# Tag Info

94

This is a pretty interesting topic, and one of the things that makes special relativity so mind blowing. But the answer is: From your perspective on board the ship, the computer will function just as fast as it would if you were using it on Earth. After all, physics doesn't care about which inertial frame of reference you're in, so it wouldn't make any ...

38

Is there a theoretical method of inferring a "universal" time that FTL travellers can use for their clocks to maintain a constant time? Generally, no. There is no universal time, period. Relativity tells us that it is impossible to put a time ordering relationship between spacetime events that are not in their respective light cones, or in other words, ...

33

The only answer I can think of that doesn't require warping the laws of physics or a ridiculously huge energy budget is: Tugmines Basically ridiculously powerful engines fastened to mildly ridiculously powerful magnetic clamps. Unmanned, a Tugmine will seek out, match velocity with and fasten onto any ship not broadcasting the correct IFF (or, if ...

27

Approach the speed of light with respect to what? Right now there is an electron flying around in a synchrotron somewhere which is moving at an appreciable fraction of the speed of light with respect to you and your computer: which means that you and your computer are moving with an appreciable fraction of the speed of light with respect to that electron. ...

26

Time dilation comes from gravity and/or velocity. Since the planet is not orbiting a black hole it would either have to orbit another super heavy mass or fly through space with a lorentz factor of 0.5 (when seen from earth) as that would equal time dilation of a factor 2. $t_{planet} = \gamma * t_{earth};$ with $\gamma$ being the lorentz factor of $\... 25 In hard sci-fi we have nothing - since we don't have FTL or anything approaching it then it's impossible to do anything beyond pure speculation in terms of anti-FTL. My suggestion would be some sort of warp or distortion field that you apply over an area. It distorts the space within the field in a way that interferes with drives, or maybe even with the ... 23 No. In General (and indeed Special) Relativity, there is actually no such thing as "the time on Earth" from the point of view of a distant observer. There is also no such thing as "the place it was set". Relativistically speaking, the only things that make sense are events - which in non-relativistic terms, can be thought of as a combination of a time and ... 20 Triangulation from X-ray Pulsars Timing and navigation are inextricably linked. The mechanical clock enabled the first calculation of longitude. GPS navigation depends on comparing arrival times (and thus distances) of different satellite signals. In a FTL future on a galactic scale, ships would want to use a 'GPS' system to determine their location in ... 19 Nothing we know of could achieve that. There are two things that distort time: velocity and gravity 18 minutes per 24 hours is a dilation factor of 1.0125. ($\frac{24hours + 18minutes}{24 hours} = 1.0125$) Velocity Velocity is out of the question as you can't just accelerate the planet and have it keep a stable orbit around the sun. Also you would ... 16 Yes. Though it's not immune, it's just informed. Luckily you have no limit on complexity or size, because it's not going to be simple or small. This isn't any kind of shielding, the time is simply adjusted given proper inputs. In the same way we would be able to calculate the effects from time dilation given the proper information about the system, like ... 16 Let's pretend the whole universe uses Earth years, days, etc., for the sake of this example. However, any universal system would work for this. Before the ship begins to travel, it decides that your destination is 0.5 light-years away. Next, it decides that you'll be traveling at exactly twice the speed of light. For the sake of simplicity, your ship's ... 16 This has nothing to do with speed of light and, indeed, with any possible means of transmission. You are effectively "backing-up to storage" whatever you need to transmit and then "recreate a perfect copy" some time later, possibly in a different location. Actually it doesn't even matter if you destroy the "original" or not. In this condition you can even ... 13 Let's first do some math, the first part taken from this pdf regarding (solar) radiation pressure (the formulas should be applicable from any source of electromagnetic radiation). The intensity$I$depends on the power$P$and the distance from the source$r$. We can write the expression $$I=\frac{P}{4 \pi r^2}$$ The force$F$depends on the intensity and ... 12 You are speaking about a spacetime geometry where the shortest path between two points will result in longer proper time of the traveller - in other words, unlike our Minkowski geometry, the universe would be governed by Riemannian geometry. Metric signature would be (+,+,+,+) instead of (−,+,+,+), which means there is no distinction between spacelike and ... 