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Put a flat earthier into space


DaveH said:
Well, anyway.... A bit has been said on this thread about observing the planets and how what you see is consistent with what is best called reality. For those who have never looked but are of sound mind and judgement, I thought you might find this bit of background information interesting.

There are a few things you can observe. For a start there are the inner planets of Mercury and Venus. Being closer to the sun and in smaller orbits, these are usually seen as very bright 'stars' close to the sun, so you see them either in the early evening or early morning sky just after sunset or before sunrise.

For both of these, with a telescope, you see them show phases just like the moon. If there was a line, Sun->Venus->Earth, then we would be looking at the dark side of Venus and not see it (it would also be day light and we would be looking at the sun), much like a new moon. If the solar system was a clock and we were at 6 o'clock and Venus at 3 o'clock then to us the side of Venus would be facing the sun and light, so we would see a half crescent.

This is an image of some of the phases from Sky & Telescope magazine:
Logon or register to see this image


Further out you have Mars and Jupiter. With all but small telescopes, you can see features on both of these. There are some lovely pictures of Mars out there, mine is only a small scope so this is a bit grainy:
Logon or register to see this image

You can see dark features, which if you watch over the course of a few nights, you see Mars rotate and the features disappear off one side, coming onto the other side again later. It means that a home astronomer can actually measure the rotation speed of Mars.

Similar with Jupiter.

You can see the various storms and features on it's bands rotate. Being a gas planet the different parts of it rotate at different speeds. But what is also interesting about Jupiter is it's 4 brightest moons. With a pair of decent sized binoculars, you can see these and if you watch night after night you see them move as they rotate around the planet, with the inner ones orbiting faster then the others. You see them pass in front, then disappear behind and if you catch it on the right night with a telescope, you see the shadow of the moon cross the planet. At one point I promised to try and get an image or video of this, but I'm constantly thwarted by bad weather on the nights this happens, and Jupiter is low in the sky at the moment, so I only have a short period before it disappears behind the neighbours trees. But if you look due south just after sunset and can see a bright 'star' that is Jupiter. If you do have any binoculars, take a look and you will see the 4 brightest moons.

I've not got any of my own pictures of Saturn. While the planet itself is mostly featureless and you can't see it rotate, there are the rings. As our position changes relative to Saturn, we see the rings at different angles and can see the shadows they cast on the planet. Most people looking through a telescope for the first time have a real wow moment seeing the moon and Saturn. Unfortunately that is even lower than Jupiter at the moment and is not that great to see at the minute (in the UK anyway).

But what does get interesting is watching the orbits of the other planets. Astronomers will often say things like "Jupiter is at opposition". Basically that means that Jupiter is on the opposite side of the earth to the sun, which means it is at the closest and most brightest it will appear. The opposite of that is when the outer planets are at conjunction or the other side of the sun. As they approach this other side, they are at the furthest points in their obits to us and so appear smaller and not as bright.

But, with the outer planets, you also get another interesting effect. The planets stars and other things in space are so far away that we can't easily perceive any depth so we often imagine the concept of a 'celestial sphere', basically like we live on the inside of a large hollow ball and space is painted on the inside (I know what this is sounding like!). The reality is not like that but it works as a hypothetical model.

I've knocked up an animation:
You must be logged on to see external links

It shows the Earth and Jupiter in orbit and there are two things to watch for. There is a faint dotted line moving round, which is the line between Jupiter and the sun. When the earth crosses this line passing between Jupiter and the sun, this is when Jupiter is set to be at opposition. You can see from this how they get so much closer together. You will also notice that the position in their orbits where they reach opposition change each time. So if the background stars on the 'celestial sphere' are fixed, then you can see Jupiter at opposition will appear in different parts of the sky each time.

The thicker line shows where we will see Jupiter appear on this celestial sphere. If you watch it carefully, you can see that relative to the background stars Jupiter appears to move quickly but as we reach opposition it slows and seems to double back on itself before moving forward and speeding up again. This is called retrograde motion and was one of the key observations that made people realise we were not at the centre of the solar system. Only the outer planets experience this. This movement can only be explained with the sun at the centre. They did try to explain it away with 'epicycles' an invisible object that the outer planets happened to jump around a bit every now and then. Moving the rotation around the sun simplified the model and it actually worked.

