This is how NASA would respond to an asteroid impacting Earth

a reply to: OneBigMonkeyToo

The air doesn’t just sit there. when a car passes you why do you feel the wind if the air is just going to sit there when the smoke moves through the air?

a reply to: NicSign

Did you learn anything at school? Sounds like you were not paying much attention, to say the least.

a reply to: oldcarpy

maybe if you went to school you have come up with a better comment

a reply to: NicSign

School, university, professional qualification, thank you very much.

Maybe if you had paid attention at school you would have a basic understanding of stuff? Perhaps you could have then been able to write a proper sentence?

a reply to: oldcarpy

again your comments are empty

Every day at some point I look up in the sky and expect to see the asteroid zooming in behind a trail of sparks and smoke, and then that will be the end. However, if an asteroid were to strike, it would probably out in the Pacific or Southern Indian Ocean and late at night when I'm sleeping. There will be a rumble, and then we all get hit by a blazing, garbage-filled shockwave moving at multiple times the speed of sound. Then that will be the end.

Hasn't happened yet, though. Fingers crossed.

originally posted by: NicSign
a reply to: DAVID64
When you drop something from a height, does it push back on your hand?
Similarly, the gas doesn’t push off the rocket unless there is resistance to cause back pressure

The analogy is false and employing it indicative of mild mental retardation. Stand on a skateboard and throw a heavy ball and you will move, not because of air resistance and pressure against your hands (if that's how it worked, you wouldn't need the ball, and let's not even go into the existence of the same air resistance from behind or the vastly greater friction on the wheels), but because of a little thing called conservation of momentum.



Specifically, when you have an explosion, the fragments of that explosion aren't just expanding in one direction. How is it that you cannot grasp that the particles of gas inside the rocket are not just flowing directly out the rear end but have a momentum in the forward direction of the rocket? And what do you think happens to all that momentum? it magically disappears or is reversed withotu affecting the body of the rocket?

Does this guy think that objects can be pushed around in a vacuum at will without any force pushing back? How does that square with Flat-Earthers "objects fall because of pressure" hypothesis? Then again, I've never understood how they imagine objects still fall in a vacuum or how this "pressure" specifically acting in a "downward" direction is any less "magical" than Newton's gravitational force.

a reply to: ElGoobero

meh...this is probably to get more funding. We know they've given the 1%ers the real timing of any ELE impact. Bunkers built long ago.

Bread & Circuses

Never A Straight Answer

originally posted by: ketsuko
a reply to: Zanti Misfit

"Solar winds will be caught by the mylar sails ..."

Yes , In Theory ..................)

a reply to: OneBigMonkeyToo

M father had a masters in electrical engineering, taught physics at local college

Worked for General Electric (GE) on guidance systems for missiles

Remember as a senior in high school trying to read one of his reference books THEORY AND PRACTICE OF INERTIAL GUIDANCE

Didn't get too far ………..

originally posted by: Theosist

originally posted by: NicSign
a reply to: DAVID64
When you drop something from a height, does it push back on your hand?
Similarly, the gas doesn’t push off the rocket unless there is resistance to cause back pressure

The analogy is false and employing it indicative of mild mental retardation. Stand on a skateboard and throw a heavy ball and you will move, not because of air resistance and pressure against your hands (if that's how it worked, you wouldn't need the ball, and let's not even go into the existence of the same air resistance from behind or the vastly greater friction on the wheels), but because of a little thing called conservation of momentum.

9First off, I fixed your video embed (don't put the entire YouTube address in between the "yvid" code -- just the part of the YouTube address after the "=" sign. In the case just the Kf0bBxmNeec goes inside the "yvid" code)


Secondly, you are correct. For example, if I threw a 5-inch diameter, 15-pound iron ball from the skateboard, the skateboard would move in the opposite direction more than if I threw a 20-inch diameter 1/4 pound inflated beach ball -- even though there would be more air resistance on the large cross-sectional-area beach ball than on the smaller cross-sectional-area iron ball.

So as you point out, air resistance is not the major factor here.

originally posted by: TheConstruKctionofLight
meh...this is probably to get more funding. We know they've given the 1%ers the real timing of any ELE impact. Bunkers built long ago.

That's all fine, but you know that the 1 Percenters get their wealth from the rest of us poor slobs. And without a decent number of us around, they'll have to wax their own yachts and change the oil in their own hovercars. So they better be planning First Class bunkers for themselves and a whole lot of Coach bunkers for us proles.

explosion of solid fragments is not gas expanding in space. The built up pressure breaks the container creating shrapnel. The pressure pushes off these pieces. Try lighting a fire, see how the smoke just goes up and not toward the ground?

originally posted by: NicSign
explosion of solid fragments is not gas expanding in space. The built up pressure breaks the container creating shrapnel. The pressure pushes off these pieces. Try lighting a fire, see how the smoke just goes up and not toward the ground?

How are gas molecules different from solid fragments in this example?

Gas molecules have kinetic energy and collide with each other or anything they encounter, exerting pressure.

In a rocket combustion chamber, what happens to the pressure exerted by gas molecules in the direction opposite the thruster?





Remember, the gas isn't simply escaping the chamber; the fuel has been combusted to create tremendous pressure and temperatre. All that molecular kinetic energy has to go somewhere, and it can't all just go "poof" out of the engine bell and not do anything to the rocket.

a reply to: wildespace

but how come you can't observe the force you use vacuum to create air flow like in the video?

a reply to: Soylent Green Is People

"Conservation of momentum is a fundamental law of physics which states that the momentum of a system is constant if there are no external forces acting on the system. It is embodied in Newton's first law (the law of inertia)."

The external force is provided by pressure gradient force, not the rocket.

originally posted by: NicSign
a reply to: Soylent Green Is People

"Conservation of momentum is a fundamental law of physics which states that the momentum of a system is constant if there are no external forces acting on the system. It is embodied in Newton's first law (the law of inertia)."

The external force is provided by pressure gradient force, not the rocket.

What would create a greater pressure variant in the skateboard thought experiment I mentioned above -- throwing the 15-pound/5-inch diameter iron ball or throwing the 8-ounce/20-inch diameter inflated plastic beach ball?

originally posted by: NicSign

- The tank car might have not imploded if it were designed to withstand the pressure gradient.
- The soda can might have not exploded if it were designed to withstand the pressure gradient.


- Submarines and deep-water submersibles are designed to withstand the tremendous pressure gradients/differences between the inside and the outside that they might experience so they do not implode like that tank car.

- Rocket fuel tanks are designed to withstand the pressure gradients they might experience so they do not explode like that soda can.


Edit to Add:
By the way, you are right that the pressure gradient between the inside of the combustion chamber and the outside is important to rocket propulsion. The difference in pressure between the inside of the chamber and the outside is what causes the expanding/combusting fuel to shoot out the nozzle -- i.e. in an attempt to equalize the pressure inside the combustion chamber with the pressure outside.

It is this equalization of pressure that makes the propellent soot with a force out of the nozzle in one direction, AND causes an equal face in the opposite direction, pushing the rocket.

Once the pressure inside the combustion chambers and the pressure outside are equalized (when the fuel is spent and there is little left to burn), their is no physics reason for their to be anything coming out of the nozzle with a force because their is no longer a pressure gradient, so the rocket propulsion stops.

a reply to: Soylent Green Is People

again you claim that there is an equal and opposite force due to gas movement from pressure gradient force but fail to provide proof