Gravity

• How Does Gravity Change With Altitude?
  Gravity decreases with altitude according to the inverse-square law: calculate it with g(h) = g₀[R/(R + h)]² above Earth.
• What Is the Gravitational Constant in Higher Dimensions?
  In D spacetime dimensions, Newton’s constant has dimension-dependent units; compactifying extra dimensions relates it to the observed four-dimensional constant.
• Does Time Dilation Cause Gravity? What General Relativity Says
  Gravitational time dilation is linked to gravity and can help describe it, but it is not the whole cause: gravity is spacetime geometry.
• Does Gravity Slow the Expansion of the Universe?
  Gravity from matter and radiation decelerates cosmic expansion, but dark energy now causes the universe’s expansion to accelerate.
• How Is the Strong Equivalence Principle Stronger Than the Weak One?
  The strong equivalence principle extends universal free fall to self-gravitating bodies and gravitational experiments; here is how it differs from the weak principle.