casings), plastics (carbon fibers too), etc. More expensive ones with titanium, but usually not in things they'll know will de-orbit quickly.

My argument, despite sub-arguments in technicalities like falling rates of mass and getting to know things, is a person falling will not burn up. Just won't. Things aren't even burning up well at de-orbiting speeds from a orbit today and posing a serious risk. Takes much longer prolonged heats to burn up the mass of our bones let alone muscles etc.

Matt

It takes more energy and fuel to lift a heavy rocket into orbit than a smaller object, but the same delta v. The speed of the orbit is the same for small objects as for heavier ones.
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Quote from: Matt on November 02, 2018, 06:32:54 AM
It takes more energy and fuel to lift a heavy rocket into orbit than a smaller object, but the same delta v. The speed of the orbit is the same for small objects as for heavier ones.

You're just sort of arguing random technicalities now, whether to maintain some sort of angle of correctness or whatever, but the initial argument is a person would burn up. They wouldn't.

What I stated is the speeds you quoted are much too fast, and related them to similar speeds, for example, the speed of equatorial orbit (which isn't the same in other orbits)

WAS

With speeds like that, it makes me wonder why we don't do slingshots using the suns SOI to get anywhere in the solar system. Lol All you'd have to do is get the object out of Earths SOI and out of the path of other SOI's and just do trajectory corrections. With correctional burns you'd think you could save enough fuel for orbital burns around other bodies even. Hmmm.

Matt

I already admitted on the previous page that I don't know whether you would get hot enough to burn up. That is beyond my knowledge. I realised that after I did that first calculation.

But the velocity calculations are what they are. To be clear, I'm talking about a vertical drop straight down to the ground. NOT an orbit. The velocity gets pretty high when you're falling in a vacuum straight down towards the ground. It doesn't matter whether it's a human or an enormous rocket, they fall at the same speed in a vacuum.
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Quote from: Matt on November 02, 2018, 06:44:29 AM
I already admitted on the previous page that I don't know whether you would get hot enough to burn up. That is beyond my knowledge. I realised that after I did that first calculation.

But the velocity calculations are what they are. To be clear, I'm talking about a vertical drop straight down to the ground. NOT an orbit. The velocity gets pretty high when you're falling in a vacuum straight down towards the ground. It doesn't matter whether it's a human or an enormous rocket, they fall at the same speed in a vacuum.

It's pretty shocking to see such a speed increase. But I did always thought mass played a huge role in gravitational influence, as mass creates gravity, even in minuscule scales. Like black holes to starts, stars influencing each other, and stars planets, and planets moons, etc.

Matt

Would you like to know why mass doesn't matter here? Or shoud we wrap up the conversation?
Just because milk is white doesn't mean that clouds are made of milk.

WAS

Quote from: Matt on November 02, 2018, 07:12:54 AM
Would you like to know why mass doesn't matter here? Or shoud we wrap up the conversation?

Sure, though I imagine it's just the size of the mass in relation to the absolute massive mass (ha pun) of Earth.