Wednesday, 17 May 2006

Night arrives over Europe and Northern Africa - NASA


Night arrives over Europe and Northern Africa, part of a set of NASA pictures showing earth from space. See if you can work out why the particular picture above is a fake.

LINKS: What a pretty blue planet - Mr Dreckard's Social Studies Classroom
'Image of the day' gallery - NASA

TAGS: Art, Science

14 comments:

  1. Something doesn't look right but I can't put my finger on it.

    The transition between full sunlight and total darkness seems very sudden. Plus, the area around Paris and the East Coast of Spain seem to pump out a relatively enormous amount of artificial light considering they are just entering twilight.

    Other than that, I can't detect any obvious flaws... (?)

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  2. Oh, the total absence of clouds is worth noting also.

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  3. bright sunlight then darness. maybe an eclipse but not sunset, apart from the fact that the shadow is not circular. yes its a fake

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  4. Well, the absence of clouds over London is an obvious flaw. But the big one is that day and night are round the wrong way. If the picture represented reality, then the sun would rise in the west and set in the east.

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  5. Night "arrives". It would be wrong if described as day "arrives". The night is coming from the east. So that's OK.

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  6. There is sea floor detail in the Atlantic. You can see the continental shelf extending around the British Isles and (look at the full size version) the mid-Atlantic ridge clearly snaking down from Iceland. In reality this is under quite a lot of water.

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  7. Doesn't the sun rise in the east and set in the west. The day/night on either side of the terminator should be reversed.

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  8. That's what I thought too Brian, but Lindsay is correct in his comment above.

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  9. I do not think it is fake. Perhaps a composition with clouds filtered out but I do not think it fake.

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  10. Those people saying that day and night are "round the wrong way" are not thinking!

    1) The sun rises in the east and sets in the west (i.e. looking down on the North Pole the Earth spins anticlockwise)
    2) Once a day, Western Europe is in darkness while Eastern Europe is in daylight. This would be called MORNING.
    3) Once a day, Eastern Europe is in darkness while Western Europe is in daylight. This would be called EVENING.

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  11. Look at it as though you are shining a torch (the sun) onto a large ball (the earth), then spin the ball anti clockwise. Night arrives at a particular spot on the ball when that spot leaves the area illuminated by the torch. This would make the curvature of the shaded area (night time) on the photo opposite to how it is shown. That is ) not (

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  12. lancashire lad, there are two other issues: the day is longer nearer the poles, so wouldn't you expect a curve like this?

    And secondly, the earth is tilted 23 degrees, so what effect does that have?

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  13. Take a look at the picture in Wikipedia's Terminator article. Click on the picture for a bigger version. You can see evening arriving in India and morning arriving over the Rockies.
    Note the curve of the terminator at the very North and South. This is the effect Berend is talking about. Because of the Earth's tilt you get all day sun at the North Pole and longer days the further North you go during the Northern summer. (This picture shows daylight in April.) In December the curves would go the other way, narrowing in the North and all day sun in parts of Antarctica.
    I still think the day/night discussion is a red herring and the reason I gave above is the dead giveaway (along with the amazing glow-in-the-dark Sahara).

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  14. It is obvious: If you use the same photographical exposure time for the whole picture then the night area would be totally black.

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