Losties! Theories and Discussion
Would you like to react to this message? Create an account in a few clicks or log in to continue.

Sines, Sines, everywhere Sines

+7
SunburnedPenguin
Lateralus
MyStarbuckHatesLost
AngeloComet
l337Jacqui
MollyCocktail
Caged_Faraday
11 posters

Page 1 of 2 1, 2  Next

Go down

Sines, Sines, everywhere Sines Empty Sines, Sines, everywhere Sines

Post by Caged_Faraday Thu May 22, 2008 2:21 am

A 4-D Quantum Mechanical Theory of the "Location" of the LOST Island
Using Classical Mechanics and Trigonometry



OK, so for my first theory post here, I'm gonna shoot the moon, and present a Physical description of the "when" and "where" of the Island. I'm going to give the big headache disclaimer now:scratch:, as I'm giving myself one even trying to put this into words.

Second disclaimer: At least one concept raised here refers to dialogue from the episode Cabin Fever, therefore, this theory would constitute at least a partial spoiler for anyone not having seem that episode.

I propose that the Island moves through space-time in an orderly and predictable pattern. In it's natural state, the island "orbits" the point defined as "here and now", 4-dimentionally, as that point itself moves through time-space.

In essence, the Island is a "satellite" of normal space-time, orbiting in a pattern not unlike the moon to the Earth as the Earth moves through space.

In order to even try to illustrate this idea, we need to reduce the illustration of space to only 2 dimentions, so as to represent time in the 3rd.

Sines, Sines, everywhere Sines IslandSpace-time1
The relative space-time position of the
Island (x), in terms of "now" (n), as it
moves linearly through time.


As "now" progresses steadily forward in time, and the Island orbits it in space-time, the Island tends to "wobble" in a regular pattern both in its spacial distance from a fixed point in regular space (it's regular map coordinates) and its offset in time (a specific distance ahead or behind the "now" point in time).

Isolating only one of these variables at a time, we can simply map either the Island's distance from a fixed spacial point, or the
Island's offset from normal time. Both of which resemble a Sine wave.

Sines, Sines, everywhere Sines IslandSpace-time3


As normal space moves forward in time (τ), the island's
spacial position varies (Δd). Δd=sin(τ).


The same holds true of the Island's time variance (how far "in the future" or "in the past" the Island is at any given time.

Sines, Sines, everywhere Sines IslandSpace-time2
As normal space moves forward in time (τ), the island's
temporal displacement (Δτ) varies. Δτ=sin(τ).


Faraday's reaction to his Stopwatch "Payload" experiment in The Economist shows that the Island was not only separated from the rest of the world in time, but that its "time offset" was changing. Also, over the course of many episodes, there has been evidence that the Island has at different points in the show been both ahead of, and behind, "normal time".

Now, the latest bit of Quantum Leaping is Locke's order from Jacob to "move the Island". I have no issue with this. In moving the Island, the equations still work, with the addition of a (possibly random) factor. Ben states that the island can be moved, but it's results are unpredictible. I can't say for sure if this is because the factor of movement is imprecise, or because Ben does not have the working equation of the Island's natural "wobble" in time-space. Either way, the Island being moved (I believe both in space and time) can be expressed by altering the equations by a factor (f) in one of two ways:

Δd=(f)sin(τ); Δτ=(f)sin(τ), therefore magnifying the Island's time-space drift. The Island would then still orbit, but would reach farther from "here and now" as it once did.
or
Δd=f+sin(τ); Δτ=f+sin(τ), therefore shifting the Island's time-space drift. By this model, depending on the factor, the Island could even remain permanently ahead or behind of real time as it occilated; or, at the least, oscilate in a "lopsided" way through space time.
OK, break out your slide-rules and start debunking. Laughing


Last edited by Caged_Faraday on Thu May 22, 2008 2:25 am; edited 1 time in total (Reason for editing : formatting issues)
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by MollyCocktail Thu May 22, 2008 2:33 am

ACK!!!

