Sun's Position Over Earth
(to update, reload page)
Courtesy: Fourmilab Switzerland

View Earth's Night Half
Day, Night & the Analemma
Earth Tilt, Sunrise & Sunset
No Sunlight on Entire Earth
Six Current Views of Earth Current Earth Weather

 
 

"PLANET OF LIFE!"

Earth, the cradle of humankind, is a watery world and the only planet on which life is known
to exist!  (1.6.x)   (1.4.1)

Earth is the third planet from the Sun, and the one against which all other planets are measured!  (1.6.x)   (1.4.1)



Click to send Photon

 

Not familiar with Celestia's 1.6.x and 1.4.1 links?  For an explanation  click here.

When you run Celestia's links above that display planetary orbits, Right Drag to reveal them in 3-D: shapes, sizes and inclinations.

EARTH'S SEASONS

Why Earth Has Seasons:
   NASA graphic

The Reasons for Seasons is a terrific interactive showing how Earth's tilt and motions create our seasons.

Why Do We Have Seasons? is another great interactive.
And here's another!

How Earth's Snow & Ice Cover Vary with the Seasons


CLIMATIC VS. ASTRONOMICAL SEASONS

Most school children know that the climatic seasons of the Northern and Southern Hemispheres are the reverse of each other's.  For example, climatically-speaking, when it is Summer in the Northern Hemisphere, it is Winter in the Southern Hemisphere.

However, the "astronomical" seasons, as well as their respective  equinoxes  and  solstices, have traditionally always been named for the "climatic" seasons of the Northern Hemisphere, (no doubt because roughly 90% of Earth's population lives there.)  Thus, the Summer Solstice, for instance, is the solstice in June that marks the start of the Northern Hemisphere's summer.

Unfortunately this traditional naming convention creates an ambiguity.  It means that astronomers in the Southern Hemisphere experience the traditional Summer Solstice at the start of their "climatic" Winter!

This is why we increasingly see the less traditional (and slightly less recognizable) terms: March Equinox, June Solstice, September Equinox and December Solstice.  Be- cause these terms eliminate the traditional ambiguity, it has become preferable in astronomical circles to use them when referring to the equinoxes and solstices.

WHY THE LENGTHS
OF THE SEASONS
ARE NOT EQUAL

Since their beginnings and ends are strictly defined by the arrival of the Sun at the equinoxes and the solstices in our sky, our astronomical seasons have durations of specific lengths.  Although many people believe that the lengths of the astronomical seasons are the same, this proves not to be the case.  This is because, while the equinoxes and solstices are spaced at equal intervals of 90° around the Celestial Sphere, Earth's changing velocity in its elliptical orbit causes the Sun to appear to arrive a little early at parts of the sky, and a little late at others.  For the Northern Hemisphere, Summer thus becomes the longest of the "astronomical" seasons and Winter the shortest.

Lengths of the
Northern Hemisphere's "Astronomical" Seasons

Spring: 92 3/4 days
Summer: 93 2/3 days
Autumn: 89 5/6 days
Winter: 89 days.

Of course, in the Southern Hemisphere, "Astronomical" Seasons are the reverse of those above.  Therefore . . .

Lengths of the
Southern Hemisphere's "Astronomical" Seasons

Autumn: 92 3/4 days
Winter: 93 2/3 days
Spring: 89 5/6 days
Summer: 89 days.

PERIHELION
& APHELION

When is Earth at perihelion and aphelion, respectively the points in its orbit closest to and furthest from the Sun?

Contrary to popular belief, Earth is closest to the Sun during the Northern Hemi- sphere's winter, NOT sum- mer!  Conversely, Earth is farthest from the Sun during the Northern Hemisphere's summer, NOT winter!  This indicates that our seasons are not caused primarily by Earth's varying distance from the Sun.  No, our seasons are actually caused primarily by Earth's changing tilt in its or- bit relative to the Sun!

In contemporary times Earth is generally closest to the Sun between January 2 and January 6, and farthest from the Sun between July 3 and July 7.  NOAA Graphic

The excellent AstroPixels site provides a very good chart of  Earth at Perihelion and Aphelion: 2001 to 2100.

EARTH ACTIVITIES

MAKE COOL PAPER MODELS OF EARTH

CANON has a cool website that offers free downloads, including one that lets you make a cool  3-D paper model of Earth  For an even greater challenge, make a  3-D paper puzzle of Earth!


MAKE PAPER MODELS OF SPACE SHUTTLE

CANON's same cool website offers these free models of the Space Shuttle:
   Orbiter (realistic)
   Orbiter (simplified)
   Orbiter on 747
   Fuel Tank-Boosters (real.)
   Fuel Tank-Boosters (simp.)
Make them all!


