Celestial Bodies Grade 9 Science

Earth Our home

Sometimes we see it in a different way…

Like at night!

The Moon

This is still the moon…can you guess what is hiding behind it?

A Moon Halo These happen quite often. Look for them when there are lots of high, but thin clouds in the sky Can you see another celestial body in the picture?

The Other Planets

Mercury Small, hot and very close to the Sun

Looks much like our Moon

It is quite easy to see Mercury. Notice the path it follows

Venus ‘Sister’ to the Earth.

Venus is also visible from Earth.

Mars The Red Planet…except it doesn’t really look red

The Mcmurdo pan on Mars. It doesn’t look too much different from parts of Earth

Here you can see the path that Mars follows as viewed from Earth

Jupiter The Failed Star with the Great Red Spot

The rings of Jupiter. Barely visible as they reflect little light

Although much larger, Jupiter is less visible than Venus Jupiter Venus

Saturn The ringed planet

Uranus…

…also has rings. It’s also tilted (compared to the other planets), it flies through space on its side.

Neptune The Great Dark Spot

The Dwarf Planets Ceres Found between Mars and Jupiter Pluto Found past Neptune Eris The largest Dwarf Planet and even further from the Sun than Pluto

Other bodies in our Solar System

Asteroids Asteroids come in all shapes and sizes. Most are found in the Asteroid Belt, between Mars and Jupiter They can be as small as a pebble and as large as 1000 km across

Most are made of silicate (stone), but some are made of iron or nickel.

Meteors (or Shooting Stars) Each streak is a piece of rock or dust burning up as it enters our atmosphere. The rock is a meteoroid. They are travelling between 10 and 70 kilometres per second.

Some are larger though. If it’s too large and hits…

…we have a meteorite But if they’re even bigger…

This can happen! This crater in Arizona is 1200 m wide, 200 m deep and was made by a meteorite about 40 m wide.

Comets Big Dirty Snowballs

Comets actually have two tails. The dust tail (yellow) and the ion tail (blue)

The Sun The Sun provides our world with the warmth and light needed to survive. Our Sun is an average sized, middle age (4.5 billion years old) star

Features of the Sun Sun spots They may appear dark, but they are actually brighter than a full moon They can also cause…

Solar flares and Coronal Mass Ejections This is a CME. The Sun throws out particles. If they hit the Earth they can cause blackouts, fry satellites and kill astronauts in space.

The Solar System And if we put it all together we have…

This is a picture (a model) of the solar system. It is NOT to scale.

These are the true scales. The rocky planets.

The Gas Giants

Everything

Stars

Most of these points of light are stars. Each star may have a solar system just like ours.

Types of stars. Red Giants Large red stars (up to 10 times larger than our Sun). Red super-giants can be even larger.

White Dwarfs Small, dim stars. They are about the size of Earth and about half the mass of the Sun

Neutron stars Very small (about km across). About 1.5 times heavier than the Sun The rotate very quickly – up to 700 times a second.

Binary stars Two stars (one usually much smaller than the other) orbit one another This is Sirius, the brightest ‘star’ in our night sky

Usually the smaller star in a binary system pulls mass from the larger star because its gravitational pull is much larger

Super nova They’re big…

…very big!

So big and bright we can see them on Earth This is a scene from the Bayeux tapestry. A supernova has been drawn in the upper right corner. The Chinese also recorded seeing it around the same time.

Nebula – the birthplace of stars Some supernova produce

Nebulae can produce amazing colours and shapes This is the Horsehead nebula.

The Cone nebula

The Veil nebula

Galaxies

There are 3 main types of Galaxies SpiralEllipticalIrregular

Our Galaxy, the Milky Way, is a Barred Spiral Galaxy However this is only a theory of what it looks like. We have never left the Milky Way in order to see what it really looks like. We live about here.

We can only see part of our galaxy…

More Spiral Galaxies 20 to 100 billion stars 50 to light years across

More Elliptical Galaxies

Irregular Galaxies Here you can see two galaxies nearing one another and how one pulls matter away from the other.

Galaxies form clusters

Constellations From the Earth we see all these stars and galaxies and see patterns, which we call

Orion the Hunter

The Universe And if you put EVERYTHING together,you have…