The power to propel us to the stars

chuckpeterson

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Every observer, no matter what their velocity, sees the light traveling at the speed of light relative to them. Freaky, but true.

It was your use of the phrase relative to them; that won the day.
Thanks for sticking with this long enough to teach me something new
 
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chuckpeterson

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Every observer, no matter what their velocity, sees the light traveling at the speed of light relative to them. Freaky, but true.
Let’s take this one step further using your example. Lets say there is a third person who is not in the station and is in fact stationary in space. This observer see’s the station passing by and sees the light beam shining out the front.

The stationary observer sees the station and observes its speed. The observer also sees the light beam shinning out the front of the station.

Now let’s expand this hypothetical and say the station is traveling at 1/2 the speed of light. The light leaving the station is either traveling the speed of the station+the speed of light;

Or, the observer is seeing the station traveling ½ the speed of light and the light speed leaving the station is traveling at ½ the speed of light?
 
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chuckpeterson

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I won't likely start a thread, but if I do or if there is a good debate/discussion, then I will tag you.
Just to expound on my ignorance, until your post I didn't even know what a "tag" was or its purpose.
 
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Yttrium

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Now let’s expand this hypothetical and say the station is traveling at 1/2 the speed of light. The light leaving the station is either traveling the speed of the station+the speed of light;

Or, the observer is seeing the station traveling ½ the speed of light and the light speed leaving the station is traveling at ½ the speed of light?

Neither. The light leaving the station is traveling at the speed of light. The observer sees the light leaving the station at the speed of light.
 
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chuckpeterson

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galileo.png

The power to propel us to the stars

Getting back to the OP; I don’t thing we can travel within our solar system and beyond using some form of “fuel”. That is why I believe we need to use the force of gravity, from solar systems to the gravity of galaxies.

The Galileo project is a good example. The Galileo space craft could not have gotten to where it went using the power of on board “fuels” to get it to where we wanted it to go. It used the forces of gravity.
 
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chuckpeterson

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Neither. The light leaving the station is traveling at the speed of light. The observer sees the light leaving the station at the speed of light.
Ok, lets jump to the core of this discussion.

Hypothetically, the station is traveling at the speed of light. A flashlight shines a beam of light out ahead of it.

How fast is that beam of light traveling?
 
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Yttrium

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Getting back to the OP; I don’t thing we can travel within our solar system and beyond using some form of “fuel”. That is why I believe we need to use the force of gravity, from solar systems to the gravity of galaxies.

The Galileo project is a good example. The Galileo space craft could not have gotten to where it went using the power of on board “fuels” to get it to where we wanted it to go. It used the forces of gravity.

So you want a gravity lens that will focus the gravity on a spaceship to propel it? Hmm. If you find a way to do it, you'll need to be careful. You don't really want to accelerate faster than one g, although you could keep the acceleration going up to the halfway point then decelerate at the same rate. Too much g-force, and you could squoosh your space travelers into thin past.

Have you heard of light sails? We could sail the starlight. It takes a real long time to accelerate and decelerate, so it would be a very long trip, but you wouldn't have to carry much fuel on board.
 
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Yttrium

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Ok, lets jump to the core of this discussion.

Hypothetically, the station is traveling at the speed of light. A flashlight shines a beam of light out ahead of it.

How fast is that beam of light traveling?

The speed of light. (But the station and flashlight would have to be energy, not matter, which doesn't really work.)
 
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sjastro

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Ok, lets jump to the core of this discussion.

Hypothetically, the station is traveling at the speed of light. A flashlight shines a beam of light out ahead of it.

How fast is that beam of light traveling?
The answer has been already given by a number of individuals including the mathematical treatment why the answer will always be c.
 
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keith99

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Let’s take this one step further using your example. Lets say there is a third person who is not in the station and is in fact stationary in space. This observer see’s the station passing by and sees the light beam shining out the front.

The stationary observer sees the station and observes its speed. The observer also sees the light beam shinning out the front of the station.

Now let’s expand this hypothetical and say the station is traveling at 1/2 the speed of light. The light leaving the station is either traveling the speed of the station+the speed of light;

Or, the observer is seeing the station traveling ½ the speed of light and the light speed leaving the station is traveling at ½ the speed of light?

Fine if you can determine just which observer is stationary. But you cannot, that actually is how teh whole relativity issue started in attempts to find just who is stationary.

Any observer in an inertial frame of reference (i.e. is not accelerating) is just as stationary as any other observer in a different inertial frame of reference.
 
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Ophiolite

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Ophiolite said: Basing your beliefs upon your own incredulity may be satisfying, but it's not very smart.

I had to look it up; reveling my obvious stupidity
No. It merely revealed a gap in your vocabulary. No one knows all the words in the English language.

believe me, you are wrong, I do believe; it just may not be what you believe
Your method of arriving at beliefs, in the face of much contrary evidence, does not encourage me to believe you about anything. I recommend, with complete sincerity and a healthy bite of concern for your well-being, that you adopt a more sceptical view of your own current beliefs.
 
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Ophiolite

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I honestly believe you know what you are talking about when I in fact know I don’t.

So please, just answer this simple question---

As a hypothetical;
I am traveling in the space station and I am sitting at a window that is facing forwards. The station is traveling at 1,000 miles a hour; I shine the flashlight out the window in front. The flashlight & I are traveling at a speed of 1,000 mph. The light shinning out from my flashlight is traveling at the speed of light plus the speed of the station.
Station 1,000 mph+light speed 186,000mps =187,060mph
No. Others have given the equations that deal with this. It's not an area that interests me much. As a geologist the fastest thing I have to think about are asteroids that hit the Earth and wipe out dinosaurs. They are much slower than light.
 
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