Comets and Meteoroids
Comets are mountain-size
chunks of ice and dust that orbit the sun.
Meteoroids are small space
rocks that orbit the sun. Sometimes a meteoroid enters Earth’s atmosphere and
burns up. The streak of light made by a burning meteoroid is called a meteor.
Meteoroids that strike Earth’s surface are called meteorites.
Stars
A star is an object in space
that produces its own heat and light. Space is filled with many trillions of
stars. Some stars are 1,000 times the size of our sun. Some stars are as small
as 16 km in diameter. That’s 87,000 times
smaller than our sun’s diameter. Our
sun is an average-size star.
Stars are mostly made of
hydrogen and helium gas. Stars are different colors- blue, white, yellow, red,
and red-orange.
Some stars are brighter than
others. A star’s brightness is described in two ways. One is its actual
brightness. That is the actual amount of light that the star gives off. The
other is how bright the star looks to people on Earth. If two stars have the same
actual brightness but one is farther away, the one that is closer will look
brighter.
Constellations
A constellation is a group of stars that
ancient people thought made patterns in the sky. Many constellations are named
for animals, heroes, or other characters in ancient tales.
The stars in a constellation are really far
apart in space. From Earth the stars look as if they were close together
because they are so far away.
As Earth revolves around the sun,
constellations appear in different parts of the sky in different seasons. Some
constellations rise high in the night sky in one season and disappear below the
horizon in another season.
BYE SCIENTISTS! J
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