# Thread: "Relative motion" falls apart when applied to plan

1. ## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by A Thousand Pardons
Originally Posted by Fortis
... As F=ma, then the only way that the earth can remain static (i.e. with the acceleration, a=0) for any finite force, F, is if the inertial mass, m, is infinite.
I disagree. Wouldn't that be the only way if it were only just the Sun and Earth in the Universe?
I think the point was that unless Earth's mass is infinite, the Sun and Earth would revolve around a common centre of gravity, in which case the Earth could not be considered "static".
But if that were the point, then that would be begging the question--in other words, asserting what you are trying to show.

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## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by A Thousand Pardons
Originally Posted by A Thousand Pardons
Originally Posted by Fortis
... As F=ma, then the only way that the earth can remain static (i.e. with the acceleration, a=0) for any finite force, F, is if the inertial mass, m, is infinite.
I disagree. Wouldn't that be the only way if it were only just the Sun and Earth in the Universe?
I think the point was that unless Earth's mass is infinite, the Sun and Earth would revolve around a common centre of gravity, in which case the Earth could not be considered "static".
But if that were the point, then that would be begging the question--in other words, asserting what you are trying to show.
Unless the forces on the earth (from everything else in the universe) exactly cancel out (which would be a fairly miraculous outcome) then there would be a resultant force acting on the earth. If the inertial mass of the earth is finite (which seems to me to be the sensible assumption to make ), then the earth will experience an acceleration. If something is accelerating, then you'd be hard pushed to argue that it also remains static.

I don't think that this is begging the question.

3. Originally Posted by Grand Vizier
If things're getting away from fluid dynamics, has anyone gone into retrograde planetary motion and the notion of epicycles yet? It's an important historical point - the problems with these were part and parcel of the downfall of Ptolemaic geocentricity even before Kepler and Newton arrived on the scene.

What explanation does the good Dr Jones give for the planets now and then moving backwards in the sky?
I started getting into the issue of the geocentric versus heliocentric views of the solar system and the nature of the planets, the sun, etc. in the geocentric view - but Gary said that all takes care of itself, so I didn't go much further with it. I was curious to see if he would bring up epicycles himself - but no.

Gary has provided no explanation for what anything in space is supposed to be or any method by which you can calculate the motion of any object in space, but he doesn't seem to see why that is a fundamental problem with his argument.

I liked the planetary motion issue because it can be personally tested.

We didn't even begin to get into the nature of stars.

4. Originally Posted by Van Rijn
Originally Posted by Grand Vizier
If things're getting away from fluid dynamics, has anyone gone into retrograde planetary motion and the notion of epicycles yet? It's an important historical point - the problems with these were part and parcel of the downfall of Ptolemaic geocentricity even before Kepler and Newton arrived on the scene.

What explanation does the good Dr Jones give for the planets now and then moving backwards in the sky?
I started getting into the issue of the geocentric versus heliocentric views of the solar system and the nature of the planets, the sun, etc. in the geocentric view - but Gary said that all takes care of itself, so I didn't go much further with it. I was curious to see if he would bring up epicycles himself - but no.

Gary has provided no explanation for what anything in space is supposed to be or any method by which you can calculate the motion of any object in space, but he doesn't seem to see why that is a fundamental problem with his argument.

I liked the planetary motion issue because it can be personally tested.

We didn't even begin to get into the nature of stars.
That's extraordinary. I should have thought that, if these guys really wanted to make a case, finding a refutation of the original arguments against the geocentric view would be the logical place to start.

(For example, with modern computers, the multiplication of epicycles within epicycles might yield to computational solutions. It seems to go against Occam's Razor, true, but the Razor is just a guideline, not a disproof. A proponent of geocentrism might retort that, since we cannot solve the n-body problem, we have to apply endless corrections to our orbit solutions anyway if we are to maintain their predictive accuracy way into the future. But maybe I shouldn't give them ideas [-X )

However, I did enjoy reading Dr Jones' re-evaluation of distance scales based on the number of photons hitting a retinal cell. It was fun looking for the flaw, which is oddly hard to find, but seems obvious once it clicks. But I think that has already been dealt with fully on this thread.

5. ## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by Fortis
Unless the forces on the earth (from everything else in the universe) exactly cancel out (which would be a fairly miraculous outcome) then there would be a resultant force acting on the earth. If the inertial mass of the earth is finite (which seems to me to be the sensible assumption to make ), then the earth will experience an acceleration. If something is accelerating, then you'd be hard pushed to argue that it also remains static.

