I don’t have to prove anything. That the Sun is traveling around the center of the Milky Way Galaxy at a very high speed as the planets revolve around the Sun in helices is a fact. I can’t find a site that can show this movement more accurately, but if anyone can I’d be grateful.
The idea in my statement is that the stability of the solar system depends on the Sun’s stability. Let’s try to visualize the Sun traveling around the center of the galaxy at 230 km/s as the planets revolve around it in helices. When the galaxy and the rest of the universe suddenly disappear, the following things will happen:
The gravitational forces that keep the Sun on a fixed and stable orbit are canceled. These forces are even bigger when considering dark matter. Their absence will cause the Sun to behave like a top whose spinning motion becomes more and more irregular due to its gas composition and internal activity. In time, the changes in the Sun’s motion can become so sudden and irregular that the entire solar system will collapse.
With the dark matter gone and so little mass left, dark energy (which is extremely powerful, accelerating and homogeneously spread across the space) will rip the system apart. If we hypothesize the absence of dark energy, we’re left with the possibility of a quick Small Crunch (that will mirror the Big Crunch scenario).
With the entire universe gone, the solar system will abruptly turn into a pocket universe, a completely different system whose parameters may not support the physical laws that we experience in our current universe. Due to a different vacuum energy, matter will reorganize differently from what we can see today.
To be fair, that link is actually a debunking of the ‘Solar System vortex’ nonsense by Jason Major of the Universe Today website, which is definitely not a ‘woo’ site.
Sure, the planets in our Solar System move in complex helices round the galaxy; but this gives us no real insight into what would happen if the rest of the universe disappeared.
I’ve already stated that the key to what may happen to the solar system in the absence of the rest of the universe is the Sun’s movement. The video can simply enable one to visualize the Sun speeding along its orbit as opposed to a stationary Sun, whose spinning motion will be entirely influenced by the differences in density of its layers & regions and by the violent reactions occurring in its core. My opinion is that the stability of the solar system depends greatly on the Sun’s ‘membership’ to the Milky Way Galaxy.
The Sun is now traveling in a path caused by the collective gravity of the rest of the galaxy, both ordinary and dark matter. If all that matter and hence all it’s gravity simultaneously went poof the Sun would not suddenly stop. It would continue on just as it was. And would drag all its planets along with it just as it does today.
The thing that seems to be hard for you to visualize is that a curved orbit in the presence of gravity and straight-line motion in the absence of gravity are exactly the same thing from the POV of the object in motion.
That was part of the wonder of Einstein’s work. Gravity bends space and an object moving “straight” through bent space is actually traveling a curve. The technical term is “geodesic” which wiki can explain further.
If net gravity increases someplace then space bends more and the curvature of anything orbiting in that gravity increases too.
If net gravity decreases someplace then space bends less and the curvature of anything orbiting in that gravity lessens too.
If net gravity decreases to zero someplace then space bends zero and the curvature of anything orbiting in that gravity lessens to zero too. So now it goes straight.
In addition to the above, until and unless you can understand that the same motion looks different depending on where you’re standing when you take a movie of it you’re not going to make progress understanding this stuff.
As an unrelated example: While you drive your car the ground isn’t moving. And while you drive your car your tires are rolling, not sliding, across the ground. So how is it possible that a moving tire and a non-moving ground are touching but aren’t sliding? How can that be? Does each part of the tire stop when it gets to the bottom? If so, then what about the preceding or following parts of the tire; they’re moving, but the part touching the ground isn’t? How can that be?
The answer is simple: motion is not absolute. The situation looks totally different depending on whether you concentrate on the ground or the tire. Also whether you concentrate on the linear motion of the car and ground or the rotary motion of the tire. In technical terms which “frame of reference” you choose determines how the exact same situation appears. The underlying reality is constant. What it *looks *like changes completely.
Your idea that the planets are traveling in helices as they follow the Sun moving through space is correct if and only if you choose a “reference frame”, a point of view, that isn’t following along with the Sun. And doing so is artificial ignorant BS carefully designed to fool people who don’t / won’t understand the fundamental truth about any motion, even that of prosaic car tires: What you see depends on where you stand.
I’m sorry, but I think you’re mistaken. Please see the statement you quote again: “That the Sun is traveling around the center of the Milky Way Galaxy at a very high speed as the planets revolve around the Sun in helices is a fact.” Do you dispute this statement? Do you think I need to prove it?
