Suns path vs equatorial line

[Kriss3d]

We know earth tilt 23 degrees. So how can the sun be directly above when at the equator ? Or is the equator only aproximatly where youd expect the sun directly above ( meaning that the line around earth would also tilt )

Looking at heatmaps of earth where you see most warm at equator. I would take it that its the mean temperature over a year ? Otherwise the "belt" of the suns path around earth being tilted would also have the belt tilt ?

Or am i getting this wrong ?

[TheBeardedDude]

Well, the equator isn't based on the orbit of the Earth around the sun, it is based on the axis of rotation of the Earth.

Edited December 7, 2016 by TheBeardedDude

[swansont]

The earth also orbits, so the projection of the tilt angle looks different over the course of the year. The sun isn't directly overhead of the equator all the time. The overhead point moves from +23º to -23º and back again over the course of the year, and that includes the equator.

[Janus]

We know earth tilt 23 degrees. So how can the sun be directly above when at the equator ? Or is the equator only aproximatly where youd expect the sun directly above ( meaning that the line around earth would also tilt )

 

Looking at heatmaps of earth where you see most warm at equator. I would take it that its the mean temperature over a year ? Otherwise the "belt" of the suns path around earth being tilted would also have the belt tilt ?

 

Or am i getting this wrong ?

On two days of the year the Sun passes directly overhead at noon at the Equator. These two days are the Autumnal and Vernal equinoxes. At the Winter Solstice, the Sun reaches 23.44 degrees from vertical (to the South), and during the Summer Solstice it reaches 23.44 degrees from vertical to the North.

As you move away from the equator, two things happen:

1) The difference between the Sun at maximum height and the vertical shifts. At 5 degrees North of the Equator the Sun only gets to within 28.44 degrees of vertical during the Winter Solstice, but climbs to 18.44 degrees from vertical during the Summer Solstice.

2) the days on which the Sun passes directly overhead get closer together converging towards the one of the Solstices (towards the Summer one if you move North and towards the Winter one if you move South).

This means that as you move away from the equator you will get more variation in temp over the course of the year and less overall warming.

 

At ~23.44 degrees from the Equator, you reach a point where the two "directly overhead" days have merged to a single day and 6 months later the Sun only reaches a maximum height of 46.88 degrees from vertical.

The line of latitude at which this happens is called a "tropic", and are individually known as the Tropic of Cancer and the Tropic of Capricorn (so named because these are the zodiac signs the Sun in when the Sun is at maximum height at that latitude), the belt between them are familiarly known as the 'Tropics'. (Thus a "Tropical island" is an island that is located at a latitude between the Tropic of Cancer and Tropic of Capricorn and no further than 23.44 degrees from the equator.)

Many globes will have the two tropics labeled.

[Sriman Dutta]

A little query- the earth's axis is tilted at 23. 5 degrees, isn't so?