Space
and the Earth
By Mary Beth Lott
How
far away is space?
Not very
far. Space begins when Earth’s air ends-
about 480 km above Earth’s surface.
That’s where the lighter molecules in air escape Earth’s gravity and
drift into space. This region, however,
is much higher than we could travel by plane.
It is about forty times higher than a jet can fly.
Where
is Earth in space?
People used
to think Earth was the center of the universe.
Today we know that Earth is just one of the nine planets that circle our
Sun. Our galaxy, the Milky Way, has
billions of stars, and our Sun is just one of those stars. There are billions of galaxies in our
universe.
What’s
so special about Earth?
Earth is the
only planet where we know there is life.
The Earth is exactly the right distance from the Sun to have the right
temperature for water to be kept in its three forms- liquid, ice, and
vapor. The Earth’s atmosphere gives us
oxygen to breathe, protects us from the Sun’s harmful rays, and keeps our
planet warm. The placement of the Sun
and Moon enable us to tell time on Earth.
“The Sun,
Moon, and…planets were made for determining and preserving the numbers of
time.” Plato, Timaeus
Fun
Fact: Some stars get “married.” Some stars are drawn together by gravity and
spend their lives together. About half
of the stars in the sky are part of a pair of stars or group of stars.
“We had the sky, up there, all
speckled with stars, and we used to lay on our backs and look up at them, and
discuss about whether they was made, or only just happened- Jim allowed they
was made, but I allowed they happened….”
Mark Twain, Huckleberry Finn
Comprehension Questions
1. How far away is space?
2. How many galaxies are in our
universe?
3. What are the three forms of water?
4.
The Sun’s atmosphere protects us and keeps us warm. True or False?
5.
Stars are drawn together by ____________.
Deeper Thought Questions
1. Some scientists describe the earth
as just a bit of dust in an obscure galaxy.
Does the earth have special significance?
2. Huckleberry Finn thought that the
stars “just happened.” In other words,
he did not believe that anyone or anything had made the stars. Jim thought that the stars had been made. Which do you believe?
Something to do:
1. Pretend you are Huckleberry
Finn. Go outside, and look up at the
stars. Think about how they were made.
2. Try to guess the time by the
position of the sun. Think about the
dependability of our universe. The sun
rises every morning at a predictable time.
Why is that so?
Answers to Comprehension
Questions: 1. 480 km above the Earth’s
surface 2. billions 3. liquid, ice,
vapor 4. False. The Earth’s atmosphere
protects us from the Sun and keeps us warm.
5. gravity
Glossary
molecule- the smallest unit into
which a substance can be divided without changing its chemical nature
gravity- the force that pulls objects
towards the Earth
drift-a slow movement towards
something
region- a large area
universe- all of space and everything
in space
galaxy-a collection of millions and
millions of stars
billion-1,000,000,000
liquid- a substance that is not solid
or gas and that can flow and be poured
vapor- a mass of very small drops of
liquid in the air; for example, steam
preserve- to keep something safe or
in good condition
speckled- having many, many small
dots of color, light, etc.
Reference: Davis, Kenneth C. 2001. Don’t Know Much about Space, HarperCollinsPublishers