Astronomers study the stars. Galileo, (Italian) was the first
astronomer to study the stars through a telescope?
What is a star? – Stars are huge glowing balls of gases
that give out large amounts of light and
heat energy. There are billions of billions of stars in the Universe.
Why can’t we see stars during the day? - We cannot see
the stars during the day because the light they give out is very
faint compared with the light from the Sun.
Why does the Sun look much brighter than the other stars? - The
stars you see at night do not seem very bright because they are
much further away than the Sun. The stars are all around us.
Why do the positions of stars appear to change when you view
them from the Earth? - If you watched the stars all night, they
would seem to move across the sky. This happens because the Earth
is spinning on its axis as it orbits the Sun
Galaxy - What is a galaxy? – A large group of stars is
called a galaxy. The Sun is in a galaxy called the Milky Way. There
are millions of other galaxies, and each of these galaxies contains
millions of stars. All these galaxies make up the Universe.
Constellation – are patterns of stars in the sky. They
were named after ancient gods, heroes and animals. There are over
88 constellations over the whole sky.
Red giants are older stars that have swollen up or puffed outwards
as a fiery mist. They could blow up or fade away depending on the
size it becomes. Red giants are many times more luminous that the
Sun due to their large size.
White Dwarf is a dying star - A star that has burnt off or is
a dying star. It is like the Sun and once it has used up its nuclear
fuel it becomes a white hot dense core that remains.
Supernova or nova is an exploding star which erupts almost overnight.
Novae occur in our Galaxy every year and can be seen with the naked
eye however, a supernova is much more violent and rare.
Pulsar – is what is left after a supernova explosion. What
is left is a very hot ball of matter, spinning at a tremendous
rate. It sends out a beam of light or radio waves like a search
light which appears to pulse on and off.
Falling stars or shooting stars – are not stars they are
tiny space rocks that enter Earth’s atmosphere and burn up
creating amazing streaks of light seen in the night sky. They are
caused by bits of rock called meteoroids and the trail of light
that the burning meteoroid produced is called a meteor. If any
of this meteoroid hits the Earth, the remaining part is called
The distances between stars are so large that they are hard to
imagine. Scientists measure these distances in light years. One
light year is the distance travelled by light in one year.
The nearest star to the Sun is called Proxima Centauri. It is
4.22 light years away. It would take a rocket from Earth over 12,000
years to reach Proxima Centauri.
Light years measure distance. It is the distance that light can
travel in one year.
When you look at stars on a clear, dark
night some appear to twinkle. This happens
because the light from the stars has to
travel through the Earth’s atmosphere.
Air currents bend the light, and make the
Dark Matter – cannot be seen but
scientist know that it is out there.
Comets – are a cluster of dust and ice with a big tail,
often referred to as ‘dirty snowballs that float through
space. They are left over from the formation of stars and planets
from billions of years ago.
yourself on the Universe to see what
to the Universe Quiz page - click