Twilight on Earth is the illumination of the lower atmosphere when the Sun itself is not directly visible because it is below the horizon.Twilight is produced by sunlight scattering in the upper atmosphere, illuminating the lower atmosphere so that Earth's surface is neither completely lit nor completely dark.It's a bizarre thing, because we kind of all looked at each other and were like, 'Sooo, what's your life been like?' It was fun." Playing on-screen lovers in "Twilight", Robert Pattinson and Kristen Stewart have repeatedly been hit with dating rumors. Besides, Kristen has had a boyfriend, actor Michael Angarano, whom she's been dating since 2006.The period may affect when pilots require a night rating to fly aircraft.In the US, civil twilight for aviation is defined in Part 1.1 of the Federal Aviation Regulations (FARs) Morning nautical twilight begins (nautical dawn) when the geometric center of the sun is 12° below the horizon in the morning and ends when the geometric center of the sun is 6° below the horizon in the morning.Providing evidence to the close bond that "Twilight" cast have been developing, Ashley revealed Peter Facinelli, who plays Dr.
The farther the Sun is below the horizon, the dimmer the twilight (other things such as atmospheric conditions being equal).
Enough illumination renders artificial sources unnecessary for most outdoor activities.
At civil dawn and at civil dusk sunlight clearly defines the horizon while the brightest stars and planets can appear.
When the Sun reaches 18 degrees below the horizon, the twilight's brightness is nearly zero, and evening twilight becomes nighttime.
When the Sun again reaches 18° below the horizon, nighttime becomes morning twilight.