You can also see that as the Earth reaches the other side of the sun to Jupiter, the line of sight goes pretty close to the sun. That means that as we watch night after night, Jupiter appears closer and closer to the sun, only really being visible around sunset, and then we lose it altogether, only to see it appear as an early evening object just before sunrise a few days later.

Just two dots going round in circles shows the beautiful simplicity of it all and how easy it is to model the solar system and what we see with two simple orbits, match exactly what is observed.

Of course it is only recently that we have had computers to model this, so astronomers used to use an orrery, a mechanical model of the solar system. Just observing the movements like this alone is not enough to figure out the scale of the universe, but you can determine the ratio of how many Jupiter orbits there are to Earth. If you have two cogs (one for each planet) with the same ratio difference then you can build a mechanical representation and it works because cogs are round just like the orbits (though many of the orbits are not quite perfect circles and have eccentricities of their own). It is worth looking at the wikipedia article or doing a google search as there some really beautiful models out there (still talking astronomy here):
You must be logged on to see external links

Computers and mechanical models are not the only tools available and if you want to predict how often a planet will come into opposition you can use maths.

We know that speed is equal to distance over time. So if we say once round an orbit is one rotation, then the rotational speed is the distance (one orbit) over time, 1 year. So for earth the rotational speed is:
se = 1 / e or
se = 1 / 365
Jupiter orbits over 4328.9 earth days, so Jupiter's rotational speed is
sj = 1 / j or
sj = 1/4328.9

The difference in speed is the speed of the earth minus the speed of Jupiter. But if we have said that 'speed = distance / time', then we can rearrange that to say 'time = distance / speed '.

Or we can say that:
difference in time = distance / difference in speed
which will give us how often they come into sync, so
opposition = distance / se - sj
The distance is one rotation so
opposition = 1 / se - sj or
opposition = 1 / (1/365 - 1/4328.9)
opposition = 398.61 days, or just over 13 months

This is exactly how often we see Jupiter reach opposition and why we are able to predict it looking larger and brighter with great accuracy.

How do we know the above maths works? Well we are all familiar with another thing where two objects move in a circle but occasionally overlap - a clock. The minute hand goes round once every 60 minutes and the hour hand goes round once every 12 hours (or 720 minutes). They align at 12 o'clock and again at 5 minutes past 1. That is no different to planets at opposition, so
sync = 1 / (1/60 - 1/720)
sync = 65.45 minutes
or if in sync at 12, they will be in sync again at 5.45 minutes past one, or 1:05:27. That is exactly what we do see.

So there you have it, the solar system really does work like clockwork.
Click to expand...
Thanks for posting that, one of the reasons I keep coming back to this thread, really interesting.👍
 
DaveH said:
Well, anyway.... A bit has been said on this thread about observing the planets and how what you see is consistent with what is best called reality. For those who have never looked but are of sound mind and judgement, I thought you might find this bit of background information interesting.

There are a few things you can observe. For a start there are the inner planets of Mercury and Venus. Being closer to the sun and in smaller orbits, these are usually seen as very bright 'stars' close to the sun, so you see them either in the early evening or early morning sky just after sunset or before sunrise.

For both of these, with a telescope, you see them show phases just like the moon. If there was a line, Sun->Venus->Earth, then we would be looking at the dark side of Venus and not see it (it would also be day light and we would be looking at the sun), much like a new moon. If the solar system was a clock and we were at 6 o'clock and Venus at 3 o'clock then to us the side of Venus would be facing the sun and light, so we would see a half crescent.

This is an image of some of the phases from Sky & Telescope magazine:
Logon or register to see this image


Further out you have Mars and Jupiter. With all but small telescopes, you can see features on both of these. There are some lovely pictures of Mars out there, mine is only a small scope so this is a bit grainy:
Logon or register to see this image

You can see dark features, which if you watch over the course of a few nights, you see Mars rotate and the features disappear off one side, coming onto the other side again later. It means that a home astronomer can actually measure the rotation speed of Mars.

