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EclipseGeeks.com - All you ever wanted to know about eclipses and other celstial bodies

Earth Solstices, Equinoxes, Aphelion, Perihelion

 

Earth Perihelion - January 2017

closest point to the Sun

Perihelion: 04th January: 14:18 GMT/UT

Earth distance to the Sun: 0.983309436 au /

91,404,322 miles / 147,100,998 km. 

 

Earth is at its fastest orbital velocity around the Sun. 

 

Earth Equinox - March 2017

20th March 2017 at 10:30 GMT/UT

 

Spring (vernal) equinox Northern Hemisphere / autumn/fall Southern Hemisphere. Sun’s centre directly overhead at equator.

 

Across the world, day and night are almost exactly the same length; 12 hours.

Sun directly overhead at equator

 

June Solstice 2015

 

: 21st June 2017 at 04:25 GMT/UT.

Summer Solstice Northern Hemisphere. Longest daylight hours of the year. Winter Solstice Southern Hemisphere. Shortest daylight hours of the year.

 

Sun directly overhead at Tropic of Cancer

 

Earth Aphelion - July 2017

most distant from the Sun

 

Aphelion: 03rd July 2017 at 20:11 GMT/UT: Earth distance to Sun: 1.016675594 au / 94,505,900miles / 152,092,504 km.

 

Earth at its slowest orbital velocity around the Sun.

 

Earth Equinox 2017

 

22nd September 2017 at 20:03 GMT/UT

Marks astronomical beginning of: autumn Northern Hemisphere; spring Southern Hemisphere.

 

Sun centre directly overhead at equator

 

December Solstice

 

21st December 2017 at 16:29 GMT/UT.

Winter Solstice Northern Hemisphere / Summer Solstice Southern Hemisphere.

 

Sun directly overhead at Tropic of Capricorn

Earth’s Primary dates of its orbit around the Sun 2017

 

Diagram of Earth’s orbit around the Sun 2017 

showing January perihelion (nearest to Sun) and July aphelion

(most distant from Sun)autumn and spring equinoxes; summer and winter solstices.  

 

Earth is closer to the Sun during Decembe and most distant during July.

March-spring-equinox-autum-Eclipse-Geeks

 

Earth's equinoxes:

Main points about an Equinox

 

1: At Earth's Equinoxes the Sun is at zenith over the Equator.

 

2:  Northern and Southern Hemispheres of Earth are equally illuminated.

 

3: The Sun's rays shine perpendicular (right angle) to Earth's surface.

 

4: At equinox the Sun’s centre is in the same plane as Earth’s Equator.

 

5: The Earth is neither tilting towards or away from the Sun.

 

6: Day and night are almost, but not quite equal.

 

7: The geometric centre of the Sun is above the horizon for twelve hours.

 

8:  Daytime Earth facing the Sun on the day of maximum equinox is slightly longer than 12 hours.

 

9:  Nightside of Earth facing away from the Sun at maximum equinox has a night less than 12 hours.

 

 

10: Earth's atmosphere refracts sunlight.

 

11: At sunrise and sunset this refraction, or bending of the Sun’s rays, has the illusory effect of the

     Sun being in the sky, but actually it is physically below the horizon.

 

12: Equinox: These physical and geometric occurrences are the reasons why at equinox, day and night are

     not exactly equal, with a day longer than 12 hours, and night a little less than 12 hours.

Earth-equinox-spring-from-Space-eclipse-geeks

 

At Earth's Equinox the Sun's centre is at zenith over the Equator.

Both the Northern and Southern Hemispheres are equally illuminated.

 

At Earth's Equinox the Sun's rays shine perpendicular (right angle) to Earth's surface and the Sun’s centre is in the same plane as Earth’s Equator. The Earth is neither tilting towards or away from the Sun.

All you Ever Wanted to know about Equinoxes

 

March Equinox, Earth from Space

Northern Hemisphere spring equinox; autumn / fall southern Hemisphere.

 

NASA Goddard Space Flight Center.

GOES Satellite Captures March Equinox.

(image credit and acknowledgment to NASA / NOAA)

 

click Earth image to enlarge.

 

The Sun in this image is artificially created although the GOES spacecraft does have sensors continually monitoring the Sun for solar activity.  (sic erat scriptum) NASA.

Equinox: when Earth is perpendicular to the geometric centre of the Sun

[Diagram licensing: EclipseGeeks.com transformed the original diagram into one which contains more info.

In keeping with required licensing the diagram is licensed under the Creative Commons Attribution Share Alike]

 

At equinox the Northern and Southern Hemispheres are equally illuminated.

 

Day and night are nearly, but not quite equal.

The surface of Earth facing the Sun on the day of the equinox will receive a few minutes more daylight, than night-time side of Earth.

