|If our solar system had two suns, would it be
summer year round and would the sun ever set
(i.e. would we ever experience nighttime)?
|Question Date: 1999-03-03|
If our solar system was like 90% of most we would
have two or more stars in it. In that case, we
would have to know the mass of each star and the
distance between them in order to compute the path
of a planet. we also would have to know the angle
between the spin axis of the planet and the plane
defined by the two stars to say something about
possible climates and seasons.
knowledge simply that a star system is a binary
one, one could not really say anything about
seasonality on the planet. More info is
Neat question!I'll help you find the answer.
First, find out what causes us to have seasons.
Once you've found that out, think about how the
sun is involved in our seasons. Is it only the
movement of the sun that causes seasons? Is it
only the movement of the Earth? Once you've
figured all that out, draw a picture of the
positions of the earth and the sun during the
different seasons. Then, draw another sun in
different places in the solar system and figure
out how it would affect the seasons on earth. I'd
love to hear your answer. Let me know how it
You could actually answer this question yourself
by building a simple model. First, take two large
balls like basketballs or soccer balls and place
them on the floor near each other. These will
represent your two suns. Next take a smaller
ball, like a tennis ball, and place this on the
floor away from the other "suns". This will be
your planet. Next, draw an elliptical orbit in
chalk on the floor (or scratch it on the ground if
you do this outside). You should decide if your
orbit will pass between the two suns or go
completely around them. You could actually draw
both to represent the two scenarios; one where the
planet passes between the suns and the other where
it goes around them both.
Now place the
"planet" in different places around each orbit and
answer these questions.
If your planet is
between the suns, will the days be longer? If
there were only one sun, would there be a
difference? Will the days be hotter or colder?
What season does this represent, summer or winter?
When the planet is on the far end of the ellipse
orbit, what season is this? Will the days be much
longer or shorter? Will the difference be very
very large compared with summer when the planet is
between the suns?
For advanced students:
An ellipse has two foci. The model above assumes
that both suns or at least one is located in one
of these foci. Place one sun at each foci and
answer the above questions again.
A word on
models: What you have done is what scientist do
all of the time; build models to understand things
better. The model you just built is both a
physical model and a conceptual model. It is
physical because it is actually there unlike a
computer model or a mathematical model. It is a
conceptual model because you do not do any
measurements even though you could.
It would depend on where the suns were located in
relation to each other and to the other planets in
0ur solar system. Having two suns would also
change the gravitational forces on our planets.
For instance, if the force on the earth is taken
as 1, the comparative force for the sun is 27.9.
That means that if, for example, a person on earth
weighed 100 pounds, then the weight of that person
on the sun would be 100 x 27.9 = 2790 pounds. The
only other gravitational force exerted in our
solar system that even comes close to this is
Jupiter, which would exert a gravitational force
of 2.64 (going along with the example). So, if
there were another sun in our solar system, it
could potentially change the planets orbits, or
even change the seasons on the planets. In terms
of whether it would be summer year-round or if the
sun would ever set, I think this would depend
largely on where the other sun was located in
relation to earth and our current sun.
If the Sun were part of a binary star system then
things would be definitely be different. Each
star would rise and set as the earth rotates about
its axis. Depending on how things are arranged
there could be times when both stars can be seen,
times when only one star is "up," and maybe times
when neither star is "up." How an extra star
would effect the weather and climate would also
depend very much on how bright the extra star is
and how far away it is. There are many, many
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