Theorem about the geographic dawn and dusk line. 50

According to the position and direction of the morning and dusk lines on the earth and their relationship with other geographical points, lines, and surfaces.

Determine the direction of rotation of the Earth.

If ab in the figure on the right is the dusk line, the earth rotates in a counterclockwise direction and the center is the north pole; If BC is a dusk line, the Earth rotates in a clockwise direction with the South Pole at its center.

Determine the east and west longitudes.

Taking the 0° meridian as the starting point, the longitude that increases with the direction of rotation is the east longitude, and the vice versa is the west longitude.

When deciding on a place.

a. It is 6 o'clock when it passes through the place on the meridian at the intersection of the equator and the morning line, and at 18 o'clock when it passes through the place on the meridian at the intersection of the equator and the evening line.

b. The place on the meridian where the direct point of the sun is located is 12 o'clock at noon, and the place on the meridian that forms the meridian coil opposite to it is 0 o'clock (or 24 o'clock).

Determine the date and season.

a. The morning and dusk lines pass through the north and south poles, coincide with a certain meridian coil, and intersect perpendicularly with all the latitude coils, and this day can be determined to be March 21 or September 23.

b. The morning and dusk lines are tangent to the Arctic and Antarctic circles, and the polar day phenomenon occurs in the Arctic Circle, which can be determined to be June 22.

c. The morning and dusk lines are tangent to the North and South Polar Circles, and the polar night phenomenon occurs in the Arctic Circle, which can be judged to be December 22.

Determine the location of the point where the sun is shining directly.

The longitude of the meridian bisecting the day hemisphere on the insolation chart is the longitude of the point where the sun shines directly. The latitude of the point of direct sunlight needs to be determined according to the latitude of the parallel line tangent to the line of morning and dusk, if the latitude of the line of latitude tangent to the line of morning and dusk is , then the latitude of the point of direct sun is equal to 90° north and south latitude (depending on the situation).

Determine the length of day and night.

The day length of a place is equal to the number of times spanned by the day arc between the parallels and the intersection of the morning and evening lines, and the night length is equal to the number of times spanned by the night arc on the latitude coil where the place is located.

Determine the sunrise and sunset times.

The sunrise time of a place is the time at the intersection of the meridian and the morning line where the place is located, and the sunset time is the time at the intersection of the meridian and the dusk line where the place is located. The formula for calculating the sunset and sunrise time in a place is 12 days length 2.

Determine the extent of the polar day and night.

The polar day or polar night phenomenon occurs in the latitude range between the morning and dusk line and the pole, and the polar day and night phenomenon in the northern and southern hemispheres is just the opposite.

Easterly locations on Earth don't necessarily see sunrise sooner: because the Earth moves from west to east.

Rotation, in the same latitude, is relative to the easterly position of the location, than the position.

The sunrise is seen first in the westerly locations, and the clocks in the easterly part are a little earlier.

The intersection of the Tropic of Cancer and the morning line on the summer solstice is four o'clock, and the intersection point with the dusk line is twenty o'clock, and the intersection point of the Tropic of Cancer and the morning line on the winter solstice is eight o'clock, and the intersection point with the evening line is sixteen o'clock. What do you want? Can you be specific?

The morning slag line is a dividing line that divides every location in the world into "sunrise zone" and "sunset zone", which is a large ring that connects the earliest and latest sunrise and sunset times of each place. At the equator, the Dawn and Dusk Line is a line located exactly 180 degrees east longitude, also known as the International Date Line (IDL), which divides the world into east and west. So in this question, if a location is at 30 degrees east longitude, this place is 150 degrees wide from 180 degrees east longitude, because the morning and dusk line crosses 180 degrees east longitude and divides the earth into east and west halves.

Therefore, according to the direction of the Earth's rotation, the place on the east side of the morning and dusk line is the "sunrise zone", and the place on the west side of the morning and dusk line is the "sunset zone". Thus, according to the description of option D, the location in question is a location on the east side of the twilight line, and the area east of the twilight line is 30 degrees east longitude.

Summary. Hello, the intersection of the morning line and the equator is 6:00 and the intersection of the evening line is 18:00.

Hello, the intersection of the morning line and the equator is 6:00 and the intersection of the dusk line is 18:00, I hope mine can help you.

Question 16: How to do it.

Hello, wait a minute, I'll read the title.

This topic is choose B.

What is parsing.

Wait a minute. The morning and dusk line is 0:00 or 12:00 at the o'clock, so Beijing is located in the eighth district of the east, according to the east and west to reduce the original lead, and the hunger can be calculated, and the Beijing time of Huaiju is 3 or 15 o'clock.

The first part of question 27, the answer plus analysis, is why it is done.

Morning and dusk line judgment method: to a rectangular chart.

That is, the kind of picture sent upstairs) as an example, determine the direction of the map to go up north and down south. (If not, find a way to convert the graphics to up-north-down-south).When the day is in the middle, the morning line is on the left and the evening line is on the right; When the night is in the middle, the left is the dusk line and the right is the morning line.

Take a side view (like if you were looking up at a globe.)

The same) as an example (the default is up north and down south), if the left is dark and the right is day, you can see the morning line; Day on the left, night on the right, you can see the dusk; All daylight, left morning and dusk; All night, left and right morning. Take a top view (from above or below) as an example, looking down on the Northern Hemisphere from daylight clockwise to the morning line and counterclockwise to the dusk line; Looking down on the Southern Hemisphere, it reaches the dusk line clockwise from daylight and counterclockwise to the morning line. Polar Day.

There is no sunrise in the ordinary sense, and the sunrise of the polar day refers to 0:00 on the same day, such as in the Northern Hemisphere, the direction is due north; Southern Hemisphere, due south.

The morning and dusk lines on Earth are the dividing line between the day and night hemispheres on the Earth's surface.

The sun altitude is 0 on the morning and dusk line.

The morning and dusk line is a large circle, bisecting the Earth.

The blue line in the figure is the twilight line in the morning and dusk line.

The dividing line between the day and night hemispheres.

In fact, because the earth is in constant motion, the actual "morning and dusk line" is also constantly changing.

I'm talking about the reading methods I learned in high school.

1.The morning and dusk lines are half of the morning and dusk circles. When the earth enters the day through the morning and dusk circle from west to east, the line it passes through is called the morning line; When passing through the morning and dusk circle into the night, the line passed through is called the dusk line.

2.Obviously, in order to correctly distinguish between the morning and dusk lines, it is necessary to first specify the direction of rotation of the Earth as shown in the given diagram.

3.In a normal lighting map, the shaded part usually represents the night!

To put it simply, the morning line from night to day is the morning line, and vice versa. Interpret it in the direction of the Earth's rotation.