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Physics, Astronomy & Cosmology / Re: Is it possible to define infinity?

« on: 03/12/2017 02:10:15 »

Not sure if this has been mentioned as yet but I had heard an explanation to these regards recently. There are 2 kinds of infinity. Countable infinity and uncountable infinity. Where countable would refer to whole numbers and uncountable includes the infinite amount of numbers between each whole number as well

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That CAN'T be true! / How does an expanding propellant move a spacecraft?

« on: 03/12/2017 01:51:21 »

Space flight is impossible by every standard that has been used. Now hear me out before totally dismissing the topic outright.

I've been thinking about the propellant system on SIS and shuttles when docking. In searches I've run across several differing explanations of how a pressurized cylinder creates the momentum to change velocity a trajectory once out of the atmosphere.

My problem is explaining how a pressurized propellant initiates a thrust or momentum change when the propellant is allowed to expand at the rate of its release. There is not an energy transfer to create such a driving force.
Secondly since objects become weightless relative to their own self frame of reference the directional loss of mass propelling an object in the opposite direction don't live either. That would be like kicking off of yourself to swim instead of kicking off of water to swim forward. And by those same standards any type of propulsion is just as useless. So what gives? If I'm wrong and I kind of hope I am, I'd appreciate an explanation that satisfies my problems.