An Astronomical Tour

Objects in the Universe

Objects in our Solar System

A solar system is a collection of objects that are gravitationally associated with a star

Objects in our solar system include star, planets, moons, asteroids, comets, meteors

Active Sun viewed in X-rays ->

<- Coronal loops

Planets Objects that orbits (revolve around) a

star Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune (Pluto is a minor planet) My very excellent mother just served us

nachos

Mercury

Venus (UV)

Earth

Earth’s Moon

Earth and its Moon

Earth and its Moon

Mars

Jupiter and the four Galilean Moons

Saturn and Its Larger Moons

Uranus (true and false color)

Neptune

Pluto and Charon (from HST faint object camera)

Our Solar System

The Planets (in size perspective)

Asteroids (Phobos, Deimos, Gaspra)

Asteroid Belt

Between the orbits of Mars and Jupiter is a large “belt” of asteroids

There are also groups of asteroids that orbit the Sun and cross the orbit of the Earth from time to time.

Comets and the Oort Cloud

Comets are “dirty snowballs” composed of frozen water and dust. As they approach the Sun they melt and leave a stream of water vapor and dust that is a “tail”

Scientists believe that these originate from a large region filled with comet cores called the Oort cloud.

Comet Halley (March 1986)

Moving Out…

Our solar system is a small part of a large collection of stars, gas, and dust called a galaxy.

Our galaxy is called the Milky Way galaxy and is a spiral galaxy.

Galaxies

HST Deep Field Photo of Galaxies

Star Deaths

When stars finish their life cycle they may explode or throw out shells of gas. Such an object is referred to as a nebula (pl. nebulae)

Nebulae are common objects in a galaxy.

Eskimo Nebula

Orion Nebula

Carina Nebula

Cat’s Eye Nebula

Sting Ray Nebula

(young)

Bug Nebula

Section of the Eagle Nebula

Other Objects…

There are special classes of stars called variable stars, neutron stars, pulsars and black holes. These may be stars in the process of evolving or the result of a star explosion.