I don't think that this is begging the question.
Of course it is. Not only are you assuming Newtonian mechanics hold exactly--which the Geocentrists deny--we know that they don't.

6. [quote="Grand Vizier"][quote="Van Rijn"]
Originally Posted by Grand Vizier
If things're getting away from fluid dynamics, has anyone gone into retrograde planetary motion and the notion of epicycles yet? It's an important historical point - the problems with these were part and parcel of the downfall of Ptolemaic geocentricity even before Kepler and Newton arrived on the scene.
Unfortunately, the majority of Geocentrist debates boil down to, "I know the Truth, why don't you just believe me?" :-?

I've only read a few who actually bother to get into the physics of things. Most either point to their religious texts, or take the stance that "it doesn't make sense for the Earth to move."

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## ToSeek,AGN Fuel, Grand Vizier, TinFoilHat

To Seek, AGN Fuel,

Thanks for the clarity of the explanation of the solar eclipse. I believe I can follow you both. It does seem to allow the cause to be something I had previously ruled out. I'll have to continue thinking about it, though. (I will post them to Dr. Jones' site for everyone's benefit there.)

Grand Vizier,

What about the question on my last post?

TinFoilHat wrote:

I'm wondering how Gary (or anyone else using his arguments) can explain the sucessful landing of the multiple probes we've put on the surface of Mars. We can see that Mars rotates. From the rate of rotation and radius of Mars, a quick calculation shows that the surface of mars at the equator is moving at a speed of over 500 miles per hour, relative to the planet as a whole, due to its rotation. We know that Mars has an atmosphere. If that atmosphere did not rotate along with Mars, any point on or near the equator of mars would feel a constant 500MPH wind blowing it sideways. None of the multiple probes we have landed on mars has detected this wind. None of them would be even capable of surviving a landing with a 500MPH crosswind in the first place! What they have shown us is that the atmosphere of Mars, though having intermittent local winds and turbulence, is as a whole rotating at the same speed as the planet Mars, and most likely has been for quite some time.

We can see from Mars that the fixed-earther's understanding of the mechanics of a rotating atmosphere is insufficient to describe the real world.
TinFoilHat, thanks for a good point. But it brings up another question. If, supposing everyone of you is correct on this board that the earth is indeed rotating as you say, as is Mars, does that mean the atmosphere is turning at the same angular velocity as the planet it is on? Like, when you say that the probes to Mars did not encounter 500 mph winds. I believe you. But in accord with what you say, I assume the atmosphere is indeed rotating RTTS (relative to the stars) and is generally still but with localized winds RTTP (relative to the planet), even on Mars, right?

So if that is all true, what is the effect of ENTERING the spinning atmosphere from outer space on these probes? Would they not necessarily have to go from the near perfect stillness of space to the spinning violence of the atmosphere suddenly upon entering it? Would they not encounter the body of the atmosphere, as a whole, that was turning at horrible rotation rates? Wouldn't this have to happen at some time for the probe to land on Mars?

Sincerely,

Gary Shelton

8. ## Re: ToSeek,AGN Fuel, Grand Vizier, TinFoilHat

Originally Posted by Gary Shelton
TinFoilHat, thanks for a good point. But it brings up another question. If, supposing everyone of you is correct on this board that the earth is indeed rotating as you say, as is Mars, does that mean the atmosphere is turning at the same angular velocity as the planet it is on? Like, when you say that the probes to Mars did not encounter 500 mph winds. I believe you. But in accord with what you say, I assume the atmosphere is indeed rotating RTTS (relative to the stars) and is generally still but with localized winds RTTP (relative to the planet), even on Mars, right?
Yes.

Originally Posted by Gary Shelton
So if that is all true, what is the effect of ENTERING the spinning atmosphere from outer space on these probes? Would they not necessarily have to go from the near perfect stillness of space to the spinning violence of the atmosphere suddenly upon entering it? Would they not encounter the body of the atmosphere, as a whole, that was turning at horrible rotation rates? Wouldn't this have to happen at some time for the probe to land on Mars?
They enter the atmosphere at whatever relative speed they have to it. If the probe is descending with a 5,000 mph (just an example, not necessarily a realistic speed) horizontal speed in the same direction as the rotation, the rotation is 500 mph, and the wind is calm, the probe would encounter a 4,500 mph headwind. Probes are designed to withstand that. Remember, too, that the atmosphere is MUCH thinner where the probe first encounters it. A 5,000 mph wind at the edge of the atmosphere doesn't provide much resistance. [Edited to add:] What was meant in the earlier post was that the probe did not find 500 mph winds relative to the planet.

