Space Exploration

[marcusluvsvols]

This is part of why i say mankind will never travel beyond our own stars orbit...unless visiting aliens shared their technology, or crashed and we could reverse engineer it...the distances between planets and stars are so incredibly vast...in most cases unimaginably so. A piece of paper may say 10,000 light years...or 100 billion miles...but we cant really visualize that. It is hard to even visualize 1 million of something. To explain a million to my kids, i always said " if i had bills that were 1,000 dollar bills...i would have to have a stack of 1,000 of them to have a million dollars." To try and really understand stellar distances isnt really possible rationally, thats why we just represent them with numbers and exponents. It seems that as far as any realistic distance goes, it seems that mankind is all alone.

 

[Grand Vol]

Question for you rocket scientists.

Space is a vacuum so that means there is no air of any kind, right? So how do rockets, thrusters, ext work in a vacuum? If there is nothing to push against how does that work?

Basically, rocket engines (and thrusters which are mini rocket engines) are a controlled explosion that vents the power of that explosion directionally. Long story short, Newtonian physics says a body in motion will stay in motion until an external force counters it (Law 1). Any body in space is actually "in motion" and the force of the explosion acts as that external force. And with Law 1, you get Law 3 about action-reaction.

Vacuum or not, any explosion will expand outwards from the central point. The rocket engines are just directing the force of that explosion out the bell of that rocket.

 

[Hunerwadel]

This never made sense to me. I guess it's the duality of light. Because a photon of light has mass, and it travels at light speed.

Actually a photon does not have mass. The duality of light refers to the fact that it can be both a wave and a particle. It is a massless particle however.

 

[hog88]

Basically, rocket engines (and thrusters which are mini rocket engines) are a controlled explosion that vents the power of that explosion directionally. Long story short, Newtonian physics says a body in motion will stay in motion until an external force counters it (Law 1). Any body in space is actually "in motion" and the force of the explosion acts as that external force. And with Law 1, you get Law 3 about action-reaction.

Vacuum or not, any explosion will expand outwards from the central point. The rocket engines are just directing the force of that explosion out the bell of that rocket.

I know how a rocket engine/thruster works with an atmosphere. My question in it's simplest form is what is that explosion (thrust) pushing against since in space there are no air molecules.

 

[VolStrom]

I know how a rocket engine/thruster works with an atmosphere. My question in it's simplest form is what is that explosion (thrust) pushing against since in space there are no air molecules.

Newton's third law: For every action, there is an equal and opposite reaction

 

[LouderVol]

Actually a photon does not have mass. The duality of light refers to the fact that it can be both a wave and a particle. It is a massless particle however.

A particle has mass, it has substance, otherwise it is a wave.

It's my understanding a photon has mass the same way it can act as a wave or a particle under observation vs not. Basically if we try to measure its mass it acts like a wave, but if we dont measure it acts like a particle.

 

[C-south]

I know how a rocket engine/thruster works with an atmosphere. My question in it's simplest form is what is that explosion (thrust) pushing against since in space there are no air molecules.

Another question I have is once you reach whatever speed couldn’t you just shut down the thrusters or whatever is propelling you and coast at that same speed until you counter that propulsion?

 

[Hunerwadel]

Newton's third law: For every action, there is an equal and opposite reaction

Newton couldn't have said it any better.

 

[hog88]

Another question I have is once you reach whatever speed couldn’t you just shut down the thrusters or whatever is propelling you and coast at that same speed until you counter that propulsion?

When we went to the moon they sling shotted around the earth and pretty much stayed at a constant speed without propulsion for the whole trip.

 

[hog88]

Newton's third law: For every action, there is an equal and opposite reaction

Withing our atmosphere the reaction to thrust pushing on air molecules is movement, hence my question.

 

[VolStrom]

Withing our atmosphere the reaction to thrust pushing on air molecules is movement, hence my question.

You don't see gravity, but it exists. Air is nothing more than friction in each direction.

 

[Orangeburst]

Withing our atmosphere the reaction to thrust pushing on air molecules is movement, hence my question.

