Transcript for July 10th to 16th

PAUL
Welcome to Idaho Skies for the second week of July. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
The brightest star of Virgo is located below the moon on the 11th.

RACHEL
Its name is Spica and it appears as a twinkling white spark of light in the low southwest.

PAUL
The reason stars twinkle and planets don’t is that planets have larger apparent surfaces than stars.

RACHEL
That’s right. Even though stars are much larger than planets, planets are tremendously closer to Earth.

PAUL
The planets’ closeness to Earth trumps the massively large size of stars and gives planets their larger apparent surfaces.

RACHEL
Because of their larger apparent surfaces, it takes more moving pockets of air to make planets twinkle.

PAUL
As a result, the normal movement of air makes star twinkle...

RACHEL
...but not planets.

PAUL
Unless of course, the air is very stormy.

RACHEL
Stars twinkle when moving pockets of air bend and refract their light.

PAUL
Each air pocket has a different temperature, density, and direction of movement.

RACHEL
So each air pocket behave like a prism with its unique optical property.

PAUL
So when a new pocket of air moves over a star, it refracts the position and colors of the star towards or away from your eye.

RACHEL
And that’s star twinkle in a nutshell.

PAUL
The star directly below the moon on the 13th is called Zubenelgenubi.

RACHEL
Zubenelgenubi is a famous double star, but one that many listeners may not have heard of before.

PAUL
The distance between Zubenelgenubi and the moon is 4 degrees...

RACHEL
...or small enough that you can see both the moon and Zubenelgenubi at the same time in a pair of binoculars.

PAUL
The distance between the two stars in Zubenelgenubi is wide enough that your binoculars can resolve the stars as individuals.

RACHEL
The real challenge is to see if you can resolve Zubenelgenubi as two stars with you’re your eyes.

PAUL
Some people can.

RACHEL
On the 15th, the ringed planet Saturn is the yellowish-white star located 2.5 degrees below the moon.

PAUL
While binoculars don’t reveal anything about the planet, a telescope of modest power is enough to let you can see its rings and largest satellite.

RACHEL
This means a spotting scope or small telescope is powerful enough.

PAUL
You’ll need a magnification of at least 25 times, however.

RACHEL
What about Titan, Saturn’s largest satellite?

PAUL
It appears as a star to Saturn’s upper right in a small telescope.

RACHEL
A spotting scope, which doesn’t flip images, will show Titan to Saturn’s lower left instead.

PAUL
In professional telescopes, Titan appears as a tiny orangish disk.

RACHEL
The orange comes from the thick clouds surrounding the satellite.

PAUL
Wait, Titan has an atmosphere of nitrogen and methane and those are colorless gases.

RACHEL
Well, solar ultraviolet acting on the methane gas in Titan’s atmosphere is converting the methane gas into more complex molecules.

PAUL
And those gases creates Titan’s pumpkin-colored clouds.

RACHEL
Astronomers call the orange compounds in Titan’s hazy atmosphere Tholins.

PAUL
And they just might be some of the precursors of life on Earth, 3.8 billion years ago.

RACHEL
That’s Idaho Skies for the second week of July. We’ll talk about great glowing clouds of gas next week.

PAUL
Be sure to read our blog for additional information. It’s at idahoskies.blogspot.com.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.