Thomas Neville Earth Science IH

Assignment 1.1: NASA picture

Citation: Block, Adam, and Tim Puckett. "Astronomy Picture of the Day." APOD: 2013 August 1. N.p., n.d. Web. 09 Feb. 2014.

    

     This is composite image of the Andromeda galaxy with the moon in the foreground. The image demonstrates the concept of angular size, a concept used mainly in astronomy to describe the apparent size of an object in space relative it its distance from Earth. A good example of this concept is how the sun appears to be the same size as the moon when viewing the two objects from Earth when in reality the sun is 400 times larger than the moon but also 400 times more distant. So in the case of this picture, the moon appears to be about 1/4^th the size of the Andromeda when in reality it is a zillion times smaller but a zillion times closer. Another interesting thing about this picture is how it was taken. Deep exposure is another concept used mostly in astronomy but also by professional and amateur photographers (look up “long exposure photography” to see what I mean.) long or deep exposure cameras like the one that was used to take this photo capture light from an area of sky for an extended period of time, thus intensifying the light visible from even most distant stars and making them visible to the naked eye. A question I have about this picture is how they took all the pictures required to create the full image from the same angle and whether they were taken by a satellite or on Earth.