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.
The Earth rotates around its axis once every 24 hours. It also revolves around the Sun once every 365.25 days. The axis of Earth's rotation is tilted 23.5 degrees from the plane formed by its orbit around the Sun.Figure 1 shows the axial tilt of Earth, with respect to its orbit.Figure 1. Earth's axial tilt.The angle of tilt equals the angle between the axis of rotation (through the poles) and a line that is perpendicular to the plane of the orbit.igure 1 shows the axial tilt of Earth, with respect to its orbit. Figure 1. Earth's axial tilt. The angle of tilt equals the angle between the axis of rotation (through the poles) and a line that is perpendicular to the plane of the orbit.