You are here:

Astronomy/Interpreting shadows

Advertisement

Expert: Jesse Martinez - 9/28/2010


Question
Hey Jesse,

        Quick bit of context. I'm a screenwriter currently writing a detective character who discovers a photograph (or perhaps a painting.... undecided) which he then uses to trace a missing person.

My question is just how much information can be gleaned from an outside photo or painting with regards light source. As a for instance-

1. Can anything more than time of day be worked out by angle? Or darkness values? Or length of shadow?

2. Could season or even month info be gleaned from position of sun. Or moon. or angle/direction of shadows?

The photo/painting is of a building with setting sun glinting off the rooftop. I've already worked out that means he knows it was painted/taken from an easterly position facing West.

I'm basically looking for anything else that can be worked out from shadow and light? Any clues that can aid the characters investigation.

Thankin' you in advance

Alex


Answer
Alex,

If the exact compass direction and the time of day were known along with the latitude of the location shadow length building height and the elevation above the horizon of the sun, you could probable make a very accurate guess, like within a week. The more information that is missing the less accurate the guess. The exact time of day would also require the compass direction of the sun angle above the horizon.

Good luck with the story.
Jesse

Astronomy

All Answers

Answers by Expert:

Ask Experts

Volunteer

Jesse Martinez

Expertise

General and specific questions about the solar system and stellar and galactic astronomy, are what I can easily answer off the top of my head. For example, what is the largest planet in the solar system? How far away is the moon? Have there been any confirmed planets in orbit around stars other than the sun? How many stars are there? The tougher ones like explaining the big bang theory and black holes I will leave to the PhD’s. Even though I could muster an answer, I would have to research it more than I would like. I would also like to answer questions that involve Astronomy with other sciences, chemistry, biology, physics, geology and mathematics as long as they are not PhD level.

Experience

I have been into astronomy since I was 8 years old. I have kept detailed journals of my observations through small telescopes. Over the years I have participated in amateur observation projects for organizations like ALPO. My personal research has involved "discovering" the moons of Jupiter with a 4½-inch Newtonian reflector without any outside information like charts and tables. In a summer long project, I determined the existence of and plotted the orbits of the four major moons of Jupiter. From these observations, my data on orbital elements was surprisingly accurate (orbital radius and orbital period).

Education/Credentials
80 hours of college credits while studying physics and geophysics. Completed correspondence photography course while in high school. Took two semesters of electronics training at a community college. Studied computers and graduated from a technical school at the turn of the millennium, gaining A+ and Microsoft Certified Professional credentials. Hablo Español. Si quieres preguntar en Español, estoy a su servicio.

©2012 About.com, a part of The New York Times Company. All rights reserved.