There is the Great Ghost Cluster in the distant void, passing messages up and down its endless stream of ghost bodies in order to log world events at the speed of voice.
This is actually an awesome writing prompt: The older ghosts get updates from the younger ones, and send stories back from their own lives, like a long telephone wire…
Odd how they chose gravity, but not the fact the earth is both rotating and revolving around the sun. Even more than that, the entire solar system is revolving around the center of our galaxy.
The way I interpreted it, is that gravity normally holds you on Earth despite all the effects you listed, and gravity not affecting this ghost, that’s the problem.
So do they just maintain their initial velocity or would we have a chance to discover the static reference velocity of the universe?
Also they would still be affected by gravity if they still exist in space. Gravity is not a force that pulls objects together. It is merely the act of going straight in curved space. Either they are in that space and they are going to move along it within the shape of that space or they are not in that space. Though really if they just moved in a straight line with no external forces they are going to be subterranean because a real straight line in our space is down.
We’re talking about ghosts here, we don’t know what laws they follow. That said, either you are right or they would be miles far from earth before being able to finish that first sentence.
to be a little pedantic, if you take in account the rate of expansion of the universe, and take as a truth that the ghost stays stationary in spacetime, earth would disappear in an instant
That’s a fair point. So then one might expect the ghost to continue their motion tangential to the orbit of the earth, and so they’ll float away.
However, the theory of general relativity suggests that gravity isn’t really like other forces. It doesn’t push or pull anything at all; but rather its bends the fabric of time and space. Objects ‘falling’ due to gravity, or ‘in orbit’ around a planet are actually moving in a direct straight line in curved space-time. And this is why gravity still applies to massless objects such as light. So then, I’d say the ghost would still be affected by gravity - and that their main concern would be falling into the earth rather than drifting away.
Would that not depend on your inertial frame? Like isn’t the entire concept of being stationary relative to spacetime not an actual thing? I’m not trying to be pedantic, BTW, I literally don’t know the answer to my question.
Yup. Same as the time travel meme that was on the front page recently, this relies on there being a fixed inertial frame which is not a thing in our weird universe.
I believe the current theory is that the big bang happened everywhere equally, like a stretch, so there is no specific spot we can point to where it happened.
I wonder if Fido knows how to handle that in his calculations.
No, because the solar system is moving together along the outer edge of the cosmos Milky Way. I don’t know if there’s anything such as a cosmic absolute frame of reference for “no motion”, but (depending on what you’re motionless in reference to) you would likely never see another soul.
Frankly. This… software rearranged my brain and changed me fundamentally.
There are no words to describe being lost in the 10^27 of space. It’s just too much, you will go insane and if you survive you will lose the ability to talk with people, lose every single thing that you thought matters. You will be alone even in the busiest of places, some part of you forever stuck in the 10^27 of emptiness between Galaxy Groups.
Wait wait wait, MY version of the religion says you must not kill because of differences in religion. We enforce this rule very strictly and with death.
But this character died stationary on the floor. Unless it’s the Earth moving away from her as part of its normal orbit, in which case she’ll get to visit it again soon
No because the sun and the earth are always moving in a line and an orbit in addition to their orbit.
The actual absolute position would resemble a curving helix or something. Nothing in the universe is ever in the same general location twice for our current understanding. Everything is moving.
I love these discussions, they’re not possible but I always learn something. Why would you believe that her drift axis is aligned with the sun and not the earth? What about the moon or Mars? Why do you think that the sun is special?
Ghosts are not matter. Thus they must be energy. But they’re still not massless. Uh uh, ghost wishes are like magnetism and uh…yeah, ghost wishes change axial drift, but only relative to things the spirit perceives as greater… fuck I need coffee to make this work.
The sun would be the natural parent coordinate system of Mars, Earth, and (grandparent of) The Moon. So I see her centered on either Earth, the Sun, the Centre of the Milkway, Centre of the Local Group, etc. etc.
The speed at which she drifted through the wall wasn’t on level of thousands of km’s per second, it was on the order of a few meters per second.
This would admittedly rule out the Sun, since the Earth has an orbital speed of 29 km/s around the sun[1], and a spin velocity of 0.5 km/s[2], giving a minimum of 28 km/s. If we factor in orbit of the sun from the Galactic Centre at 240 km/s, giving 240 +/ 29, which is still too high for our range. If we factor in the speed of the Galaxy, then we’re just adding more zeroes.
