ASTRONOMYASTRONOMY

Where are we in the universe?

Where are we in the universe?

We live on Earth, the third planet of our

solar system.

We live on Earth, the third planet of our

solar system.

Our solar system is located in the Milky Way Galaxy, a

collection of 200 billion stars (together with their

solar systems).

Our solar system is located in the Milky Way Galaxy, a

collection of 200 billion stars (together with their

solar systems).

SPIRAL GALAXIES

SPIRAL GALAXIES

Spiral galaxies are galaxies with a central,

dense area and spiraling arms (which are often

sites of star formation).

Spiral galaxies are galaxies with a central,

dense area and spiraling arms (which are often

sites of star formation).

There are two types of spiral galaxies, "S" (normal

spiral) and the less common "SB" (barred

spiral, with an elongated center).

There are two types of spiral galaxies, "S" (normal

spiral) and the less common "SB" (barred

spiral, with an elongated center).

Normal SpiralNormal Spiral

Barred Spiral, with an elongated center

Barred Spiral, with an elongated center

Our Solar System

Our Solar System

Our solar system consists of the sun, planets, dwarf planets (or plutoids), moons, an asteroid

belt, comets, meteors, and other objects. The sun is the center of our solar system; the planets, over 61 moons, the asteroids, comets, meteoroids and other

rocks and gas all orbit the Sun.

Our solar system consists of the sun, planets, dwarf planets (or plutoids), moons, an asteroid

belt, comets, meteors, and other objects. The sun is the center of our solar system; the planets, over 61 moons, the asteroids, comets, meteoroids and other

rocks and gas all orbit the Sun.

The PlanetsThe Planets

The nine planets that orbit the sun are (in order from the

Sun): Mercury, Venus, Earth, Mars, Jupiter (the biggest

planet in our Solar System), Saturn (with large, orbiting

rings), Uranus, Neptune, and Pluto (a dwarf planet or

plutoid).

The nine planets that orbit the sun are (in order from the

Sun): Mercury, Venus, Earth, Mars, Jupiter (the biggest

planet in our Solar System), Saturn (with large, orbiting

rings), Uranus, Neptune, and Pluto (a dwarf planet or

plutoid).

A belt of asteroids (minor planets made of rock and metal) orbits

between Mars and Jupiter. These objects all orbit the sun in

roughly circular orbits that lie in the same plane, the ecliptic

(Pluto is an exception; this dwarf planet has an elliptical orbit tilted

over 17° from the ecliptic).

A belt of asteroids (minor planets made of rock and metal) orbits

between Mars and Jupiter. These objects all orbit the sun in

roughly circular orbits that lie in the same plane, the ecliptic

(Pluto is an exception; this dwarf planet has an elliptical orbit tilted

over 17° from the ecliptic).

The inner planets (those planets that orbit close to

the Sun) are quite different from the outer planets

(those planets that orbit far from the Sun).

The inner planets (those planets that orbit close to

the Sun) are quite different from the outer planets

(those planets that orbit far from the Sun).

The inner planets are: Mercury, Venus, Earth, and

Mars. They are relatively small, composed mostly of

rock, and have few or no moons.

The inner planets are: Mercury, Venus, Earth, and

Mars. They are relatively small, composed mostly of

rock, and have few or no moons.

The outer planets include: Jupiter, Saturn, Uranus, and

Neptune. They are mostly huge, mostly gaseous, ringed, and have many moons (plus

Pluto, which is a dwarf planet that has one large moon and

two small moons).

The outer planets include: Jupiter, Saturn, Uranus, and

Neptune. They are mostly huge, mostly gaseous, ringed, and have many moons (plus

Pluto, which is a dwarf planet that has one large moon and

two small moons).

Small BodiesSmall Bodies

There are other smaller object that orbit the Sun,

including asteroids, comets, meteoroids and dwarf

planets.

There are other smaller object that orbit the Sun,

including asteroids, comets, meteoroids and dwarf

planets.

Asteroids (also called minor planets) are rocky or metallic objects, most of which orbit the Sun in the asteroid belt between Mars and Jupiter.

Asteroids (also called minor planets) are rocky or metallic objects, most of which orbit the Sun in the asteroid belt between Mars and Jupiter.

Comets are small, icy bodies that orbit the sun. They have

very long tails.

Comets are small, icy bodies that orbit the sun. They have

very long tails.

Meteoroids are small bodies that travel through space.

They are stony and/or metallic and are smaller than asteroids. Most are very tiny.

Meteoroids are small bodies that travel through space.

They are stony and/or metallic and are smaller than asteroids. Most are very tiny.

The Sun The Sun

Our sun is a star located at the center of our Solar System. It is a huge,

spinning ball of hot gas and nuclear reactions that lights up the Earth and provides us

with heat

Our sun is a star located at the center of our Solar System. It is a huge,

spinning ball of hot gas and nuclear reactions that lights up the Earth and provides us

with heat

HOW FAR AWAY IS THE SUN?

HOW FAR AWAY IS THE SUN?

Our sun is a medium-sized yellow star that is 93,026,724

miles (149,680,000 km or 1 Astronomical Unit) from the

Earth.

Our sun is a medium-sized yellow star that is 93,026,724

miles (149,680,000 km or 1 Astronomical Unit) from the

Earth.

THE TEMPERATURE OF THE SUN

THE TEMPERATURE OF THE SUN

The Sun's core can reach 10 to 22.5 million°F. The surface temperature is approximately 9,900°F (5,500°C). The

outer atmosphere of the Sun (which we can see during a solar eclipse) gets

extremely hot again, up to 1.5 to 2 million degrees. At the center of big sunspots the

temperature can be as low as 7300 °F (4300 K, 4000 °C). The temperature of the

Sun is determined by measuring how much energy (both heat and light) it

emits.

