Tuesday, December 8 YOU NEED YOUR JOURNAL AND A PENCIL

Sun, Moon, & Earth Sun Moon Earth

What is a planet?  tdefine/what-is-a-planet/ tdefine/what-is-a-planet/  Our understanding about the universe and our place in it has changed over time. New information can cause us to rethink what we know and reevaluate how we classify objects in order to better understand them. New ideas and perspectives can come from questioning a theory or seeing where a classification breaks down  A planet must:  orbit the sun  be large enough so that its own gravity molds it into a spherical shape  it must have an orbit free of other small objects

The Terrestrial Planets

Mercury  The smallest of the terrestrial planets, about a third of the size of Earth.  It has a thin atmosphere, which causes it to swing between burning and freezing temperatures.  Average surface temperature: 243°F  A dense planet, made of iron and nickel  Surface has many deep craters and is covered by a thin layer of tiny particle silicates.  In 2012, scientists found evidence of water ice (in craters shaded from the sun)  Mercury’s thin atmosphere and close proximity to the sun make it impossible to host life as we know it

Venus  About the same size as Earth  Thick, toxic carbon monoxide-dominated atmosphere that traps heat, making it the hottest planet in the solar system.  Average surface temperature: 867°F  Surface - volcanoes and deep canyons  The planet is hostile to life as we know it.

Earth  The largest of the four terrestrial planets  Only planet to have extensive regions of liquid water.  Average surface temperature: 59°F  Earth has one moon.

Mars  The Red Planet  Small, rocky  Mars is too cold and its atmosphere is too thin to allow liquid water to exist at the surface for long.  Has the largest volcanic mountain in the solar system.  Average surface temperature: -81° F  Has 2 small moons

Asteroid Belt

Outer Planets  Jupiter  Saturn  Uranus  Neptune The gas giants

Jupiter  Largest planet in the solar system  More than twice as massive as all other planets combined. Could hold more than 1,300 Earths  Great Red Spot – a giant hurricane-like storm  Has the strongest magnetic field of all planets  Atmosphere 90% hydrogen, 10% helium  Average surface temperature: -234°F  Has at least 63 moons

Saturn  Sixth planet from the Sun and 2 nd largest - big enough to hold 760 Earths.  Farthest planet from Earth visible to the naked human eye, but through a telescope you can see it’s rings – made of rocks and ice  Gas giant made up mostly of hydrogen - 96%.  Only planet less dense than water – would float in a bathtub  Yellow and gold bands are super-fast winds in the upper atmosphere  Has at least 62 moons  Average surface temperature: -288°F

Uranus (YOOR-UN-US) “urine us”  Blue-green color  Atmosphere 82.5% hydrogen, 15.2% helium, 2.3 % methane  Average surface temperature: -357°F  Smaller of the gas giants but it is still a giant – 60 Earths could fit inside.  Axial tilt: 97.77°, compared to Earth’s 23.5°.  Spins in the opposite direction  Has 27 known moons

Neptune  Greatest distance from the sun, goes around the sun once every 165 Earth years  Thought to be composed of 25% rock, 60-70% ice, and 5 – 15% gases  Atmosphere 80% hydrogen, 19% helium, 1.5% methane  Has 6 rings and 13 confirmed moons  Average surface temperature: -353°F

Can we live on another planet?  What is the most important ingredient for life? 

Food to eat Planets need to supply chemicals that creatures can use for energy “Air” to breathe A planet’s atmosphere can supply life with chemicals in gas form (e.g., air) Comfortable temperature Planets can be hot, moderate (i.e., Earth) or cold Ability to move A planet’s surface (solid, liquid, gas) affects how creatures can move Gravity The more massive a planet is, along with its size, determines the pull of gravity on a creature Life Requirements Related Planetary Characteristics

Tour the solar system 

Pre-AP Science Fair Drop-off