Question Re:- Transit of Venus

[Bryanpoprobson]

Some of you must have seen the stuff on the web from this Crow person? He has raised an issue regarding the alleged transparency of Venus during transits of the Sun. What I am trying to get my head around, should this be expected? After all the Sun is 8.4 light minutes away and Venus is 2.2 Lm's away during transit. Do we view a past image of the sun as Venus transits, in that Venus occupies a region 6.6 minutes before the light from the sun reaches it. Or does this have no baring on what we see..? I've never really thought about this before..

[Zakalwe]

It's possibly something to do with Residual Bulk Image in the sensor. It's possible that the sensor on SDO does not employ any sort of Near Infra-Red  flush routine which may mean that the pixel wells retain some charge between readouts. This article explains it well:
http://gxccd.com/art?id=418&lang=409

Of course, the hard-of-thinking will automatically move to their default position:



without bothering with any of that research or investigation nonsense.... 

[Allan F]

What exactly is the question? Is the image of Venus brighter than it should be? There's probably some light bending around the edges - atmosphere diffraction.

[onebigmonkey]

I'm still trying to get my head around the relative light delays...

[bknight]

Some of you must have seen the stuff on the web from this Crow person? He has raised an issue regarding the alleged transparency of Venus during transits of the Sun. What I am trying to get my head around, should this be expected? After all the Sun is 8.4 light minutes away and Venus is 2.2 Lm's away during transit. Do we view a past image of the sun as Venus transits, in that Venus occupies a region 6.6 minutes before the light from the sun reaches it. Or does this have no baring on what we see..? I've never really thought about this before..

He also has a video that the moon is/hollow/somewhat transparent as eclipses he has "shown videos that the sun shines through the moon.

[Gazpar]

Some of you must have seen the stuff on the web from this Crow person? He has raised an issue regarding the alleged transparency of Venus during transits of the Sun. What I am trying to get my head around, should this be expected? After all the Sun is 8.4 light minutes away and Venus is 2.2 Lm's away during transit. Do we view a past image of the sun as Venus transits, in that Venus occupies a region 6.6 minutes before the light from the sun reaches it. Or does this have no baring on what we see..? I've never really thought about this before..

He also has a video that the moon is/hollow/somewhat transparent as eclipses he has "shown videos that the sun shines through the moon.

The sun shines through the moon?
I myself never seen something like that with my telescope. Here is an example of the occultation of Aldebaran by the Moon:

[bknight]

Some of you must have seen the stuff on the web from this Crow person? He has raised an issue regarding the alleged transparency of Venus during transits of the Sun. What I am trying to get my head around, should this be expected? After all the Sun is 8.4 light minutes away and Venus is 2.2 Lm's away during transit. Do we view a past image of the sun as Venus transits, in that Venus occupies a region 6.6 minutes before the light from the sun reaches it. Or does this have no baring on what we see..? I've never really thought about this before..

He also has a video that the moon is/hollow/somewhat transparent as eclipses he has "shown videos that the sun shines through the moon.

The sun shines through the moon?
I myself never seen something like that with my telescope. Here is an example of the occultation of Aldebaran by the Moon:

You need to watch one of his videos as I can't explain it, just reporting.

[Gazpar]

He thinks Lunar eclipses are manipulated, lol.

[Bryanpoprobson]

I'm still trying to get my head around the relative light delays...

It's does give you a pause for thought, but having a quick think about it, it takes 4 to 8 hours for a transit to occur, with the suns (maximum) relative size being 32', I would think that it transits too slowly for this to be a noticeable effect.

[Al Johnston]

I'm still trying to get my head around the relative light delays...

It's does give you a pause for thought, but having a quick think about it, it takes 4 to 8 hours for a transit to occur, with the suns (maximum) relative size being 32', I would think that it transits too slowly for this to be a noticeable effect.

Was it not a similar effect with the transit of Mercury that provided evidence for Einstein's General Theory of Relativity?

[Bryanpoprobson]

Was it not a similar effect with the transit of Mercury that provided evidence for Einstein's General Theory of Relativity?

That was to do with perihelion shift, Newtonian physics predicts the shift of the perihelion by a certain amount. Basically relativity predicts a further shift due to gravity being a distortion in space time and Mercury's shift was in line with the predictions of relativity rather than Newton. OR something like that.

[Bryanpoprobson]

http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html

[ka9q]

I think, but am not sure, that one way to look at the relativistic precession of Mercury's perihelion is that the curvature of spacetime caused by the sun's gravity effectively changes the number of degrees in a circle around it to something slightly different from 360.

[Peter B]

I think, but am not sure, that one way to look at the relativistic precession of Mercury's perihelion is that the curvature of spacetime caused by the sun's gravity effectively changes the number of degrees in a circle around it to something slightly different from 360.

Oh my, you've just triggered a memory from long ago, on the now late and sadly missed Self Service Science Forum. Back in 2002 this American guy named Donde appeared, with a claim that Pi had an arbitrary value. There were a bunch of threads in which we explored that concept. If you go to http://www2b.abc.net.au/science/k2/stn/archives/archive56/newposts/570/topic570023.shtm there's a post early on with links to all the earlier threads discussing this fascinating  topic.

Then Donde got the idea that extra-solar navigation would be impossible because...well...it seemed to be he had no idea that a spacecraft could track its target and alter its course as necessary: http://www2b.abc.net.au/science/k2/stn/archives/archive33/newposts/218/topic218528.shtm

[Luckmeister]

Then Donde got the idea that extra-solar navigation would be impossible because...well...it seemed to be he had no idea that a spacecraft could track its target and alter its course as necessary:

It doesn't help that more than one pop-sci tv show has stated that the accuracy required to send a space probe to a distant planet is equivalent to hitting a golf ball in Los Angeles and having it land on a Miami golf green. Since in-flight spacecraft course correction was not mentioned, some HB's took it as proof that the missions would be impossible to accomplish.