The Sun's core can reach 10 to 22.5 million°F. The surface temperature is approximately 9,900°F (5,500°C). The

outer atmosphere of the Sun (which we can see during a solar eclipse) gets

extremely hot again, up to 1.5 to 2 million degrees. At the center of big sunspots the

temperature can be as low as 7300 °F (4300 K, 4000 °C). The temperature of the

Sun is determined by measuring how much energy (both heat and light) it

emits.

AGE OF THE SUNAGE OF THE SUN

The Sun formed 4.5 billion years ago, as the solar

system coalesced from a cloud of gas and dust.

The Sun formed 4.5 billion years ago, as the solar

system coalesced from a cloud of gas and dust.

STUDYING THE SUNSTUDYING THE SUN

Astronomers study the Sun using special instruments. Scientists

analyze how and why the amount of light from the Sun varies over time, the effect of the Sun's light on the Earth's climate, spectral lines, the

Sun's magnetic field, the solar wind, and many other solar phenomena. The outer regions of the Sun (the corona) are studied during solar

eclipses.

Astronomers study the Sun using special instruments. Scientists

analyze how and why the amount of light from the Sun varies over time, the effect of the Sun's light on the Earth's climate, spectral lines, the

Sun's magnetic field, the solar wind, and many other solar phenomena. The outer regions of the Sun (the corona) are studied during solar

eclipses.

STARSSTARS

Each star in the sky is an enormous glowing

ball of gas. Our sun is a medium-sized star.

Each star in the sky is an enormous glowing

ball of gas. Our sun is a medium-sized star.

Stars can live for billions of years.Stars can live for billions of years.

A star is born when an enormous cloud of hydrogen gas collapses until it is hot enough to

burn nuclear fuel (producing tremendous amounts heat and radiation). As the nuclear fuel

runs out (in about 5 billion years), the star expands and the core contracts, becoming a

giant star which eventually explodes and turns into a dim, cool object (a black dwarf, neutron

star, or black hole, depending on its initial mass). The largest stars have the shortest life

span (still billions of years); more massive stars burn hotter and faster than their smaller

counterparts (like the Sun).

A star is born when an enormous cloud of hydrogen gas collapses until it is hot enough to

burn nuclear fuel (producing tremendous amounts heat and radiation). As the nuclear fuel

runs out (in about 5 billion years), the star expands and the core contracts, becoming a

giant star which eventually explodes and turns into a dim, cool object (a black dwarf, neutron

star, or black hole, depending on its initial mass). The largest stars have the shortest life

span (still billions of years); more massive stars burn hotter and faster than their smaller

counterparts (like the Sun).

There are larger groups of stars, called clusters.There are larger groups of stars, called clusters.

WHY ARE STARS HOT AND BRIGHT?

WHY ARE STARS HOT AND BRIGHT?

Nuclear Fusion and Nucleosynthesis

Nuclear Fusion and Nucleosynthesis

Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by

tremendous atomic collisions that alter the atomic structure and release an enormous

amount of energy. This makes stars hot and bright. In most stars, the primary reaction

converts hydrogen atoms into helium atoms, releasing an enormous amount of energy.

This reaction is called nuclear fusion because it fused the nuclei (center) of atoms

together, forming a new nucleus. The process of forming a new nucleus (and

element) is nucleosynthesis.

Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by

tremendous atomic collisions that alter the atomic structure and release an enormous

amount of energy. This makes stars hot and bright. In most stars, the primary reaction

converts hydrogen atoms into helium atoms, releasing an enormous amount of energy.

This reaction is called nuclear fusion because it fused the nuclei (center) of atoms

together, forming a new nucleus. The process of forming a new nucleus (and

element) is nucleosynthesis.

WHAT IS THE CLOSEST STAR?

WHAT IS THE CLOSEST STAR?

The closest star to us is the sun! Other than that, the closest star is Proxima Centauri, aka Alpha Centauri C (the dimmest star in

the Alpha Centauri system). Proxima Centauri is 4.3 light-years from the Sun. It has an absolute magnitude of 15.5.

The closest star to us is the sun! Other than that, the closest star is Proxima Centauri, aka Alpha Centauri C (the dimmest star in

the Alpha Centauri system). Proxima Centauri is 4.3 light-years from the Sun. It has an absolute magnitude of 15.5.

WHY DO STARS TWINKLE?WHY DO STARS TWINKLE?

The scientific name for the twinkling of stars is stellar

scintillation (or astronomical scintillation). Stars twinkle when

we see them from the Earth's surface because we are viewing

them through thick layers of turbulent (moving) air in the

Earth's atmosphere.

The scientific name for the twinkling of stars is stellar

scintillation (or astronomical scintillation). Stars twinkle when

we see them from the Earth's surface because we are viewing

them through thick layers of turbulent (moving) air in the

Earth's atmosphere.

What is Astronomy?

What is Astronomy?

That's easy.  Astronomy is the study of Outer

Space.

That's easy.  Astronomy is the study of Outer

Space.

Why should we study Outer Space? 

Why should we study Outer Space? 

We study Outer Space because we are part

of it.  That's right.  You are part of outer

space, everything is.

We study Outer Space because we are part

of it.  That's right.  You are part of outer

space, everything is.

THAT’S ALL THANK YOU!THAT’S ALL

THANK YOU!