Measure the shift of the nearby star relative to the To move - any star that does must be nearby. Most stars are distant enough so that they won't appear Sky using observations separated by six months. Now we can measure the position of a nearby star on the We do however have an even larger baseline that we can use: the Earth's Orbit. But, it is still not big enough if we want to measure distances to the nearest stars. Within the Solar System we can use the diameter of the Earth as a long baseline to measure distances. You and your friend would see the object in two DIFFERENT places. You both look at the same object, say Jupiter, and by cell phone compare where the object is located against the background stars. Now you stand on one side of the Earth and your friend stands on the other. What about using the Earth itself as a large baseline?
Suppose that instead of measuring the distance across a river, you'd like to measure the distance to some object outside the Earth. It should be evident that the greater the baseline used the greater the distance that can be measured.