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Astronomy:the science of the stars
The universe is made up of stars, planets, and other matter
scattered throughout space.
The Milky Way is a large spiral galaxy（螺旋星系） measuring about
100,000 light-years across. It is about 14 billion years old and takes 225
million years or so to rotate（旋转） once. Like all spirals, it contains
plenty of gas and dust, from which new stars are formed. The dense
nucleus（核心） is the oldest part and has no gas left for new star.
The Solar system
1.Mercury(水星)
2.Venus(金星)
3.Earth(地球)
4.Mars（火星） 7.Uranus（天王星）
5.Jupiter（木星） 8.Neptune（海王星）
6.Saturn（土星） 9.Pluto（冥王星）
Our solar system is made up of the sun and the objects that orbit it.
These include the nine planets (and probably more than nine) and their
moons, as well as asteroids（小行星）, comets, and meteors（流星）.
The sun is the nearest star to the earth. It is a globe of hot gas, mostly
hydrogen（.氢）, and lies at the center of our solar system. It contains
no solid material.
Stars are large balls of hot gas that produce light and heat through
nuclear reactions. Our Sun is an average yellow star, but seems bright
because it is so close.
Mercury The Roman god of merchants and travellers
Venus The Roman goddess of love
Mars The Roman god of war
Jupiter The king of the Roman gods
Saturn The Roman god of seeds and sowing
Uranus The Greek god of the sky
Neptune The Roman god of the sea
Pluto The Roman god of the dead
Stars are large balls of hot gas that produce light and heat through
nuclear reactions. Our Sun is an average yellow star, but seems
bright because it is so close.
Planets are the largest objects that circle around the stars. They
may be rocky, like the earth, or made mostly of gas and liquid, like
Jupiter. The word planet is Greek for "wanderer." The name comes
from the way planets appear to move against the stars over time. It
is thought that the planets formed at about the same time as the sun.
As the original cloud of gas and dust collapsed to for the sun, some
matter was spun out into a flattened disk. Over several million
years, the dust and gas gathered together to form the planets and
moons. Denser rocks gathered near the sun and lighter gases farther
out.
Our planet, the earth,
is a large ball of rocks
and metals covered with
water and soil. It
belongs to a group of
nine planets that move
around a star called the
sun. It is surrounded by
a blanket of gases called
the atmosphere, has one
moon, and as far as we
know, is the only planet
that supports life.
NASA’s Mars detector（探测器）,Opportunity, succeeded in finding
signs that water once existed on the planet. Opportunity landed on
Mars in January. Scientists now believe that the planet could once
have supported life.“Although we still can’t say that life could have
existed in this environment, it is now certain that there was water on
Mars,” said one of the scientists working on the Mars mission.（任务）
How Life Began on the Earth
Discussion:
1.Life is a mystery to our beings.Scientists study the
origin of life by exploding space. Do you really think
space fights are meaningful? Discuss the advantages
and disadvantages of space flights.
2.Why is the earth the only one of all the planets on
which life can survive? Has life started in other stars
except on the earth?
Read“How Life Began on the Earth”,then answer
the following questions:
1. What’s the main idea of the text?
Main idea: How life begin on the earth
2. How many parts can the text be divided into? What’s the
main idea for each part?
Two parts:
Part1(para1):Water made it possible for life to begin to
develop.
Part2(para2,3,4): The development of living things.
Read Part1 and answer questions:
1.How did water come into being on the earth?
The explosion of the earth produced water vapour,
which turn into water when the earth cooled down.
2.What’s the significance of the presence of water on
the earth?
It allowed the earth to dissolve harmful gases into
oceans and seas.
Read Part2 and answer questions:
1.Why were mammals different from dinosaurs?
Because they produce their young from within their bodies.
2.Fill in the diagram:
Small plants in water
1
3
6
2
4
5
7
8
9
2.shellfish and all sorts of fish 3. Green plants on land
4.insects(on land) 5.amphibian on land in water 6.forests
7.reptiles on land 8. Dinosaurs on land 9.mammals on land
Read“How Life Began on the Earth”,fill in the
diagram of life’s origins and process:
Harmful gases
Insects
Amphibians
Reptiles
Dinosaurs
Mammals including
The human beings
3_____________
1.water
2.land animals
Plants in the seas
Land plants
1. The Big Bang is the term used to describe a huge
explosion that scientists believe happened around 15 billion
years ago, creating our universe. Nobody knows what
caused the Big Bang, since we cannot look back to a time
before it. But just after the event, the universe is believed to
have been a knot of tightly packed particles only about the
size of a pea. Its temperature was ten thousand trillion,
trillion degree Celsius.
Homework:
discussion:
1.Why is the presence of plants important for
the development of life?
2.Is the earth getting warmer each year? If so,
what effects will this have? What’s the “green
house effect,” which some scientists say might
destroy our plant? Will the burning of coal, oil,
and natural gas cause the earth to become a
dead planet like Venus?
Goodbye!