Any point on earth can be located by specifying its latitude and longitude, including Washington, DC. Lines of latitude and longitude form an imaginary global grid system. Any point on the globe can be located exactly by specifying its latitude and longitude.
How can you detect time?
Time zones are another arbitrary societal choice, like the origin point of the Prime Meridian. They are based on longitude and defined by Earth’s rotation, which completes a full circle (360 degrees) each day (24 hours). Each hour then, Earth rotates through 360/24 = 15° of longitude: the width of one time zone.