MAKE PAPER MODEL OF ORION SPACECRAFT

NASA's new spacecraft will take us back to the Moon and beyond:  3-D paper model of Orion.


MAKE PAPER MODEL
OF JAMES WEBB
SPACE TELESCOPE

NASA's space observatory at Earth-Sun L2 point will look deeper into space and further back in time than Hubble!
3-D paper model of JWST. Blueprint (high res) 


MAKE YOUR OWN COMPASS

From the National Oceanic & Atmospheric Admin. (NOAA), here's an activity that's fun!  And potentially useful too!  Make Your own Compass.  Moreover, when you use the compass you make, you'll be confirming that Earth has a magnetic field!


VERIFY HOW
GRAVITY WORKS

For thousands of years even the smartest people in the world accepted that heavier objects always fell to Earth faster than lighter objects.  After you do the following simple little experiment, you will surely wonder why they never did something similar themselves!  And you'll be smarter than they were (well —about gravity anyway.)

Drop a quarter and a dime at the same time.  (Note: the former is over twice as heavy as the latter!)  Does one fall faster than the other?  Does it make any difference if you drop them at the same time from a different height?  To be sure of your answer, go ahead and repeat this quick experiment several times.  It won't take you long to know more about gravity than the ancient "experts" did!

CELES-TIPS

The following will help you enjoy this page's 1.6.x and 1.4.1 links that run events directly in CELESTIA.  If you're new to the program, these tips will also help you learn to use it.

  • If CELESTIA's clock (i.e. the program's date and time) is not visible at the top-right of its window, press the V key until you see it.  This will also turn on information text in other corners to help you keep track of several as- pects of the event you're viewing.  Keeping an eye on CELESTIA's clock at the top-right will help you appreciate how much time is passing in each view.
  • Pressing the "un-shifted" L key and K key respectively will speed up and slow down CELESTIA's flow of time by a factor of 10 in version 1.6.x and 1.4.1.
  • Pressing Shift+L and Shift+K respectively will speed up and slow down CELESTIA's flow of time by a factor of 2 in version 1.6.x only.
  • Pressing the J key (either shifted or "un-shifted") will reverse CELESTIA's flow of time in version 1.6.x and 1.4.1.

You'll find more information about many of CELESTIA's controls on our  Learning Center  page.


  EARTH

 Earth Day/Night Map

(to update, reload page)  Courtesy: Fourmilab Switzerland

View Earth in 3-D    3-D in Orbit    WorldWind Explorer
Current Distances and Views from the Sun and Moon
Current View of Earth & Moon from Sun   Interactive
Current Location in Orbit

Physical Properties:
      Diameter:    Compare   Compare in 3-D
            Equatorial: 12,756.274 km   Polar: 12,713.504 km
      Rotational Flattening:    0.003353
      Mass:    5.9724 trillion trillion tons
      Volume:    1.08321 trillion cubic kilometers
      Mean Density (Water = 1):    5.52
      Surface Gravity (standard):    9.81 m/s 2
      Surface Temperatures:  average  14°C  (57°F)  

      Axial Tilt:    23.44°    (1.6.x)  
            Variation:    22.1° - 24.5°; 41,000-yr cycle
            Where Poles Point 
      Rotation:
            Period:

                  Synodic ("Day" in Earth hrs):    24.00
                  Sidereal (in Earth hrs):    23.9345
            Surface Speed vs Latitude
      Albedo (geometric):    0.37
      Magnetic Field   
            Previously Unknown Radiation Belt
            Van Allen Belts 
            Magnetopause 
            Solar Interaction
            Comparison

More Earths in 3-D:
      NASA's Overview of Earth   Globe Viewer
      WebGL Earth      Point & Opposite Point (zoom in)
            Web GL Hello World Globe  zoom way in!
      SketchFab  Alt+Drag moves shadows  #2  #3  #4
      Location & Antipode
 © 2010-13 "SkyMarvels.com"
Copying NOT permitted!
Earth Surface:
      Land Area:    29.2%
      Area Covered by Water:    70.8%
            The World's Water 

