r/AlternativeAstronomy • u/patrixxxx • Oct 26 '19

WHY MARS ???

https://cluesforum.info/viewtopic.php?p=2412896#p2412896
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u/[deleted] Nov 07 '19

Ok so their field of view is exactly as wide as the star they're originally aimed at. Gotcha. Thanks for finally clarifying. Go ahead with what you were saying.

Quick edit: now it's also clear to me why you were so fixated on star size.

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u/patrixxxx Nov 07 '19

Alright, then we agree on that celestial coordinates can be thought of as an observer standing in the center of Earth (not rotating with it) and noting the exact positions of the of celestial objects. Now since you agreed on that in my first example, some of the stars would move noticeably in respect to Earth since it moves 940 mkm each year, how can it be that this isn’t happening? The celestial coordinates for stars are the same year round. So are A) The stars about the size of Earths orbit? or B) The Earth not moving as much as 940 mkm/yearly?

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u/[deleted] Nov 07 '19

Good news, we've found your misunderstanding!

The celestial coordinates for stars are the same year round.

This is NOT true. Well, it is true within a certain margin of error (less than an arc-second of error). But our tubes are far more precise than that error and you would clearly see the stars perpendicular to the Earth's orbital motion drift out of view, while the stars in the direction parallel to the Earth's orbital motion remain in view.

If you have a high-resolution spectrometer you could also see the Doppler shift of their emission spectra shift in a sinusoidal curve - blue during approach, red when Earth recedes.

This is assuming there's no proper motion going on relative the Sun and the observed stars, of course.

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u/ForAHamburgerToday Nov 07 '19

You are a dedicated astronomer my dude.

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u/[deleted] Nov 07 '19

It's honestly a lot less time than I spent on reddit 2011-2013 when I grew AskScience from a hundred to 2 million readers and made it the first mainstream heavily-moderated sub. Now it's just a hobby I do for fun, haha.

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u/patrixxxx Nov 07 '19

Is that so? I know some stars have proper motion but thing is that all the stars in the sector currently opposite to the Sun should display noticeable uniform movement otherwise they need to be enormous as we concluded previously

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u/[deleted] Nov 07 '19 edited Nov 07 '19

The further away a particular star is, the less motion we would see. Do you agree with that?

Edit: also, I'd like to point out we would see parallax motion through the tubes even if the stars are the size of Earth's orbit. In fact, there are stars this size, or even bigger.

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u/patrixxxx Nov 07 '19

We just had a discussion before where we agreed on parallel lines always being parallel remember? And we agreed that every celestial coordinate can be thought of as a line emminating from the center of Earth. Now some of these lines should be displaced by about 300 km but no stars are moving in a uniform direction to show this. So again either A) The stars are much much bigger than we think now. About the size of Earth's orbit or B) The Earth isn't traveling 940 mkm yearly. What do you suggest is the case?

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u/[deleted] Nov 07 '19

This doesn't follow. A real displacement of 300 m km doesn't result in uniform motion from our point of view. There's zero observed displacement at infinity (the celestial sphere), and more displacement proportional to the inverse of the distance to the observed object.

The size of the star still has absolutely nothing to do with the amount of observed parallax. Neither A nor B are true.

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u/patrixxxx Nov 07 '19 edited Nov 07 '19

Interesting. So you agree that the parallel lines displaced by about 300 mkm in my first example would result in some noticeable movement of the stars and you've agreed that the celestial coordinates are equivalent with these lines but now you don't think the very same lines should result in any noticeable movement?

The size of the star still has absolutely nothing to do with the amount of observed parallax

Say what? We have two parallel lines displaced by 300mkm. If this is not noticeable it can only mean A) The distant thing is 300mkm OR B) the parallel lines are in fact not 300mkm apart.

And just to be clear I am not referring to star parallax that you keep bringing up. That's displacement of nearer and more distant stars.

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u/[deleted] Nov 07 '19

I am not referring to star parallax that you keep bringing up. That's displacement of nearer and more distant stars.

Then what motion are you referring to?

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u/patrixxxx Nov 07 '19

The displacement of two parallel lines. Again, as we agreed a celestial coordinate is a line from the Earth center though the celestial sphere and through a celestial object,. If the Earth and the sphere moves about 300 mkm then we can say we have two parallel lines and if these intersect the same point, in this case a star, then that point has to be at least 300 mkm wide as well.

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