WPBT2's Star Gazers

Episode #11-50 "The Reasons For The Seasons"
Air Dates December 12- December 18, 2011



FIVE MINUTE EPISODE SCRIPT
DEAN: Hey there star gazers.  I’m Dean Regas, outreach astronomer for the Cincinnati Observatory.

JAMES: And I’m James Albury, director of the Kika Silva Pla Planetarium in Gainesville, Florida.  We’re here to give you insight into our changing seasons.

DEAN: Next week is the winter solstice.  On Thursday, December 22nd, sun worshippers can rejoice!  This is the time when the Northern Hemisphere experiences the shortest days and longest nights.

JAMES: Wait a second, rejoice? On the darkest day?  What’s to celebrate?

DEAN: Well, that means every day after December 22, the sun will get higher in the sky and stay up longer above the horizon.  The sun will stop its southward migration and start heading north again.

JAMES: I wish it would hurry up already, it’s freezing out here!

DEAN: Let’s show you the reasons for the seasons…

(stop drop)

JAMES: The changing seasons and the changing amount of daylight we get across the year are caused by the tilt of the earth.  As our planet rotates daily on its axis, we also revolve around the sun.  But our rotational axis is tilted compared to our orbit around the sun and we keep this slanted view.

DEAN: The Earth is tilted 23 and a half degrees and this is the cause of the seasons.  When we, in the Northern Hemisphere, are tilted most directly toward the sun we soak up solar energy to the max.  That day is called the summer solstice and it usually occurs on June 20th or 21st.  At this point the sun’s rays shine most directly on us in the United States.  We get more energy per square inch and thus it’s hotter.

JAMES: Now the opposite occurs when the earth swings around to the opposite side of the sun.  Here, we, in the Northern Hemisphere, are tilted away from the sun.  The sun’s rays feebly strike us at a low angle spreading out the same energy over a larger area.  Each square inch gets a lot less energy than in summer.  We call this the winter solstice and that usually occurs on December 21st or 22nd.    

(Close-up on James holding the sun, being blasted by prominences and cmes while Dean speaks below off camera or on the hoverboard at a safe distance)

DEAN: The sun’s output is the same all year round.  But the difference in our seasons is how much of that energy we soak up.  It has nothing to do with how close or far we are from the sun.  We’re closest to the sun every year in January and farthest from the sun in July.  So the distance isn’t the difference… now, let’s see how our tilt affects the view from down on earth. 

(Back on the horizon)

JAMES: We have our skies set to December 22nd just before sunrise.  Let’s trace the path that the sun takes across the sky on this, the “shortest” day of the year.  The sun will rise south of east, and reach its highest point in the southern sky around noon.  Then the sun will set south of west. 

DEAN: For most of the country you’ll get about 9-10 hours of daylight on this day.  That also means you’ll get 14-15 hours of darkness! 

JAMES: Let’s compare this to the spring equinox – next year it will be on March 20.  Now let’s trace the pathway that the sun takes on this day.  The sun will rise due east… reach its highest point above the southern horizon… and then set due west. 

DEAN: Notice how the sun goes higher in the sky than it did in December.  The higher the sun, the more direct energy we get.

JAMES: And look at how much longer the sun was in the sky!  12 hours of daylight…

DEAN: And 12 hours of darkness.  Equal day, equal night.  That’s why they call it the equinox.  What about on the summer solstice?  Now our sky is set to June 20th, 2012 and we can watch the sun rise north of east… go very high in the south… and set north of west. 

JAMES: The sun went higher still in the sky.  And the hours of daylight reach a whopping 14-15 hours for most of the U.S… 

DEAN: And only 9 or 10 hours of darkness.  And all of this is caused by the 23 and a half degree tilt of the earth.  The winter and summer solstices mark the extremes in the daily passage of the sun.  So next week, on December 22, watch where the sun sets. 

JAMES: But after the winter solstice, the sun will begin its slow trip north until we reach the other extreme: summer solstice on June 20. 

DEAN: So soak up the solstice sun – because the longer days are returning and summer is coming… slowly…

BOTH: Keep looking up!

 

Episode #11-50 "The Reasons For The Seasons"
Air Dates December 12- December 18, 2011



ONE MINUTE EPISODE SCRIPT
DEAN: Thursday, December 22nd, is the winter solstice, when we experience the shortest days and longest nights.

JAMES: Why does this happen?  Let’s show you the reasons for the seasons…

(stop drop)

JAMES: As our planet rotates on its axis, we also revolve around the sun.  But our axis is tilted compared to our orbit around the sun.

DEAN: the earth is tilted 23 and a half degrees and this is the cause of the seasons.  When we’re tilted most directly toward the sun we soak up solar energy to the max.  That’s the summer solstice. 

JAMES: When the Earth swings around to the opposite side of the sun we, in the Northern Hemisphere, are tilted away from the sun.  The sun’s rays strike us at a low angle spreading out the same energy over a larger area.  That’s the winter solstice.    

JAMES: So next week, on December 22, watch where the sun sets. 

DEAN: And soak up the solstice sun – because the longer days are returning…slowly

BOTH: Keep looking up!

 

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