sphere articles

Is the ecliptic a real thing?

The question of whether the ecliptic is a real thing often arises because we associate "real" with something tangible we...

Why do supernova remnants look like rings rather than spheres?

The brilliant, expanding clouds of gas and dust left behind after a massive star dies—known as supernova remnants—rarely...

What is the apparent path of the Sun along the celestial sphere or equivalently the plane determined by the Earth's orbit called?

The apparent path traced by the Sun across the background stars over the course of a year, which also corresponds to the...

What is the apparent great circle annual path of the Sun in the celestial sphere as seen from the Earth?

The line traced by the Sun across the backdrop of the distant stars over the span of one year defines a fundamental conc...