Photo by Robin Loznak, courtesy of the Daily Inter Lake
Robin Loznak took this week's photo from the summit of Big Mountain near Whitefish. She pointed her camera at Polaris ("the North Star"), and then left the shutter open for 70 minutes, recording the "motion" of stars in the northern part of the sky. Such "motion" is referred to as "apparent" because it is not caused by the movement of the stars, but rather the spin of the Earth on its axis. It's like being on a merry-go-round and thinking that your surroundings are moving. The Sun and Moon "move" across our for the same reason. Since Polaris is directly above the North Pole, it stays put while the other stars seem to circle around it.
A rock among stars . . .
Term: circumpolar stars, meteoroid
|*More about Comet Swift-Tuttle|
|*American Meteor Society Site|
|*More about meteor showers|
|*Neat photo of a meteor shower|
|Next picture of the week|
Earth Science Teacher at Helena High School