Or do you find the video to be inaccurate? I have already admitted to it, but it is the only one I’ve found showing the solar system in motion. If you could produce a better one, it would actually help the discussion in this thread, thank you.
What would help the discussion in this thread is if you knew what the hell you were talking about. You are spewing ignorance, not fighting it. Read the (former Doper, I hear) Phil Plait link. The video is a worthless pile of garbage.
(And yes, I would love for you to “prove” that the planets orbit the sun in helixes. It could be entertaining to watch.)
To a very good first-order approximation. In fact, to a very good umpty-order approximation, which only breaks down when you’re close to extremely dense objects.
The spanner in the works here is the tidal force, which is a lot more important in GR because it’s how we define how curved the spacetime is in a given region: The more deformed a body wants to become due to tides, the greater the curvature.
Anyway, if you’re in a reasonably reasonable gravity field, the amount of curvature over the volume inhabited by a human being is minimal. Tidal forces can be neglected, which is exactly analogous to taking a straight-line tangent to a curve and using that straight line as a good approximation of the curve over a small region. The fact this works so well over quantum scales makes physicists happy, because our field theories only account for special relativity, which is the flat spacetime special case (hence the name) of general relativity. It makes physicists doubly happy because we can stand up without out feet getting pulled away from our heads.
So, dragging it back to your point: The only way you’re going to see a “pure” example of things following a geodesic, utterly unaffected by tidal forces, is to look at objects which are essentially not extensive; that is, point particles, and things we can model as point particles with a negligible loss of accuracy. Photons are a prime example, because they can have long lifetimes and we can see them. That’s why being able to correctly predict the quantitative amount of gravitational lensing caused by massive objects is such an important experimental test of GR: It allows us to look at one specific part of the theory.
Yes, the Sun’s orbit is stable. But a straight-line uniform-speed motion is even more stable, and that’s what the Sun would be doing if the rest of the Universe disappeared. What do you think would happen, it would crash into something?
If the rest of the universe disappeared, we could treat the sun as motionless or nearly so. There’d still be its orbital motion around[sup]1[/sup] Jupiter and the other planets, but other than that, we couldn’t detect any other motion. So we may as well assume that the sun has stopped moving.
The question in the OP, like many other similar questions[sup]2[/sup], is poorly specified. I can think of two things that need to be specified. First, when you say the “rest of the universe”, does that include the photons and gravitons and other forms of energy, or just the matter? Several upthread assumed that the energy would not go away, so we wouldn’t know about this for 4 years. I think it’s equally likely, perhaps even more likely, that the energy would go away at the same time and we’d find out within at most a couple years, depending on what you call the solar system.
That brings up the second underspecified part: what exactly is the Solar System? Well, there’s lots of definitions, but perhaps the best is “everything gravitationally bound to the Sun”. But that definition doesn’t specify a region. (Oort Cloud objects could be up to two lightyears away, but there are almost certainly objects within that distance that aren’t bound. And not just the five space probes that are leaving the system.) So if photons are disappeared along with matter, the question should specify how far away that happens.
[sup]1[/sup] not quite the right preposition, but I can’t think of a better one.
[sup]2[/sup] questions where alien space bats perform some magical action and we’re asked about the consequences.
[QUOTE=Wikipedia]
This concept was a guiding factor in Einstein’s development of the general theory of relativity. … But because the principle is so vague, many distinct statements can be (and have been) made which would qualify as a Mach principle, and some of these are false. The Gödel rotating universe is a solution of the field equations which is designed to disobey Mach’s principle in the worst possible way.
[/QUOTE]
Yeah, sure. One gold star and three brownie points to any of the Board’s physicists who can explain this to me, without using words like “tensor.” Assume I’m a blithering dolt.
“Look,” whispered Chuck, and George lifted his eyes to heaven. (There is always a last time for everything.)
Overhead, without any fuss, the stars were going out.
It might be helpful to look at electromagnetic mass as an analogy. This is a real, well established consequence of Maxwell’s equations–that if you accelerate a charged particle, its own field pushes back with a force proportional to acceleration. So it’s indistinguishable from inertia, and thereby mass.
It’s possible to argue that all of the mass of an electron comes from this; that it’s nothing more than a ball of charge.
Could we use a similar argument that gravity provides the mass for everything else, including uncharged objects? Well, it doesn’t quite work out the same, since gravity is always attractive. So you can’t push off your own field. But everything is immersed a giant gravity field from distant objects. The net force is weak, since distant objects pull in all directions, but the summed contribution is humongous–it doesn’t even go down with distance, since gravity falls off with 1/n^2, but there are n^2 objects at a given distance.
