constant motion and perspective

[Carrock]

This is an instance when our perceptions mislead us because accuracy in normal situations is unhelpful, even dangerous.

 

If you see a running lion or a fast car in the distance, not heading towards you, it seems slow and not much of a threat. If it's getting any bigger, it's worth some extra attention.

 

You give most of your attention to more important things.

 

Anyone who's tried to approach a nervous wild animal will be particularly aware of this attitude.

 

Think of walking along a quiet road near a busy road and giving equal attention to each of the dozens of cars on that road and the one car on the quiet road which happens to be heading straight towards you.

[michel123456]

Father Ted will also explain why time does not seem to diminish when far away?

I mean, in the OP I stated that constant speed is not observed as such. That is , because of perspective, lengths are observed as contracted AND also because the time tick remains the same no matter the distance.

One could imagine another kind of universe where the time tick is observed contracting at the same rate with observed length: that would produce the observation of constant velocity as a constant.

[swansont]

Father Ted will also explain why time does not seem to diminish when far away?

 

 

Does time in a Galilean system depend on visual perception?

[Strange]

I mean, in the OP I stated that constant speed is not observed as such.

 

But it is measured as such.

[J.C.MacSwell]

 

But it is measured as such.

 

…and with experience and judgement we become accustomed to considering it by observation alone in everyday life. We have been wired to subconsciously do the fuzzy calculations to interpret what we see.

[Strange]

Father Ted will also explain why time does not seem to diminish when far away?

 

It explains why someone who is not very bright is confused by perspective. Take from that whatever you think is appropriate.

[michel123456]

 

…and with experience and judgement we become accustomed to considering it by observation alone in everyday life. We have been wired to subconsciously do the fuzzy calculations to interpret what we see.

And we are so much accustomed that we are unable to realize how weird it is.

 

It explains why someone who is not very bright is confused by perspective. Take from that whatever you think is appropriate.

I am able to construct geometrically a perspective. I did that for years professionally and I am afraid this technique is getting lost. I am really worried by the wiki article:

 

 

Methods of construction

Several methods of constructing perspectives exist, including:

• Freehand sketching (common in art)
• Graphically constructing (once common in architecture)
• Using a perspective grid
• Computing a perspective transform (common in 3D computer applications)
• Mimicry using tools such as a proportional divider (sometimes called a variscaler)

 

• I am at bullet 1 "Freehand sketching (common in art)" and bullet 2 "Graphically constructing (once common in architecture)".

From the answers I got in this thread I understand that fellow members are under bullet 4 "Computing a perspective transform (common in 3D computer applications)" and have no clue about conic sections, nor the way observed shortening happens. It is not simply about objects looking smaller, it is about the relation and position* of these objects.

And finally it is about the way you look everyday at everything around you. Even a still picture like the one below corresponds to acceleration.

Maybe you find it evident but you are the genius here.

 

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* for example see here http://www.scienceforums.net/topic/81113-bad-photoshop/

Edited March 27, 2016 by michel123456

[Strange]

Even a still picture like the one below corresponds to acceleration.

 

It might correspond to "apparent" acceleration but if you were to use the sleepers as units of measurement, you would find there was no acceleration.

 

I'm not really sure what point you are trying to make any more. You have spotted an interesting optical illusion. Is that it?

[michel123456]

 

It might correspond to "apparent" acceleration but if you were to use the sleepers as units of measurement, you would find there was no acceleration.

 

I'm not really sure what point you are trying to make any more. You have spotted an interesting optical illusion. Is that it?

I was thinking that the same effect happens when looking in a telescope.

[Strange]

I was thinking that the same effect happens when looking in a telescope.

 

The same illusion might occur. But, of course, when you make MEASUREMENTS you will find the illusion is ... what shall we call it: an ILLUSION.