1.One would not specify the position of the moon in terms of miles north and miles west of Piccadilly Circus and feet above sea level.
specify: to state something in an exact and detailed way
Payments will be made for a specified number of months.
2.I personally find it hard enough to visualize three-dimensional space!
visualize:I remember meeting him but I just can't visualize him
3.) I shall generally use diagrams in which time increases upward and one of the spatial dimensions is shown horizontally.
spatial:of, concerning or existing in space
4)The ripples spread out as a circle that gets bigger as time goes on
ripples: thing like this in appearance or movement
slight ripples on the surface of the metal
5)If one stacks snapshots of the ripples at different times one above the other, the expanding circle of ripples will mark out a cone whose tip is at the place and time at which the stone hit the water.
stacks: circular or rectangular pile of hay, straw, grain, etc, usu with a sloping top for storage in the open;
snapshot: a photograph taken quickly and often not very skilfully
cone: solid body that narrows to a point from a circular flat base
6)They will lie within or on the expanding sphere of light emitted from the event P
sphere:range or extent
7)we would not be able to tell whether the light was being deflected or if instead the star was really where we see it.
~ (sth) (from sth) (cause sth to) turn from its direction of movement
The missile deflected from its trajectory.
8)
The light deflection has, however, been accurately confirmed by a number of later observations
deflection: or being deflected
The smallest deflection of the missile could bring disaster.