Monday, March 20, 2017

Idaho Skies Transcript for March 24th, 25th, and 26th

PAUL
Welcome to Idaho Skies for March 24th, 25th, and 26th. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
The solar system is made of three types of planets.

RACHEL
The first type is terrestrial, like Mercury, Venus, Earth, and Mars.

PAUL
These planets have dense metallic cores and rocky mantles.

RACHEL
What atmospheres they have are low mass, compared to the mass of the planet overall.

PAUL
Then there are the gas giants, like Jupiter and Saturn.

RACHEL
These planets have rocky cores that are more massive than the terrestrial planets.

PAUL
However, their hydrogen and helium atmospheres are far more massive than their cores.

RACHEL
In fact, the gas giants consist of 90% hydrogen and helium.

PAUL
And their composition is closer to the sun than any other planet.

RACHEL
So in the case of Jupiter, astronomers sometimes refer to it as a failed star.

PAUL
In other words, if it had more gas and it would light up like a second sun.

RACHEL
The final type is the ice giants, like Uranus and Neptune.

PAUL
These planets have massive cores and a thick mantle of gases.

RACHEL
But unlike the gas giants, their atmospheres consist mostly of elements heavier than hydrogen and helium.

PAUL
What the solar system does not have are Super Earths.

RACHEL
These have been detected in solar systems around other stars.

PAUL
A Super Earth is a rocky planet like a terrestrial planet, but as massive as Neptune.

RACHEL
That’s approximately four times heavier than Earth.

PAUL
I guess three out of four isn’t bad.

RACHEL
That’s Idaho Skies for the 24th, 25th, and 26th of March.

PAUL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Idaho Skies Transcript for March 22nd and 23rd

RACHEL
Welcome to Idaho Skies for March 22nd and 23rd. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Werner von Braun was born 105 years ago on the 23rd.

PAUL
Von Braun is best known for his work on the early American space program.

RACHEL
In the US, he helped create the Redstone missile.

PAUL
This is the missile that put the first American satellite into orbit.

RACHEL
The Redstone was further upgraded in order to launch the first American into space.

PAUL
In this case, Alan Shepard’s flight was suborbital.

RACHEL
However, Von Braun’s rocket work goes back to before World War II.

PAUL
As a student, he became excited by the prospect of space travel.

RACHEL
His excitement in 1930, lead him to join the VfR, an amateur rocket organization in Germany.

PAUL
Unfortunately, the Nazi party came to power three years later.

RACHEL
The German military wanted to use rockets to get around limitations set in the Versailles treaty that ended World War I.

PAUL
In their quest to secretly build rockets, they co-opted the VfR and some of its members.

RACHEL
This included von Braun.

PAUL
Many historians feel Von Braun was not totally innocent in this event.

RACHEL
Because he was willing to work with the current German government to advance his interests in rocketry.

PAUL
With the help of military money, Von Braun eventually perfected the rocket as a weapon of war.

RACHEL
The V-2 missile killed thousands of civilians.

PAUL
But far more slave labors died building it.

RACHEL
It’s a shame that an amazing tool of exploration began as a weapon of destruction.

PAUL
That’s Idaho Skies for the 22nd and 23rd of March.

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

For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for March 20th and 21st

PAUL
Welcome to Idaho Skies for March 20th and 21st. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Finally! Spring begins on the morning of the 20th.

RACHEL
Spring, by definition, begins the moment the sun’s path above Earth’s surface passes directly over the equator.

PAUL
A stargazer will notice that during the summer, the sun rises north of due east.

RACHEL
And that the sun sets north of due west.

PAUL
This is a sign that the sun’s path across the sky is higher in the summer.

RACHEL
And therefore, the sun’s path above Earth is above the equator.

PAUL
The reason why is because Earth’s spin axis isn’t straight up and down.

RACHEL
That’s straight up and down, relative to the plane of its orbit around the sun.

PAUL
Instead, Earth’s spin axis is tilted 22.5 degrees.

RACHEL
And when that tilt faces towards the sun, the sun appears above the equator for us in the Northern hemisphere.

PAUL
Also, the days are longer and the sun shines more directly upon the surface.

RACHEL
Which means Idaho experiences spring and summer weather.

PAUL
Saturn appears just three degrees away from the moon on the first day of spring.

RACHEL
So after waking up on the morning of the 20th, look for the moon in the southeast.

PAUL
Saturn will be the pale yellow-white star to the moon’s lower right.

RACHEL
The distance between them is close enough that they’re both visible at the same time in binoculars.

PAUL
That’s Idaho Skies for the 20th and 21st of March.

RACHEL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

Tuesday, March 14, 2017

The Moon and Jupiter on the Morning of Pi Day

Getting ready to leave this morning, I had to take a moment to photograph the waning gibbous moon next to Jupiter. This was taken with a cellphone camera and without a tripod. So it's not the best, but not too bad either. I hope you had a chance to see the moon and Jupiter this morning like I did.

Jupiter is the star to the left of the moon and Spica is the fainter star to the lower left of the moon.

