My brother and I are having a debate about night vision and our abilities to discern distant stars.

According to his theory, the only thing keeping us from seeing the stars during the day is the fact that our pupils aren't dilated enough to see them. He agrees that if our pupils WERE dilated during day time, we'd fry our eyes due to sunlight. He believes that if you were in a cave some miles down, however, that your pupils would dilate and that you'd be able to see the stars by looking up through a hole to the surface.

In his words then, if your eyes are night adapted (pupils dilated) you'd be able to see the stars even in daylight.

From my thinking, the presence of sunlight would act as a filter and obscure the stars rendering them invisible both on the surface AND in the cave.

There is a wager at stake... a shiny penny... to the winner. Any facts/info folks have that could put this issue to rest would be appreciated.

• cave views - leonard - February 18, 2002 - 05:22 UTC
• Seeing Stars - bobmay - February 19, 2002 - 03:05 UTC
  • Sextant - mpinson - February 19, 2002 - 19:43 UTC
• from a deep mine maybe - ed_sd - March 1, 2002 - 06:09 UTC