      NASA / JPL's Photojournal pages for Earth
      Maps:
            USGS: The National Map  (great mapping tool)
            NatGeo MapMaker  (Layer 41 adds Time Zones)
            Interactive Album of Map Projections 2.0
            MetaBunk Earth Route Simulator
            Standard Time Zones of the World    Another
            World Population Density 3-D    2-D
            DSN Current Day & Night Map
            Biome Viewer
      Earth's Dynamic Surface:
            USGS "This Dynamic Earth"  online edition
            USGS "This Dynamic Planet"   Front  Back  Site
            U.S. Volcanoes & Current Activity Alerts
            Plate Tectonics: Plate Borders & Motions
            NASA GSFC Plate Boundaries: Oceans Drained
            USGS How Plate Tectonics Works 
            NOAA's Natural Hazards Viewer
            Tectonic Explorer
      Earth's Paleo-History: Maps, Apps & Vids
            Earth Viewer (3-D )  Awesome interactive!
            What Did Earth Look Like "___" Years Ago?
            From USGS, the  Breakup of Pangaea 
            Pangaea Fossil Distribution 


EARTH FROM ABOVE ITS NORTH POLE
(at its Equinoxes)

Earth Atmosphere:
      Structure:
            NASA   Graphic 1   NASA Graphic 2
            NASA Video ascending through Atmosphere
      Composition 

Earth Structure:
      3D Earth Exploded View
      Compared to Other Inner Planets
      Earth Structure Video

Spacecraft in 3-D:
      Boeing CST-100 Starliner 
      Explorer 1:   #1   #2 
      Hubble:  #1   #2    #3   #4
      ISS:  #1   #2   #3   #4    Tour
      JWST:  #1   #2   #3   Bluepr 
      Mir Space Station
      SpaceX Crew Dragon    Sim

Comparison of Earth-Satellite Orbital Geometries

Ring System:    No

Planet Classifications:
      Inner Planet  (along with Mercury, Venus & Mars)
      Terrestrial Planet  (defines term)
      Reference Planet:
            Planets with smaller orbits are  Inferior Planets
            Planets with larger orbits are  Superior Planets

Earth Orbit:  (1.6.x)   (1.4.1)
      Name of its Plane:   "The Ecliptic"
      Period (sidereal) :    365.2564 solar days
      Period (tropical) :    365.2422 solar days
      Distance from Sun:
            Mean:    1 AU (essentially defines measurement),
                  149,597,870.7 km  (defined in 2012)
                  Dates of:    early Apr, early Oct (current era)
            Perihelion:    147,098,300 km   (0.9833 AU)
                  Date of:    betw. Jan 2 and Jan 6 (current era)
            Aphelion:    152,097,400 km   (1.0167 AU)
                  Date of:    betw. Jul 3 and Jul 7 (current era)

From perihelion to aphelion, Earth's orbital velocity is continually decreasing!  From aphelion to perihelion, it is continually increasing!

      Velocity:
            Mean:    107,240 km/hr
                  Dates of:    early Apr, early Oct (current era)
            Min:    105,440 km/hr
                  Date of:    betw. Jul 3 and Jul 7 (current era)
            Max:    109,040 km/hr
                  Date of:    betw. Jan 2 and Jan 6 (current era)
      Eccentricity:    0.0167
            Compared to Perfect Circle 
      Orbit's Inclination to Ecliptic:    0° (it IS Ecliptic)
      Equinoxes & Solstices 
      Perihelia & Aphelia 

  VIEW EARTH'S VARYING TILT RELATIVE TO THE SUN


           

Tilt our planet with the slider control.  Its animation, and the one just above it, show how Earth's orbital position and tilt (relative to the Sun) are directly related.

View Earth's Tilt Today

Milankovitch Cycles   
      Orbital Cycles:
            Orbital Eccentricity:
                  Period:    approx. 100,000 yr
                  Min. Eccentricity:    0.000055  (NASA: 0.0034)
                  Max. Eccentricity:    0.0679  (NASA: 0.058)
            Apsidal (Perihelion) Precession:
                  Period:    approx. 112,000 yr
      Axial Cycles:
            Obliquity (Axial Tilt):
                  Period:    approx. 41,000 yr
                  Min. Tilt:    22.1°
                  Max. Tilt:    24.5°
            Axial Precession:  (Precession of Equinoxes) 
                  Period: 25,800 years
                  North Axis Direction:  (J2000)
                        Right Ascension:    18h 0m 0s   (270.00°)
                        Declination:    66° 33' 38.55" (66.56°)
                        In Constellation Draco
                  North Axis Map      South Axis Map
      Global Warming

View of Earth in CELESTIA:
      With Location Labels ON:  (1.6.x)   (1.4.1)
      With Location Labels OFF:  (1.6.x)   (1.4.1)

Number of Moons:    1    (Luna, aka "The" Moon)
      NASA's Overview of the Moon (in 3-D!)
      Compare to Other Moons
      Spin-Orbit Resonance with Earth:     Yes, 1 to 1
            (so the same side of Moon always faces Earth)
      View Earth-Moon Barycenter video

