5/11 - 8th Grade Agenda Learning Objective: Learn about the Outer planets and Comets Collect HW: Reading & Notetaking p.251– 253 Video: When we left Earth Textbook Reading: p.573 - 577 HW: Reading & Notetaking p.254– 256

Daily Reflection Prompt: Write 3 questions about Comets

Uranus 7th Planet from the Sun Has thin rings Tilted on its axis Has 18+ moons

Neptune 8th Planet from the Sun Has a large moon called Triton Has 18+ moons

Neptune’s moon Triton Triton has a thin atmosphere made up of Nitrogen

Pluto Not a “planet” anymore It’s a “Dwarf Planet” Has a single moon called Charon Pluto is smaller than our moon Some objects of Pluto’s size have been found outside of Pluto’s orbit Many astronomer don’t consider Pluto a planet

What are Comets? “Dirty snowball” about the size of a mountain. Comets are loose collections of ice, dust, and small rocky particles whose orbits are usually very long, narrow ellipses.

How does a Comet’s tail form? As a comet approaches the sun and heats up, some of its gas and dust stream outward, forming a tail. The name comet means “long-haired star” in Greek.

Comets originate from Kui____ Belt & Oo__ Cloud per Comets originate from Kui____ Belt & Oo__ Cloud rt Kuiper belt is 100 X beyond Neptune’s orbit Oort cloud is 1000X the distance between Pluto and the sun

Comet’s Orbit

Close up of a Comet “Dirty Snowball”

Close up picture of comet Rosetta space craft landed in 2014. It took pictures of Churyumov-Gerasimenko comet

What are Asteroids? Most asteroids revolve around the sun between the orbits of Mars and Jupiter. Most asteroids are small—less than a kilometer in diameter Only Ceres, Pallas, and Vesta are more than 300 kilometers across.

Close up of an Asteroid

What are “shooting stars”? “Shooting Stars” are Meteors A meteoroid is a chunk of rock or dust in space. Meteoroids come from comets or asteroids. Meteroids form when a comet breaks up and creates a cloud of dust that continues to move through the solar system.

How big are most meteors we see? Very small Less than size of a penny They appear very bright because they are burning up against a black sky

Meteor Crater in Arizona

What do we need for “life as we know it” to exist on a planet? Liquid water Suitable temperature range Suitable atmosphere Are these the conditions necessary for life?

Some bacteria can thrive in nearly boiling temperature

Some life forms can survive with out sunlight These tubeworms live thousands of feet underwater There is no sun light They get energy by converting chemicals nears the thermal vents

Is there Life on Mars? Mars once had water on the surface Mars may have once had the conditions needed for life to exist. Life doest not appear to exist on Mars

Is there Life on Europa? Ice Moon of Jupiter If there is liquid water on Europa, there might also be life. Plans are under way to send robotic probes to drill holes through the Ice Sheets

Is there Life on Titan?

Is there other life in the Universe? There are 100 Billion stars in our Galaxy There are more than 100 Billion Galaxies in the Universe Do you think there are other life forms in the Universe?