9. ## Re: ToSeek,AGN Fuel, Grand Vizier, TinFoilHat

Originally Posted by Gary Shelton
So if that is all true, what is the effect of ENTERING the spinning atmosphere from outer space on these probes? Would they not necessarily have to go from the near perfect stillness of space to the spinning violence of the atmosphere suddenly upon entering it? Would they not encounter the body of the atmosphere, as a whole, that was turning at horrible rotation rates? Wouldn't this have to happen at some time for the probe to land on Mars?

Sincerely,

Gary Shelton
Yes, of course. However, the rotation speed is a modest issue as far as velocity is concerned. The relative speed difference between the spacecraft and planet is much more substantial. (And why is this rotation rate "horrible"?). Anyway, from:

The lander should come streaking in through the martian atmosphere, going about 12,000 miles per hour. Given atmospheric friction, the outside surface of the heat shield will be as hot as the surface of the sun (1,447 degrees Celsius, or 2,637 degrees Fahrenheit), but the rover will be protected by the heat shield and will stay at about room temperature inside the lander. The heat shield also aerodynamically acts as the first "brake" for the spacecraft, slowing Spirit down by thousands of miles per hour.
The spacecraft comes in at a shallow angle to the planet's surface to increase the time in the upper atmosphere.

Do a google search on "reentry heating" "reentry friction" "heat shield" and "aerobraking" - this is a standard issue for landing spacecraft.

10. Originally Posted by Grand Vizier
(For example, with modern computers, the multiplication of epicycles within epicycles might yield to computational solutions. It seems to go against Occam's Razor, true, but the Razor is just a guideline, not a disproof. A proponent of geocentrism might retort that, since we cannot solve the n-body problem, we have to apply endless corrections to our orbit solutions anyway if we are to maintain their predictive accuracy way into the future. But maybe I shouldn't give them ideas
Now you've done it! Coming to a website near you: The Neo-Ptolemaic model of the solar system. Actually, it wouldn't surprise me if somebody could come up with quite a good software orrery using many, many "wheels within wheels," basing the approximations on direct observation. But it wouldn't be able to predict the effects of future perterbations or allow you to map the orbit of a newly found asteroid after a few observations, because it wouldn't be based on physical principles.

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## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by A Thousand Pardons
Originally Posted by Fortis
Unless the forces on the earth (from everything else in the universe) exactly cancel out (which would be a fairly miraculous outcome) then there would be a resultant force acting on the earth. If the inertial mass of the earth is finite (which seems to me to be the sensible assumption to make ), then the earth will experience an acceleration. If something is accelerating, then you'd be hard pushed to argue that it also remains static.

I don't think that this is begging the question.
Of course it is. Not only are you assuming Newtonian mechanics hold exactly--which the Geocentrists deny--we know that they don't.
So, a non-relativistic body (and I think the earth can be regarded as non-relativistic ), of finite inertial mass, will not accelerate when it experiences a net force? Even in QFT, where forces are mediated by the exchange of particles such as photons, etc., momentum is conserved at the vertices.

I'm pretty sure that the argument doesn't require Newtonian mechanics to be 100% correct. Even if the acceleration experienced by the earth is ten orders of magnitude less than that predicted with classical mechanics, then it still moves.

Finally, if geocentrists just deny anything that doesn't fit in with their world-view, then there is absolutely no point in arguing with them. (And perhaps that is the case.)

12. ## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by Fortis
I'm pretty sure that the argument doesn't require Newtonian mechanics to be 100% correct. Even if the acceleration experienced by the earth is ten orders of magnitude less than that predicted with classical mechanics, then it still moves.
I agree. ATP/milli, we know that Newtonian mechanics is not a complete theory of the cosmos. We know that General Relativity is the more accurate explanation. But the plain fact is, it's harder to understand GR, the maths is a lot more complex, and for non-relativistic conditions, Newton is a very, very good first approximation when we're trying to demonstrate basic physics to geocentrists who haven't even got that skill yet.