My brain just slid out of my ear.
I will leave the debunking to a more mathmatically skilled Lostie.
MollyCocktail
MollyCocktail
Others

Number of posts : 325
Age : 48
Location : Orchid Station, The Island
Humor : Insane
Registration date : 2008-05-13

Character sheet
Name: Jacob

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by l337Jacqui Thu May 22, 2008 6:50 am

Wow...yeah, I can't even look at this lol...college just let out about 2 weeks ago. Please don't make me do maaaaath!!! Neutral
l337Jacqui
l337Jacqui
Others

Number of posts : 266
Age : 40
Location : Kent, OH
Registration date : 2008-05-18

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by AngeloComet Thu May 22, 2008 10:30 am

I don't understand the algebra and won't pretend to.

This appears to say that the Island moves. You seem to be stating that the Island moves, in an orbit, both spatially and in time. Provided I am correct on that assessment, I can respond.

Firstly, I don't like the idea that the Island moves in space at all. I think it can - as Christian has instructed Locke to make happen - I just don't think it does it constantly. (Why the request to move it if it's already moving?)

I do like the idea about moving in time, though. Just a little bit. As though it's oscillating on time - so sometimes the 'wave' is at a peak and a rocket payload will be delayed by 30 minutes, and other times it's pushed forward a little so a dead doctor appears washed up on the shore when he's not even dead on The Freighter.

I like that. I'm not sure if it's what you've stated, but the fact that what you stated made me think like that earns you a +1. Even though that's not what we do here!

I do like th
AngeloComet
AngeloComet
On Jacobs List

Number of posts : 626
Age : 46
Location : Manchester, United Kingdom
Humor : Dry and witty. Like my women.
Registration date : 2008-05-13

Character sheet
Name: Jack

http://www.angelocomets-lost-place.blogspot.com/

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by MyStarbuckHatesLost Thu May 22, 2008 11:15 am

Thank the Gods your posting said what it did. For a minute there, I thought there was a worse speller than me on this site.

Though impressive, I can't agree with this one. General realativity is based upon spacetime being utterly inseparable. You can't have one without the other. Remember E=mc2 Matter and energy are inseparable in the same way that space and time are.

Since the island does not move in space (or it would change positions relative to the freighter, which it has not) then it cannot move in time.

However, that does not mean that there is not some kind of time warping phenomenon surrounding the island (not something that is the island itself) which affects the spacetime locations of any physical object passing through the warping effect.

This effect would most likely be linked to mass since gravity fields produced by any appreciable mass can and do affect the rate of time passage in close proximity to the mass. For example: If a person approaches the event horizon of a stationary black hole of about one solar mass, the rate of time passage to the person aproaching that event horizon would seem to be unchanging. However, the rate of time passage for the person approaching the event horizon as seen by an observer outside the effect of the black hole would be different. The outside observer would see the person approaching the event hoizon as going slower and slower as they got closer to the black hole. Though the person on approach to the balck hole would perceive time as passing at a normal rate, it is actually slowing as they near the event horizon. Upon crossing the event horizon (assuming the tidal stresses didn't tear them into pieces the size of atoms, which they would) time would come to a complete standstill.

There is a different outcome,however, when crossing the event horizon of a rotating black hole. upon approach to the event horizon, the effects are the same as approaching a stationary black hole, but upon crossing the event horizon (again, ignoring the tidal forces tearing you to shreds) the person (or whatever is left of their mass) can be transported to any other place or time in this, or even another universe. Just where and when you wind up depends on factors such as your angle of approach to the event horizon, speed at which you are traveling and mass and rotaional velocity of the black hole.

I am not suggesting that the island has a black hole (impossible, though that would be cool) I am suggesting that the rate of time passage can be altered, relative to an outside observer's point of view, without physically moving the island itself.

I would have posted this as a separate theory but I have a feeling that this comment will cause bigger brain freezes than your original posting so it is probably safer to keep the uber-nerd data on one page.
MyStarbuckHatesLost
MyStarbuckHatesLost
On Jacobs List

Number of posts : 681
Age : 61
Location : Winston Salem, North Carolina U.S.A.
Humor : check out TheFlatSpin.com and you'll be sorry you asked that.
Registration date : 2008-05-14

http://www.theflatspin.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Thu May 22, 2008 5:38 pm

MyStarbuckHatesLost wrote:General realativity is based upon spacetime being utterly inseparable.
Exactly... that's part of my point and all of my problem.