Monday, March 13, 2017

Idaho Skies Transcript for March 17th, 18th, and 19th

RACHEL
Welcome to Idaho Skies for March 17th, 18th, 19th. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Theses are your last days to see Venus before it approaches too close to the sun.

PAUL
However, if stargazers wait until the 19th, they’ll see Venus and Mercury close together.

RACHEL
To see these two planets, stargazers need look in the low west at about 7:40 PM.

PAUL
Venus will appear as the very bright star just above the horizon, so it can’t be missed.

RACHEL
Tiny little Mercury is fainter than Venus and located to the left of the planet.

PAUL
The angular distance between Mercury and Venus is nine degrees.

RACHEL
That makes their span just under the width of your fist when viewed at arm’s length.

PAUL
However, in the solar system, the planets are very far apart.

RACHEL
Mercury is located on the other side of the solar system while Venus is closer to Earth than the sun.

PAUL
Both are rocky worlds that are smaller than Earth.

RACHEL
But the differences between them and Earth are surprising.

PAUL
Mercury is an airless world that looks a lot like the moon.

RACHEL
Venus is a world with an atmosphere denser and hotter than Earth’s atmosphere.

PAUL
Both are hot, but surprisingly, Venus is hotter than Mercury.

RACHEL
Yep, even though Mercury is closer to the sun, Venus has a hotter surface temperature.

PAUL
The increased surface temperature is due a run-away greenhouse effect.

RACHEL
That effect is created by the planet’s carbon dioxide-rich atmosphere.

PAUL
That’s Idaho Skies for the 17th, 18th, and 19th of March.

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

For Idaho Skies this is Rachel...

PAUL
...and Paul.

RACHEL
Dark skies and bright stars.

Idaho Skies Transcript for March 15th and 16th

PAUL
Welcome to Idaho Skies for March 15th and 16th. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
The first liquid-fueled rocket launch took place on March 16th, 1926.

RACHEL
The rocket was designed and built by physicist Robert Goddard.

PAUL
Goddard was a professor at Clark University in Massachusetts.

RACHEL
After several laboratory tests, he began constructing the rocket in January 1926.

PAUL
And the launch took place for real in Auburn, Massachusetts.

RACHEL
Specifically on the farm of his aunt Effie.

PAUL
The rocket’s propellants were liquid oxygen and gasoline.

RACHEL
At launch, the rocket didn’t leave its support frame.

PAUL
Instead, it shot a hot flame and roared.

RACHEL
That is, until it burned off enough propellant that it could finally lift itself.

PAUL
Then the rocket rose steadily and gained speed.

RACHEL
The entire flight lasted for 2.5 seconds and the rocket climbed to an altitude of 41 feet.

PAUL
While not an impressive flight, it proved that liquid-fueled rockets were possible.

RACHEL
German rocket enthusiasts like Werner von Braun used the results to this flight to design the V-2 missile.

PAUL
After World War II, the improvements made by von Braun where incorporated into the mighty Saturn V.

RACHEL
And in the end, the technology placed one dozen Americans on the moon.

PAUL
From a 41 foot high flight to the moon is 43 years. Not too bad.

RACHEL
Thanks to Dr. Goddard.

PAUL
Be sure to buckle your seatbelts, the next 43 years promise civilian access to space.

RACHEL
That’s Idaho Skies for the 15th and 16th of March.

PAUL
Be sure to follow us on Twitter at Idaho Skies for this week’s event reminders and sky maps.

For Idaho Skies this is Paul...

RACHEL
...and Rachel.

PAUL
Dark skies and bright stars.

Idaho Skies Transcript for March 13th and 14th

RACHEL
Welcome to Idaho Skies for March 13th and 14th. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Jupiter is just five degrees away from the moon late on the evening of the 14th.

PAUL
What’s that other star to the right of the moon and below Jupiter?

RACHEL
Why it’s Spica. It’s just six degrees away from the moon.

PAUL
The moon, Jupiter, and Spica form a triangle in the low southeast at 10:00 PM.

RACHEL
And the triangle is just small enough to fit inside the view of your binoculars.

PAUL
Take a closer look at Jupiter and you’ll see at least two of its four major satellites.

RACHEL
The satellites will form a straight line with the planet, so you can’t confuse them for background stars.

PAUL
From the bottom of your binocular view and going up, the objects are Callisto, Ganymede, and Jupiter.

RACHEL
Sharp-eyed stargazers may detect Europa between Ganymede and Jupiter.

PAUL
...and Io on the other side of Jupiter.

RACHEL
Listeners with a telescope or spotting scope will find Europa and Io much easier to see.

PAUL
Jupiter is one very large planet.

RACHEL
It’s ten times wider than Earth and 318 times more massive.

PAUL
Astronomers believe Jupiter has a nickel-iron core some 30 times more massive than the entire Earth.

RACHEL
And that heavy metal core is surrounded in a thick blanket of metallic hydrogen.

PAUL
Hydrogen, which is a gas on Earth, turns into a liquid when squeezed by Jupiter’s immense gravity.

RACHEL
And that compressed hydrogen may even be metallic.

PAUL
In other words, it may conduct electricity.

RACHEL
That’s Idaho Skies for the 13th and 14th of March.

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.