Some parts of this thread reminded me of the famous exchange in scene 7 of Monty Python's The Life of Brian:

FRANCIS: Yeah. I think Judith's point of view is very valid, Reg, provided the Movement never forgets that it is the inalienable right of every man--
STAN: Or woman.
FRANCIS: Or woman... to rid himself--
STAN: Or herself.
FRANCIS: Or herself.
REG: Agreed.
FRANCIS: Thank you, brother.
STAN: Or sister.
FRANCIS: Or sister. Where was I?
REG: I think you'd finished.
FRANCIS: Oh. Right.
REG: Furthermore, it is the birthright of every man--
STAN: Or woman.
REG: Why don't you shut up about women, Stan. You're putting us off.
Calm. :-#

13. ## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by Yorkshireman
Originally Posted by Fortis
I'm pretty sure that the argument doesn't require Newtonian mechanics to be 100% correct. Even if the acceleration experienced by the earth is ten orders of magnitude less than that predicted with classical mechanics, then it still moves.
I agree. ATP/milli, we know that Newtonian mechanics is not a complete theory of the cosmos. We know that General Relativity is the more accurate explanation. But the plain fact is, it's harder to understand GR, the maths is a lot more complex, and for non-relativistic conditions, Newton is a very, very good first approximation when we're trying to demonstrate basic physics to geocentrists who haven't even got that skill yet.
Indeed! And virtually all geocentrtics refute relativity anyway and assume Newtonian mechanics is 100% accurate for the sake of their deomonstrations that the earth can not be rotating. If you're going to show that a proof is inconsistent you must stick to the premises of the proof.

If they want to demonstrate that the eath can not be moving according to GR that's a whole different kettle of fish.

14. ## Re: Fortis, Grand Vizier, Maksuta

Originally Posted by Fortis
Originally Posted by A Thousand Pardons
Originally Posted by Fortis
Unless the forces on the earth (from everything else in the universe) exactly cancel out (which would be a fairly miraculous outcome) then there would be a resultant force acting on the earth. If the inertial mass of the earth is finite (which seems to me to be the sensible assumption to make ), then the earth will experience an acceleration. If something is accelerating, then you'd be hard pushed to argue that it also remains static.

I don't think that this is begging the question.
Of course it is. Not only are you assuming Newtonian mechanics hold exactly--which the Geocentrists deny--we know that they don't.
So, a non-relativistic body (and I think the earth can be regarded as non-relativistic ), of finite inertial mass, will not accelerate when it experiences a net force? Even in QFT, where forces are mediated by the exchange of particles such as photons, etc., momentum is conserved at the vertices.
You are deriving a general principle where none has been asserted.
I'm pretty sure that the argument doesn't require Newtonian mechanics to be 100% correct. Even if the acceleration experienced by the earth is ten orders of magnitude less than that predicted with classical mechanics, then it still moves.
If general relativity allows any reference frame, then it allows even the Earth-fixed, Earth-centered one, and it doesn't move, in that reference frame. If one ignores that possibility, then one is ignoring basic notions of commonly accepted physics. If one assumes something that we know isn't true, then of course you can prove anything you want--but that doesn't make it true, or the proof valid.
Finally, if geocentrists just deny anything that doesn't fit in with their world-view, then there is absolutely no point in arguing with them. (And perhaps that is the case.)
That is my point. One shouldn't deny the use of general relativity just because it annoyingly doesn't fit one's own argument. Nevermind that one or another geocentrist also rejects general relativity, that doesn't mean that we can.
Originally Posted by Yorkshireman
Originally Posted by Fortis
I'm pretty sure that the argument doesn't require Newtonian mechanics to be 100% correct. Even if the acceleration experienced by the earth is ten orders of magnitude less than that predicted with classical mechanics, then it still moves.
I agree.
I disagree, see my answer to Fortis. Unless you have a good proof that General Relativity is not the best explanation of physics, to date, you're out of luck on that.
ATP/milli, we know that Newtonian mechanics is not a complete theory of the cosmos. We know that General Relativity is the more accurate explanation. But the plain fact is, it's harder to understand GR, the maths is a lot more complex, and for non-relativistic conditions, Newton is a very, very good first approximation when we're trying to demonstrate basic physics to geocentrists who haven't even got that skill yet.
I think that is the wrong approach--denying the results of generally accepted physics.
Some parts of this thread reminded me of the famous exchange in scene 7 of Monty Python's The Life of Brian:

::snip::
REG: Why don't you shut up about women, Stan. You're putting us off.
Calm. :-#
I assumed that that last part was the point you were making. Sorry to be so inconvenient.
Originally Posted by worzel
Indeed! And virtually all geocentrtics refute relativity anyway and assume Newtonian mechanics is 100% accurate for the sake of their deomonstrations that the earth can not be rotating. If you're going to show that a proof is inconsistent you must stick to the premises of the proof.

