[WTF_Seriously]

I know, the simple answer to the thread title is just like RE meteors.

With the Geminids coming up I started thinking how meteors would work in the FE model. As I would understand FE theory, a meteor would have to start out under the effect of UA and be accelerated at the same rate as the earth.  Afterall, it starts at a distance from earth similar to all of the other celestial bodies so why would it not be affected by UA the same way.  What causes a meteor to suddenly lose acceleration and 'fall' into the Earth's atmosphere.

[secretagent10]

If I had to guess, maybe I’d start with the wiki “explanation” of planetary bodies (balls bouncing on a basketball court are round but the basketball court isn’t) which seems to concede that planetary bodies are in fact spherical as they appear?

Which I guess allows meteorites to also exist? That’s my assumption based on the wiki but if some actual FE'er wants to explain go ahead.

[markjo]

Perhaps you should also look at the entry on Universal Acceleration.  Universal, as in, it accelerates the entire universe (except for things on the the surface of the earth and some undetermined distance above).

[AATW]

There are of course annual meteor showers like the Perseids. This makes sense with the RE model, the earth passes through the part of its orbit of the sun where they are. Not sure what the FE explanation is, if any, became in that model the earth isn’t orbiting the sun once a year

[WTF_Seriously]

Perhaps you should also look at the entry on Universal Acceleration.  Universal, as in, it accelerates the entire universe (except for things on the the surface of the earth and some undetermined distance above).

That's my curiosity.  The meteor starts out from a position where UA should be accelerating it like all other heavenly bodies.  Perhaps the explanation would be that meteors exist at a level where they are just slightly out of the full effect of  UA. As such, they are ever so slowly 'falling' toward the earth and at some point enter the atmosphere.  I guess that would work.  Of course AATW makes a point that this doesn't cover.

[Magicalus]

I have a question pertaining to this topic as well: do meteors curve in FE?

What I mean is, are their paths straight as we perceive them, or do they curve as they fly, thus moving over the Earth's surface how we measure them moving. In this case, assume the standard refraction shtick to explain why they appear straight. That's an argument for another day.

[jimster]

If meteors are subject to UA the same as the universe, what is the universe accelerating with respect to? If the universe is everything that can be perceived by senses or instruments, can we ever know what is "outside" the universe? Is the only way to know that through "faith"? Is there evidence of something beyond the universe it could be accelerating in relationship to? Seems like you would be forever speculating with no way to know if you are right. Is FE "faith based"?

[JPJ]

The bigger issue, is that a meteor colliding with the earth at that velocity would cause a blast of Old Testament proportions.

[Pete Svarrior]

If meteors are subject to UA the same as the universe, what is the universe accelerating with respect to?

https://wiki.tfes.org/Universal_Acceleration

Seems like you would be forever speculating with no way to know if you are right. Is FE "faith based"?

https://wiki.tfes.org/Evidence_for_Universal_Acceleration

Now, please stay on topic. Your unfamiliarity with UA doesn't belong in this thread.

a meteor colliding with the earth at that velocity

Define "that velocity".

[JPJ]

Define "that velocity".

You’d figure it doing a velocity transformation.



Tl;dr divide the lorentz equation for spatial coordinates by the equation for time coordinates, do the math and end up with

V’=V-U
      1-VU
        c2

V’=velocity measured in the moving frame
V=velocity measured in the stationary frame
U=velocity of moving frame relative to stationary frame

That’s the full derivation, but its easier to just figure the relative velocity using the rest frame of each object and go straight to the velocity addition formula.





You have to change the signs if the objects are moving towards each other, though.

https://en.wikipedia.org/wiki/Relative_velocity

[Pete Svarrior]

Define "that velocity".

[explains what relativity is, poorly]

Right. So when you were saying the number was ludicrously large, you didn't know what the number was?

Coincidentally, how do you feel about spirit levels?

[JPJ]

Right. So when you were saying the number was ludicrously large, you didn't know what the number was?

 I wanted to give you the chance to figure it out yourself.

If the earth’s velocity in the rest frame of the meteor is .9c and the meteor’s velocity is 0 in the earth’s rest frame, the relative velocity would be .9c.

[Pete Svarrior]

I wanted to give you the chance to figure it out yourself.

lol. Yes, I'm sure this was all about giving me the exciting opportunity to figure out that . That is exactly what you were doing here.

If the earth’s velocity in the rest frame of the meteor is .9c and the meteor’s velocity is 0 in the earth’s rest frame

*BZZZT* Oh no, your assumptions don't match the scenario you're discussing! You were talking about meteors in FET, which do not travel at 0.9c relative to the Earth. I guess you'll just have to try again.

lmao. Congratulations - you've wasted all this time desperately looking up how to perform Lorentz transformations for a scenario where - a calculation you would have known was completely redundant if you took more time learning the basics of relativity (or if you had even read the equation before plugging numbers into it). And you had to use a "do my homework for me plz" app. You truly are priceless.

Like, take 2 seconds to look at the equation you're using.



In your infinite wisdom, you decided that . Therefore:



Simplify:





No need for a "plz mr computer do my high school homework for me ;_;" site.

