One for the deep thinkers - or over thinkers...(physics ?)

[TassieTiger]

2 weeks ago - I purchased a huge electronic telescope, and ever since - we’ve received 300mm of rain lol. This telescope is now for hire, marketed as a drought breaker.

After purchasing said scope - I started watching ewe toob vids on solar systems and that lead to tangents, etc...of universal physics.

To my question...this has been bugging me so bad, in fact I emailed professor of Columbia physics university- requesting help (Shout our to prof Brian Greene lol) . I’m sure he is now, doubled up laughing at my patheticsm...but I digress.

Gravity. There I said it.
When physics teachers show pics of how gravity works...they generally show a “depression” in the fabric of space time, where the sun/earth/mass of object, indents space time creating a leading edge, for the moon or what ever, to be in a constant fall, Thus remain in orbit around the central mass. Like this picture...

BC96557A-B224-43E7-B42C-DC1E854465DD.jpeg (173.94 KiB) Viewed 4184 times

Now my issue (and I’ll call it mine for now as I’m the one who can’t work it out) - in space, there’s no up, down, left or right - so whilst the depression in the fabric of space time might be there, it ALSO must be opposite, it must be left, right, in fact - it must be 360’s ? so wouldn’t it be pulling against the same ? - Follow? So if that’s the case, the moon or what ever, is not orbiting on the edge of a gravitational depression, because the depression must be opposite, and in every other direction...which then - doesn’t make bloody sense.

What am I missing ??

[Stix]

Im finding it hard to understand your way of describing it....but i think i know what you mean...

You mean they effectively picture this "fabric" as a 2 dimensional object--like a peice of paper with the gravitational forces only depicted as being effective across that piece of paper...(am i right...?)...

Anyway...the way i see it, is that picture is wrong--because the effects of this "fabric" will be 3 dimensional--so happening from all around it--& this picture doesnt depict that.
Nor does the picture show the Moon's impact on the fabric--it too will have an influence on this "fabric", although not as strong as the bigger object in the middle, & they will be in some kind of balance...

Anyway...i dont fully understand this fabric concept either--you are right--the effects happen from all around, but i guess its the best way they have to illustrate something you cant see...

Its all mind bending stuff--but very interesting...

The scientific evidence suggests that the faster we travel throughout space, the longer we live in relation to objects not travelling so fast...

In other words, if you could travell at 90% of the speed of light & go for a one year hoot part way across the galaxy, by the time you have returned to earth, hundreds or more earth years would have elapsed & all your family & friends would have long died--yet you would have only experienced living for a year...

See if you can find that in your telescope for me mate...

[TassieTiger]

You’ve got the concept Stix - the 2d image presented in schools seems to me, to be flawed - yes - because the pull would be from every direction...I’m sure it’s not, but my head needs to know lol.

Yes - the 90% speed of light can be applied in the same way that time progresses faster At sea level than Mt Everest...there is some strange, mind bending crap out there...

How’s this one - Hawkins theory suggests that if you throw your credit card into a black hole, the information on the credit card - ceases to exist - like it was NEVER here...pass me the Panadol.

[Stix]

Say what...!!!!

Fuk the panadol...!!!

Have you seen my credit card... ....i cant pay it ffs...

Show me the bloody black hole man...!!!!

[TassieTiger]

Haha. If you got close enough to throw It in - you’d have bigger issues lol.

If anyone wants to expand their mind / or just be entertained by the smartest ppl on the planet debating religion, consciousness, free will, Einstein etc - look to the world science festival you tube channel. It puts a few things in to perspective...and much of it is mind blowing...
https://m.youtube.com/user/worldsciencefestival


Perspective? As does this video...
https://m.youtube.com/watch?v=4Tm6Z1y3h94

[Stix]

Fark you Tassie...!!
You led me into a little fantasy of how to make a credit card disappear...so you then cant bring reality into my little financial freedom escapism fantasy...!!!

[TassieTiger]

Well - Brian Greene just told me the world is an illusion - so tell that to the bank and tell em to go jump...

