# What causes the Earth to have gravity?

I've always wondered how our planet Earth or any other large spheroid-shaped thing in our universe has gravity?

Does it have a small black hole on its core causing it to have gravitational force?

Take our planet as an example: what causes it to have gravity?

• Mass. Mass and a very small amount of energy to be more precise. – Rob Jeffries Nov 30 '16 at 20:01
• Something worth noting: science never describes the true reason why something happens. It concentrates on predicting the effects of what happens. When one asks science "why," we answer by showing a deeper and more powerful model (such as Newtons' law of universal gravitation or Einstein's relativity). If you want the "real" reason for gravity, turn to philosophy or religion. They'll dare to try to answer such ontological questions. – Cort Ammon - Reinstate Monica Nov 30 '16 at 20:32
• @RobJeffries: What "very small amount of energy" are you referring to? – Keith Thompson Nov 30 '16 at 20:41
• @KeithThompson Just taking a stab at this, but maybe rotational energy? The rotational energy would be a cause of frame dragging which helps to distort the space-time around the mass and as GR tells us, space-time distortion is gravity. – zephyr Dec 1 '16 at 1:38
• The total mass-energy of the Earth is it's rest mass $\times c^2$ plus a negative term due to its potential energy plus a positive term due to the kinetic energy of its constituents. The latter two terms are tiny in comparison to the first. @KeithThompson – Rob Jeffries Dec 1 '16 at 16:50