Partial Information Source: NASA Fact Sheets


ADJECTIVES MEANING
"pertaining to Earth"

      earthen, earthly, earthy
      geo-, geological, geotic
      terran (often capitalized), terrestrial, terrene (all from Latin: Terra)
      telluric, tellurian


EARTH'S TILT  (current)

Equinoxes, Solstices & the
Sun's Apparent Motion


THE SUN'S LOCATION IN EARTH'S SKY

     
      The Sun's Skypath   Poster
      Motion of the Sun Simulator


EARTH'S PRECESSION

Earth's precession is its gradual "wobble" that causes each of our home planet's poles to trace a circle against the background stars every 25,800 years.  The result of gravitational forces primarily of the Sun, the Moon and Jupiter on our planet's equatorial bulge, this fundamen- tal motion of Earth is not unlike that of the precession
of a gyroscope.  The effect causes our planet to have different North Stars during its 25,800-year cycle!

                 North Axis Map      South Axis Map

Our current North Star is Polaris (alpha Ursae Minoris), though Thuban (alpha Draconis) was our North Star in the era when the pyramids were being built!  Above you can see when Deneb and Vega will be our North Stars.

Unlike Earth's rotational axis, its "precessional axis" is essentially fixed.  While its north end points toward the constellation Draco, its other end points toward the southern constellations of Dorado and Pictor.  Around this axis, the direction of Earth's wobble is clockwise when we look down on Earth's Northern Hemisphere.

You can find an explanation of how you may view Earth's precession in CELESTIA 1.6.x on  our Tips page.


TOURING THE OCEAN BOTTOM
video credit: NOAA, US Dept of Commerce

EARTH'S WATER CYCLE
video credit: NASA

WATCHING EARTH BREATHE
video credit: NASA/JPL Caltech

NASA: Aquarius Ocean Circulation
video credit: NASA/Goddard Space Flight Center

EARTH AT NIGHT
video credit: NASA Earth Observatory

EARTH FROM ORBIT 2012
video credit: NASA

IMAGE Spacecraft Picks up Earthly Aurora
video credit: NASA/IMAGE Mission

NASA: A Landsat Flyby
video credit: NASA Goddard Space Flight Center

Also check out the videos on our  Earth Weather  page.

LINKS TO MORE NASA VIDEOS & INFO

You must have the noted player installed to view these.  Note: you might have to click on these more than once, as some NASA servers (like https://svs.gsfc.nasa.gov in particular) can be temperamental and slow to connect.  If a video does not load, try again at another time.

Draining the Oceans.  Intriguing View of Earth without its Oceans!  (QuickTime)  Video Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.  U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Geophysical Data Center, 2006, 2-minute Gridded Global Relief Data (ETOPO2v2).  The Blue Marble Next Generation data is courtesy of Reto Stockli (NASA/GSFC) and NASA's Earth Observatory.

Ocean Current Flows Around the Mediterranean Sea.  (Windows Media Player or QuickTime)  Video Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio.

Earth's Water Cycle:   Video Tour  from NASA/Goddard Space Flight Center.

Hourly Evaporation from the GEOS-5 Model.  Note how evaporation, fueled mainly by the Sun, varies with day and night much more greatly over land than over the oceans.  (QuickTime)  Video Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio The Blue Marble data is courtesy of Reto Stockli (NASA/GSFC).




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Planet Comparison HD vid.


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Sky-Gifts.  Your support is greatly appreciated!

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Current Int'l Space Station:

     3-D in Orbit  Compare

SKY VIEWING
SOLAR SYSTEM
THE SUN
MERCURY
VENUS
EARTH
THE MOON
MARS
JUPITER
SATURN
URANUS
NEPTUNE
SMALLER WORLDS
STELLAR OBJECTS
EXOPLANETS
DEEP-SKY OBJECTS
SCALE OF THE COSMOS
———————
SKY-FUN / SKY-GAMES

 

Earth's Mean Tilt Today
relative to the Sun

 


USGS's LATEST

Daily Earthquake Map
The National Map
EarthExplorer
Waters GeoViewer
CO2 Viewer  (slow loading)


NOAA's LATEST

Aurora Forecast:

    N Lights: (Aurora Borealis)
    S Lights: (Aurora Australis)

Tides and Currents   Map


NASA's LATEST

Earth from Space Today

ISS (Int'l Space Station) Info:

      Live ISS Stream
      Spot the Station


ESA's LATEST

ISS Location

ESA Missions


EARTH FUN FACTS

Roughly 90% of our planet's human population resides in the Northern Hemisphere!   Here the  World Population  is represented in a very cool 3-D graph!.

