In the absence of an external force, an object in motion will remain in motion indefinitely
MAYBE DARK MATTER AND/OR GRAVITY COULD BE THE EXTERNAL FORCE
Newton’s first law states “An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the
same direction unless acted upon by an unbalanced force.”
In an ideal situation, with no friction
, a rotating body will rotate forever. Period. That is what Newton was saying.
Now the rotation of the Earth is not quite an ideal situation. The gravitational pull from both the moon and the sun cause tidal motion in the
Earth’s oceans. This in turn causes tidal friction as the oceans bump up against the continents as the tides rise and fall.
This is what is causing the Earth’s rotation to slow. Please note that because of the mass of the Earth, this is a very, very slow process. This has
been going on for billions of years and it is not going to stop tomorrow.
The presence or absence of dark matter has little to do with this.
Now space is not a perfect vacuum and the Earth also passes through tons of cosmic dust on a daily basis (about 40,000 kg /day). To a degree, this
influx of dusts and debris also adds to the friction of the Earth’s rotation and orbit. But, because this cosmic dust is mostly coming in from all
directions at the same time, the effects tend to cancel each other out.
Let us suppose your fabled planet X actually existed. Let us say that there was a planetary body that passed between the sun and the Earth. exactly
midway between the Earth and Venus. Based on various tables of astronomical data, the distance to the point half way between the Earth and Venus is
approximately 54 times the average distance from the Earth to the moon.
Since the mass of the moon is 1/81 of the mass of the Earth, if the mass of planet X was 10 times more massive that the earth, it would be 810 times
more massive then the moon.
Since Newton’s laws state that the force of gravity between two objects is a function of the mass of those objects divided by the square of the
distance between the objects, that means that the force of gravity that this hypothetical planet X would exert on the earth would be 810/(54*54), or
27% of the force exerted by the moon. Now if the lunar (and solar) tides have failed to stop the Earth’s rotation over the course of billions of
years, then adding 27% will probably not make that much of a difference.
IF A COMPASS WAS USED IN SPACE, WHERE WOULD NORTH BE? IS THERE A NORTH IN THE UNIVERSE?
A compass in space would align itself to whatever magnetic fields were in the vicinity (solar, the Earth, your space craft, etc.).
It seems to me that the direction of North is space would be a purely philosophical question. Toward Polaris?