Click here to see an example of a secure and flexible seat in trot. Watch closely as the rider's hips, pelvis, and legs flex freely with the horse's movement. Horse's willingly raise their back up under a seat like this, probably because it feels a bit like getting a gentle back rub with each step.
The celestial sphere is divided by the celestial equator. In astronomy and navigation, the celestial sphere is an imaginary sphere (ball) of a very large unspecified size. The sphere is concentric with the Earth. This means that the celestial sphere and the earth have the same centre. They also rotate upon the same axis.
The Universe - 01 Celestial Bodies & the Universe. All astronomical objects in the sky, such as the Sun, the Moon and the stars, are collectively known as celestial bodies. They are separated from each other by immense regions of emptiness called space. The space, along with the celestial bodies, make up what we call the Universe.