It appears to be possible to work things such that these distant objects to contribute to our notions of inertia, but they depend on counterintuitive effects like waves moving backwards in time. It’s not the weirdest thing in physics, but it’s certainly speculative at best (and, as best I can tell, cranklike at worst).
That’s just one of the variations on Mach’s principle, though. Others are more or less controversial. For instance, “Mach5”, as listed in the Wikipedia article, is very likely to be true and at the least has no contradiction with the laws of physics as we understand them: The total energy, angular and linear momentum of the universe are zero.
It is technically incorrect. Use a proper reference frame. In the heliocentric reference frame, the planets orbit the sun in ellipses. Which is to say, if you could sit in a magical boat floating upon the sun’s photosphere (surface) and observe the motion of the planets, they would be approximately elliptical from your (the sun’s) point of view (not accounting for the sun’s wobble caused by the planets). In a galactocentric reference frame, the planets move in a non-uniform, curved helix, which changes orientation a little based on the solar system’s varying trajectory. Which is to say, the planets traverse the galaxy (not the solar system) in a helix-like epicyclic path.
Thank you for the correction. I appreciate your rigor.
Not only does it look different but the value of variables can also change such as in the classic example of the ping-pong game in the train, where the speed of the ball includes the speed of the train as well for an outside onlooker.
I’ve already said this, but I can repeat it if necessary: the key to my argument is the Sun’s motion. I’ve mentioned the helices and that video only so that the reader can change the reference frame and see the consequences of the solar system being cut off from the rest of the universe. (I don’t understand how one would image I can support the idea the solar system is a vortex while pointing to a site which debunks that very idea.)
Of course the frame of reference determines the way things appear. It is crucial to see that the basic image of the solar system as a stable entity consisting of a central star orbited by planets whose elliptical paths lie roughly in the same plane changes when one looks at the solar system from outside. The Sun’s apparent stability is in fact a consequence of the forces exerted by gravity within the galaxy, which coerces the Sun to follow a fixed path at a constant speed.
I don’t think it would. In my opinion, the changes would prevent the solar system from preserving its current state.
Here are some aspects that should be considered in my estimation:
The Sun’s velocity changes. In the absence of the Milky Way, the Sun’s trajectory turns from a curved path into a rectilinear one and its speed increases. Of course these changes alone wouldn’t matter to an observer situated within the solar system, but there are further implications that will become visible to an inside observer as well.
There is no space for the Sun to continue its rectilinear motion at an increased speed (or any speed for that matter). The OP asks what would happen if the rest of the universe disappeared. The question is not what would happen if all the celestial bodies in the universe disappeared except the solar system. The rest of the universe in the OP refers to everything else including the space. This means there would be no space for the Sun to travel along a linear path at way over 250 km/s.
When the rest of the universe disappears, the solar system will suddenly find itself in a pocket universe. If the Sun could continue its curved motion within this pocket universe, there would probably be no consequences visible to an inside observer – but the absence of the Milky Way would send the Sun shooting along an impossible rectilinear path, which to me is equivalent to a screeching halt.
I don’t see how new space can be created for the Sun to continue its journey. The idea that the Sun’s rectilinear motion can lead to the formation of a new tube-like universe doesn’t make sense.
The idea that the Sun can continue its journey without creating new space but just by dragging the entire pocket universe along with it doesn’t hold water either. The Sun would be situated at the center of a space bubble, a universe in itself with no outside observers. In the absence of any external reference frame, the Sun’s rectilinear motion no longer makes sense.
Two possible consequences are: a) when the Sun’s travel cease abruptly, the solar system could be affected by the shock and any internal observer would feel it, and b) the Sun’s motion would become an irregular one (due to its gaseous composition and nuclear reactions), with sudden changes of speed and direction, similar to that of a spinning top whose principal rotation axis does not go through its center of mass. If the train in the classic example constantly shakes and jerks or if the locomotive stops suddenly, the game of the ping-pong players can no longer continue. In my book the consequences I’ve mentioned spell catastrophe.
The problem is my knowledge of physics is quite negligible and of course can be labeled as ignorance. The purpose of my intervention here is not that I should argue with people but that I should put the little knowledge I have to the test and learn something in the process. If you are kind and patient enough to do it, please show any stupid mistake you find in my reasoning.