As a side note, note that this is different from the equation you proposed in the first place:

V’=V-U
      1-VU
        c2

Which, formatted in a way that's actually readable (and correcting the idiotic "c2" blunder) would be:



Not that any of this is surprising - you don't know what or are, so you would obviously use them interchangably. Though, since you proposed that , we can reach the same outcome - , therefore .

I'll give you a chance to have your final word before we add this alt to the list, OK? Please don't make another one. It'll be the same story each time. You don't know how to not make your alts obvious, and the attempts you're making are only making you easier to spot.

[JPJ]

Good attempt at deflection, but you don’t address the issue.



Do the math. Do it manually if you want. Show your work if you are confident that the relative velocity wouldn’t be “ludicrous”.

You are right that it’s basic high school math, so you shouldn’t have any problem with it. It’s harder to argue with a program, though, especially one that you don’t have to plug any formulas into and gives the step by step solution. And it only takes minutes. All you have to do is type in “relative velocity”.

*BZZZT* Oh no, your assumptions don't match the scenario you're discussing! You were talking about meteors in FET, which do not travel at 0.9c relative to the Earth. I guess you'll just have to try again

I didn’t assume that.  Relative velocity is calculated using either a rest frame or some other third frame that is assumed to be stationary wrt to the moving objects as a benchmark.  The base equation for relative velocity is

V_r=V_A+V_B

The velocities on the right hand side of the equation have to be relative to something other than the two moving objects.  You can’t use the relative velocity between two objects to determine the relative velocity between them.  That’s a tautology.  Instead, you have relate the velocities of each to a third frame.  If you want to know the relative velocity of two cars approaching head on, you add each of their velocities, relative to the road.  The relative velocity of one car going 75 mph relative to the road and another going 25  mph relative to the road would be 100 mph. Or you could assume rest frames, either way you get the same result.  That’s not even basic high school math.  It’s common sense.

The assumption I made, and the assumption that the calculations are based on is that wrt to some frame that is stationary to both , the velocity of the meteor would be 0 and the velocity of the earth would be .9c.

If you think those assumptions should be different, make your own.

[Pete Svarrior]

Do the math. Do it manually if you want. Show your work if you are confident that the relative velocity wouldn’t be “ludicrous”.

But this has nothing to do with "the math" and everything to do with the "0.9c" figure you pulled out of your ass. You started your argument with "If the earth’s velocity in the rest frame of the meteor is .9c and the meteor’s velocity is 0 in the earth’s rest frame". Both of these statements are unsubstantiated (and internally inconsistent, as your own calculation shows).

It’s harder to argue with a program, though, especially one that you don’t have to plug any formulas into and gives the step by step solution.

Considering your history of plugging irrelevant numbers into programs you don't understand, it's fairly easy to argue with your methodology.

I didn’t assume that.

Fantastic. Explain, in detail, how you arrived at your argument. Where did you get your initial figures from?

[JPJ]

Fantastic. Explain, in detail, how you arrived at your argument. Where did you get your initial figures from?

I did. You just aren’t connecting the dots.

Starting with two assumptions.  The earth has been accelerating at 1g for at least a year or so and the meteor and the earth are moving towards one another.

The basic equation for relative velocity can be stated as:

The velocity of A relative to B is the velocity of A relative to something other than B plus the velocity of B relative to something other than  of A.

I shouldn’t have to explain the bolded language, but given RET penchant for circular logic, I’m not so sure.

To find the relative velocity of two moving objects,  you have to introduce a separate frame that is assumed to be inertial, like I did with the car example.  Usually, the earth is assumed to be that frame, but we obviously can’t use it in this situation.  So we have to use a hypothetical inertial observer, in the same way that is done here.

https://www.khanacademy.org/science/physics/special-relativity/einstein-velocity-addition/v/applying-einstein-velocity-addition

He finds the relative velocity of the two moving objects by adding their velocities relative to a third inertial observer. Notice he says that “both of these velocities are in my frame of reference”. The equation could be stated as:

The velocity of A relative to C is the velocity a A relative to B plus the velocity of C relative to B.

What would be the velocity of the earth as measured by the inertial observer?  Since the observer is inertial and the earth has been accelerating for a year or more, its velocity will asymptotically approach c, but never reach it.  So .9c is a good approximation of the velocity relative to the inertial observer.

What would the velocity of the meteor be as measured by the inertial observer? I chose to use 0 because the actual value doesn’t matter.

 As long as the earth is accelerating, the earth’s velocity will continue to increase, but never reach c relative to an inertial observer.  It doesn’t matter if relative to that observer, the earth is only accelerating at .00000000000000001 m/s^2, it’s velocity will continue to increase relative to the inertial observer, just very slowly. Acceleration is the rate of change in velocity, The only way it’s velocity would stop increasing is if it stopped accelerating icompletely.

In Newtonian mechanics,  any velocity greater than .1c added to .9c will exceed c.  That’s why we have to do a Lorentz Transformation to find the relative velocity, but all that does is keep the relative velocity from exceeding c, it doesn’t keep it from increasing.