When I imagined "the Island" orbiting 4-dimentionally, relative to the "normal" passage of time, I originally didn't fixate on the x/y axiis of it's orbit. When I came to add mathematical model to it, which I thought would help explain it, I needed 2 axiis to define the path of said orbit.

The first was obviously time. Now the second could have also been time, but trying to conceive an "object" travelling forward, backward, left, and right through time would have caused many (including myself) to bleed from the eyes and nose like Horace.

So, with space and time so intrinsicly linked, I didn't think it too big a jump to assume the 2nd axis is spacial, therefore a distance. Distance from wher, is the question. A question I wasn't considering exploring. The Physicists come up with the equations, let the Engineers apply them.

My fatal flaw was this:
the Island tends to "wobble" in a regular pattern both in its spacial distance from a fixed point in regular space (it's regular map coordinates)
Simply put, I never should have said that, especially about map coordinates. Is it possible? Sure. Is it practicle? Not really.

The spacial movement isn't neccessarily supposed to imply the Island is bouncing about the South Pacific. I see its "drift" through space in one of 3 ways.

1. The physical distance is simply the neccessary correction to place the island in the "correct" location in space as the Earth travels through space. Basically, the equation correcting itself to account for the Earth's own movement.

2. The physical "drift" on the island is such a minor factor of the equation (perhaps meters in terms of years) that a shift of 3 to 4 meters would be negligable. This still fits with Faraday's all important compass bearing, assuming that bearing defines the axis upon which the island drifts. Even if the island was moving by a few meters, it would only be moving toward and away from him, as long as he followed that bearing.

3. The physical "drift" of the island is not in terms of the island itself moving, but it's "exit portal" (the point into which one would arrive in "normal space") moves instead. This would explain why, when travelling from the island, Ben seems to arrive, unpredictably, in places like Tunisia; and why he states to Locke that moving the island is difficult and unpredictable.

If all time-space movement is actually through bending/folding space, number 3 would be the most accurate, where the time-space fold places the island adjacent to a different point in time-space. The equations then would explaine not when and where the island was, but when and where it was adjacent to, at any given point.

And to those who simply replied about not wanting to do math scratch ... sorry.
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Lateralus Thu May 22, 2008 6:54 pm

ouch...
Its been a long time since i've had to do any real math.

Is this like saying if i was to jump into the air in Kansas and hang there(somehow free from gravity), i could wait till i was over California, then touch down? The earth would rotate beneath me giving me the impression i was moving west but I would not be moving at all, the earth beneath me would be rotating east.
Lateralus
Lateralus
On Jacobs List

Number of posts : 526
Age : 46
Location : Little Rock, AR
Humor : "I hate you Milkman Dan"
Registration date : 2008-05-16

Character sheet
Name: Lateralus Finn

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Thu May 22, 2008 7:10 pm

Lateralus wrote:ouch...
Its been a long time since i've had to do any real math.

Is this like saying if i was to jump into the air in Kansas and hang there(somehow free from gravity), i could wait till i was over California, then touch down? The earth would rotate beneath me giving me the impression i was moving west but I would not be moving at all, the earth beneath me would be rotating east.

That would in fact be the spacial movement illustrated in the 1st possibility, yes.

Oddly, it's been a long time since I've had the opportunity to do any real math... and I find I'm enjoying it. Then again, I'm a geek; I know this.
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by SunburnedPenguin Thu May 22, 2008 7:18 pm

Most of this goes over my head - I have a huge interest in physics, quantum mechanics, space/time etc, but I am nothing more than an armchair enthusiast who like to pretend she knows what shes on about Very Happy

I think I get what you mean though....its kinda how I imagine the island to be, if you read my theory "smoke in a snow globe".

I imagine it to be existing within the same space of the world, but within its own magnetic field, and in its own....um...dimension? I think.

