NST1502
ASSIGNMENT 3
QUESTION 1
Define the following terms:
1.1Planet
The definition of planet has changed several times since the word was
coined by the ancient Greeks. Greek astronomers employed the term ἀστέρες
πλανῆται (asteres planetai), 'wandering stars', for star-like objects which
apparently moved over the sky. Over the millennia, the term has included a
variety of different celestial bodies, from the Sun and the Moon to satellites
and asteroids.
1.2Oort cloud
The Oort Cloud is a predicted collection of icy objects farther away than
everything else in the solar system. It fits with observations of comets in the
planetary region of the solar system, but scientists have yet to observe any
object in the Oort Cloud itself.
1.3Solar system
Solar system: A set that includes a star and all of the matter that orbits it,
including planets, moons, asteroids, comets, and other objects. Solar wind:
The constant stream of particles and energy emitted by the sun. Space
weather: The conditions in space that can affect Earth, satellites, and space
travel.
1.4Galaxy
A galaxy is a huge collection of gas, dust, and billions of stars and their solar
systems, all held together by gravity. We live on a planet called Earth that is
part of our solar system.
1.5The moon
the large round object that circles the Earth and that shines at night by
reflecting light from the sun.
1.6Atmosphere
the envelope of gases surrounding the earth or another planet. "part of the
sun's energy is absorbed by the earth's atmosphere"
1.7Earth
, Earth is a terrestrial or inner planet consisting of a thin outer crust, an
intermediate mantle, and a dense inner core. It has an atmosphere composed
primarily of nitrogen and oxygen and is the only planet on which water in liquid
form exists, covering more than 70 percent of its surface.
1.8Lithosphere
The lithosphere is the solid, outer part of Earth. The lithosphere includes the
brittle upper portion of the mantle and the crust, the outermost layers of
Earth's structure. It is bounded by the atmosphere above and the
thermosphere (another part of the upper mantle) below.
1.9A star
a natural luminous body visible in the sky especially at night. : a self-luminous
gaseous spheroidal celestial body of great mass which produces energy by
means of nuclear fusion reactions.
1.10 Universe
The universe is everything. It includes all of space, and all the matter and
energy that space contains. It even includes time itself and, of course, it
includes you. Earth and the Moon are part of the universe, as are the other
planets and their many dozens of moons.
QUESTION 2
2.1 Differentiate between revolution and rotation. (2)
1. Rotation is the movement of an object on its own axis. On the other hand,
revolution is the complete round trip around something, i.e. another object or
center.
2. Rotation is when the object spins around an internal axis. Conversely,
revolution is when the object travels around an external axis.
2.2 When considering revolution and rotation, which one creates day
and night, and which one creates the seasons? (2)
Rotation creates day and night.
Revolution creates the seasons.
2.3 Use the difference mentioned in 2.1 above to outline the effects of
revolution and those of the rotation. (2) Rotation:
• The rotation of the earth causes day and night.