# Tracking the Sun in a Plane **URL:** \ **Category:** Factual Questions\ **Created:** [September 11, 2002, 4:56am UTC](https://boards.straightdope.com/t/tracking-the-sun-in-a-plane/127929 "2002-09-11T04:56:49Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\ **Post date:** [September 11, 2002, 4:56am UTC](https://boards.straightdope.com/t/tracking-the-sun-in-a-plane/127929/1 "2002-09-11T04:56:49Z")
Let’s say I happen to live at the Equator. And let’s say I happen to have a special plane. My plane can fly as fast as I want; for as long as I want. Let’s also say it’s exactly 12:00 PM (noon) when I take off going directly west. I continue to fly along the equator all day and it feels like I am tracking the Sun across the face of the earth, i.e. the Sun remains in the same place in the sky relative to my plane (directly overhead). If at some point I decide to land, it will still be 12 noon where ever I happen to set down. In order to always keep the relative time at 12 noon how fast must I fly? What if instead of flying along the equator I was at 40 degrees latitude? How fast would I have to fly then? And how do I figure it out? ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [September 11, 2002, 5:09am UTC](https://boards.straightdope.com/t/tracking-the-sun-in-a-plane/127929/2 "2002-09-11T05:09:28Z")
40,000 km in 24 hrs at the equator. The same question was asked and answered in the last few months. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [September 11, 2002, 5:09am UTC](https://boards.straightdope.com/t/tracking-the-sun-in-a-plane/127929/3 "2002-09-11T05:09:39Z")
> [@](#): > > \*Originally posted by dolphinboy \* > \*\*Let’s say I happen to live at the Equator. And let’s say I happen to have a special plane. My plane can fly as fast as I want; for as long as I want. Let’s also say it’s exactly 12:00 PM (noon) when I take off going directly west. > > I continue to fly along the equator all day and it feels like I am tracking the Sun across the face of the earth, i.e. the Sun remains in the same place in the sky relative to my plane (directly overhead). If at some point I decide to land, it will still be 12 noon where ever I happen to set down. > > In order to always keep the relative time at 12 noon how fast must I fly? What if instead of flying along the equator I was at 40 degrees latitude? How fast would I have to fly then? And how do I figure it out? \*\* The earth is approximately 24000 statute miles in circumferance. It turns once in 24 hours so your speed at the equator would have to be about 1000 mph. The speed at any latitude angle, l, would be 1000_cos(l). In the example you gave it would be 1000_cos(40[sup]o[/sup]) = 766 mph. ---
**Author:** ![femtosecond](https://avatars.discourse-cdn.com/v4/letter/f/f08c70/32.png) [@femtosecond](https://boards.straightdope.com/u/femtosecond)\ **Post date:** [September 11, 2002, 1:04pm UTC](https://boards.straightdope.com/t/tracking-the-sun-in-a-plane/127929/4 "2002-09-11T13:04:37Z")
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