Similar with Jupiter.

You can see the various storms and features on it's bands rotate. Being a gas planet the different parts of it rotate at different speeds. But what is also interesting about Jupiter is it's 4 brightest moons. With a pair of decent sized binoculars, you can see these and if you watch night after night you see them move as they rotate around the planet, with the inner ones orbiting faster then the others. You see them pass in front, then disappear behind and if you catch it on the right night with a telescope, you see the shadow of the moon cross the planet. At one point I promised to try and get an image or video of this, but I'm constantly thwarted by bad weather on the nights this happens, and Jupiter is low in the sky at the moment, so I only have a short period before it disappears behind the neighbours trees. But if you look due south just after sunset and can see a bright 'star' that is Jupiter. If you do have any binoculars, take a look and you will see the 4 brightest moons.

I've not got any of my own pictures of Saturn. While the planet itself is mostly featureless and you can't see it rotate, there are the rings. As our position changes relative to Saturn, we see the rings at different angles and can see the shadows they cast on the planet. Most people looking through a telescope for the first time have a real wow moment seeing the moon and Saturn. Unfortunately that is even lower than Jupiter at the moment and is not that great to see at the minute (in the UK anyway).

But what does get interesting is watching the orbits of the other planets. Astronomers will often say things like "Jupiter is at opposition". Basically that means that Jupiter is on the opposite side of the earth to the sun, which means it is at the closest and most brightest it will appear. The opposite of that is when the outer planets are at conjunction or the other side of the sun. As they approach this other side, they are at the furthest points in their obits to us and so appear smaller and not as bright.

But, with the outer planets, you also get another interesting effect. The planets stars and other things in space are so far away that we can't easily perceive any depth so we often imagine the concept of a 'celestial sphere', basically like we live on the inside of a large hollow ball and space is painted on the inside (I know what this is sounding like!). The reality is not like that but it works as a hypothetical model.

I've knocked up an animation:
You must be logged on to see external links

It shows the Earth and Jupiter in orbit and there are two things to watch for. There is a faint dotted line moving round, which is the line between Jupiter and the sun. When the earth crosses this line passing between Jupiter and the sun, this is when Jupiter is set to be at opposition. You can see from this how they get so much closer together. You will also notice that the position in their orbits where they reach opposition change each time. So if the background stars on the 'celestial sphere' are fixed, then you can see Jupiter at opposition will appear in different parts of the sky each time.

The thicker line shows where we will see Jupiter appear on this celestial sphere. If you watch it carefully, you can see that relative to the background stars Jupiter appears to move quickly but as we reach opposition it slows and seems to double back on itself before moving forward and speeding up again. This is called retrograde motion and was one of the key observations that made people realise we were not at the centre of the solar system. Only the outer planets experience this. This movement can only be explained with the sun at the centre. They did try to explain it away with 'epicycles' an invisible object that the outer planets happened to jump around a bit every now and then. Moving the rotation around the sun simplified the model and it actually worked.

You can also see that as the Earth reaches the other side of the sun to Jupiter, the line of sight goes pretty close to the sun. That means that as we watch night after night, Jupiter appears closer and closer to the sun, only really being visible around sunset, and then we lose it altogether, only to see it appear as an early evening object just before sunrise a few days later.

Just two dots going round in circles shows the beautiful simplicity of it all and how easy it is to model the solar system and what we see with two simple orbits, match exactly what is observed.

Of course it is only recently that we have had computers to model this, so astronomers used to use an orrery, a mechanical model of the solar system. Just observing the movements like this alone is not enough to figure out the scale of the universe, but you can determine the ratio of how many Jupiter orbits there are to Earth. If you have two cogs (one for each planet) with the same ratio difference then you can build a mechanical representation and it works because cogs are round just like the orbits (though many of the orbits are not quite perfect circles and have eccentricities of their own). It is worth looking at the wikipedia article or doing a google search as there some really beautiful models out there (still talking astronomy here):
You must be logged on to see external links

Computers and mechanical models are not the only tools available and if you want to predict how often a planet will come into opposition you can use maths.

