As non-astronauts in a rotational reference frame as a human on the surface of the earth, or as astronauts on a spaceship which uses rotation to simulate gravity will see the Coriolis effect as a fictional force due to our rotational reference frame. I am having no problem finding examples of this but the question I have is does an astronaut on the IIS, which is tidally locked to the earth and appears to have a inertial reference frame still experience that fictitious force as they are in a rotational reference frame from our perspective?
To extend this question one layer higher, I know that neighboring stars can impart the a Coriolis effect fictitious force on us even on the earth but it is unclear if there is also a component of the sun which will product that same effect from our frame of reference on earth.
The Coriolis effect, like the tidal effect, is a differential effect. It depends on the difference of two velocities.
If you’re in one of those spinner barrels at a fun fair, then your speed, relative to the center, is greater at the rim of the barrel than it is toward the center. (At the center, the relative velocity is zero.) So, when you try to throw a ball “up” and catch it, the ball seems to curve.
On the surface of the earth, objects at the equator are moving faster, relative to the earth’s center, than objects at, say, 45 degrees north latitude. This is part of why hurricanes move into spiral patterns.
The ISS is so small, and so very far away from the earth’s center, that the difference in velocity observed at any two points is so very small that the Coriolis effect is almost nil. Ditto for tidal difference: the point on the ISS farthest from the center of the earth just isn’t far enough from the point on the ISS nearest to the center of the earth. Without a significant difference, the differential of the gravitational pull is not observable.
ETA: general relativity isn’t relevant here at all. The GR effect is much too small to observe, save by hyper-accurate clocks.
I only mentioned GR to avoid the simple newtonian based answer as I care about the context of the reference frames.
I am not worried about the size of the effect, just if the fictional force exists in both frames, on the IIS, if an object is thrown in a non perpendicular direction in relation to the earths axis does the fictitious force named the Coriolis effect exist.
Even if it is not observable, does the fictitious force exist in an orbital reference frame.
On further reflection, maybe a golfball or a cannon on the moon would be a better question and would detract less from my core misunderstanding.
As the moon is tidally locked, if you were at 45" north latitude and fired a cannon ball directly south that landed at 45" south latitude would it land on the same meridian you are on or would it drift due to the Coriolis effect, as your only “rotation” from that frame of reference would be the orbital period of the earth/moon. (please ignore solar winds and the small lunar atmosphere)
If your talking about the Coriolis force, then it depends on where you are. If you believe you are stationary on the Earth’s surface, then an object you are observing will appear to have a force acting on it. However, you are not stationary and what you are observing is the combined forces acting on the object and yourself. What you are observing as the Coriolis force acting on the object is the opposite of the gravitational force acting on you, the observer.
Objects in orbit, like the ISS, have motions governed strictly by gravity, and so would not observe the Coriolis force. This is exact the same case as an observer on the Earth’s equator. This is also why the Sun doesn’t show the Coriolis force as it lies on the solar system’s ecliptic, which is the same as the the equator on Earth. Any other star is too far removed to have any effect here.
This really only comes up while we are standing in one place on the Earth. We have a force acting on us so we’re not in what’s called an “inertial frame of reference”. This inertial frame of reference requires the observer to have NO force acting on them, so that the forces acting on the object we’re observing are “true” and “correct”.
Yes, absolutely. It exists on the ISS, just as a tidal force exists there. It exists in almost all scenarios involving rotation.
If you’re on an ordinary carousel, and move directly “outward” from the center toward the rim, you’ll find yourself “inexlicably” moving backward, against the rotational direction of the ride. If you start at the rim and move inward, you’ll find yourself propelled forward, with the rotational direction of the ride.
This pretty much generalizes to any rotational situation.
Orbits are a special case, because the rotational speed, the rotational angle per unit time, diminishes as you get farther away from the center. This adds a new element to the effect.
(Larry Niven, in his “Smoke Ring” and “Integral Trees” stories mentions the odd sense of direction you get when in orbit: “Forward equals up, up equals backward, backward equals down, and down equals forward.” This was also confusing to the Geminii astronauts when they first sought to match orbits and dock with an unmanned orbiting object, and with two Geminii capsules. Only when you get really close to each other can you use naive “Newtonian” momentum.
“Tidal locking” has zero to do with Coriolis. And you say a couple places something about some other body causing a Coriolis force. That’s also inaccurate thinking.
If you are rotating, you experience Coriolis. If not, not. If you have any rotation there is some Coriolis; even if your rate of rotation is exceedingly slow and the force exceedingly weak.
Unlike unaccelerated linear motion, rotation is absolute. In the abstract, per GR, you can’t tell the difference between unaccelerated linear motion and being stationary. More precisely: “stationary” is an undefined concept.
This result does not hold for rotation. Under any rotation at any rate, even a perfectly constant rate, you’ll feel an acceleration. And if you feel that and try to move yourself or move something else, e.g. your artillery shell on the moon, you / it *will *experience Coriolis. The only question is how much.