Do you recall a few years ago, a smartArse person Got sent a bill and then sent back a picture of a spider with a note, saying this picture is an original xxx, and is valued at $20,000, so therefore they owed him money - but they could keep the change based on his good will ? Very funny stuff.

[Stix]

I told the bank that last week...but i didnt answer the door the man in the Sheriffs uniform the following day...

But still...dam you...i was just signing a contract to buy my own farm before you ruined it...!!

[TassieTiger]

Put it down to gravity...can ANYONE explain wtf or am I in for another sleepless night...

[on_one_wheel]

Well - Brian Greene just told me the world is an illusion - so tell that to the bank and tell em to go jump...

Do you recall a few years ago, a smartArse person Got sent a bill and then sent back a picture of a spider with a note, saying this picture is an original xxx, and is valued at $20,000, so therefore they owed him money - but they could keep the change based on his good will ? Very funny stuff.

I remember that one

Here it is
https://geekologie.com/2008/11/good-ide ... rawing.php

[TassieTiger]

Was very funny that spider - the reply was good too lol.

An another note - if you ve ever wanted to actually see Jupiter and Saturn - now is the time.
In the east after about 7 (before the moon gets up an hour later) get your binos out and you can see soooo much more than I ever thought possible.

The night before I got my telescope - I put my 60x spot scope on tripod and kids were amazed. We could make out red spot in Jupiter and clearly see the rings of Saturn. We could see 5 moons orbiting Jupiter - all with binos and spotting scope. The two planets are not only close to each other but also close to earth - it could be 135 years until they get closer. It’s pretty cool to see with your own eyes.

[Stix]

Tassie...are you talking about now--late June 2020...?

Because the moon is already in the sky come dark...and it sets in the west heading towards 9pm...

Also, where abouts in the sky is the planets if its now...?...got clear skies here--ill get out n see what i can see with a scope...

[Oldbloke]

That video is only used to demonstrate the concept but only in 2 dimensions.

I think I'm correct in saying that it all happens in 3 dimensions. That would be hard to demonstrate. Not sure if that helps?

[TassieTiger]

Jupiter and Saturn are close together - just slightly towards east right now. Moon ruins the bifion a little - too bright.
If you have an iPhone - download free app called planets. It’s brilliant.

[TassieTiger]

That video is only used to demonstrate the concept but only in 2 dimensions.

I think I'm correct in saying that it all happens in 3 dimensions. That would be hard to demonstrate. Not sure if that helps?

Nope. DoesNt help lol. It’s not only the visibility that messes it up - it’s concept as well.

The gravity of the sun pulls the earth in and the earth has its own gravity - so both masses should pull each other together, but because of the elliptical plane as per the 2d photo, the earth is on the edge of falling out of orbit - constantly - this why it stays away BUT, that edge on which is there in the 2d conceptual photo - would not be there, because the depression that is shown, is in reality 100% all around both the sun and the earth...it’s hard to put into words.
Another demonstration I saw has a rubber sheet pulled tight and a bowling ball thrown into middle to show gravity. BUT in space, there’s no up/down - that rubber sheet wouldn’t be depressed at all ?

[Stix]

No iye-fown here...lol...

Googled it n found it though...

Im looking east over the entire metro area so not the greatest...can see a lot of aberation probably from the odd thin cloud & hot air rising from the burbs below...but can see the moons of Jupiter very clearly...!!!!...very cool...!!

It would look great through a telescope...!!

Its interesting looking through different scopes too...!!

To see the difference is amazing...it really shows the chromatic abberation scopes have, & the different points at which they focus the light at infinity,,,
Ive always had the focus ring set back a touch from infinity for astro photography & viewing, but the difference in infinity focus setting between a cheap $400 bushnell to a Leo VXIII is amazing--the cheaper one is closer to accurate for infinity setting, but the Leo gives sharper image, although more chromatic abberation at its sharpest...
The cheaper scope is pretty poor at dusk compared with the Leo too...

Anyway...good stuff...wish i had a telescope...id be out the back with a yard camp fire checkin it out...
Maybe its a good thing i dont have a telescope--havent had a drop for over a month now, & a telescope out there might make that a different story...