It is the gas expansion from the liquid or solid rocket propellant as it combusts and exits the nozzle
I would think the thrusters on the Apollo command module were just high pressure inert gas released to space

 

[LouderVol]

Another question I have is once you reach whatever speed couldn’t you just shut down the thrusters or whatever is propelling you and coast at that same speed until you counter that propulsion?

For the most part you can. Most of our launches are still near earth and in earth's gravity so you have to counter that. But in deeper than earth orbit space that need goes away. I have no idea how big that bubble is. I dont know of it matches the magnetic sphere we have.

 

[Hunerwadel]

A particle has mass, it has substance, otherwise it is a wave.

It's my understanding a photon has mass the same way it can act as a wave or a particle under observation vs not. Basically if we try to measure its mass it acts like a wave, but if we dont measure it acts like a particle.

Like I said I'm no physicist but I play one on VN. One thing I am sure of though is that light has no mass either as a particle or a wave. Either or is not really accurate. Light is actually both. An extrapolation of that is why Schrödinger's cat is both dead and alive.

Light has no mass so it also has no energy according to Einstein, but how can sunlight warm the earth without energy?

 

[hog88]

It is the gas expansion from the liquid or solid rocket propellant as it combusts and exits the nozzle
I would think the thrusters on the Apollo command module were just high pressure inert gas released to space

Yeah but what was that gas pushing on to move the capsule?

 

[Grand Vol]

I know how a rocket engine/thruster works with an atmosphere. My question in it's simplest form is what is that explosion (thrust) pushing against since in space there are no air molecules.

It's pushing against the sides of the chamber itself.

 

[Orangeburst]

Like I said I'm no physicist but I play one on VN. One thing I am sure of though is that light has no mass either as a particle or a wave.

Light has no mass so it also has no energy according to Einstein, but how can sunlight warm the earth without energy?

Light is not particle and is electromagnetic radiation. Have a cookie!

 

[Orangeburst]

Yeah but what was that gas pushing on to move the capsule?

The mass of the object opposite the discharge side

 

[hog88]

It's pushing against the sides of the chamber itself.

I partially understand the explanation Huner gave, it's just one of those things that has puzzled me.

 

[Grand Vol]

Yeah but what was that gas pushing on to move the capsule?

I think you're getting caught up on the vacuum thing. Basically, the explosion is "pushing" against the chamber that ignites the fuel and oxidizer and then "following" the path of least resistance out the rear of the rocket. That "path" is what is producing thrust by pushing against the rocket motor which in turn is pushing the entire assembly.

Atmospheric content or lack thereof has nothing to do with the basic dynamics of a rocket engine.

 

[LouderVol]

Like I said I'm no physicist but I play one on VN. One thing I am sure of though is that light has no mass either as a particle or a wave.

Light has no mass so it also has no energy according to Einstein, but how can sunlight warm the earth without energy?

It has no observable mass. Not necessarily no mass at all. They way I have heard it explained is we dont have the tools to "see" anything relating to light, because it is the very thing we use to study itself.

Why can light not escape black holes if it has no mass? Gravity only works on things with mass. Waves can escape but light cant. At least some waves can.

 

[Grand Vol]

It has no observable mass. Not necessarily no mass at all. They way I have heard it explained is we dont have the tools to "see" anything relating to light, because it is the very thing we use to study itself.

Why can light not escape black holes if it has no mass? Gravity only works on things with mass. Waves can escape but light cant. At least some waves can.

Is light a particle or a wave?

 

[Orangeburst]

Is light a particle or a wave?

I looked it up and came up with conflicting info. It has to have mass with black hole?

Looks to exhibit properties of both

 

[Grand Vol]

I looked it up and came up with conflicting info. It has to have mass with black hole?

Light, to my limited physics understanding, behaves as both a particle and a wave. Hence, scientists won't call it either one since it acts strangely having attributes of both. Light, along with gravity, sometimes baffles the scientific community since it doesn't "fit" into the models.

 

[Orangeburst]

Light, to my limited physics understanding, behaves as both a particle and a wave. Hence, scientists won't call it either one since it acts strangely having attributes of both. Light, along with gravity, sometimes baffles the scientific community since it doesn't "fit" into the models.

Let’s ask Huff. He is a polymath