FLT I can create a comic strip to show the characteristics a planet must have to support life I can create a comic strip to show the characteristics a planet must have to support life

New Planet discovered...Planet Rthea – Could There be Life?

Discovery of New Planet! Planet Rthea, a part of a Solar System, is a possible candidate for life Planet Rthea, a part of a Solar System, is a possible candidate for life

Let’s investigate whether life is possible on this new planet, Rthea!

Let’s investigate the LOCATION of planet Rthea to see if it is a possible location for life to form!

Habitable Zone Theoretical shell around a star where any planet present would have liquid water on its surface Theoretical shell around a star where any planet present would have liquid water on its surface HZ range should not vary over time HZ range should not vary over time Stars increase luminosity as they age Stars increase luminosity as they age If this happens too quickly (super-massive star), planets are only in window for life for short amount of time If this happens too quickly (super-massive star), planets are only in window for life for short amount of time Lowers time to develop life Lowers time to develop life

Rthea Located in Habitable Zone? Rthea Located in Habitable Zone?

Is Rthea Located in Habitable Zone? Yes! Yes! This planet is located within the expected shell of distance in which liquid water can be on the surface of the planet! This planet is located within the expected shell of distance in which liquid water can be on the surface of the planet! Pictures of the planet show liquid water covering a large portion of the Rthea’s surface! Pictures of the planet show liquid water covering a large portion of the Rthea’s surface!

The relative position of Rthea appears capable of supporting life… so let’s look at the planet itself!

Planet Characteristics that Support Life Terrestrial Terrestrial Silicate rocks Silicate rocks Rocks not accreted to gaseous outer layers Rocks not accreted to gaseous outer layers Gas Giants = no life Gas Giants = no life No surface No surface Enormous Gravity Enormous Gravity Satellites are good candidates, however Satellites are good candidates, however

Composition of Rthea? Rthea is a terrestrial planet, not a gas giant Rthea is a terrestrial planet, not a gas giant

Mass of Planets need to be Just Right for Life Low Mass Low Mass Bad news for life Bad news for life Lesser gravity – difficult for atmosphere retention Lesser gravity – difficult for atmosphere retention Smaller planets lose energy from formation quickly  geologically dead Smaller planets lose energy from formation quickly  geologically dead Approximately 0.3 Earth masses needed to sustain life Approximately 0.3 Earth masses needed to sustain life

Mass of Rthea High Mass High Mass Earth is largest by mass and density of terrestrial bodies in the Solar System Earth is largest by mass and density of terrestrial bodies in the Solar System Large enough for molten core (heat engine) Large enough for molten core (heat engine) Large enough for atmosphere through gravity Large enough for atmosphere through gravity Large enough for liquid outer core and metal inner core (magnetic field) Large enough for liquid outer core and metal inner core (magnetic field)

Magnetic Fields and Life Planets need protection from solar wind Planets need protection from solar wind Solar wind- stream of charged particles from stars consisting of electrons and protons Solar wind- stream of charged particles from stars consisting of electrons and protons Planet must have molten metal interior Planet must have molten metal interior

Does Rthea have a Magnetic Field? Yes! Yes! Solid metal core with liquid outer core, causing magnetic field Solid metal core with liquid outer core, causing magnetic field Protects the from solar wind Protects the from solar wind

Atmosphere and Life Atmosphere – layer of gases that surround a material body of sufficient mass Atmosphere – layer of gases that surround a material body of sufficient mass Held by gravity Held by gravity Helps regulate temperature Helps regulate temperature Protects planet from meteors and radiation Protects planet from meteors and radiation Composition favors life (oxygen and carbon dioxide) Composition favors life (oxygen and carbon dioxide)

Does Rthea have an Atmosphere? Yes! Yes! The atmosphere is made up of The atmosphere is made up of Nitrogen (78%) Nitrogen (78%) Oxygen (20.9%) Oxygen (20.9%) Argon (.93%) Argon (.93%) Carbon Dioxide (.0390%) Carbon Dioxide (.0390%) This composition could support life This composition could support life Atmosphere absorbs/reflects harmful radiation Atmosphere absorbs/reflects harmful radiation Visible and Radio reach surface Visible and Radio reach surface

Composition of Planets Four elements vital for life Four elements vital for life Carbon Carbon Hydrogen Hydrogen Oxygen Oxygen Nitrogen Nitrogen

Tectonic Activity of Planet Supply surface with life-sustaining material Supply surface with life-sustaining material Supply atmosphere with temperature moderators (CO 2 ) Supply atmosphere with temperature moderators (CO 2 ) Recycles important chemicals/materials Recycles important chemicals/materials Helps increase environmental complexity Helps increase environmental complexity Rthea is tectonically active!! Rthea is tectonically active!!

Rthea is actually EARTH ! Rthea is actually EARTH !

Partner Talk What characteristics makes Earth (Rthea) suitable for life? What characteristics makes Earth (Rthea) suitable for life?

Life-Supporting Orbits Stability is critical Stability is critical Eccentricity Eccentricity Greater e, greater temperature fluctuation Greater e, greater temperature fluctuation Living organisms can only withstand certain fluctuations Living organisms can only withstand certain fluctuations Complex organisms have greater temperature sensitivity Complex organisms have greater temperature sensitivity

Is Earth’s Orbit Suitable? Yes! Yes! Earth’s Orbit Earth’s Orbit Almost circular Almost circular E <.02 E <.02

Life-Supporting Rotation Rotation around axis at tilt Rotation around axis at tilt Planet should have moderate seasons or biospheric dynamism will disappear Planet should have moderate seasons or biospheric dynamism will disappear Without tilt, planet would be colder (warm weather could not move poleward) Without tilt, planet would be colder (warm weather could not move poleward) Should not be radically tilted because seasons would be extreme Should not be radically tilted because seasons would be extreme Speed of Rotation Speed of Rotation Should be relatively quick so day- night cycle is not too long (temperature differences if long days/nights) Should be relatively quick so day- night cycle is not too long (temperature differences if long days/nights)

Earth’s Rotation? Earth’s tilt varies between 21.5 and 24.5 degrees every 41,000 years Earth’s tilt varies between 21.5 and 24.5 degrees every 41,000 years Day is only 24 hours Day is only 24 hours Moon plays crucial role Moon plays crucial role Moderates Earth’s climate by stabilizing axial tilt Moderates Earth’s climate by stabilizing axial tilt

Earth COULD have life! Galactic Neighborhood Galactic Neighborhood Arm of Milky Way galaxy Arm of Milky Way galaxy Star Star Spectral class G2 Spectral class G2 Low stellar variation Low stellar variation Distance from Star Distance from Star Earth is located in Habitable Zone Earth is located in Habitable Zone Liquid Water Liquid Water Composition/Size Composition/Size Terrestrial planet, relative high mass Terrestrial planet, relative high mass Magnetic Field Magnetic Field Atmosphere Atmosphere Orbit Orbit Nearly circular Nearly circular Rotation Rotation Tilt allows seasons Tilt allows seasons Short night/day Short night/day

Comic Strip Make a comic strip demonstrating 4 characteristics unique to Earth to support life Make a comic strip demonstrating 4 characteristics unique to Earth to support life

Sample Comic Strip comic-strip-writing-worksheet-2.pdf comic-strip-writing-worksheet-2.pdf comic-strip-writing-worksheet-2.pdf Your comic needs a beginning, middle, and end. Your comic needs a beginning, middle, and end. You need to use all six boxes and there needs to be a drawing in each box You need to use all six boxes and there needs to be a drawing in each box Be creative!! Be creative!!