Here’s a good illustration using the same set up as the Khan Academy Video.  Note that the magnitude will be the same if viewed from either object.

http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/einvel2.html#c1

If the velocity of A is .9c (the velocity of the earth relative to the inertial observer)

and the velocity of B is -.5c (because it is going in the opposite direction), then the relative velocity is -0.96.



 if the velocity of B is -.9c, the relative velocity is -.99c



  if the velocity of B is zero, the relative velocity is -.9c



The relative velocity will always be “ludicrous”, no matter what the velocity of the meteor is relative to the 3rd inertial frame, as long as the velocity of the earth relative to the inertial frame is .9c or greater.

I hope that clears up your confusion.

[Pete Svarrior]

Ah, there's the pricelesspearl I know and love. So many fuck-ups in such a short post! Let's dig in.

Starting with two assumptions. The earth has been accelerating at 1g for at least a year or so

You forgot to define the frame of reference in which this is occurring. (Hint: there is no frame of reference in which this assumption will hold in its entirety.)

Also, I love the burning precision of "at least a year or so". I'll assume you meant "one year", but feel free to present a different figure when you revise your argument.

and the meteor and the earth are moving towards one another.

How fast?

Usually, the earth is assumed to be that frame, but we obviously can’t use it in this situation.

Of course we can.

So we have to use a hypothetical inertial observer

Okay. If that's your frame of reference then the Earth would not be accelerating at 1g after an infinitesimal length of time. So that's the correction you'll have to make to your first assumption.

So .9c is a good approximation of the velocity relative to the inertial observer.

It's an absolutely terrible approximation. Under your assumptions (which are incorrect anyway, but we may as well finish going through this), that figure would be just around 0.46c.

I chose to use 0 because the actual value doesn’t matter.

Of course it matters. It's absolutely crucial, and by fucking it up you've introduced a contradiction in your argument. After all, the meteor is affected by UA just like everything else is, so its velocity relative to your observer will only be marginally different from that of the Earth. So you're off by just around 0.46c here (or 0.9c if we continue with your incorrect calculation from the step before).

A less batshit figure here would be something like 0.45982c, assuming it's moving in the same direction as the Earth.

In Newtonian mechanics,  any velocity greater than .1c added to .9c will exceed c.

Indeed. However, the velocity you chose was . I'll give you a hint: . That's why you wasted your time performing Lorentz transformations on numbers that didn't need it, and why you ended up with the same number you initially plugged in. This, by the way, is why mindlessly using online calculators is a shit idea. You wrote paragraphs and paragraphs of diatribes on something you don't understand even the fundamentals of.

The relative velocity will always be “ludicrous”, no matter what the velocity of the meteor is relative to the 3rd inertial frame, as long as the velocity of the earth relative to the inertial frame is .9c or greater.

Unsubstantiated and incorrect.

I look forward to your revised argument.

[DuncanDoenitz]

With the greatest respect for Pete and JPJ's Relative-arguments, aren't we just accelerating down a mathematical rabbit-hole here? 

OK, the velocity of a meteorite is going to be somewhere between 0 and C.  So where do they come from, and what makes them collide with Earth (or vice versa). 

[Pete Svarrior]

I'm not sure I understand the question.

There is nothing novel about where meteors "come from" under FET. A meteor is a meteoroid that entered the Earth's atmolayer. Meteoroids are usually fragments of comets or impact debris from other bodies.

There is also nothing novel about them colliding with Earth. OP proposes that something has to "cause a meteor to suddenly lose acceleration and 'fall'", but that's blatantly not the case. Both bodies are affected by UA, so their relative velocity will be unaffected by it. The meteoroid will continue to travel with its initial velocity, and will continue to be affected by other factors, like gravitation.

OP seems to think that UA is the only source of any velocity ever. I don't know how to address that other than with a hearty "WTF, Seriously?"

[AATW]

There is nothing novel about where meteors "come from" under FET. A meteor is a meteoroid that entered the Earth's atmolayer. Meteoroids are usually fragments of comets or impact debris from other bodies.

There is also nothing novel about them colliding with Earth. OP proposes that something has to "cause a meteor to suddenly lose acceleration and 'fall'", but that's blatantly not the case. Both bodies are affected by UA, so their relative velocity will be unaffected by it. The meteoroid will continue to travel with its initial velocity, and will continue to be affected by other factors, like gravitation.

There's no issue with meteoroids hitting earth in FE, if they're nudged out of the region where UA operates then they'll "fall" to earth, or rather the earth will accelerate up and hit them but the effect is the same. The issue I see is that there are certain meteor showers which occur at predictable times of the year. This makes sense in the RE model - the earth is travelling through the part of its orbit around the sun where those meteors are. Is there a FE explanation?
And then you have things like Halley's comet which has a ~75 year orbit, it was visible when I was a kid and has been periodically through history. We knew when it was coming, we know when it'll be back. Halley's prediction of its orbit and when it would return was done using Newtonian physics and his prediction was correct. Things like that are pretty good evidence for the model being correct. Is there any FE thought on periodic comets like that?