Idaho Skies Transcript for July 27th, 28th, and 29th

RACHEL
Welcome to Idaho Skies for July 27th, 28th, and 29th. We’re your hosts, Rachel...


PAUL
...and Paul.


RACHEL
The moon is full on the 27th.


PAUL
Since the full moon is close to Mars, we know that Mars is near opposition.


RACHEL
This means that a straight line drawn from the sun to Earth would extend to the moon...


PAUL
...and pass very close to Mars if extended farther.


RACHEL
During an opposition of Mars, Earth appears very close to the sun.


PAUL
Recall that when the inner planets, Mercury and Venus, cross the face of the sun from our perspective we call it a transit.


RACHEL
Well, for someone on Mars, Earth can also transit the sun.


PAUL
And these Earth transits occur in cycles of four due to the orbital periods of Earth and Mars.


RACHEL
When a transit cycle begins, Mars sees its next Earth transit 26 years later.


PAUL
After that transit, the third transit of a cycle occurs 79 years later.


RACHEL
And finally, the last transit of a cycle occurs 100 years after the third transit.


PAUL
The last Earth transit occurred on May 11th, 1984 when there were no active spacecraft around Mars to observe it.


RACHEL
And it was the third Earth transit of a cycle.


PAUL
So the next one occurs one hundred years later on November 10th, 2084.


RACHEL
And perhaps Mars will have colonists by then.


PAUL
Just wait until both Venus and Earth transit the sun simultaneously!


RACHEL
That occurs in the year 571,471.   


PAUL
That’s Idaho Skies for the 27th, 28th, and 29th of July.


RACHEL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.


For Idaho Skies this is Rachel...


PAUL
...and Paul.


RACHEL
Dark skies and bright stars.