One-off: Black drop problem an SR effect?

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Discussion Overview

The discussion centers around the "black drop" problem observed during the solar transit of Venus and its potential explanations, including whether it could be attributed to special relativity (SR) or general relativity (GR). Participants explore various hypotheses regarding the nature of the phenomenon, including atmospheric effects and optical phenomena.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that the "black drop" effect might be explained through special or general relativity.
  • Another participant argues that it is an atmospheric phenomenon related to Venus' atmosphere.
  • A different viewpoint posits that the effect is due to optical phenomena caused by light refraction at the solar edge as it passes through Venus' atmosphere.
  • A later contribution mentions that the TRACE satellite observed a similar phenomenon during the solar transit of Mercury, which raises questions about the atmospheric explanation since Mercury lacks an atmosphere.
  • Another participant notes that the black drop effect may be more closely related to the clarity of the viewing equipment rather than atmospheric conditions.

Areas of Agreement / Disagreement

Participants express differing views on the cause of the black drop effect, with no consensus reached. Some support atmospheric explanations, while others highlight optical phenomena and the implications of observations from Mercury.

Contextual Notes

Participants acknowledge that the phenomenon remains unresolved and complex, with various assumptions and conditions affecting the interpretations presented.

OneEye
One-off: "Black drop" problem an SR effect?

From a Reuters science article (http://story.news.yahoo.com/news?tmpl=story&cid=585&e=1&u=/nm/20040511/sc_nm/space_venus_dc )

Reuters Science, Scientists Prepare for Rare Astronomical Event:

[The solar transit of Venus] will allow scientists to study the famous "black drop" problem which makes timing the transits difficult. As the black disc of Venus appears on the sun it seems to have a dark neck, or become pear-shaped, for a short time. The opposite occurs when it leaves the sun.
This sounds like something one would want to explain through SR - perhaps GR.

Any comments from anyone?
 
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No, it's an atmospheric phenomenon (Venus' atmosphere, that is!).

http://www.vt-2004.org/Media/vt-comm-03.html a more suitable site for following this rare event ... a bit like Halley's comet - most people will see such a thing only once in their lifetime (and many, not even that!).

You might find the Teachers' Guide, on the VT site, of interest (and there are plenty of links to explore the whole thing in much more detail). :biggrin:
 
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Yes, I always thought it was an optical phenomena due to a slight refraction of the light at the solar edge passing through the atmosphere of Venus.
 
Okay, thanks.

Boy, I sure made that simple question complicated, didn't I?

I must be management material!
 
Glad we could help.

Don't stop asking questions! Questions are good; curiosity is good. :smile:

Perhaps more managers should ask more questions?

Kind Regards
Nereid
 
Actually...

OneEye said:
Okay, thanks.

Boy, I sure made that simple question complicated, didn't I?

Actually, it's apparently not that simple.

I've just been corrected by an article that I came across which stated that the TRACE satellite recently detected the same black drop phenomena in the recent solar transit of Mercury,...which casts doubt on the previous explanation since Mercury has NO atmosphere.

So apparently, the effect is still considered an unresolved (and somewhat bothersome) paradox.

Thanks for the question; it made me re-check my assumptions.

Anyone thought this one through...and come up with OTHER possibilities??
 
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With the benefit of more than a century in observational astronomy (equipment, techniques, detailed understanding of 'seeing', ...), and many thousands of high quality images of the transit, from many locations and using a wide variety of equipment, ... the conclusion (so far) on the 'black drop effect' is ...

"Scientifically, solar photographers confirmed that the black drop effect is really better related to the viewing clarity of the camera or telescope than the atmosphere of Venus.[/color]"

Source: Astronomy Picture of the Day
 

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