Components of the Universe Lesson 3

Universe All of the things that exist in space

Galaxy One of the very large groups of planets and stars in the universe

Star A huge ball of very hot gases in space

Constellation A group of stars that form a shape or pattern

Sun The only star in our solar system

made up of one star and all the planets and other objects that revolve around that star Solar System Solar – “of the sun”

Planet A heavenly body that revolves around a star

satellite A celestial body that orbits another larger body

Asteroids and Comets Both asteroids and comets orbit the sun. Asteroid – a chunk of rock (less than 1000 km in diameter) Comet – a mass of frozen gas, cosmic dust, and ice crystals; – a bright heavenly body with a long tail of light; – large dirty snowball

Meteoroids, Meteors, Meteorites A meteoroid is a piece of small rock or metal-like debris which travels in outer space. Most meteoroids are no bigger than a pebble. Large meteoroids are believed to come from the asteroid belt. Smaller meteoroids may have come from the Moon or Mars. If a meteoroid falls into the Earth's atmosphere, it will heat up and begin glowing. This is called a meteor. If you have ever seen a "falling star", you were actually seeing a meteor. Most of the original material burns up before it hits the surface of the Earth. Any leftover part that does strike the Earth is called a meteorite. A meteorite can make a crater, or hole, in the ground when it hits it. The larger the meteorite, the bigger the crater.

Our Solar System

The Sun is the center of our solar system.

The Sun Huge ball of hot flowing hydrogen and helium gases Ultimate source of Earth’s energy Considered a “medium” star 150 million miles away from the Earth Makes one complete turn every 200–250 million years 1 million Earths would fit inside the Sun. 109 Earths could fit across the Sun’s diameter. The Sun is the largest star in the Milky Way Galaxy, but compared to other stars in the universe, it is tiny.

Stars are classified by color and brightness. – blue = hottest – red = coolest Sunspots are the darker and cooler areas on the sun. The Sun (and other stars) Solar flares are sudden temporary bursts of hot gases from a small area on the sun’s surface

There are 9 planets (including Pluto, a dwarf planet)

Know your planets in order. 17 My very excellent mother just served us nachos and pizza.

Mercury  no atmosphere, covered with craters and dust Venus  same size as Earth; the hottest and brightest planet because of its atmosphere Earth  only planet to support life Mars  has reddish soil and its atmosphere is mostly made of carbon dioxide; known as “The Red Planet” The Inner Planets There are four inner planets. Inner planets are rocky and dense. Have few or no moons

The Asteroid Belt Separates the inner from the outer planets

The Outer Planets The outer four planets are called gas giants – mostly made up of hydrogen and helium; have many moons Jupiter  largest planet in the solar system; has a storm that has lasted over 400 years Saturn  known for its large beautiful rings Uranus  axis is tilted more than other planets; looks like it has fallen over Neptune  has the fastest winds in the solar system

Pluto  small and rocky; not considered a planet anymore (called dwarf planet) Pluto

Revolution is based on the distance from the sun.

In general, planets closer to the sun have higher surface temperatures. The exception is Venus which is hotter than Mercury!

We live in the Milky Way Galaxy. One of the largest in the universe Has more than 100 billion stars Considered a spiral galaxy Galaxies are classified by their shape: spiral, barred spiral, elliptical, and irregular Beyond our Solar System Centaurus A Image Credit & Copyright: Tim Carruthers

Space Exploration The telescope was invented in Russian satellite Sputnik 1 was launched in s  Man entered space 1969  Neil Armstrong walked on the moon Today, space exploration focuses on other parts of the universe (deep space) Space probes are used to explore space and conduct scientific research. docs/StarChild/space_level1/pr obes.html docs/StarChild/space_level1/pr obes.html

Hubble Telescope The Hubble Space Telescope's launch in 1990 was one of NASA’s most successful science missions. Hubble is a telescope that orbits Earth. Its position above the atmosphere gives us a view of space that we cannot get from ground telescopes. Since 1990, the Hubble has beamed hundreds of thousands of images back to Earth to help us better understand many mysteries of the universe. Source: