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1 point

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18th Jul 2017

You're just a couple hundred years out of date on your physics. Neither freefall nor orbit (orbit being freefall) are accelerated frames of reference in relativity. They're only accelerated frames of reference if you ignore spacetime in favor of space.

But seriously, try this: https://www.amazon.com/dp/B004P1JDYY/ref=dp-kindle-redirect It's really readable about how relativity works by one of the greatest physics minds of the century, with math no worse than Pythagorean theorem.

1 point

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11th Jan 2017

Flat means not curved. I.e., euclidean. A map is flat. A globe isn't. Since it doesn't curve, it doesn't come back upon itself. There isn't enough stuff in the universe to cause everything to get attracted back to itself, when you count in the repulsive force of "negative energy" (aka "dark energy").

Try this one: https://www.amazon.com/dp/B004P1JDYY/ref=dp-kindle-redirect

1 point

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11th Aug 2016

A much better explanation that has almost no math:

https://smile.amazon.com/Six-Not-So-Easy-Pieces-Relativity-Space-Time-ebook/dp/B004P1JDYY/ref=sr_1_1

Object don't roll together because the lycra is lower at one point than the other, but because the lycra is stretched. I.e., a non-stretchy thing (like twine) taped to the lycra before you put the weight there will be too short.

1 point

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20th Jul 2017

> we never experience forces large enough to require more precission

Yet, we're discussing a video game where we use black-hole powered technology to form Einstein-Rosen bridges providing FTL travel between the Earth and the Moon. I'm pretty sure that if we're going to discuss whether a portal is moving or not, you need to use the Einstein calculations for what is moving. (Remember that the original question surrounding this was "can portals be placed on moving objects" and someone said "yes, because the sun is going around the middle of the galaxy.")

> if you found sources that shows things at a BA level of physics

I already provided three Wikipedia pages (with actual quotes from actual Einsten) and a textbook by potentially the most famous teacher in theoretical physics. I'm not sure just what you're looking for, if not a different textbook or something. General Relativity isn't really an intro physics topic.

That said, here are some texts that I found really helpful:

https://en.wikipedia.org/wiki/QED:_The_Strange_Theory_of_Light_and_Matter if you want a explain-to-Mom level of how quantum physics works, as explained by the guy who won a nobel prize for figuring out a really easy way to explain quantum physics to theoretical physicists. Altho given the pictures in it, I wouldn't recommend getting the Kindle version.

"Six Not So Easy Pieces" https://www.amazon.com/dp/B004P1JDYY/ref=dp-kindle-redirect if you want relativity explained by the same guy, with math at the level of Wizard of Oz Scarecrow math. :-) Again, it's probably best to skip the Kindle version for this. ("Six Easy Pieces" is great if you don't have much understanding about science or physics at all, but I assume you know enough to skip explanations of the Scientific Method and the concept of Symmetry/Concervation laws and stuff like that.)

https://www.amazon.com/dp/B002TJLF7W/ref=dp-kindle-redirect goes into the topic as well, in an understandable way, coming at it from a somewhat orthogonal direction.

https://www.amazon.com/Quantum-Universe-Anything-That-Happen-ebook/dp/B006U6IBEU/ref=sr_1_6 is another take on quantum physics and how it interacts with relativity. It presents it in a very different way from QED, and if you really get interested I'd recommend reading both those books.

> you can stabilise wormholes wit antimatter

Negative matter, yes, which means negative gravity rather than negative charge. And the portal gun has a black hole in it. That's because it's fiction. :-)

Nevertheless, if you're going to argue "the portal is moving because the Solar system orbits the galaxy," you're going to have to use Newtonian physics to make that argument, which is wrong in the *fictional* space of the game. Because according to Newton, there's no such thing as a black hole *or* an Einsten-Rosen wormhole, as these concepts just don't have any meaning in an environment where space is absolute and there's no upper limit on relative velocity. And according to Einstein, the portal isn't moving just because the surface it is on is orbiting.

And if you want some fiction about how portals would *actually* work, there's this https://www.amazon.com/Timemaster-Robert-L-Forward/dp/0312852142/ref=asap_bc written by a physicist guy who built the gravity detectors they took up in the space shuttle. (I thought it was the "forward mass detector" like the one at the front of the space ship. Nope. The Robert Forward Mass Detector.)

> ISS accelerometer should show close to 0g as it is in free fall

Exactly! So the ISS isn't accelerating, is it? Which means it's undergoing inertial movement. That, right there, is general relativity. The only other question to ask is "why does it *look* like it's bending, if it's really going in a straight line?" That's basically general relativity right there. :-)

1 point

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4th Jun 2017

A dimension is something where the measure is independent of other measures. One thing is orthogonal to another if its measure is independent. So temperature is a dimension, time is a dimension, width is a dimension, friendliness is a dimension, etc.

What you want to look at is vectors. A vector isn't just a series of numbers. It's a series of numbers that has certain properties independent of its frame of reference. If you draw a line segment on graph paper, that's a vector, in that it has the same length regardless of at what angle you draw the squares on the graph paper. x^2 + y^2 and all that. It implies there's something real about the vector independent of the numbers being used to describe it.

Similarly, if you have a typical office desk that's five feet wide and three feet high and four feet deep, it's going to be the same shape regardless of what direction you look at it from.

It's also going to last the same length of time, regardless of what direction you look at it from.

Time *is* related to the other three spatial dimensions. When you turn your head, width becomes height, and height becomes width. When you move fast enough, forward becomes future and future becomes left, or some such.

Give this a go for a start: https://www.amazon.com/dp/B004P1JDYY/ref=dp-kindle-redirect

As an aside, here's a discussion of what happens when time flows in the same direction as space: http://www.gregegan.net/ORTHOGONAL/00/PM.html

0 points

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18th Jul 2017

> You should probably go brush up on basic physics

You should probably brush up on advanced physics.

> This is literally newton's second law.

You may have heard of this guy named Einstein? If Newton was right, the speed of light would not be an upper limit on velocity.

But seriously, try this: https://www.amazon.com/dp/B004P1JDYY/ref=dp-kindle-redirect It's really readable about how relativity works by one of the greatest physics minds of the century, with math no worse than Pythagorean theorem.

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