If they want to demonstrate that the eath can not be moving according to GR that's a whole different kettle of fish.
We have the same responsibilities.

15. ATP, shall we take this argument to another topic? We're going off thread here now.

Cheers, Rob.

16. Originally Posted by Yorkshireman
ATP, shall we take this argument to another topic? We're going off thread here now.
It's been discussed before many times, and I've been involved in a lot of them, so I'd probably join another.

But I've only responded to comments here, when others have felt they were germane to the argument of the thread, so I guess I'm not the one to ask.

17. Originally Posted by Van Rijn
Originally Posted by Grand Vizier
(For example, with modern computers, the multiplication of epicycles within epicycles might yield to computational solutions. It seems to go against Occam's Razor, true, but the Razor is just a guideline, not a disproof. A proponent of geocentrism might retort that, since we cannot solve the n-body problem, we have to apply endless corrections to our orbit solutions anyway if we are to maintain their predictive accuracy way into the future. But maybe I shouldn't give them ideas
Now you've done it! Coming to a website near you: The Neo-Ptolemaic model of the solar system. Actually, it wouldn't surprise me if somebody could come up with quite a good software orrery using many, many "wheels within wheels," basing the approximations on direct observation. But it wouldn't be able to predict the effects of future perterbations or allow you to map the orbit of a newly found asteroid after a few observations, because it wouldn't be based on physical principles.
Agreed on the physical principles. But we have to take ourselves back to a time before Kepler and Newton. Those physical principles have not been elucidated, all we've got is some gravitational acceleration stuff from Galileo. Thought experiment - suppose we worked up such a program and sent it back in time on a laptop - no need to go any further, geocentricity proven...

Incidentally, I was thinking that such a program might relate to Fourier analysis. I'm totally handwaving - but sine waves, circular epicycles - simple harmonic motion seems to creep in here. I can sort of envisage the simple elliptical orbits we use as being somehow the sum of a infinitely converging series of epicycles... (In other words, maybe they are actually the same thing - in a mathematical, not a physical sense, of course.) But I don't know if this would fly.

I don't know what to do about perturbations. Now we're in physical theory, means linkages, means gravity (or springs or something ) and the whole house of cards falls over.

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Meteora wrote:
They enter the atmosphere at whatever relative speed they have to it. If the probe is descending with a 5,000 mph (just an example, not necessarily a realistic speed) horizontal speed in the same direction as the rotation, the rotation is 500 mph, and the wind is calm, the probe would encounter a 4,500 mph headwind. Probes are designed to withstand that. Remember, too, that the atmosphere is MUCH thinner where the probe first encounters it. A 5,000 mph wind at the edge of the atmosphere doesn't provide much resistance.
Van Rijn wrote (Quoting on the Spirit Landing on Mars):
Quote:
The lander should come streaking in through the martian atmosphere, going about 12,000 miles per hour. Given atmospheric friction, the outside surface of the heat shield will be as hot as the surface of the sun (1,447 degrees Celsius, or 2,637 degrees Fahrenheit), but the rover will be protected by the heat shield and will stay at about room temperature inside the lander. The heat shield also aerodynamically acts as the first "brake" for the spacecraft, slowing Spirit down by thousands of miles per hour.
If space probes can slow down to the 500 mph of Mars, that's one thing. But have we ever successfully sent probes in the Jovian atmosphere? Someone in this thread reported wind speeds of 28,000 mph there.

I suppose we have spacecraft able to meet that speed (how fast have we gone, BTW?), but it seems to me that the differences between localized currents there would be so great as to cause more problems than slowing down to the speed of the Martian atmosphere. Yes? No?

Sincerely,

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Originally Posted by Gary Shelton
If space probes can slow down to the 500 mph of Mars, that's one thing. But have we ever successfully sent probes in the Jovian atmosphere? Someone in this thread reported wind speeds of 28,000 mph there.
Actually, yes. Galileo.