I like this thread, its forcing me to think....I dont do that half as much as I should Razz
SunburnedPenguin
SunburnedPenguin
Admin

Number of posts : 1411
Age : 49
Location : Near Cardiff
Humor : You'll get used to it :)
Registration date : 2008-04-14

Character sheet
Name: Kudos Manilla

http://www.losties.darkbb.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Thu May 22, 2008 7:43 pm

SunburnedPenguin wrote:I like this thread, its forcing me to think....
Maybe we need a topic for "Makes You Think". alien Actually, I was curious about the general practice of moving theories from L-T to here. Where should they go? There doesn't seem to be a Topic for "Imported Theories".
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by SunburnedPenguin Thu May 22, 2008 7:57 pm

You can just copy the text into a new post if its your theory, maybe you could state that it was originally posted on LT but thats up to you. Its your theory, you can put it anywhere you like Smile
SunburnedPenguin
SunburnedPenguin
Admin

Number of posts : 1411
Age : 49
Location : Near Cardiff
Humor : You'll get used to it :)
Registration date : 2008-04-14

Character sheet
Name: Kudos Manilla

http://www.losties.darkbb.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by AngeloComet Thu May 22, 2008 9:26 pm

"you can put it anywhere you like Smile"


I like it when girls say that.

(I'm very sorry for the crudity I have just delivered into this fine, intellectual post. But not sorry enough not to post.)
AngeloComet
AngeloComet
On Jacobs List

Number of posts : 626
Age : 46
Location : Manchester, United Kingdom
Humor : Dry and witty. Like my women.
Registration date : 2008-05-13

Character sheet
Name: Jack

http://www.angelocomets-lost-place.blogspot.com/

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by MollyCocktail Thu May 22, 2008 9:37 pm

AngeloComet wrote:"you can put it anywhere you like Smile"


I like it when girls say that.

(I'm very sorry for the crudity I have just delivered into this fine, intellectual post. But not sorry enough not to post.)

I now have soda all over my screen.
HAHAHAHAHAHAHA!!
MollyCocktail
MollyCocktail
Others

Number of posts : 325
Age : 48
Location : Orchid Station, The Island
Humor : Insane
Registration date : 2008-05-13

Character sheet
Name: Jacob

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Thu May 22, 2008 9:40 pm

AngeloComet wrote:"you can put it anywhere you like Smile"


I like it when girls say that.

(I'm very sorry for the crudity I have just delivered into this fine, intellectual post. But not sorry enough not to post.)
I appreciate the crudity... it takes the attention off of the flawed physics and bad math. Very Happy
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by MyStarbuckHatesLost Thu May 22, 2008 10:57 pm

"you can put it anywhere you like Smile"


I like it when girls say that.

(I'm very sorry for the crudity I have just delivered into this fine, intellectual post. But not sorry enough not to post.)

AC, We need name in three days...time for a new list!

Lateralus. Your jumping in the air thing would work except the atmosphere would carry you along so you wouldn't wind up in Ca. Try driving.
MyStarbuckHatesLost
MyStarbuckHatesLost
On Jacobs List

Number of posts : 681
Age : 61
Location : Winston Salem, North Carolina U.S.A.
Humor : check out TheFlatSpin.com and you'll be sorry you asked that.
Registration date : 2008-05-14

http://www.theflatspin.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by SunburnedPenguin Thu May 22, 2008 11:20 pm

lol! lol!

I walked right into that one eh! Smile
SunburnedPenguin
SunburnedPenguin
Admin

Number of posts : 1411
Age : 49
Location : Near Cardiff
Humor : You'll get used to it :)
Registration date : 2008-04-14

Character sheet
Name: Kudos Manilla

http://www.losties.darkbb.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Lateralus Fri May 23, 2008 2:37 am

MShl, and i guess i would hit a cellphone tower or two along the way too.
Lateralus
Lateralus
On Jacobs List

Number of posts : 526
Age : 46
Location : Little Rock, AR
Humor : "I hate you Milkman Dan"
Registration date : 2008-05-16

Character sheet
Name: Lateralus Finn

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by tracker Fri May 23, 2008 2:48 am

Sines, Sines, everywhere Sines Homer8

I agree with everything except......mmmmmmmmmmmmmmmmmmmmmmmmmbeer
tracker
tracker
Others

Number of posts : 237
Age : 67
Location : Charleston, SC
Humor : Hell hath no fury like a woman's corns.......Archie Bunker
Registration date : 2008-05-14

Character sheet
Name:

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by TheHolyStickman Fri May 23, 2008 10:46 pm

Yes! I think I got it. Woo! 10 points to me. I liked the bit about time moving around "now" so that the dead doc and the thing that Daniel had sent over.

