Entire Solar System
This simulation gives
two simultaneous views of the Solar System; one centred on the Sun, the other
one the Earth.
Alternative simulations:
single
view centred on Sun
single view centred
on Earth
On the Sun centred view, you can zoom in or out to display the inner
planets or the entire Solar System.
On the Earth centred view, you can zoom in to inspect a detail of coastline
or zoom out to a view of the Earth and Moon in their orbit around the Sun.
The Tilt control changes the position of the viewer (for both views); from
looking "down" from "above" the plane of the ecliptic (the plane of
the Earth's orbit around the Sun) onto the Earth's North pole, to looking
"up" from "beneath" the plane of the ecliptic onto the Earth's South
pole.
Adjusting the Tilt to view the to Solar System from different angles
you can see how most planets orbit around the Sun near the same plane as
the Earth in near circular orbits.
Pluto (the outer planet) deviates the most - with an eccentric orbit tilted
17 degrees to the Ecliptic (the plane of the Earth's orbit). Mercury (closest
to the Sun) also has an eccentric and tilted orbit.
Notice how the Earth's axis of spin is tilted compared to the axis of its
orbit around the Sun. Try comparing the two views to see how the Earth's
position in its orbit matches the Sun's shadow on the Earth, and how the
tilt of the axis affects the position of the shadow. Can you tell what time
of year it is from the position of the Earth in its orbit? (see the simulations
about the seasons)
You can adjust the time interval (1/2 hour, a day or a week) between the
images displayed :
With 1/2 hour between views, you can see the rotation of the Earth and the
slower (but same direction) orbit of the Moon.
With intervals of a day the orbits of the faster moving inner planets are
more obvious - and looking once a week the movement of the outer planets
is discernable.
With the "Step" control activated, you'll see a short pause between the 1/2
hourly or daily images. With "Step" deactivated the simulation will run faster,
with more of an impression of continuous movement.
Viewing the Earth at daily or weekly intervals shows the Earth at the
same time of day (every day or every week) so that the same part of the Earth
will be facing the Sun on each snapshot (roughly - given the eccentricity
of the Earth's orbit).
This "almost stop motion" view shows that a day is a little bit longer
than the time it takes for the Earth to spin a complete revolution (a sidereal
day - relative to the stars) . One day is a complete revolution plus a bit
(1/365 extra of a revolution) so that the same part of the Earth (as it moves
in its orbit) is facing the Sun.
Observing the Earth at weekly intervals gives a direct illustration of how
the times of dawn and dusk vary throughout the year for places at different
latitudes.
One of the most noticable features of the Solar System is how small the Sun
and planets are in comparison to the distances between them. Most illustrations
of the Solar System magnify the Sun and planets to show some detail on them
at the same time as indicating their relative positions.
The planet and Sun images here are also (by default) enlarged - but on the
Earth centred view you can switch to a properly scaled view.