Cheers Tassie...

[Stix]

Tassie i imagine what you are trying to, as if a planet were a ball, & the space around it being water--so the all the water has to move to allow the ball to move through it...but then imagine the image of the water being illustrated as a three dimensional plotted grid of lines linking equally spaced dots...as the ball/planet moves through the water/grid, all the lines linking the dots move to accomodate the ball, & so the lines appear to be warped...
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[TassieTiger]

Tassie i imagine what you are trying to, as if a planet were a ball, & the space around it being water--so the all the water has to move to allow the ball to move through it...but then imagine the image of the water being illustrated as a three dimensional plotted grid of lines linking equally spaced dots...as the ball/planet moves through the water/grid, all the lines linking the dots move to accomodate the ball, & so the lines appear to be warped...
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Yes, exactly - but doesn’t that then screw up the gravity equation ? Because the body in orbit cannot be on an a precipitous edge of falling, if that edge is negated by water on the opposing side ? I know what I’m trying to say dam it.

If there is no gravity in space - no up or down, how can there be an “edge” of what is meant to be the orbital path? In 3D imagery - they show it as the body pushing outwards on 3 planes - much better - but that goes someway to proving the orbital path or “edge of falling” cannot be there...as when they introduce the 2nd orbiting body, it clearly shows something very different.
I’ll see if I can find a 3D pic to show what I mean.

Anyway. It’s cool lookin up now and again. That app is very easy and very cool - it shows you the direction where you actually look - what is there and even what’s on other side of globe. Try it. It’s free.

[Stix]

This guy sums it up at the 8:15 minute mark...
We dont have a special ability to visualise the 4 dimensional experience we live...

https://www.youtube.com/watch?v=AwhKZ3fd9JA

Also, go to 6:48--he states those pics dont show all dimensions--that they only show spacial curvature & not time as well...

thats why we see things in a linear way i guess. ..

I know none of this helps... sorry...

Anyway...im sure this probably explains why my groups always have a random in there--because someone somewhere experienced Déjà vu which sent a small rippling wave through the fabric of space time that wobbled my bloody bullet...!!

[mickb]

The simple answer is the fabric they use in the demonstration isnt meant to completely represent physical space . It demonstrates two or more physical bodies which do exist in space and a range of mathematical relationships between them( which you cant actually see visually) The purpose of the fabric is behaving in a way that matches some of the mathematical relationships. Its just a tool to supplement getting ones head around the maths.

Another way of thinking about such tools is when a 'line' is used to represent the distance between two points. A line itself cannot exist physically since it has zero thickness, its just "the shortest distance between two points". It would therefore be invisable itself , but its a useful visual to draw a line in diagrams in order to represent certain relationshiips between the two points. math and physics has a lot of examples like this.

One way to get ones head around it is to learn some of the math. Some of the basic gravity staff is not too hard, planks constant and centripetal force etc, highschool level physics and a bit of reading usually covers learning rhe basic formulas. When you start thinking maths, the visual representations just look really cool and give less headaches.

[Oldbloke]

Take an aspro and go got bed. Lol

[Flyer]

When a lemon falls from a tree, it comes to rest on its side.

Lemons are not perfect spheres, and neither are planets nor even our sun. In fact, there is no such thing as a perfect sphere with a perfect centre of mass/gravity in any object. All have small imperfections down to the atomic level and beyond.

All the planets in our solar system orbit around the same plane (within 7 degrees). Ever wondered why that is? The answer is in the diagram you posted.

Mass warps spacetime in all directions. The distribution (shape) of the mass determines how the fabric is warped. If the mass were a pefect sphere with perfect density, then it would have equal pull (effects of gravity) on all sides in all three dimensions.

Spacetime has four dimensions, but I'll save that for another time as it's not that relevant in this instance. What is relevent is the shape/centre of gravity of the larger mass, and from which direction the smaller mass approaches.