I didnt get the bit about space though, could you explain that bit for me CagedF I'm a little confused.
TheHolyStickman
TheHolyStickman
The Chosen Ones

Number of posts : 1115
Age : 29
Location : Norfolk England
Humor : Witty
Registration date : 2008-05-18

Character sheet
Name: Roger Gilmour

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by TheHolyStickman Fri May 23, 2008 11:00 pm

Btw I can completley imagine Daniel explaining this to someone. So cool
TheHolyStickman
TheHolyStickman
The Chosen Ones

Number of posts : 1115
Age : 29
Location : Norfolk England
Humor : Witty
Registration date : 2008-05-18

Character sheet
Name: Roger Gilmour

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Sat May 24, 2008 3:17 am

TheHolyStickman wrote:I didnt get the bit about space though, could you explain that bit for me CagedF I'm a little confused.
Like I had said earlier, when the idea first came to me, I was simply thinking about "orbiting in time". When I started adding a mathematical model to it, I ended up with movement in 2 dimentions. One was obviously movement forward and backward in time. The second dimention of movement was harder to deal with, but, since space-time is inherently linked, it only made sence that movement in time has to be paired with movement in space (really some kind of physical movement). Don't think space, like black with stars... simply physical movement. The question, and the common arguement against my theory, is regarding the island moving physically in terms of its position on Earth.

That being said, I'd say re-read my follow-up post. I do a better job explaining that second dimention of movement. Of course, the best answer is "I don't know. It's all theory. Smile
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by TheHolyStickman Sat May 24, 2008 10:26 am

So the island moves around a fixed point in the sea and when the island is moved that "fixed point" moves. Woo! 10 more points to me.

That is right CagedF? Right?
TheHolyStickman
TheHolyStickman
The Chosen Ones

Number of posts : 1115
Age : 29
Location : Norfolk England
Humor : Witty
Registration date : 2008-05-18

Character sheet
Name: Roger Gilmour

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Sat May 24, 2008 7:26 pm

TheHolyStickman wrote:So the island moves around a fixed point in the sea and when the island is moved that "fixed point" moves. Woo! 10 more points to me.

That is right CagedF? Right?
That is one possible way to look at it.
I have to say, honestly, I don't know. I was working on a theory only to explain the time movement of the island. Once I put it into a mathematical equation, I discovered I had, well... a remainder... extra movement in another direction. If time is forward and backward, I still had to deal with "left and right". What that is, honestly, I'm not sure. So, I call it "spacial movement". Where, how, and how much that movement occurs is anyone's guess. That's my best answer.
Guess I'm not getting my Doctorate in Quantum Island Physics for this one. scratch
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Alaina Sun May 25, 2008 12:45 am

Ah Physics I love it but I will have to reread and give and give a proper response during my lunch on Monday I have had a bit to much to drink today to remember all of my physics knowledge this evening.

CF I have to say you are one of my new favorite theorist!
Alaina
Alaina
Others

Number of posts : 136
Age : 49
Location : North Carolina
Registration date : 2008-05-16

Character sheet
Name:

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Caged_Faraday Sun May 25, 2008 12:59 am

Alaina wrote:Ah Physics I love it but I will have to reread and give and give a proper response during my lunch on Monday I have had a bit to much to drink today to remember all of my physics knowledge this evening.
No, I assure you, my physics is far more sound when you're drunk. Smile
Alaina wrote:I have to say you are one of my new favorite theorist!
Thank you.
Caged_Faraday
Caged_Faraday
Moderator

Number of posts : 660
Age : 48
Location : Don't ask where... ask when.
Humor : Bitterly sarcastic
Registration date : 2008-05-21

Character sheet
Name: Cagey

http://ianscott76.blogspot.com

Back to top Go down

Sines, Sines, everywhere Sines Empty Re: Sines, Sines, everywhere Sines

Post by Sponsored content


Sponsored content


Back to top Go down

Page 1 of 2 1, 2  Next

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum