What makes up the Universe?

• Subatomic particles• Atoms• Planets and planetoids• Planetary systems• Stars and star systems• Nebulas• Galaxies• Cluster• Supercluster

Galaxies are collections of stars with a common gravitational center.

Andromeda and the Milky Way by Hubble Space Telescope. www.nasa.gov

What is a galaxy?

There are 4 kinds of galaxies:

• Spiral• Barred spiral• Elliptical• Irregular

Perseus cluster of galaxies. scienceblogs.com

Spiral galaxy – central bulge of old stars with arms of young stars

Colliding spiral galaxies in Arp 274. apod.nasa.gov

Barred spiral galaxy – central rod of old stars with arms of young stars

Hubble observes NGC 1073. www.nasa.gov

Barred spiral galaxy – central rod of old stars with arms of young stars

Elliptical galaxy – spherical cluster of mostly old stars

Odd galaxy couple on space voyage. www.nasa.gov

Elliptical galaxy – spherical cluster of mostly old stars

Irregular galaxy – no recognizable shape

Starburst in a dwarf irregular galaxy. apod.nasa.gov

Irregular galaxy – no recognizable shape

Nebulas are clouds of gas and dust. They are the birthplace of stars and galaxies.

Pillar and jets. www.nasa.gov

What is a nebula?

There are 4 kinds of nebulas:

• Emission• Reflection• Dark• Planetary

Hubble’s lagoon. apod.nasa.gov

Emission nebulaEmission nebula – produces its own lightA beautiful Trifid. apod.nasa.gov

Reflection nebula

Reflecting Merope. apod.nasa.gov

Reflection nebula – reflects the light of neighboring stars

Dark nebula – blocks the light of stars behind it

Hubble observes the popular Horsehead nebula. www.spacetelescope.org

Planetary nebula – clouds of star material exhaled by a dying star

Hubble observes glowing, fiery shells of gas. www.nasa.gov

• Balls of hot gasses

• Produce own light through nuclear fusion

Andromeda and the Milky Way by Hubble Space Telescope. www.nasa.gov

What is a star?

There are 7 Star types:

• Oh• Boy• A• Failing• Grade• Kills• Me

Perseus cluster of galaxies. scienceblogs.com

Hot

Cold

Young

Old

Blue

Red

Small

Large

www.cmso.info.

The Solar System is the star system which has Sol for its center.

What is the Solar System?

The Milky Way. popchassid.com

Where is our Solar System?

Parts of the Solar System

• Sol• Inner planets• Asteroid belt• Outer planets• Kuiper Belt• Oort Cloud

The Solar System. solarsystem.nasa.gov

Solar sytsem. spaceplace.nasa.gov

Inner planets – Rocky planets (Mercury, Venus, Earth, Mars)

• Thin atmosphere• Thick, rocky layers• Metallic cores

The Inner Planets. www.astronomy.ie

Outer planets – Gas giants (Jupiter, Saturn, Uranus)

• Thick atmosphere• Thin rocky layers• Small metallic cores

The Outer Planets. www.astronomy.ie

The Solar System. www.astronomy.ie

How do planets move?

• Axial tilt• Rotation• Revolution

Axial tilt. en.wikipedia.org

Rotating Earth. superiorplatform.com

Revolving planet. oncirculation.com

Solar System in motion. myweb.rollins.edu

A planetoid is a rocky body orbiting the Sun. It is smaller than a planet.

Planetoids are also known as asteroids.

What is a planetoid?

Asteroid belt – region filled with rocky bodies orbiting the Sun

The asteroid belt. www.jpl.nasa.gov

Kuiper belt – outer region of planetoids orbiting the Sun (includes Pluto)

The Kuiper Belt. heasarc.nasa.gov

Oort Cloud – outermost group of planetoids forming a “shell” around the Sun

The Oort Cloud. spaceplace.nasa.gov

What are comets?

Orbit of a comet. www.nasa.gov

Comets. spaceplace.nasa.gov

Comets. neo.ssa.esa.int