We know that speed is equal to distance over time. So if we say once round an orbit is one rotation, then the rotational speed is the distance (one orbit) over time, 1 year. So for earth the rotational speed is:
se = 1 / e or
se = 1 / 365
Jupiter orbits over 4328.9 earth days, so Jupiter's rotational speed is
sj = 1 / j or
sj = 1/4328.9

The difference in speed is the speed of the earth minus the speed of Jupiter. But if we have said that 'speed = distance / time', then we can rearrange that to say 'time = distance / speed '.

Or we can say that:
difference in time = distance / difference in speed
which will give us how often they come into sync, so
opposition = distance / se - sj
The distance is one rotation so
opposition = 1 / se - sj or
opposition = 1 / (1/365 - 1/4328.9)
opposition = 398.61 days, or just over 13 months

This is exactly how often we see Jupiter reach opposition and why we are able to predict it looking larger and brighter with great accuracy.

How do we know the above maths works? Well we are all familiar with another thing where two objects move in a circle but occasionally overlap - a clock. The minute hand goes round once every 60 minutes and the hour hand goes round once every 12 hours (or 720 minutes). They align at 12 o'clock and again at 5 minutes past 1. That is no different to planets at opposition, so
sync = 1 / (1/60 - 1/720)
sync = 65.45 minutes
or if in sync at 12, they will be in sync again at 5.45 minutes past one, or 1:05:27. That is exactly what we do see.

So there you have it, the solar system really does work like clockwork.
Click to expand...
define "anyway" ;)
 
ned_werby said:
define "anyway" ;)
Click to expand...

:lol:

"When you say "Well" at the start there, do you mean like a deep hole with water in it? That makes absolutely no sense."
nahwee said:
Thanks for posting that, one of the reasons I keep coming back to this thread, really interesting.👍
Click to expand...

I was thinking about this last night. I really hope one day to see this thread on the GOLD board (but hopefully not for a long time yet), because it really does showcase some of the best and worst the SMB has to offer.

Hell, it showcases the best and worst I personally have to offer, often within a couple of pages of each other.

The whole thing is a journey, though. A story in itself. An unveiling.

It's Alice In Wonderland 3: This Time The Bitch Can Only Get Out Of This Damned Rabbit Hole If She Has PROOF...

...and don't even be thinkin' about pickin' up that lookin' glass, y'hear?
 
Last edited:
DaveH said:
Well, anyway.... A bit has been said on this thread about observing the planets and how what you see is consistent with what is best called reality. For those who have never looked but are of sound mind and judgement, I thought you might find this bit of background information interesting.

There are a few things you can observe. For a start there are the inner planets of Mercury and Venus. Being closer to the sun and in smaller orbits, these are usually seen as very bright 'stars' close to the sun, so you see them either in the early evening or early morning sky just after sunset or before sunrise.

For both of these, with a telescope, you see them show phases just like the moon. If there was a line, Sun->Venus->Earth, then we would be looking at the dark side of Venus and not see it (it would also be day light and we would be looking at the sun), much like a new moon. If the solar system was a clock and we were at 6 o'clock and Venus at 3 o'clock then to us the side of Venus would be facing the sun and light, so we would see a half crescent.

This is an image of some of the phases from Sky & Telescope magazine:
Logon or register to see this image


Further out you have Mars and Jupiter. With all but small telescopes, you can see features on both of these. There are some lovely pictures of Mars out there, mine is only a small scope so this is a bit grainy:
Logon or register to see this image

You can see dark features, which if you watch over the course of a few nights, you see Mars rotate and the features disappear off one side, coming onto the other side again later. It means that a home astronomer can actually measure the rotation speed of Mars.

Similar with Jupiter.

You can see the various storms and features on it's bands rotate. Being a gas planet the different parts of it rotate at different speeds. But what is also interesting about Jupiter is it's 4 brightest moons. With a pair of decent sized binoculars, you can see these and if you watch night after night you see them move as they rotate around the planet, with the inner ones orbiting faster then the others. You see them pass in front, then disappear behind and if you catch it on the right night with a telescope, you see the shadow of the moon cross the planet. At one point I promised to try and get an image or video of this, but I'm constantly thwarted by bad weather on the nights this happens, and Jupiter is low in the sky at the moment, so I only have a short period before it disappears behind the neighbours trees. But if you look due south just after sunset and can see a bright 'star' that is Jupiter. If you do have any binoculars, take a look and you will see the 4 brightest moons.

