2. ▪ The Universe or cosmos contains all galaxies, stars, and planets.
▪ Our Solar System is located in the MilkyWay galaxy, which is one of many
galaxies in the Universe.
▪ So far there are 51 galaxy that has been discovered but there are an
estimated number of about 100 to 200 billion in all.
▪ Astronomers stated that there are at least one hundred billion galaxies in
the observable universe.They’ve counted the galaxies in a particular region,
and multiplied this up to estimate the number for the whole universe.
▪ Optical telescopes have been used for astronomical observation since the
time of Galileo, but the technology has moved on significantly since then.
▪ Cosmology is the branch of science that studies the origin, evolution and
fate of the universe.
3. Theories behind the Origin of the Universe
▪ The Big BangTheory - is the leading explanation about how the
universe began. In this theory, energy and matter divided and
became distinct from each other. After the massive explosion,
dust and portion of the condensed matter and energy spread out.
At its simplest, it talks about the universe as we know it starting
with a small singularity, then inflating over the next 13.8 billion
years to the cosmos that we know today.
- It is coined from Sir Fred Hoyle, in a talk last March 1949 BBC
Radio Broadcast. It was started byVesto Slipher, and was
developed along the way by Alexander Friedmann,Albert
Einstein and many more.
5. Theories behind the origin of the Universe
▪ Steady State – It states that the universe has been present ever
since and therefore has no beginning and no end. According to
this theory, the density of matter in the expanding universe
remains unchanged due to a continuous creation of matter. It was
spearheaded by Sir Fred Hoyle.
Continuation:
6. Theories behind the origin of the Universe
▪ Pulsating Universe – it combines both the Big Bang and the
Big Crunch as a part of a cyclic event.This theory, which is
more commonly known as the oscillating or cyclic universe
theory, that postulates that the universe goes through regular
cycles of expansion and destruction.The Big Crunch states
that at a certain point in time, it will stop expanding and
collapse into itself, pulling everything with it until it eventually
turns into the biggest black hole ever. It is also one of the
scenarios predicted by scientists in which the Universe may
end.
Continuation:
9. What is the Solar System?
It includes: the satellites of the planets;
numerous comets, asteroids, and meteoroids; and the
interplanetary medium.
10. What are the theories on the origin of the solar system?
Theory ofVortices - postulated that the space was entirely filled
with matter in various states, whirling about the sun like a vortex.
Rene Descartes - He invented this theory in the mid 1600’s, He
explained that once the particles in the universe began to move,
the overall motion would have been circular because there is no
void in nature.Whenever a single particle moves, another particle
must also move to occupy the space where the previous particle
once was.This type of circular motion (vortex) would have created
the orbits of the planets about the sun with heavier objects
spinning towards the outside of the vortex and lighter objects
remaining closer to the center.
11.
12. 2. Nebular Hypothesis – in this theory, thin, dim clouds of dust and
gas out in the cosmos would collapse in on themselves under the
force of gravity.The nebular hypothesis is the most widely
accepted model in the field of cosmogony to explain the formation
and evolution of the Solar System. Immanuel Kant – He postulated
the nebular hypothesis using Newton’s idea of gravity. From this
spinning disk, stars and planets would form, and from this type of
formation, the rotation of earth and the other planets would be
explained.
13.
14. 3. Laplace’s NebularTheory - It is a theory that states a slowly
rotating nebula ( a cloud of vast gas and dust ) collapsed under
gravity forming an oblate spheroid due to the increase in it’s spin
rate. Pierre Simon Laplace – a French mathematician, He
proposed this idea in the year of 1700.
15. 4. Leclerc-Buffon Idea - Georger-Louis Leclerc and Comte de
Buffon conceived the idea that a comet collided with the Sun
sending matter off to form the planets
16. 5. Chemical Composition Analysis – It was Harold Urey who
initially studied the meteorites and their chemical analysis. He
concluded that meteorites contain matter that had changed very
little in the early history of the solar system.This set a new trend in
understanding the solar system whose origin can be based on its
chemical composition.
17. 6. Solar Nebular Disk Model (SNDM) –Developed by Soviet
astronomer Victor Safronov. According to this model, our star
system was formed 4.568 billion years ago when a small part of a
giant molecular cloud experienced a gravitational collapse. Most of
the collapsing mass collected in the center forming the Sun while
the rest flattened into a protoplanetary disk, out of which the
planets, moons, asteroids, and other small solar system bodies
formed.
