Why Moving the Sun Closer Wouldn't Make Nights Brighter
Nights would stay dark even with a closer Sun (you're in Earth's shadow). But days would be much brighter — light intensity follows the inverse square law, so half the distance = 4x the brightness.
A thought experiment: would moving the Sun closer to Earth make nights brighter? No — nighttime occurs because your side of Earth faces away from the Sun. You are in the planet's shadow. A closer, brighter Sun would still not illuminate the night side directly. However, we are NOT receiving the Sun's "full brightness" despite the vacuum of space. Light follows the inverse square law: it spreads out in all directions as it travels. By the time sunlight reaches Earth (150 million km away), it has spread across an enormous sphere. Moving the Sun to half the distance would quadruple the intensity — not double it. What a closer Sun would change: - Daytime would be significantly brighter and hotter - Night sky would remain dark (Earth's shadow still exists) - Moonlight would be brighter (Moon reflects sunlight, so more sunlight = brighter reflection) - The habitable zone would shift, likely making Earth uninhabitable The inverse square law is why the Sun appears as a small disc despite being enormous — at 150 million km, even a star 1.4 million km in diameter subtends only 0.5° of arc.