Earth Sciences 1086F/G Lecture Notes - Lecture 2: Hubble Space Telescope, Fried Egg, Frisbee

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 1086F/G
• Professor: Anthony Withers

Document Summary

That is, it was created at some time in the distant past and will forever exist as seen now. Shooting star", nothing much seems to be happening. The distances between stars and galaxies in the universe are so vast it would be unwieldy to describe them in miles or kilometres (it would be like measuring the distance from toronto to tokyo in inches or centimetres). Instead, scientists use light-years to measure distances in space. A light-year is the distance that light travels in one year. Light travels at about 300,000 km per second; there are 31,500,000 seconds in a year. Multiply that and you will see that light travels 9. 4608 1012 km per year. That is way too big a number to work with, so we measure distance in terms of numbers of light years (table 2. 1). Table 2. 1: light-travel distances to some familiar objects in the universe, as measured from the sun.