# Question #3c233

Mar 9, 2017

A quark, meson, boson.

#### Explanation:

Gravity is simply a function of mass. Therefore, anything which has mass has inherent gravity. It might be that neutrinos are the smallest but since we have yet to fully understand them it cannot be said they have any mass at all.

Mar 27, 2017

Energy is source of gravitational field. Energy can be mass or momentum . A photon for instance, generates a gravitational field.

#### Explanation:

This is Einstein's formula: ${E}^{2} = {p}^{2} {c}^{2} + {m}^{2} {c}^{4}$ The second term is absent for the photon, but not the first.