The Cosmological Constant as Event Horizon
  General Relativity allows for a cosmological constant ($\Lambda$) which has
inspired models of cosmic Inflation and Dark Energy. We show instead that
$r_\Lambda = \sqrt{3/\Lambda}$ corresponds to an event horizon: a causal
boundary term in the action. Our Universe is expanding inside its Schwarzschild
radius $r_S=\rL=2GM$, which could have originated from a uniform free falling
cloud of mass $M$ that collapsed as a Black Hole (BH) 25 Gyrs ago. Such a BH
Universe allows for large-scale structure formation without the need of
Inflation or Dark Energy.