I've not got any of my own pictures of Saturn. While the planet itself is mostly featureless and you can't see it rotate, there are the rings. As our position changes relative to Saturn, we see the rings at different angles and can see the shadows they cast on the planet. Most people looking through a telescope for the first time have a real wow moment seeing the moon and Saturn. Unfortunately that is even lower than Jupiter at the moment and is not that great to see at the minute (in the UK anyway).

But what does get interesting is watching the orbits of the other planets. Astronomers will often say things like "Jupiter is at opposition". Basically that means that Jupiter is on the opposite side of the earth to the sun, which means it is at the closest and most brightest it will appear. The opposite of that is when the outer planets are at conjunction or the other side of the sun. As they approach this other side, they are at the furthest points in their obits to us and so appear smaller and not as bright.

But, with the outer planets, you also get another interesting effect. The planets stars and other things in space are so far away that we can't easily perceive any depth so we often imagine the concept of a 'celestial sphere', basically like we live on the inside of a large hollow ball and space is painted on the inside (I know what this is sounding like!). The reality is not like that but it works as a hypothetical model.

I've knocked up an animation:
You must be logged on to see external links

It shows the Earth and Jupiter in orbit and there are two things to watch for. There is a faint dotted line moving round, which is the line between Jupiter and the sun. When the earth crosses this line passing between Jupiter and the sun, this is when Jupiter is set to be at opposition. You can see from this how they get so much closer together. You will also notice that the position in their orbits where they reach opposition change each time. So if the background stars on the 'celestial sphere' are fixed, then you can see Jupiter at opposition will appear in different parts of the sky each time.

The thicker line shows where we will see Jupiter appear on this celestial sphere. If you watch it carefully, you can see that relative to the background stars Jupiter appears to move quickly but as we reach opposition it slows and seems to double back on itself before moving forward and speeding up again. This is called retrograde motion and was one of the key observations that made people realise we were not at the centre of the solar system. Only the outer planets experience this. This movement can only be explained with the sun at the centre. They did try to explain it away with 'epicycles' an invisible object that the outer planets happened to jump around a bit every now and then. Moving the rotation around the sun simplified the model and it actually worked.

You can also see that as the Earth reaches the other side of the sun to Jupiter, the line of sight goes pretty close to the sun. That means that as we watch night after night, Jupiter appears closer and closer to the sun, only really being visible around sunset, and then we lose it altogether, only to see it appear as an early evening object just before sunrise a few days later.

Just two dots going round in circles shows the beautiful simplicity of it all and how easy it is to model the solar system and what we see with two simple orbits, match exactly what is observed.

Of course it is only recently that we have had computers to model this, so astronomers used to use an orrery, a mechanical model of the solar system. Just observing the movements like this alone is not enough to figure out the scale of the universe, but you can determine the ratio of how many Jupiter orbits there are to Earth. If you have two cogs (one for each planet) with the same ratio difference then you can build a mechanical representation and it works because cogs are round just like the orbits (though many of the orbits are not quite perfect circles and have eccentricities of their own). It is worth looking at the wikipedia article or doing a google search as there some really beautiful models out there (still talking astronomy here):
You must be logged on to see external links

Computers and mechanical models are not the only tools available and if you want to predict how often a planet will come into opposition you can use maths.

We know that speed is equal to distance over time. So if we say once round an orbit is one rotation, then the rotational speed is the distance (one orbit) over time, 1 year. So for earth the rotational speed is:
se = 1 / e or
se = 1 / 365
Jupiter orbits over 4328.9 earth days, so Jupiter's rotational speed is
sj = 1 / j or
sj = 1/4328.9

The difference in speed is the speed of the earth minus the speed of Jupiter. But if we have said that 'speed = distance / time', then we can rearrange that to say 'time = distance / speed '.

