Where is the sun overhead at noon on December 10?

Answer 1

AS THE EARTH spins on its axis, the sun is virtually directly overhead at all places along the Tropic of Capricorn, in the Southern Hemisphere at noon on December 21, 2009. This is at latitude 23.44o South.

HOWEVER, the sun's overhead position about 91 days earlier was directly over the equator. And it has been gradually moved southwards. But by December the 10th the sun will only have reached latitude 22.95oSouth.

So all we have to do is look at a map and see what is situated at latitude 22.95o South.

• Thohoyandou, South Africa, is located at latitude 22.95 degrees South.
  

Therefore, at the solar time of 12 noon the sun will be directly overhead there. And, as the earth spins, the entire circle of the earth at that latitude will experience overhead sun at noon (solar time) on that day, December 10th.

SHALL WE GO around the earth, chasing the mid-day sun at latitude 22.95o South, on December 10th?

We'll start in Rio de Janeiro, Brazil. The sun will be directly overhead there at mid-day. But, to keep the sun overhead we must move west with the sun to San Paulo, then we quickly follow the sun due west to

• Paraguay
• Argentina
• Chile
• then we are in (or over!) the Pacific Ocean, before we reach
• Australia, arriving in Queensland, going right across Australia and leaving from Western Australia. Next we cross the
  
• Indian ocean to
• Farafangana, Madagascar. Another landmark in our journey, still travelling due west, could well be
• Banhine National Park, Mozambique, then
• Botswana, then
• Windhoek, Namibia. Next is the
• South Atlantic Ocean. We go right across that ocean and land at
  
• Rio, arriving exactly 24 hours after we started! And it has been midday for the entire journey! Did you keep awake?
  

NOTE: The sun has been inching slowly southwards during our 24 hour trip so now it will be just a bit further south in the sky than it was when we first saw it in Rio the day before. It is slowly inching towards its southernmost destination, at latitude 23.44o South, and will arrive there on December 21st.

BUT WHERE is Thohoyandou in this round-the-world trip? We haven't shown it in the list above. But if you look on a map, you'll see where it should come in our list of places that all experience overhead sun at noon on December 10th, 2009.

Answer 2

AS THE EARTH spins on its axis, the sun is virtually directly overhead at all places along the Tropic of Capricorn, in the Southern Hemisphere at noon on December 21, 2009. This is at latitude 23.44o South.

HOWEVER, the sun's overhead position about 91 days earlier was directly over the equator. And it has been gradually moved southwards. But by December the 10th the sun will only have reached latitude 22.95oSouth.

So all we have to do is look at a map and see what is situated at latitude 22.95o South.

• Thohoyandou, South Africa, is located at latitude 22.95 degrees South.
  

Therefore, at the solar time of 12 noon the sun will be directly overhead there. And, as the earth spins, the entire circle of the earth at that latitude will experience overhead sun at noon (solar time) on that day, December 10th.

SHALL WE GO around the earth, chasing the mid-day sun at latitude 22.95o South, on December 10th?

We'll start in Rio de Janeiro, Brazil. The sun will be directly overhead there at mid-day. But, to keep the sun overhead we must move west with the sun to San Paulo, then we quickly follow the sun due west to

• Paraguay
• Argentina
• Chile
• then we are in (or over!) the Pacific Ocean, before we reach
• Australia, arriving in Queensland, going right across Australia and leaving from Western Australia. Next we cross the
  
• Indian Ocean to
• Farafangana, Madagascar. Another landmark in our journey, still travelling due west, could well be
• Banhine National Park, Mozambique, then
• Botswana, then
• Windhoek, Namibia. Next is the
• South Atlantic Ocean. We go right across that ocean and land at
  
• Rio, arriving exactly 24 hours after we started! And it has been midday for the entire journey! Did you keep awake?
  

NOTE: The sun has been inching slowly southwards during our 24 hour trip so now it will be just a bit further south in the sky than it was when we first saw it in Rio the day before. It is slowly inching towards its southernmost destination, at latitude 23.44o South, and will arrive there on December 21st.

BUT WHERE is Thohoyandou in this round-the-world trip? We haven't shown it in the list above. But if you look on a map, you'll see where it should come in our list of places that all experience overhead sun at noon on December 10th, 2009.