Hydrogen is by far the most abundant element in the universe. It makes up about 93 percent of all atoms in the universe and about three-quarters of the total mass of the universe. Hydrogen occurs both within stars and in the interstellar space (the space between stars).
It is an imaginary line from the Earth's north pole to its south pole, passing through the center of the Earth. Imaginary in the sense that it is not marked in any way; howeve â¦ r, Earth rotates around this axis.
Also called axis of abscissas. (in a plane Cartesian coordinate system) the axis, usually horizontal, along which the abscissa is measured and from which the ordinate is measured. 2. (in a three-dimensional Cartesian coordinate system) the axis along which values of x are measured and at which both y and z equal zero.