 

Although the geometric centre of the Sun is above the horizon for twelve hours, you may well deduce that day and night are equal all over the planet; however that is not quite true:  

 

Sunrise is defined as the moment the leading upper edge of the Sun's disc becomes visible above the horizon, and not when the centre of the sun becomes visible. Similarly sunset is when the Sun’s trailing edge disappears below the horizon.

 

It takes several minutes for the sun to fully rise and fully set; this adds several minutes to the daylight side, and subtracts from the night-side of Earth; therefore daytime on the equinox day is slightly longer than 12 hours.

 

 

 

 

Refraction by Earth's Atmosphere

In addition the atmosphere of Earth refracts light. This refraction, or bending of the Sun’s rays has the effect of making the leading upper edge of the Sun to be visible while it is actually and physically still below the horizon. The same refraction occurs at sunset and the sun can still be seen when it is actually lbelow the horizon, and is seen for several minutes after it has set.

The astronomical autumn / fall / spring is different to the metrological beginning of autumn / fall / spring.

01st September 1st day of autumn/fall  Northern Hemisphere | 1st day of spring Southern Hemisphere

astronomical season  (Click on season diagram to enlarge)

 

The astronomical season is defined by the position of Earth’s inclination towards the Sun, and the zenith of the Sun over the equator, the Tropic of Cancer and the Tropic of Capricorn.

metrological season

The metrological season is based weather, and is for the purposes of recording climate data. It is important to have set dates that data can be compared, so the meteorological autumn always begins on 1 September for the Northern Hemisphere; and 01st September marks the metrological beginning of spring in the Southern Hemisphere.

 

Marks astronomical beginning of: Autumn/fall Northern Hemisphere / Spring Southern Hemisphere Sun directly overhead at equator.

Equinox-autumn-fall-september-image-from-Space-eclipse-geeks

Earth Equinox September

marks astronomical beginning of autumn/fall Northern Hemisphere | spring Southern Hemisphere.

Click Earth image to enlarge.

 

image credit:

NASA’s Earth Observatory  

Celestial-Equator-September-Equiniox-diagram-Eclip

 

Southward Equinox / September Equinox 

The Sun rises directly in the east and sets directly in the west. The centre of the Sun is directly overhead at the equator,

Some may ask, ‘What is an equinox?’

Here is the answer to equinoxes.

 

Main points on eqinoxes

 

  • At Earth's Equinoxes the Sun is at zenith over the Equator.

 

  • Northern and Southern Hemispheres of Earth are equally illuminated.

 

  • The Sun's rays shine perpendicular (right angle) to Earth's surface.

  •  

  • At equinox the centre of the Sun is in the same plane as Earth’s Equator.

 

  • The Earth is neither tilting towards or away from the Sun.

  •  

  • Day and night are almost, but not quite equal.

 

  • The geometric centre of the Sun is above the horizon for twelve hours.

  •  

  • Daytime Earth facing the Sun on the day of maximum equinox is slightly longer than 12 hours.

  •  

  • Nightside of Earth facing away from the Sun at maximum equinox has a night less than 12 hours.

 

  • The atmosphere of Earth refracts sunlight.

 

  • At sunrise and sunset this refraction, or bending of the Sun’s rays, has the illusory effect of the Sun being in the sky, but actually it is physically below the horizon.

  •  

  • Equinox: These physical and geometric occurrences are the reasons why at equinox, day and night are not exactly equal, with a day longer than 12 hours, and night a little less than 12 hours.

Equinox-autumn-fall-september-image-from-Space-eclipse-geeks

Earth Equinox September

marks astronomical beginning of autumn/fall Northern Hemisphere, spring Southern Hemisphere.

 

Central point of Sun directly overhead at equator

 

Click Earth image to enlarge.

image credit:

NASA’s Earth Observatory

seasons_winter-December-solstice-small-photo-eclip seasons_spring-vernal-March-equinox-small-photo--e

Earth Equinox March

marks astronomical beginning of spring Northern Hemisphere,  autumn/fall Southern Hemisphere.

 

Central point of Sun directly overhead at equator

 

Click Earth image to enlarge.

 

image credit:

NASA’s Earth Observatory  

seasons_summer-June-solstice-small-photo-eclipse-geeks

June Solstice

marks astronomical beginning

of Summer for Northern Hemisphere

 

Winter Solstice Southern Hemisphere.

 

Central point of Sun directly over the Tropic of Cancer.

