Our Solar System

The Sun• Our Sun is a medium-sized yellow star in the middle of its life cycle.

• Its the center of our Solar System and holds objects in orbit by gravitational pull.

• More than 1,000,000 Earths can fit inside the Sun.

• It’s fueled by nuclear fusion of small atoms to form larger ones, and it’s the only source of energy in the solar system.

• It has features: sun spots, solar flares, and prominences.

Mercury• Terrestrial planet with a solid rocky surface

• Covered with craters• Extreme temperatures (from -170 ºC up to 467 ºC)

• Thin atmosphere so its temperatures vary by day and night

• Fastest planet to revolve around the Sun, thus named Mercury

• No moons … why not?

Venus• Terrestrial planet with a solid, rocky surface

• Earth’s “twin” in size

• Extremely hot temperatures (470 ºC) due to thick atmospheric cloud cover and green house effect.

• Retrograde motion (it rotates clockwise)

• No moons … why not?

Earth• Terrestrial planet with a solid, rocky surface

• Frozen caps at North & South Poles

• Capable of supporting life due to [C], 70% water, and protective atmosphere

• Seasons due to axis tilt

• 1 Moon: Luna where we have landed multiple times and sent more than 70 spacecraft

Earth’s Moon “Luna”• The moon acts like a mirror; it reflects sunlight to Earth

• Phases of the moon occur as the moon revolves around Earth and reflects sunlight.

• Tides -- high tide and low tide -- are caused by the moon’s gravitational pull

Mars• Terrestrial planet with a solid, rocky surface

• Red surface due to [Fe]

• Enormous active volcanoes and dust storms

• Thin atmosphere• Frozen polar caps like Earth

• Liquid water once?• 2 Moons: Phobos and Deimos

Asteroids• Made of rock, minerals, and rare elements

• More than 100,000 orbit in the “Asteroid Belt” between Mars and Jupiter

• Could collide with Earth, but probably won’t

• The largest asteroid named Ceres is a dwarf planet

• Moons: a few asteroids have moons!

Meteors or “Shooting Stars”

• Pieces of rock that are falling toward Earth are meteors

• They glow brightly as they burn up due to fluid friction

• Called “meteoroids” if they are far away, “meteors” if they have a bright tail, and “meteorites” once they hit Earth

Jupiter• The largest “gas giant” with no solid surface

• Faint rings• Made of elements [H] and [He] with a hot, solid core of [Fe] -- almost a star!

• “Red Spot” is a massive storm

• 60+ Moons: the four largest are named Io, Europa, Ganymede, Callisto, but there are more…

Saturn• Second largest gas giant without a solid surface

• Famous for bright, icy rings that we can see from Earth with a telescope. The rings have large divisions.

• Mostly made of elements [H] and [He]

• Less dense than water!• 60+ Moons: Titan and Phoebe and more, some orbit in the gaps of the rings

Uranus• Gas giant without a solid surface

• Made of elements [H] and [He] and water, ammonia and methane

• Bluish reflection due to methane (CH4) gas

• Faint rings, but the brightest clouds

• Axis is turned “sideways” so it has wild seasons

• Retrograde motion• 27 Moons: Ariel and more…

Neptune• Gas giant without a solid surface

• Bluish reflection due to methane (CH4) gas but more vivid than Uranus

• Six faint rings• Farthest planet from the Sun, usually

• 13 Moons: Triton is the largest and 12 more…

Dwarf Planets & Plutoids

• Ceres is the largest asteroid in the asteroid belt

• Pluto has a solid, icy surface, 3 moons, and it orbits in a tilted plane. Charon is the largest moon of Pluto.

• Makemake is smaller than Pluto, but farther

• Haumea is similar to Pluto in size and rotates the fastest

• Eris is larger than Pluto, but farther away

• More to be discovered…

Comets• Made of rock, ice and dust

• Comets consist of a head, coma, and two tails that point away from the Sun

• “Short-period” comets come from the “Kuiper Belt” and orbit the Sun every 200 years or less

• “Long-period” comets come from the “Oort Cloud” and take longer to orbit the Sun

Stars like our SunStars are classified in many ways: by color and temperature, mass, age in life cycle, brightness and…

The Life Cycle of Stars

Stars age through a life cycle that includes many stages.

Galaxies• Galaxies are groups of billions of stars, usually classified by their shape: spiral, elliptical, or irregular.

Spiral: like our Milky Way Galaxy

Elliptical

Irregular (or chaotic)