Assume that you are a professional explorer (of geographical landscapes) and you are on an exploration of a desert in a northen hemispherical country near to the equator during a mid-summer.

Before you started your exploration, through your friend-cum-guide of that specific area you were informed that a solar power plant related works are in progress. Also it was informed that an oasis is located due North of the power plant at a distance of 2 km.

Unfortunately on a dry and hot day, at 12:00 noon you are lost in the desert about which you have some idea (like its layout), though not a thorough one. Also you do not have any instruments with you (which can provide you navigation). As you are wandering through the endless sands under a hot sun, with your supplies depleted, you felt desparate at some point and decided to give up. Like a miracle, at that moment you can feebly identify instruments (like Solar Panels, wires etc.) used for solar power plant at a distance.

Here comes the question:

As a professional explorer, with your limited supplies, and available information you wished to walk towards the oasis (where you can find shelter/refreshments and possibly a way out as well !).

Can you identify which useful information can aid /guide you going towards the oasis ?

  • 2
    $\begingroup$ You should add the information whether or not you are below or up from the Cancer Tropic... Since this is summer, if we are below it, the shade (or orientation of solar panels) will be different from up. $\endgroup$
    – Martigan
    Aug 30, 2017 at 12:29
  • $\begingroup$ Well, @Martigan, good catch. I appended accordingly! Thanks. $\endgroup$ Aug 30, 2017 at 12:59
  • $\begingroup$ Assuming the world is tilted off the solar plane, then in high summer, the 'overhead' sun at 'noon' (local) will actually be a little to the north of you. I'll assume the explorer can create a plumb line, and has a watch that was set to the local sun time (maybe it's on double daylight saving, and that would really put things out), so the explore does know that the sun passes 'overhead' at noon. Terms to search for are "celestial navigation" and "the equation of time". $\endgroup$ Aug 30, 2017 at 14:53

3 Answers 3


The useful information will be gained from the:

Solar Panels


For solar panels to collect sunlight, they need to be pointed at the sun. The sun will travel from East to West as the Earth turns, but in the Northern hemisphere it will tend to be towards the South at 12:00 noon. Therefore, the solar panels at 12:00 noon should be pointing South, so travel the opposite direction to find the oasis.

Update: If the solar panels are facing a fixed direction they should be facing true south. The above answer was assuming they were the type that oscillate and follow the sun.


The direction can be determined from

Your shadow


At exactly noon local time, your shadow will point either directly north, south, or you will cast no shadow, depending on your latitude.
If your shadow points north or south, draw a line where it currently points in the sand. If you cast no shadow, do not draw anything.
Wait a few minutes until your shadow shifts. The shadow is now pointing more eastward than it was a noon.

If you originally cast no shadow, north is 90 degrees left of where the shadow is pointing. Otherwise, north can be determined by:
In the case that your shadow moves to the left of your line, north is in the opposite direction of the line. In the case that the shadow moves to the right, the line points north.

The accuracy of this method can be improved by using a thinner object to cast the shadow, such as the poles or wires from the solar panels.


The solar power plant must be able to accommodate people occasionally: maintenance workers and such. That means it must have bathroom facilities. Where does it get the water? There's probably some piping that goes to the oasis. That's probably a factor as to why they put the plant so close the oasis in the first place. Just follow the pipes.

  • $\begingroup$ Though it is considered as an additional data (which is not provided in the Original Problem Statement (O.P.S), this is a good idea ! $\endgroup$ Aug 31, 2017 at 6:41

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