Is Earth the only planet in the universe that bears a form of intelligent life? Based on scientific observations so […] ...

Density is the mass per unit volume. Density can be found using this equation. Density is sometimes measured in g/cm 3. Make sure that you use units that are consistent with the question in an exam.

But one variable has been missing from the Drake Equation, which a team led ... including the density of dark energy, could explain our own existence." Another 24 percent is dark matter; only ...