The Age of the universe is argueably mankind's greatest discovery of the 20th century.
Astronomers say the age of the universe is between 12-20 billion years old, and
scientists at NASA say the age of the universe is 13.7 billion years old .As if that's not
already hard to comprehend the universe is expanding! Now your probably wondering
how does one calculate the age of the universe and how do we know the universe is
expanding. Well hopefully this ISP has the answers you are looking for. So lets take it
In 1915, Albert Einstein developed the General Theory of Relativity, which explained
how gravity works. When Einstein figured his theory must apply to the whole
universe aswell, he realized that all of space should be either contracting or expanding.
Although Einstein refused to believe his own theory like all astronomers for thousands of
years before him he had assumed that the size of the universe was not changing.
Meanwhile, on another continent, Vesto Slipher, an astronomer at the Lowell
Observatory in Flagstaff , Arizona, was finishing a detailed study of the night sky. He
examined several of the faint, fuzzy nebulae that he saw in his telescope. He carefully
measured the nebulae's spectra (the amount of light they emitted at different
wavelengths). He found that the spectra of nearly all of them were redshifted , their light
was redder than it should have been. Slipher knew that when an object's light was
redshifted , it was moving away from Earth, and that the object's speed was proportional
to the redshift. He calculated the nebulae's speeds, and found they were all moving away
from us incredibly quickly one, the Sombrero Nebula, moved away at 2.5 million miles
per hour. To perhaps explain redshifting better allow me to give you an example. You
are standing on a sidewalk with you eyes closed, and you hear the sound of a car's
engine gettin...