A diagram showing the different rotation axes.
The Earth's Rotation
The Earth is rotating around an axis
(called its rotational axis). Some objects rotate about a
horizontal axis, like a rolling log. Some objects, such as a skater,
rotate about a vertical axis. The Earth's axis is tipped over about
23.5° from vertical.
How do we define up and down in space? What would "vertical" mean?
For the Earth, we can think of vertical as straight up and down with
respect to the plane in which the Earth orbits the Sun (called the ecliptic).
Earth's rotational axis points in the same direction relative to the stars, so that
the North Pole points towards the star Polaris. Think of the Earth as
a spinning top, tipped over to one side. Over very long time periods (thousands of years) the direction of Earth's axis slowly changes due to precession.
The Earth rotates around once in 24 hours - that's a rate of 1000
miles per hour!. The time it takes for the Earth to rotate completely
around once is what we call a day. It's Earth's rotation that gives
us night and day.
The combined effect of the Earth's tilt and its orbital motion result in the seasons.
Shop Windows to the Universe Science Store!
The Fall 2009 issue of The Earth Scientist
, which includes articles on student research into building design for earthquakes and a classroom lab on the composition of the Earth’s ancient atmosphere, is available in our online store
You might also be interested in:
Let's get rid of some common misconceptions about the seasons. The Earth's orbit is in the shape of an ellipse, so that sometimes the Earth is a little bit closer to the Sun than at other times. Is this...more
Ok. Let's get some terminology down first. If a body (like the Earth) is orbiting around the Sun, we say it is closest to the Sun at perihelion and farthest from the Sun at aphelion. If a body (like the...more
"The movements of the heavenly bodies are an admirable thing, well known and manifest to all peoples. There are no people, no matter how barbaric and primitive, that do not raise up their eyes, take note,...more
If Uranus is the "tilted planet", Mercury might be called the "upright planet". The spin axis of Uranus, which defines the locations of the planet's North and South Poles, is tilted by 98°. The spin axis...more
Mercury has a weak magnetic field. Like Earth's magnetic field, Mercury's dipole field is tilted with respect to the planet's spin axis. This means that Mercury's magnetic poles and its geographic poles...more
Earth's atmosphere changes over time and space, giving rise to weather and climate. Fundamental Concept 4.1 Weather is the state of Earth's atmosphere at a particular place and time. The climate of a particular...more
Atmospheric circulation transports matter and energy. Fundamental Concept 3.1 Horizontal and vertical energy imbalances in the Earth System produced by unequal heating of Earth's surface create movement...more