All of Earth's water  would fit into a sphere about 1,380 km (860 miles) in diameter! 

3% of Earth's water is fresh water; 97% is salt water!

Glaciers contain roughly 2/3 of Earth's fresh water!

At present, glaciers blanket roughly 1/10 of Earth's land area.  During the last major Ice Age about 10,000 years ago, they blanketed almost 1/3 of Earth's land area!

In its orbit around the Sun, Earth's speed (on average) increases by roughly 1 km/h every hour between aphelion and perihelion!  On average
it decreases by that same amount every hour between perihelion and aphelion!

You weigh more at the poles than at the Equator!  About
a half of one percent more! This is because Earth rotates on its axis, creating centrif- ugal effect, which decreases your weight most greatly at the Equator!

For the same reason, Earth bulges at the equator.  The result is that sea level at the equator is about about 21 kilometers (about 13 miles) further from Earth's center than sea level at the poles!

In the Northern Hemisphere spring is about three days longer and summer is close to five days longer than in the Southern Hemisphere!
            . . . likewise . . .
In the Northern Hemisphere autumn is about three days shorter and winter is close to five days shorter than in the Southern Hemisphere!

The umbra, the dark portion of Earth's shadow, has an average length nearly equal to the diameter of the Sun!

Astronauts on board the International Space Station witness 16 sunrises and 16 sunsets every 24 hours!

EARTH INTERACTIVES

QUICK ACCESS LIST

Note: some links are echoed elsewhere on this page and may include descriptive text.

NASA's Overview Earth (in 3-D!)

NASA's WorldWind Explorer Earth (in 3-D!)  Takes you to destinations, lets you show day and night, time zones and more!

Surface Speed vs Latitude

The Reasons for Seasons

Comparison of Earth Satellite Orbital Geometries

Rendezvous!  is a cool satel- lite orbit simulation!  Can you rendezvous with the "target vehicle"?

ESA's fantastic  ISS Virtual Tour  takes you all over the International Space Station!  Map at upper right tells you where you are and lets you "jump" to different modules.

ISS Docking Simulator  from SpaceX

Newton's Cannon!  helps you understand the velocity re- quired to orbit Earth.

Newton's Cannon!  another version, this from  KCVS/ca

Stuff in Space  may startle you with a live 3D view of everything orbiting Earth!  Satellite Map  is similar.

Links to interactive features that show Earth's orbit in 3-D can be found on our  Solar System page

NASA's Eyes on the Earth

Here's a NASA "Special":  Ocean Worlds   

Is our climate changing?  Find out here with  NASA's Climate Time-Machine

Discover the application of space-related discoveries and improvements in everyday things all around you in this very cool 3-D feature:  NASA Home and City.  Takes a moment to load.   Home   City

From the ESO, here's a very nice 3-D interactive of the  Hubble Space Telescope

Roughly 90% of our planet's human population resides in the Northern Hemisphere! World Population  shows Earth as a cool 3-D graph to give you a feel for this.

Compare Earth to "__" 3-D


SKYMARVELS™
CELESTIA ADD-ONS FEATURING EARTH

Solar
Eclipse Finder

Lunar
Eclipse Finder


SKYMARVELS™
POSTERS FEATURING EARTH

Time Zones

The Sun's Skypath

Earth's Tides

Our Corner of the Cosmos

Anatomy of the Milky Way


SKYMARVELS™
VIDEOS FEATURING EARTH

The Sun's Signature

Earth's Structure (short)

Earth's Structure (longer)

Perseid Meteor Shower 2010

Geminid Meteor Shower 2010

Geminid Meteor Shower 2012

Perseid Meteor Shower 2013

 

The Speed of Light

Stunning Fields of View 001

Stunning Fields of View 002

Have You Ever . . . ?

"celestia4all" Site Preview


Solar Eclipses:

   Solar Eclipses thru 2012

   Solar Eclipse 2010 Jul 11

   Solar Eclipse 2012 Nov 13

   Solar Eclipse 2013 Nov 3


Lunar Eclipses:

   Lunar Eclipses thru 2012

   Lunar Eclipse 2010 Jun 26

   Lunar Eclipse 2010 Dec 21

   Lunar Eclipse 2011 Jun 15

 

Moon's Occultation of Venus 2010 May 16

Moon's Occultation of Venus 2010 Sep 11

 

How Big Is Our Moon?

The Same Side of the Moon Always Faces Earth

The Earth-Moon Barycenter

The Solar System Barycenter

Phases of the Moon