Page 18 - Geography for Secondary Schools Student’s Book Form One

Geography for Secondary Schools
Student’s Book Form One

heat cannot be generated due to the collision therefore, they could potentially have at
of cold particles of primordial matter as least the same age. However, but this has not
claimed by Kant. Also, mutual collision been the case. In fact, current astronomical
of particles cannot generate motion in the researchers have found that while other
primordial matter. Moreover, the random galaxies are very old, there are many young
motion of the particles cannot generate galaxies around and far from the Earth.
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circular motion in the primordial matter.
On top of that angular velocity of rotary Inter-Stellar dust hypothesis
speed of the nebular cannot increase due to In 1943, a Russian scientist Otto Schmidt
increase in size of the nebular as assumed proposed a theory known as Inter-Stellar
by Kant. dust hypothesis. The theory explains

Big Bang theory the complex problems of the origin and

This theory was proposed by Lemaitre characteristics of the solar system and the
Georges and Edwin Hubble in the 1920s. Earth. According to the Inter-Stellar dust
The Big Bang theory explains that about 15 hypothesis, the Sun, during its ‘galactic
billion years ago, a great explosion occurred. revolution, captured the dark matter of the
This explosion caused the expansion of universe. The dark matter (Inter-Stellar
universe expand. This explosion is known dusts) of gaseous cloud and dust particles
as the big bang. At the time of this event, all had their own angular momentum. The
matter and energy in space were contained in dark matter after being attracted by the
one point. The explosion pushed matter and sun during its ‘galactic revolution’ started
energy outward expanding in all directions, revolving around the primitive rotating sun.
forming a collection of dust, gas, and stars The intense heat from the sun dispersed
held together by gravitational attraction. the gaseous particles towards the margins
Later, the sun, gas, and dust collided and of the disk. Collision among the dust
aggregated into small grains, eventually particles started the process of aggregation
forming larger bodies called planetesimals and accretion around the bigger particles
(very small planets). which became the essentials of the future
Some of these small planets reached planets. With the passage of time, these
diameters of several hundred kilometres, embryos captured more and more matter
and later formed the current eight
planets (Mercury, Venus, Earth, Mars, and grew in size to become asteroids.
Jupiter, Saturn, Uranus, and Neptune) Furthermore, these asteroids grew in size
and their satellites. However, scientists due to continuous acceleration of nearby
and institutions such as NASA (National matter around them; thus, they became
Aeronautics and Space Administration) planets. The hypothesis has been criticised
are still investigating to find out if there is that gravitational force of the primitive sun
existence of other planets in the outer space. was incapable of capturing dark matter
The critique of the theory is that it appears scattered in the universe. The second
all galaxies emerged at the same time; critique of this hypothesis is that some

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