Selection of the coordinate system is essential for rotation problems. Otherwise, mistakes may occur

due to inaccurate measurement of angular speed. Approximate inertial coordinate system selections

for rotation problems should be the gravitational field of the celestial body higher than the object being

rotated: (1) the Earth fixed Cartesian coordinate system for normal rotation problem; (2) heliocentric –

a geocentric Cartesian coordinate system for satellites orbiting the Earth; (3) the Galaxy Heart –

heliocentric Cartesian coordinates for Earth’s rotation around the Sun. In astrophysics, mass

calculation error and angular velocity measurement error lead to a black hole conjecture.

**Author(s) Details**

Zifeng Li

Petroleum Engineering Department, Yanshan University, Qinhuangdao 066004, Hebei, China.

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