Stars - Science 9

Star

A powerful ball of flaming gases that emit electromagnetic waves in all directions

Blue stars

Hottest stars

Red stars

Least hot/coolest stars

White and yellow stars

Medium temperature stars

Nuclear reaction

Why are stars hot?

The lower the number(magnitude), the brighter the star

Relative brightness of stars

Sirius

A bright star outside the solar system

Sirius

Has a magnitude of -143 of brightness

Sun

Has a magnitude of -26.7

Sun

A yellow medium-sized star

Sun

With surface temperature of 6000K

Sun

Middle-aged star; will continue burning for some 5 billion years more

About 5 billion years more

How long will the sun continue burning for?

Apparent Magnitude

The brightness of the stars when viewed from Earth

Absolute magnitude

The brightness of the stars if they were placed at a standard distance of 31.6 light-years from Earth

White dwarfs

Smallest stars

Supergiants

Largest stars

Nebulae

Stars are continuously being formed/birthed from..

Nebula

Clouds of interstellar material

Nebula

A cloud in space

Nebula

Made of gas and dust (can have stars inside)

Nebula

Most of the ones we see are inside our Milky Way Galaxy

Large, massive, bright nebulae

The hot gas in it emits light

Large, massive, bright nebulae

Emission nebula

Colder, darker nebulae

Dark dust blocking the hot gas behind it

Nebulae

Young stars form in..

Supernova

Massive star explodes

Supernova remnant

Leftovers from an explosion— smaller, less gas

Sun

A yellow dwarf, middle-aged star

Sun

Approximately 4.5 billion years old

Sun

Its core is about 15 million degrees Celsius

Light year

The distance that light travels in one year in a vacuum

10 trillion kilometers

1 light year is equivalent to..

Star clusters

Loose groups of stars that move through space together

Stellar association

Consists of up to a hundred stars spread over hundreds of light years of space

Open cluster of stars

Consists of as many as a thousand stars occupying less than a hundred light years of space

Globular cluster of stars

Densest type of star cluster

Globular cluster of stars

Consists of up to a million stars spread over a space smaller than that of a stellar association

8.6 light years

How far is Sirius from Earth? (LY)

Approximately 400 light years

How far is Antares from Earth? (LY)

Galaxy

A large group of stars

Galaxy

Made of billions to trillions of stars

Spiral, elliptical, irregular

3 types of galaxies

Spiral Galaxies

Have flat disk, spiral arms (like a pinwheel), central bulge and a surrounding halo

Spiral Galaxies

Have lots of gas and dust, younger stars in their arms

Spiral Galaxies

Little gas or dust in their halo and central bulge

Milky Way

A large barred spiral galaxy

It appears as a milky band of light in the sky

It is named the Milky Way because..

Milky Way

Has about 200 billion stars, and has lots of gas and dust

Milky Way

About 100,000 LY wide

250 million years

How long does it take for the sun to revolve around the center of the Milky Way?

Orion Arm

Part of the Milky Way that the Solar System is in

Andromeda

A spiral galaxy that can be seen from the Northern Hemisphere

2.5 million

How many light years away from us is Andromeda?

About 4 billion years

How many years will it take until the Andromeda galaxy collides with the Milky Way?

Elliptical Galaxies

Most common galaxies

Elliptical Galaxies

Can be football-shaped, stretched-out circles, ellipses

Elliptical Galaxies

Contain mostly older stars

Elliptical Galaxies

Not as bright as spiral galaxies, and has very little dust and gas

Elliptical Galaxies

Make up about 60% of all galaxies

Irregular Galaxies

Have no definite shape or structure

Irregular Galaxies

Often messy in appearance, without a bulge or any trace of spiral arms

Irregular Galaxies

Filled with gas and dust and lots of bright young stars

Irregular Galaxies

About 20% of all galaxies

Irregular Galaxies

Large and Small Megallanic Cloud

Star-formation

Collisions of galaxies can trigger bursts of..

There will be change in the shape of the galaxies

When galaxies collide, what can happen to their shapes?

Distances

Individual stars do not collide due to their..

Local Group

Includes the Milky Way, Andromeda, and over 30 other smaller galaxies

Virgo Cluster

Has hundreds to thousands of galaxies

Virgo Cluster

60 million LY away

Virgo Cluster

Closest to the Local Group

Coma Cluster

Made up of thousands of galaxies

Coma Cluster

One of the densest known galactic groupings in the universe

Coma Cluster

Galaxy cluster that spans 20 million light years

Supercluster

Larger grouping of galaxies

Supercluster

Mapped and grouped into long strings

• 300m to a b light years long

Supercluster

100-300M light years wide and 10-30 million light years thick

Laniakea Supercluster

Includes Local Group and Virgo Cluster

Laniakea Supercluster

100,000 times the mass of the Milky Way

“Immense heaven” in Hawaii

Meaning of Laniakea

Earth, Solar System, Orion Arm, Milky Way, Local Group, Laniakea, Universe

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