12 Let's start with the energy-momentum equation: $$E^2=p^2c^2+(m_0c^2)^2\tag{1}$$ This can be derived according to the Minkowski metric. This works because the inner product of the four-momentum,$\langle\mathbf{P},\mathbf{P}\rangle$, is equal to$|\mathbf{P}|^2=-(m_0c)^2$. We can also use $$\langle\mathbf{P},\mathbf{P}\rangle=P^\alpha\eta_{\alpha\beta}P^\beta=... 12 Travelling at near-light speed is indistinguishable from being at rest. This is the principle of Galilean relativity, and is preserved under special relativity: there is no feasible experiment to determine whether you are stationary or moving at a constant velocity. So there are no practical problems that would occur simply from moving at near-light speed ... 12 From all of the answers and the comments therein, I think the issue is simply a lack of understanding of relativity, so this answer is mostly just going to be a primer in how to think about it. I am not a teacher, nor a physicist. Forgive me if I make errors, and point them out so I can correct them. However, I am friends with an excelent physics teacher, ... 11 Change how you think about gravity. It's common to think that you generate a gravity well, and then that gravity distorts spacetime. But that's not the case. Mass distorts spacetime, and that distortion effect is gravity. You're running into issues because you're trying for a secondary effect. You want to generate a gravity well (which crushes things ... 11 Chaff Since few spaceships are likely to be steered manually, chances are they've got instruments and RADAR/LIDAR style sensors so they can tell what speed it is safe to fly at. At high speeds, even simply dust can cause major damage (or drain shields / power etc) - so these automatic instruments adjust the speed to try and reduce the possibility of damage. ... 11 Wow that's a whole lot of question marks, I'm going to give you the Larry Niven special on 1G travel times. This comes straight out of the essay Bigger Than Worlds which I thoroughly recommend to any serious world builder, according to Niven it takes: four years to the nearest star, twenty-one years to the galactic hub, twenty-eight to Andromeda galaxy-... 11 As others have pointed out, messing with spacetime here on a scale that doesn't screw up earth's orbit, etc etc would make time seem slower for people observing us from a different frame of reference. Since we want as many people as we can to notice we can: Alter spacetime around the objects we use to measure time One could argue that most people tell the ... 10 Rivers are measured in flow rate, the volume that passes a given cross section in a given period. This makes it easy for us because your town boundary is a cross section. Let's go with cubic metres per second (m^3/s) for the flow rate and an arbitrary value of a factor of 10 on the time dilation. Generally the flow rate of a river is fairly constant. It'... 10 Everything dies. In fact, everything dies in a manner much more spectacular than if you had crashed the moon against Earth. Or Venus. Or even Saturn. The physics and mathematics behind this are enough to fill a few books, but the short version of it only needs you to take a couple things into account: Wormholes have mass. Yes, even if they are the Ellis/... 9 A day in deep space is the same length as on Earth. About 86,400 seconds. It looks the same to someone in either place. The only difference shows up when deep space clocks and Earth clocks check against each other. Gravitational time dilation on Earth goes like this:$$T = {{T_0}\over {\sqrt{1-{{2gR}\over{c^2}}}}}$$Where,$T_0\$ is the proper time ...

9

Your universe has a much, much lower speed of light than ours. Say, 1000 meters per second. Relativistic effects become dominant at attainable speeds.

8

How about sand bombs? Containers full of fine particles that spread out into dust in an area of space. They would continue to disperse, so the effect would be temporary, but for a limited duration, there would be a fairly large amount of particles in space that might bounce off the hull of a ship. I have to imagine what the transition from high ...

8

Negative mass. You have FTL so the door is open for other spooky entities joining the party. Negative mass produces a repulsive effect - the opposite of gravity. A cloud of negative mass will produce a repulsive effect on other mass. This will be constant, and the negative mass particles will chase the positive mass of the ship, continuing to repel it - ...

8

In general, there are no effects doe to being at speed. We are travelling at 90% c from their point of view — does that suddenly make things happen? Now moving through space at high speed has real problems because the oncoming gas and dust will be near lightspeed, and lorentz contraction of the path you’re on will make you see a higher density of material. ...

8

There are no relativistic effects. This is a pedantic answer directly addressing the OP's question. The encoded information is effectively a snap shot of the person. A snap shot image doesn't experience anything. It's simply a signal travelling across interstellar space. The person is simply reconstituted from the information in the encoded signal. The ...

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