Time has been studied by philosophers and scientists for 2,500 years. Astronomer Carl Sagan had it right when he said that time is “resistant to simple definition.” Lots of us think we know what time is, but it is hard to define. You can not literally see or touch time, but you can see its effects. The evidence that we are moving through time is found in everything – our bodies age, buildings weather and crumble, trees grow. Most of us feel the pressure of time as we are pushed to meet deadlines and make appointments. Our lives are often dictated by what time we need to be somewhere. picked by kakana 4 months ago