Like a dinner plate – which is just a squashed sphere, but provides an exagerated mental picture of what an oblate spheroid looks like – the large mass creates a deeper depression in spacetime around its edges (the widest part of its mass, all else being equal). This is where the small mass will orbit. All our planets and the sun are like this: squashed in the middle, with the planets orbiting the sun around its largest diameter (the edge of the dinner plate, so to speak).

So that explains why one mass orbits another in a particular plane.

The next question is, why do they orbit in a particular direction?

mickb alluded to it by mentionijng centriptal force. It just means that whatever direction the smaller mass enters the larger mass's orbit, it will keep travelling in that same direction. It cannot keep going in a straight line because it has been pulled into orbit, but it is still going in the same direction in orbit. In addition to this, multiple smaller masses orbiting a large mass will have their own gravitational pull and draw other objects in with them until everything is orbitting in the same direction.

There is no "clockwise" or "anti-clockwise" of course, because there is no up or down in space: it is all relative to the viewer. "Planes of reference" is also an important concept when defining spacetime, as nothing in the universe stays in the same position. In fact, in quantum physics String Theory, some particles can exist in two places (or more) at once. Then we start getting into other dimensions.

So the short answer to your question is, your diagram shows only a particular effect of gravity, which is orbiting masses. It does not explain exactly how gravity works – humans still don't really understand it (and it behaves differently at the sub-atomic level) – but it does explain the interaction between two (or more) masses when they enter each other's spheres of influence. At least, that is the current theory.

[straightshooter]

Take an aspro and go got bed. Lol

Classical Mechanics is the limit of my Physics understanding so I will have to consult my best Sci-Fi comics and get back to you.
Meanwhile take Oldbloke's advice.

[mickb]

Take an aspro and go got bed. Lol

Classical Mechanics is the limit of my Physics understanding so I will have to consult my best Sci-Fi comics and get back to you.
Meanwhile take Oldbloke's advice.

Oldbloke posted that advice 2.5 hours later than anyone else. If this is a deep thinking thread, he failed.

[Stix]

Take an aspro and go got bed. Lol

Classical Mechanics is the limit of my Physics understanding so I will have to consult my best Sci-Fi comics and get back to you.
Meanwhile take Oldbloke's advice.

Oldbloke posted that advice 2.5 hours later than anyone else. If this is a deep thinking thread, he failed.

It was all he could come up with after sitting up till the wee hours watching yoo-choob vids trying to find an easily rationalised answer...

How do i know this...??...

[TassieTiger]

Lolz x 10

[Blr243]

Too technical , can someone please put up a topic “one for the slow thinkers”. So I can contribute too

[Stix]

I watched a clip last night after all this mind bending stuff, that explained how the universe is so much bigger than expected, because of its constant expansion since the big bang....yep--get that...

It went on to say that because its expanding at an increasingly higher rate (accelerating) away from us (Earth) that eventually, some of the objects we can just see now (the most distant objects/matter/galaxies in the observable universe/as seen by Hubble deep space) will soon be so far away that they will just disappear--so...they'll be so far away & this distance will be ever increasing, that the light wont ever reach us... i get that-...kinda...-

Now because of the expansion, the wavelengths of light coming back to us effectively flatten out to a point of no longer being in the visible spectrum...i get that too.. ....just like hearing the music from a car travelling away from you progressively gets lower in pitch & beats per minute progressively get less/(they decellerate at the rate of the car moving away from you)...yep...righto...

BUT...!!!??!?!?!

If nothing can travel faster than the speed of light, & the universe is expanding at a rate lesser than the speed of light, then the light emitted from these objects/matter/galaxies now, will surely continue to reach us...& even if the wavelength is flattened out to flat, it cant just cease to exist- because matter cannot be created or destroyed, & light is apparently matter--& energy (in this case light radiation) cant just vanish, it can only change its form-or maybe better put, it cant go into a "negative" wavelength & just cease to be... --it must still be there..!!....sssoooo...???...what gives....??

Tassie...can you throw any light on this problem ...(( ...get it...light on... ah i think im funny sometimes))

[luvmeadler]

Does all this mean i will hit the target if i open one eye

[Oldbloke]

I say, take 2 Aspros and go to bed.