What about the moon or Mars?
So, to come full circle on my comment: Yeah maybe, the relative speed of moon and Mars would be on the order of meters per second that we see in the panel. I just don’t see why they of all planetary bodies would be chosen for ghosts, instead of other natural origins.
Yeah I thought that too, if the spirit isn’t gravitationally bound earth would move away from it considerably faster. This did get me to ask myself a good question. (This isn’t it) What if we assume the spirit in the comic is dark matter and preserved any momentum at the time of death? So Earth’s gravity is pulling on it but not enough to overcome the momentum the spirit had when it broke off from the body. The Sun and Earth could be special in that constructed situation. The question I thought was, does the electromagnetic, strong and weak forces have anything to do with keeping me planted on the planet?
Not exactly. Things are moving relative to each other, but it really is all relative and local. There’s no central point in the universe that the earth is moving away from. The earth is moving relative to the sun. But relative to you, the earth isn’t moving. Relative to the earth, the sun is moving.
There’s no reason for her to move away from the earth unless she’s being accelerated by something. It’s not like the earth would zip away because it is moving relative to some distant, arbitrary point and she suddenly becomes “stationary”. There’s no universal “stationary”.
I guess where it gets messy is that the earth IS being accelerated to some extent by different things (other planets, the moon, etc). I’m not sure how much. So if she didn’t accelerate along with it at all, it would move away from her.
There’s no reason for her to move away from the earth unless she’s being accelerated by something.
Isn’t the Earth accelerated by the Sun’s gravity, while she isn’t anymore? If yes, she would keep going straight while Earth keeps following its circular orbit, which is equivalent to her moving away from Earth.
I think the existence of ghosts at all implies at the least some sort of spiritual plane or dimension that they’re partially in, or at the “worst” straight up magic wherein ghosts cannot interact with the physical world, even with gravity.
Being able to see may be part of that magic or a function of the spiritual plane as well.
That would, I think, be able to explain the events of the comic.
If instead we assume ghosts were entirely explainable by science, that could change things. We’d also have to account for the photons interacting with her and letting her see.
Edit: no, as other people pointed out it doesn’t make any sense that she wouldn’t be “affected” by gravity even with no mass.
That’s the assumption in my comment: “while she isn’t anymore” accelerated by gravity. I think that’s what we could infer from the trajectory on the comics.
there is no center of the universe, nor a universal grid that things can reference. one of the most fundamental tenets of astrophysics is that everything is relative and statements like “travelling straight” are simply nonsensical unless you specify what it’s travelling straight in relation to.
If she is still affected by gravity, but passes through matter, she would immedietly fall through the floor and start orbiting the earth through the planet.
Without gravity she would no longer follow the earth’s/sun’s/etc. orbit.
but the question is what would determine the trajectory then, there is no universal arbitrary straight line, that’s a concept that just doesn’t make sense under physics as we know it.
Even massless particles gain an effective mass and thus interact with gravity/spacetime; according to everything we’ve observed and calculated so far the only sensible result is acting like light does, and weakly interacting with gravity.
Well, yea, idk how moving through spacetime without following it’s curvature would makes any sense. Which is what gravity is. Meaning the comic makes no sense.
There absolutely is a coordinate system like that, in the comic it would be the spirit’s coordinate system with them at the center. There actually is an absolute center of the universe and it is you and me, and everything else in the universe is at the center of it’s universe (depending on your definition of the universe). That’s what special relativity is all about, each thing is at the center of it’s own universe and you have to translate any measurements between coordinate systems.
All the comic implies is that a sprit doesn’t follow null geodesics, but that’s general relativity.
There actually is an absolute center of the universe and it is you and me
I think that’s the observable universe, not just a specific definition of the universe. I believe the consensus is that the observable universe is only a part of the universe centered on each observer, and there’s no center to the “full” universe.
In the comic you are still conscious. Forever. Not being able to move in any direction, the universe around you slowly drifting away. You will be swallowed by the darkness between the stars for a hundred billion years, all the while fully aware that you are completely and utterly alone with your own thoughts.
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