The document summarizes key evidence that supports the Big Bang theory of the origin and evolution of the universe: 1) Redshift of light from distant galaxies provides evidence that the universe is expanding from an initial point over 13 billion years ago. 2) The discovery of cosmic microwave background radiation provides remnants of light and thermal energy from shortly after the Big Bang. 3) Abundances of light elements like hydrogen and helium in old stars and gas clouds match ratios predicted from nuclear fusion processes in the early hot universe.

1. 12 HE │ HUMSS │ GAS │ ICT

3. At the end of this lesson, you should be
able to…
Describe the evidences of Big Bang
theory.
Describe the formation of heavier
elements during star formation and
evolution

4. Proposed by the Belgian
Astronomer Georges
LemaȊtre (1894-1966) as the
“primeval atom” theory. In
1922, Russian
Mathematician Aleksandr
Friedmann formulated the
governing equation of the
theory that paved the way
for its recognition as the
“Big Bang” in 1940.

5. According to the Big Bang
Theory, about 13.7 billion
years ago, all matter and
energy in the universe existed
in a compact point called
singularity. Then an
imbalance in the compact
point caused it to expand.
This event is referred to as
the big bang which hurled the
matter and energy in all
directions.

9. Redshift
Presence of microwave radiation
in the universe
Abundances of the light elements
in the universe

10. American astronomer
Edwin Hubble (1889-
1953) proved that, as
observed from the Earth,
the light emitted by the
faraway galaxies shifted
down toward the red end
of the spectrum. This
essentially means that
the galaxies are moving
away from Earth.

11.  Also known as the cosmic microwave
background radiation (CMB), this radiation
is the thermal leftover of the transition
phase that occurred when the hot early
universe cooled enough for the atoms to
combine. The CMB was discovered by Robert
Wilson (1936) and Arno Penzias (1993-1978)
and for which they earned the Nobel Prize in
Physics in 1978. the two scientists observed
a measurable degree of inconsistencies on
the CMB in the different regions in the
universe-an evidence that contradicted the
steady state theory, which stated that
everything in the universe is constant and

12. The actual abundances of hydrogen and
helium deduced from the spectra of the
oldest stars and gas clouds matched with
what were expected from the big bang
reactions. These findings agree with the
hypothesis of the big bang theory.

13. 1.What conditions after the big bang
allowed the formation of chemical
elements?
2.Do you agree with the statement
“We came from stardust”? Explain
your answer based on what you
have learned from this lesson.