I
am beginning to like these short posts. They impose so little on my time. More importantly,
they impose far less on my brain.
Given
below is the image from an article in the Hindustan
Times of today (2012-08-02) entitled After
Moon, India reaches for Mars.
Look
at it carefully.
The
shadow of the spacecraft looms over what appears to be at least 5% of the
Martian surface. At first glance, it appears wider than the path of a Solar eclipse on the earth! The image is the imagination of the artist, from what vantage
point, I haven’t a clue except that it has to be at least as far away from the planet
as the spacecraft is. Otherwise, capturing the space craft and its shadow in
its details, and also the planet to the extent in the image is impossible. But, is the
shadow itself possible? Remember, the Sun is much farther away than it is from the earth.
The earth from space
Mars from space
Take
a look at the images above, not artist’s impressions but true photographs of the
earth and Mars (all from the Net). Just assume that the artist’s
impression is from a similar vantage point. Do you imagine that a spacecraft at
that altitude will cast a shadow (from light from the Sun) that can be seen at that size from the assumed
distance? That is a rhetorical question. Please do not answer that.
The
artist did not think along the lines I had sketched above. The first lesson in ray optics will tell you that at that distance, the Sun's rays will be parallel. Just think: How large is the shadow of an airplane on the surface of the earth? Do we see shadows of all the satellites that are up there circling the earth?
You may argue that, “An
artist does not necessarily think, she only feels. She has made the image more
striking. Do you deny that?” No I do not deny that. But the dramatics - introducing the shadow - has distorted reality. Well, that goes under the rubric of the artist’s liberty, I suppose.
I
have nothing to say against this line of argument.
Raghuram
Ekambaram
5 comments:
what is logical may not be rational
what is rational may not be real
what is reality no body knows
-anonymous
what is logical may not be rational
what is rational may not be real
what is reality no body knows
-anonymous
DS sir,
It is truly only the rationalist who allows for skepticism. The rationalist does not even assert that there is THE TRUTH, aproxy for reality, perhaps.
Whatever it may be, the reality to get the kind of shadow the artist has imagined can only be unreal!
RE
I think the artist must have had a purpose in drawing the shadow. Could it be that he wanted to give the impression that the spacecraft is very close to the planet?
matheikal, that is precisely why I posted this piece. If the spacecraft is very close to the planet, the size of the shadow will not be much bigger than the spacecraft.
There is no way of reckoning that would justify the size of the shadow in realistic terms.
RE
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