![]() 07/16/2014 at 01:49 • Filed to: None | ![]() | ![]() |
What I'm trying to say is, in space can a spaceship go straight up (at a 90 degree angle) or straight down? Time flows only forward and backward, not up or down. The Sun and other planets create depressions in space time fabric. However they cannot (and never) "sink" due to the Strong Force, Gravity, Newton's Laws, Relativity and Special Relativity. But, could a spaceship going at the constant of light speed (2.9972x10^8 meters per second) go under our galaxy?
For your time have a stanced C6 Audi A6 and some Ferrari parts.
![]() 07/16/2014 at 01:51 |
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There really isn't 'up' in space. It's more like (x,y,z).
![]() 07/16/2014 at 02:23 |
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Beat me to it.
![]() 07/16/2014 at 02:38 |
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I believe that a spaceship can travel in any direction if thrust is provided in the opposite direction.
![]() 07/16/2014 at 04:47 |
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This sounds like some bullshit argument they use in Star Trek to explain why the ships always approach eachother on the same plane/head on.
![]() 07/16/2014 at 10:07 |
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Well, as a physicist I may try to answer your question. I say try because, sorry, it is not very well formulated, it seems to me like a curiosity.
You ask about "going up" or "going down". But every movement is relative. You can't say that something is going up or down unless your reference frame, or from where are you looking to that moving thing. Suppose, for example, you are Batman, hanging upside down. From your point of view, an apple falling from a tree will have an upward movement, so in your reference frame, the apple is "going up". But Robin, your sidekick, is in the ground, and he sees the apple "going down". This is a very simplified example, but it shows clearly (in my opinion) why you can't define movement without specifying a reference frame.
Furthermore, suppose now you are a little worm living inside that falling apple. Suppose there's no acceleration so, since F=ma, there's no force either. If there's no force, you can't feel anything (imagine yourself in an elevator. You only feel something when there's an acceleration or decceleration), so for your inertial reference frame ( inertial because there's no acceleration, so no force), the apple is not moving, but the world around the apple is "going up", until the ground touches the apple.
About the forces, you were great with gravity, but the strong force is what "glues" the protons and neutrons together inside the atoms' nuclei. However, it have an incredibly small range, i.e., you can't feel the strong force if you are further than a few angstroms (1 angstrom=10^-10 m) of the gluonic field (gluons are the virtual particles responsible by the strong force, by gluing the particles). Newton's Laws are valid only in inertial frames and in only for nonrelativistic speeds, i. e., v << c.
There's a confusion also between Special Relativity and General Relativity, but don't worry. The only difference (and an immense difficulty in the calculations), that for the first, special relativity, the fabric of space-time is completely flat (in 4 dimensions). All that stuff about warping the fabric of space time is subject of the general relativity. In a mathematical language, we say we describe the spacetime as a Minkowski space with a constant metric tensor (for special relativity) whereas for the general relativity the metric tensor can vary with the position (and vary due to the mass distribution or the electromagnetic fields).
Now, returning to your question, but answering with another question, how do you define "under our galaxy", if "under" and "over" depends on our reference frame?
![]() 07/16/2014 at 10:41 |
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yep that's it.
![]() 07/16/2014 at 11:51 |
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First off you're a physicist, I ENVY YOU :).
The FOR (Frame of Reference) is a ship coplanar to Earth in a straight path.
![]() 07/16/2014 at 12:17 |
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1 point defines, well, a point, but 1 point defines infinite lines and planes;
2 points defines 1 line, but infinite planes;
You need three points to define a plane. I assume that by "coplanar to Earth" you mean coplanar to the orbit of Earth, right? There's not wrong with that, but since we live in the Milky Way and we are unable to see us from a great distance, I don't know if anyone knows if the orbit of the planets is coplanar with our galaxy's disc. Our orbit around the sun can be even perpendicular to the galactic plane, like the rings of Uranus (no jokes, please) are almost perpendicular to its orbit:
But this is not important. If you have enough speed (and enough patience), you can leave our galaxy. You even don't need a ship moving at c (since it is impossible, because it would require an infinite amount of energy), but you do need a huge amount of time. Our galaxy is huge, with something around 100,000 light years of diameter (50,000 light years of radius, meaning that a light ray emitted from the center would take 50,000 years to reach the edge of the galaxy). The best estimate of our galaxy's disc thickness is around 1,000 light years, meaning that a light ray emitted from the center would take 1,000 years to "escape" from the galaxy. Considering a ship travelling at 99.99% of c, the ship would still take a lot of time to escape the Milky Way.
However, here lies a problem. For the people of Earth, the ship would take thousands of years to travel out of the galaxy (or "under" it). For the ship's crew, the trip would be much shorter because, at relativistic speeds, the length is contracted, and those 1,000 light years are contracted to a few. Supposing again the ship is travelling at 99.99% of the speed of light (0.9999 c), and the distance (for an observer at earth) is 1000 light years, the total distance, for a traveler inside the ship is
So, the ship's crew would take some months to arrive at the destination. Neat, huh?
![]() 07/16/2014 at 12:47 |
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Ah, the infamous Twin Paradox could be brought up.
![]() 07/16/2014 at 14:04 |
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Yeah, that paradox :-)
Did my answer helped? I hope I could clarify some things on your head.
![]() 08/11/2014 at 23:57 |
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If you really want to have fun with that question, go watch the old Starblazer anime series. The treat space and the movement of spaceships therein as a giant naval exercise. It's hysterical.