Originally Posted by Gary Shelton
I suppose we have spacecraft able to meet that speed (how fast have we gone, BTW?), but it seems to me that the differences between localized currents there would be so great as to cause more problems than slowing down to the speed of the Martian atmosphere. Yes? No?
As far as I know, there's no evidence of this for Mars.

20. Originally Posted by Gary Shelton
I suppose we have spacecraft able to meet that speed (how fast have we gone, BTW?)
Without doing the math, I can't tell you an exact upper limit for our current tech, but assuming the fuel, we could get pretty fast (though it would take time to accelerate) because there is no (okay extremely little to the point of negigable) air resistance in space. This means that thrust forward is totally turned into acceleration (compare with a plane were at a certain speed the drag cannot be overcome by acceleration). This only stops when the craft's speed is at relativistic speeds and the increased accelertion is countered by the increase of mass due to the increased speed (obviously minus the fuel as well.) At the moment we can't send huge amounts of fuel into space because it plainly isn't worth it, so instead we slingshot probes about planets, transferring a tiny amount of the planet's momentum to the probe. This can get a probe up to very good speeds Cassini's flyby Jupiter accelerated it by 4,500 mph. The Huygen's probe entered Titin's atmosphere at 13,275 mph so these speeds are pretty good, and we could get them faster in needed, the big problem with doing it is that we need to slow down to go into orbit, and that requires a heap of fuel (or air braking which require heat shields etc.) For instance Cassini needed to fire its engines for 94 minutes to reduce its velocity by the 1,400 mph it needed to achieve orbit.

Originally Posted by Gary Shelton
but it seems to me that the differences between localized currents there would be so great as to cause more problems than slowing down to the speed of the Martian atmosphere. Yes? No?
Nope, there is no difference. What you do is enter the atmosphere at about 35,000 mph and air brake until you reach the local air speed (obviously using parachuttes for the last part of that.) What it would affect is the landing area, but since there is not really a solid surface in Jupiter, any probe we were dropping into it wouldn't be heading for a landing zone anyways so that wouldn't matter. Once the probe was down to the local speed it would be stationary compared to the air about it so it wouldn't matter if the air was travelling at 26,000mph or 19,000mph.

Originally Posted by Taibak
Actually, yes. Galileo.
I guess that depends on if you mean "successful" as in survived entry, or "successful" as in it did what it was expected to do.

21. Actually you don't need to go very far to see some serious speed. At the end of its missions the Space Shuttle reenters the earths atmosphere at around 17,000 mph.

22. I'd also add that at the end of the Apollo missions, the Command Module entered the Earth's atmosphere at 24,500 mph, but had shed almost all that speed by the time the drogue chutes deployed at 5 miles altitude. But since Gary thinks Apollo is faked I might be wasting my time here...!

23. Originally Posted by Gary Shelton
If space probes can slow down to the 500 mph of Mars, that's one thing. But have we ever successfully sent probes in the Jovian atmosphere? Someone in this thread reported wind speeds of 28,000 mph there.
No, Jovian wind speeds can be pretty high (a few hundred mph), but nothing like that. Now, the velocity of the Galileo atmospheric probe was a bit under 30,000 mph on entry. Obviously, a spacecraft can only take these conditions for a limited period of time, but it only needs to do it long enough to drop the velocity to something where a parachute, rocket, etc. comes into play.

24. Originally Posted by Van Rijn
Originally Posted by Gary Shelton
If space probes can slow down to the 500 mph of Mars, that's one thing. But have we ever successfully sent probes in the Jovian atmosphere? Someone in this thread reported wind speeds of 28,000 mph there.
No, Jovian wind speeds can be pretty high (a few hundred mph), but nothing like that. Now, the velocity of the Galileo atmospheric probe was a bit under 30,000 mph on entry.

[...]
I've seen Gary make this mix-up somewhere else. He is confusing local wind speeds (generally low) with the velocity of spacecraft relative to planetary bodies (generally high). Perhaps the distinction should be made more explicit.

25. Originally Posted by Yorkshireman
I'd also add that at the end of the Apollo missions, the Command Module entered the Earth's atmosphere at 24,500 mph, but had shed almost all that speed by the time the drogue chutes deployed at 5 miles altitude. But since Gary thinks Apollo is faked I might be wasting my time here...!
The crew of Apollo 10 reached 24,791 miles per hour at re-entry on 26th May 1969. This remains the fastest that man has ever travelled (relative to the Earth, anyhow!).