Your posts fail to address any of the statements I’ve made on the question in the OP - they include only taunting remarks about my person. This is not how one fights ignorance. On the contrary.
I won’t address the rest of your post since I’m assuming the OP means “everything else in the universe disappears” not “Spacetime collapses,” but I will respond to this.
Why would the Sun’s speed increase? There’s no reason for that.
You are correct. There is little question the OP meant all celestial bodies disappearing, not the fabric of spacetime collapsing. He specifically said: “If there were no more stars…”, then further clarified this by saying ‘"In my scenario we still have mass and gravity and physics and all of the principals that make our solar system “function.”’
He was obviously not an astrophysicist. There is no basis for applying a strained, esoteric interpretation to his simple question. He simply wanted to know if all celestial bodies suddenly vanished, how would this affect our solar system.
Another example: by “no more stars” this technically includes the sun. Did he mean if the sun also disappeared? We must use common sense. In casual conversation a layperson does not normally refer to our sun as a star. Therefore we would not apply an uncommon interpretation to his straightforward question and think he was meaning if the sun itself vanished. Likewise he was asking if the entire universe of celestial bodies vanished, not if spacetime itself somehow contracted.
The solar system exists within a somewhat non-flat region of space. Take that away and you have erased a fraction of the GR time dilation that the regional gradient imposes. Our reference frame would then have a minutely different temporal rate, which, if my brain is working properly, would be a little higher. Hence, we would actually start moving slower.
But, with nothing else in the universe, it would be extremely difficult to assess our speed. We would have the only meaningful reference frame, unless we could send out a fast probe to observe and report from outside the system. The solar wind might produce a heliotail, but, with no resistance at “prow”, there would be no bow shock. We would have to make very refined observations of the gas cloud building up around the heliopause in order to even figure out which direction we were moving.
But “moving” only has meaning if you mean “moving relative to some other object”. With no other objects in the universe besides the solar system, it would be meaningless to say that the solar system is moving.
Not that it would “screech to a halt”. Just that with no universe there’s no motion relative to the rest of the universe, which means there’s no way to determine motion.
Our planet is moving relative to the Sun. The Sun is moving relative to the galaxy. The galaxy is moving relative to the local group. The local group is moving relative to the distant galaxies. Distant galaxies are moving relative to the observable universe. Now, it’s possible we’re going 99.999% of the speed of light relative to some other superstructure outside the observable universe. But that’s irrelevant, since those objects are outside our light cone and we will never be able to interact with them, even if they’re moving at the speed of light. And so it’s meaningless to talk of motion relative to objects outside the observable universe.
So if every object outside the solar system vanished, then there’s no way to detect if the solar system is moving, because it’s a meaningless measurement.
As for complaining that there’s no way of telling what the laws of physics in our new “pocket universe” will be, I think that’s irrelevant. Of course the alien space bats can do whatever they want. But the question in the OP is only meaningful if we assume that the laws of physics will remain unchanged aside from the single change of magically vanishing everything, if we allow the laws of physics to change then there’s no way to answer the question.
What excited me about this thread to start with was hypothesizing on what would happen to the solar system were the rest of the universe to disappear. This is the reason why I mentioned the Sun’s immense speed, the black energy and the pocket universe. Of course the Sun’s movement wouldn’t make sense if there was no other objects in relation to which to move.
But.
The Sun’s speed means kinetic energy, and if everything else disappeared (including spacetime as I assumed initially) the solar system would really have to come to a screeching halt.
a) Supposing spacetime around the solar system disappeared, the crash would depend on how fast the Sun moves. I’m far from being good at physics, but I expect the Sun’s speed should be higher than 250 km/s if we considered at least the additional movements of the Local Group and the Laniakea Supercluster. If such a sudden pocket universe could exist, the Sun’s crash would be more violent if its speed were higher.
b) I understand that everybody’s presupposition in this thread is that spacetime should stay intact and only the entirety of celestial objects should disappear, leaving the solar system alone across the endless black cosmic sky. I will comply and state that the Sun’s movement could still make sense if vacuum energy led to the creation of new particles in relation to each the Sun moved. (Yet, there would be no crash, indeed.)
I wonder if spacetime could really stay the same. Can 99.9(9)% of all matter in the universe disappear without affecting spacetime at all? I doubt it. And another thing about I wonder here but have no idea how to assess is vacuum catastrophe: Is it more likely to occur when almost all the matter in the universe goes poof?
