SOLAR SYSTEM

Earth the water planet

Earth is the third planet of our solar system. It has one natural moon, 5 natural quasi-satellites, two space stations, a couple dozen space telescopes, and ~5,000 operational satellites (Starlink, OneWeb, Iridium, GPS, etc.) that orbit around it. Earth is the densest planet (and object) in the solar system.

Earth 4K image

Pan, zoom, or go full-screen with this megapixel image of Earth.

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Original image: NASA

Earth facts

CHARACTERISTIC	VALUE
Mass:	5.9 x 10²⁴ kg
Radius:	6,378 km
Density:	5.52 gm/cm³
Distance from Sun:	149.6 million km
Rotational period:	23.93 days
Orbital period:	365.26 days
Orbital velocity:	29.79 km/sec
Eccentricity of orbit:	0.017
Tilt of axis:	23.45 °
Inclination of orbit:	0.0 °
Surface gravity:	9.78 m/sec²
Escape velocity:	11.2 km/sec
Albedo:	0.37
Surface temperature:	14°C mean
Atmosphere:	N₂ = 78% O₂ = 21% water vapor = 1% CO₂ = 0.04%
Moons:	1

Earth features from space

Here are the major surface features that can be seen from space without magnification:

FEATURE	TYPE
Amazon River	South America
Chernobyl cooling pond	Ukraine
Ganges River	India
Grand Canyon	USA
Great Barrier Reef	Australia
Great Pyramids of Giza	Egypt
Greenhouses of Almeria
Himalayas	Asia
Kennecott Copper Mine	USA
Palm Island	Dubai
River Thames	United Kingdom
Cities at night	worldwide

Earth vs. Moon ratios

Planet sizes are to relative scale.

EARTH

diameter = 1
gravity = 1
surface pressure = 1
solar irradiance = 1
day = 1
year = 1

MOON

diameter = 0.27
gravity = 0.17
radiation = 45
surface pressure = 0
solar irradiance = 1
day = 27.5
year = 0.075

Earth from Saturn

The pale blue dot, taken by Voyager 1

"Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known."

-- Carl Sagan, Pale Blue Dot, 1994

Two things are infinite - the universe and human stupidity; and I'm not sure about the universe.

- Albert Einstein