Must be true - it's in the Guiness Book of Records!

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Grand Vizier wrote:
I've seen Gary make this mix-up somewhere else. He is confusing local wind speeds (generally low) with the velocity of spacecraft relative to planetary bodies (generally high). Perhaps the distinction should be made more explicit.

I understand your point. I should have stated that the atmosphere of Jupiter was turning with the planet at those speeds. Relative to the "ground" of Jupiter, it might only be like what Van Rijn says, yes.

I have one more question for you all. If we have ascertained that a space craft can enter even the Jovian atmosphere without problem, because of its ability to have its flight trajectory and speed altered to "merge" with the planet's airspeed, what about meteors and other things striking the atmosphere of earth?

These things would not have the ability to adjust to the earth's turning atmosphere. They just come at us, though I'm sure the angles vary. Would we not see them deflected substantially upon a straight in entry?

Sincerely,

27. Originally Posted by Gary Shelton
These things would not have the ability to adjust to the earth's turning atmosphere. They just come at us, though I'm sure the angles vary. Would we not see them deflected substantially upon a straight in entry?
The velocities due to rotation reach a maximum near the equator, around 1000 mph, whereas the meteoroids come in much, much faster than that. Still, some break apart, and produce elements that zigzag a bit sometimes.

28. Originally Posted by Gary Shelton
I have one more question for you all. If we have ascertained that a space craft can enter even the Jovian atmosphere without problem, because of its ability to have its flight trajectory and speed altered to "merge" with the planet's airspeed, what about meteors and other things striking the atmosphere of earth?
These things would not have the ability to adjust to the earth's turning atmosphere. (snip)
In case we gave the impression that the Shuttle, Apollo, Mars landers etc 'steer' and adjust their speed into the planets' atmosphere, this is not really accurate. Essentially all of the braking is caused by the atmosphere itself and the spacecraft is quite a passive recipient of this resisting force. It's true that the Shuttle can steer to an extent (it does some big S-turns coming in through the atmosphere, to shed speed faster), but it's more a case of trying to keep a level of control over what the atmosphere is doing to the spacecraft anyway.

Spacecraft like Apollo has much less ability to 'steer' and in effect re-entered the atmosphere on a ballistic trajectory, like a big meteor. They could effect a small amount of control by angling their heatshield and firing attitude jets, but that was it. They had nothing like enough fuel to substantially alter their speed, unaided. There is not much difference between that and a 'natural' meteor, (apart from the heatshield of course.)

Having said that, meteors tend to enter the atmosphere even faster than the examples we've given above. I don't have a figure to hand, but some come in at 40-50 miles per second or even faster.

Some do skip out of the atmosphere entirely, like a rock skipping off a pond (grazers), others break up as ATP says above.

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Rob wrote:
Having said that, meteors tend to enter the atmosphere even faster than the examples we've given above. I don't have a figure to hand, but some come in at 40-50 miles per second or even faster.
A T P wrote:
The velocities due to rotation reach a maximum near the equator, around 1000 mph, whereas the meteoroids come in much, much faster than that. Still, some break apart, and produce elements that zigzag a bit sometimes.
I just figured what 40 miles per second means. It is 144,000 miles per hour. Wow, pretty fast. So to clarify your point. You two are saying that due to the tremendous velocities of these things that they overcome the relatively minor speed of the air into which they enter, right?

Assuming your response in the positive, I guess the question that is begged is have there ever been any sufficiently slower moving objects strike the atmosphere such that they were visibly "grabbed" by the atmosphere and deflected in their path in the direction of the atmosphere's rotation? Is there filmed evidence of such an event?

Further, have any space missions reported seeing any slow moving space objects "grabbed" and hurtled along with the air in its rotational flow?

Sincerely,

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Originally Posted by Gary Shelton
Assuming your response in the positive, I guess the question that is begged is have there ever been any sufficiently slower moving objects strike the atmosphere such that they were visibly "grabbed" by the atmosphere and deflected in their path in the direction of the atmosphere's rotation? Is there filmed evidence of such an event?
I'd say any landing of a spacecraft would qualify. They come in at high speed relative to the atmosphere and lose speed until they descend vertically hanging from parachutes. Or landing like a plane, in the case of the Space Shuttle.

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