Cosmology
                     COSMOLOGY
Introduction
• Cosmology is a branch of astronomy 
that involves the origin and evolution 
of the universe, from the Big Bang to 
today and on into the future. 
• According to NASA, the definition of 
cosmology is "the scientific study of 
the large scale properties of the 
universe as a whole."
Source: www.space.com
Aspect of 
Astronomy
• Cosmologists puzzle over exotic 
concepts like string theory, dark 
matter and dark energy and whether 
there is one universe or many 
(sometimes called the multiverse). 
• While other aspects astronomy deal 
with individual objects and 
phenomena or collections of objects, 
cosmology spans the entire universe 
from birth to death, with a wealth of 
mysteries at every stage. 
Source: www.space.com
History of 
cosmology & 
astronomy
• In the 16th century, Polish scientist 
Nicolaus Copernicus suggested that 
Earth and the other planets in the 
solar system in fact orbited the sun, 
creating a profound shift in the 
understanding of the cosmos. 
• In the late 17th century, Isaac Newton 
calculated how the forces between 
planets — specifically the gravitational 
forces — interacted.
Source: www.space.com
History of 
cosmology & 
astronomy cont.
• The dawn of the 20th century brought 
further insights into comprehending 
the vast universe. Albert Einstein 
proposed the unification of space and 
time in his General Theory of 
Relativity. 
• In the early 1900s, scientists were 
debating whether the Milky Way 
contained the whole universe within 
its span, or whether it was simply one 
of many collections of stars.
Source: www.space.com
General 
Relativity
• Using General Relativity to lay the 
framework, Hubble measured other 
galaxies and determined that they 
were rushing away from the us, 
leading him to conclude that the 
universe was not static but expanding.
Source: www.space.com
Cosmologist 
Stephen Hawking
• In recent decades, cosmologist 
Stephen Hawking determined that the 
universe itself is not infinite but has a 
definite size. However, it lacks a 
definite boundary.
Source: www.space.com
Cosmological 
missions
• Launched in November 1989, NASA's 
Cosmic Background Explorer (COBE) 
took precise measurements of 
radiation across the sky. The mission 
operated until 1993.
Source: www.space.com
Cosmological 
missions cont.
• Although NASA's Hubble Space 
Telescope is probably best known for 
its astounding images, a primary 
mission was cosmological. 
• By more accurately measuring the 
distances to Cepheid variables, stars 
with a well-defined ratio between their 
brightness and their pulsations, 
Hubble helped to refine 
measurements regarding how the 
universe is expanding.
Source: www.space.com
Cosmological 
Instruments
• NASA's Wilkinson Microwave 
Anisotropy Probe (WMAP) was a 
spacecraft that operated from 2001 to 
2010. 
• WMAP mapped tiny fluctuations in the 
cosmic microwave background (CMB), 
the ancient light from the early 
universe, and determined that 
ordinary atoms make up only 4.6 
percent of the universe, while dark 
matter makes up 24 percent.
Source: www.space.com
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