 

Click Earth image to enlarge.

image credit: NASA’s Earth Observatory

December Solstice

marks astronomical beginning of winter for

Northern Hemisphere (winter solstice)

summer for Southern Hemisphere (summer solstice)

 

Central point of Sun directly overhead at Tropic of Capricorn

 

Click Earth image to enlarge.

image credit: NASA’s Earth Observatory

dates, times, and distances of Earth's solstices, equinoxes, aphelion and perihelion

Solstice-equinoxes-2015-22-December-small-eclipse- Solstice-equinoxes-2015-22-December-med-image-ecli

Earth’s Primary dates of its orbit around the Sun

 

Northern Hemisphere

(information for new astronomers)

 

Earth is closer to the Sun during winter,

and farthest from the Sun during summer.

 

Southern Hemisphere

(information for new astronomers)

 

Earth is closer to the Sun during summer,

and farthest from the Sun during winter.

 

June Solstice 2015

21 June 2015

16:38 GMT/UT

 

Summer Solstice Northern Hemisphere

Winter Solstice Southern Hemisphere

 

Sun directly overhead at Tropic of Cancer

 

Earth Equinox - March 2015

20 March 2015

22:45 GMT/UT

 

Spring Northern Hemisphere

Autumn Southern Hemisphere

 

Sun directly overhead at equator

 

Earth Perihelion - January 2015

04 January 2015

06::36 GMT/UT

 

Earth distance to the Sun

0.983277390 au

91,401,343 miles / 147,096,204 km

 

December Solstice

22 December 2015

04:48 GMT/UT

 

Winter Solstice Northern Hemisphere

Summer Solstice Southern Hemisphere

 

Sun directly overhead at Tropic of Capricorn

 

Earth Equinox

23 September 2015

08:21 GMT/UT

Marks astronomical beginning of:

 

Autumn Northern Hemisphere

Spring Southern Hemisphere

Sun centre directly overhead at equator

 

Earth Aphelion (most distant from  Sun)

06 July 2015

19:40 GMT/UT

 

Earth distance to Sun

1.016682122 au

94,506,507 miles / 152,093,481 km

 

 

Earth-primary-dates-orbit-around-Sun-diagram-Eclipse_Geeks

 

Primary dates of Earth’s orbit around the Sun: Year 2017

 

Key to Orbit of Earth around Sun Diagram

 

1: Perihelion: 04th January: 14:18 GMT/UT

Earth distance to the Sun: 0.983309436 au / 91,404,322 miles / 147,100,998 km. Earth at this point is at its fastest orbital velocity around the Sun.

 

2: 01st March: Metrological beginning of spring N. Hemisphere / autumn S. Hemisphere.

 

3: Equinox: 20th March 2017 at 10:30 GMT/UT:

spring (vernal) equinox Northern Hemisphere / autumn/fall Southern Hemisphere. Sun’s centre directly overhead at equator. Across the world, day and night are almost exactly the same length; 12 hours.

 

4: 01st June: Metrological start of summer N. Hemisphere / winter S. Hemisphere.

 

5: Solstice: 21st June 2017 at 04:25 GMT/UT.

Summer Solstice Northern Hemisphere. Longest daylight hours of the year. Winter Solstice Southern Hemisphere. Shortest daylight hours of the year. Sun directly overhead at Tropic of Cancer.

 

6 Aphelion: 03rd July 2017 at 20:11 GMT/UT: Earth distance to Sun: 1.016675594 au / 94,505,900miles / 152,092,504 km.

Earth at its slowest orbital velocity around the Sun.

 

7: 01st September: Metrological start of spring N. Hemisphere/ autumn S. Hemisphere.

 

8: Equinox: 22nd September 2017 at 20:03 GMT/UT

Marks astronomical beginning of: autumn Northern Hemisphere; spring Southern Hemisphere.

Sun centre directly overhead at equator

 

9: 01st December 2017: Metrological start of winter N. Hemisphere / summer S. Hemisphere

 

10: Solstice: 21st December 2017 at 16:29 GMT/UT.

Winter Solstice Northern Hemisphere / Summer Solstice Southern Hemisphere. Sun directly overhead at Tropic of Capricorn.

 

6 Aphelion:  03rd July 2017:  20:11 GMT/UT

7: 01st September: Metrological start of spring N. Hemisphere/ autumn S. Hemisphere.

8: Equinox: 22nd September 2017 at 20:03 GMT/UT

9: 01st December 2017: Metrological start of winter N. Hemisphere / summer S. Hemisphere

10: Solstice:  21st December 2017 at 16:29 GMT/UT.

 

Quick Key to Earth's orbit:

1: Perihelion: 04th January: 2017: at 14:18 GMT/UT.

2: 01st March: Metrological beginning of spring N. Hemisphere / autumn S. Hemisphere.

3: Equinox: 20th March  2017 at 10:30 GMT/UT.

4: 01st June: Metrological start of summer N. Hemisphere / winter S. Hemisphere.

5: Solstice:  21st June 2017 at 04:25 GMT/UT.

Click diagram of Earth's orbit to enlarge