Ridiculous a bit a know, but is this Sci Fi theme even possible?

Question

For two planets to lie in the same orbit?

In Sci Fi movies or TV it would usually be a planet directly opposite of earth always on the other side of the sun from us.

I know its highly improbable, but is it possible?

Answer 1

No.

Two points--first we have space probes that have been able to view the point directly on the opposite side of the Sun--and there's nothing there.

Second, orbital mechanics does make it impossible.  If, hypothetically, you could place a planet in that position with the right orbital speed, it wouldn't stay there.  Orbital disturbances (called perturbations) would change the orbit enough to maeke it move from behind the Sun within a few decades--centuries at most.

There are two stable points on Earth's orbit wwhere you can have an object that will stay put.  They are called the Trojan Poiints. One is 120 degrees ahead of Earth in its orbit (1/3 of the way around) and the other 120 degrees behind Earth in its orbit.  Both, however, are visible from Earth.

Answer 2

yes

why would it be impossible? even stars exhibit this type of behaviour and we can watch them.. they're called binary star systems.... (their orbits are locked by each others gravity, thus they travel the same orbit in space)

it wouldn't be hard to imagine that a binary planet system is out there somewhere... especially when we're now seeing there are even more planets then stars (until recently we haven't realy had the technology to see what we're seeing now...)

i believe the universe is infinite.... and so, not is everything possible, somehwere out there, everything has already, currently, or in the future will occur.

Answer 3

yes.

do a search for "lagrange points".

Answer 4

Not for long, unless they are traveling the same orbital direction at the same speed.

Answer 5

If geo-stationary orbits are possible for sattelites, then why not for planets? One mass acting on another will hold it's own orbit! Binary stars have been proven, so planets are more than possible!

Answer 6

It is possible, however it would probably not be a stable system unless there was another planet causing them to "locked" into their positions.

Answer 7

It is possible.  And the two planets could be invisible to each other if the orbit is a perfect circle.  It is unlikely that the planets would be able to stay exactly opposite each other for very long periods of time because of other gravitational asymmetries in the solar system.  We would also be able to detect its gravity even if we couldn't see it.

Only problem is, that theme's been done.  It was in a movie, "Journey to the Far Side of the Sun."

Answer 8

There are actually stability points that would allow that to exist, however it would not be directly opposite the sun from the Earth all the time, and would thus be visible at least part of the time.  (the Earth doesn't orbit in a perfect circle, but an ellipse - ditto for its 'partner' if that existed...)