Venus passes in front of our sun

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Discussion Overview

The discussion revolves around the transit of Venus across the Sun, including its implications, visual observations, and related questions about energy blockage and photographic representation. It touches on both the scientific and cultural aspects of the event.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about the percentage of the Sun's energy blocked from Earth during the transit, suggesting a formula involving the areas of Venus and the Sun.
  • Others argue that the apparent size of the planets must be considered rather than their actual sizes, proposing the use of angular sizes to calculate the light blockage more accurately.
  • One participant questions the circular path observed in photographs of the transit, expressing confusion about the expected trajectory and suggesting that camera movement may have influenced the image.
  • Another participant speculates that optical defects could also explain the circular appearance in the photos.
  • There are playful remarks about Venus being referred to as the "goddess of love" and its heart-shaped representation in cultural contexts.
  • Some participants share personal experiences of witnessing the transit, noting challenges such as weather conditions affecting visibility.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the calculation of energy blockage and the interpretation of photographic evidence. The discussion remains unresolved on these technical points.

Contextual Notes

Limitations include potential misunderstandings of angular size calculations and the effects of observational equipment on image representation.

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Interesting question to consider. How much of the Sun's energy in percentage was blocked from the Earth during its passage across the sun? Would it be Venus pi radius squared divided by Sun's pi radius squared times 100 to determine percentage?
 
Last edited:
seniorracer71 said:
Interesting question to consider. How much of the Sun's energy in percentage was blocked from the Earth during its passage across the sun? Would it be Venus pi radius squared divided by Sun's pi radius squared times 100 to determine percentage?

No, you can't use the actual sizes of Venus and the Sun. You have to use the apparent size. This requires you to figure out the angular size of each object. Once you do that you can find the apparent area of each one and then subtract Venus from the Suns area to get a good approximation of the amount of light blocked by Venus. You can use a calculator to help, such as this one: http://rechneronline.de/sehwinkel/angular-diameter.php
Just input the first two values and it should give you the angular diameter of Venus and the Sun.
 
In the eighth photo from the top (it's a sequence of photos with subtext "A composite sequence photo of the steps of the entire transit of Venus seen over the sky of Seoul"), Why does it appear to follow a circular track? Intuitively it doesn't make sense to me but I'm sure I'm just not thinking about it in the right way. I expected it to be more of a straight path.
 
some_letters said:
In the eighth photo from the top (it's a sequence of photos with subtext "A composite sequence photo of the steps of the entire transit of Venus seen over the sky of Seoul"), Why does it appear to follow a circular track? Intuitively it doesn't make sense to me but I'm sure I'm just not thinking about it in the right way. I expected it to be more of a straight path.

I would guess that the camera wasn't rotated as the Sun progressed across the sky. This happens if you don't use an equatorial mount.
 
Drakkith said:
I would guess that the camera wasn't rotated as the Sun progressed across the sky. This happens if you don't use an equatorial mount.

Or there is some serious pincushion defect to the optics used to capture the sequence.
 
Venus passes in front of our sun! What a cheeky little planet.
 
  • #10
Garth said:
Is is my imagination or is 'the goddess of love' heart shaped?

When Venus rises with the Sun
:rolleyes:

Garth

Transit with the etruscan vase! :!)


I did see the transit here, after a looong wait for clouds to clear...for about a minute... :rolleyes:
 

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