Or we can say that:
difference in time = distance / difference in speed
which will give us how often they come into sync, so
opposition = distance / se - sj
The distance is one rotation so
opposition = 1 / se - sj or
opposition = 1 / (1/365 - 1/4328.9)
opposition = 398.61 days, or just over 13 months

This is exactly how often we see Jupiter reach opposition and why we are able to predict it looking larger and brighter with great accuracy.

How do we know the above maths works? Well we are all familiar with another thing where two objects move in a circle but occasionally overlap - a clock. The minute hand goes round once every 60 minutes and the hour hand goes round once every 12 hours (or 720 minutes). They align at 12 o'clock and again at 5 minutes past 1. That is no different to planets at opposition, so
sync = 1 / (1/60 - 1/720)
sync = 65.45 minutes
or if in sync at 12, they will be in sync again at 5.45 minutes past one, or 1:05:27. That is exactly what we do see.

So there you have it, the solar system really does work like clockwork.
Click to expand...


Fantastic. *insert chef's kiss gif*
 
fyl2u said:
:lol:

"When you say "Well" at the start there, do you mean like a deep hole with water in it? That makes absolutely no sense."


I was thinking about this last night. I really hope one day to see this thread on the GOLD board (but hopefully not for a long time yet), because it really does showcase some of the best and worst the SMB has to offer.

Hell, it showcases the best and worst I personally have to offer, often within a couple of pages of each other.

The whole thing is a journey, though. A story in itself. An unveiling.

It's Alice In Wonderland 3: This Time The Bitch Can Only Get Out Of This Damned Rabbit Hole If She Has PROOF...

...and don't even be thinkin' about pickin' up that lookin' glass, y'hear?
Click to expand...
I don't know about you, but when I filter through the madness I find it both fascinating how conspiracy theorists think, but it also raises some questions that get me thinking.

Take your current battle of tangents and right angles. I've never thought about how to prove that mathematically and when I started I realised you need calculus and I hit something I have either not seen before or not seen for a long time and memory not really working. Now I realise there is some knowledge I need to refresh or learn.

I doubt if I'll ever post the proof here, because it is clearly a waste of time and I think it was your example of two parallel lines then drawing a circle between, explains it in a far simpler way.

So there is actually no point in working it out, but now I can see a problem that I don't know how to solve straight off, and I like a puzzle to work out. That is what keeps me coming back to this thread. Might be a sad insight into my life that I'd much rather sit and work out a maths problem than watch the latest reality singing/dancing/baking show (or do the decorating I've been putting off).
 
DaveH said:
I don't know about you, but when I filter through the madness I find it both fascinating how conspiracy theorists think, but it also raises some questions that get me thinking.

Take your current battle of tangents and right angles. I've never thought about how to prove that mathematically and when I started I realised you need calculus and I hit something I have either not seen before or not seen for a long time and memory not really working. Now I realise there is some knowledge I need to refresh or learn.

I doubt if I'll ever post the proof here, because it is clearly a waste of time and I think it was your example of two parallel lines then drawing a circle between, explains it in a far simpler way.

So there is actually no point in working it out, but now I can see a problem that I don't know how to solve straight off, and I like a puzzle to work out. That is what keeps me coming back to this thread. Might be a sad insight into my life that I'd much rather sit and work out a maths problem than watch the latest reality singing/dancing/baking show (or do the decorating I've been putting off).
Click to expand...

Nothing sad about that, mate. Just hearing that others feel the same way gives me a warm fuzzy feeling. Thank you for sharing!
 
DaveH said:
Not the path I was trying, but mathematical proof that a tangent is always at right angles
You must be logged on to see external links
Click to expand...
not proof in what we are discussing. Triangles have not been mentioned on this thread and right angles don't exist. You know this! It's easy to see if you try harder.
 
Last edited:
fyl2u said:
Oh, right angles exist, they're just not always equal.
Click to expand...

I read his posts as an attempt to imply drawing a true right angle is impossible/ extremely difficult to achieve. Now, this is a further attempt to deflect acceptance of maths/ fundamental aspects of how we prove theories. Rather than accept the right angle (with an amount of acceptable tolerance) and progress with the debate in a positive manner.
He is progressively abstract with his deflections. Or should I say ridiculous?
 
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