Transcript: March Week 3

PAUL
Welcome to Idaho Skies on Radio Boise. This is the third week of March. We’re your hosts, Paul..

RACHEL
..Rachel..

KRIS
..And Kris

PAUL
Hip hip hooray, Spring beings on the 20th at 6 PM.

RACHEL
The point at which the sun crosses the equator from the southern hemisphere marks the beginning of spring in the northern hemisphere.

KRIS
Astronomers call this point the Vernal Equinox.

RACHEL
In a world without an atmosphere the day and night are equal in length on the day of the equinox.

KRIS
But because of refraction through the atmosphere, the sun rises five minutes earlier and sets five minutes later.

RACHEL
From this day until the beginning of Autumn the days grow longer and the nights shorter.

PAUL
Be sure to look for the moon shortly before midnight on the 22nd.

KRIS
That’s because you’ll find the Pleiades close to the moon.

RACHEL
Most people know the Pleiades as the Seven Sisters.

KRIS
But astronomers call it M-45.

RACHEL
The Pleiades will be just half a degree from the crescent moon’s upper left on the night of the 22nd.

KRIS
Since the moon is a crescent and the Pleiades star cluster is on the dark part of the moon, the star cluster is less affected by moonlight.

RACHEL
So this should be a nice view for your binoculars.

PAUL
Wernher von Braun was born 95 years ago on the 23rd.

KRIS
Science fiction stories and the science writer Hermann Oberth created his intense interest in space flight when he was young.

RACHEL
Initially von Braun worked with a group of amateur rocket enthusiasts called the VfR.

PAUL
In German, VfR was the abbreviation for the Society for Space Travel.

KRIS
Due to the Versailles Treaty, Germany was prevented from developing large artillery.

RACHEL
So the German military acquired an interest in rocketry as a way to get around the limitations of the treaty.

KRIS
The German military provided funding to the VfR in the hopes that the civilian club would develop a successful rocket.

RACHEL
Eventually there was enough success that the German military changed the VfR to a military research program and put the young von Braun in charge of developing a missile with military use.

KRIS
During tests of the V-2 it achieved a peak altitude of 117 miles. That made the V-2 the first vehicle to reach the boundary of space.

RACHEL
In the end, Germany spent a lot of money very late developing a weapon that didn’t make much a difference in the war’s final outcome.

PAUL
But had the V2 been fully funded early in the war, things could have turned out different.

KRIS
That’s because von Braun’s team was designing a two stage missile capable of reaching the shores of the United States.

RACHEL
It’s sad to think that von Braun and his V-2 missile have such a mixed history.

KRIS
That’s Idaho Skies for the third week of March. Next week’s show is a little bit of Venus and a little bit of the Beehive star cluster.

For Idaho Skies this is Kris…

PAUL
..Paul..

RACHEL
.. and Rachel.

Transcript: March Week 4

PAUL
Welcome to Idaho Skies on Radio Boise. This is the last week of March. We’re your hosts, Paul..

RACHEL
..Rachel..

KRIS
..And Kris

PAUL
Look to the moon’s lower left shortly before midnight on the night of the 27th .

KRIS
There you’ll see a large sprinkle of stars called the Beehive Star Cluster.

RACHEL
The cluster, which appears larger than the moon, is located in the constellation of Cancer the Crab.

KRIS
Cancer is a faint constellation, so you probably won’t notice it.

PAUL
But the Beehive star cluster is quite easily seen with the naked eye in dark skies.

RACHEL
In fact the ancients knew about it. But they only saw it as a tiny cloudy spot.

KRIS
Back then it was used as a weather indicator.

RACHEL
That’s right. If it couldn’t be seen in clear skies, then there were thin clouds overhead.

KRIS
We call these clouds cirrus clouds. Often cirrus clouds precede the arrival of a cold front.

RACHEL
And cold fronts are responsible for some our most violent weather.

KRIS
Galileo was the first to turn a telescope on the Beehive. He saw over 35 stars in the nearby star cluster.

PAUL
The Soviet Venera 8 landed on Venus 35 years ago.

RACHEL
On March 27, 1972, the Venera 8 spacecraft went into orbit around Venus after releasing a lander.

KRIS
The lander’s parachute opened at an altitude of 36 miles and the capsule began refrigerating itself in preparation for the harsh conditions it would experience upon landing.

PAUL
During the parachute descent, the lander detected a cloud bank at an altitude of 22 miles.

RACHEL
It also discovered that winds below an altitude of six miles were blowing at less than ½ a mile per hour.

KRIS
For 50 minutes the lander reported on the conditions at the surface. Those conditions were an atmospheric pressure 90 times greater than that of earth and air temperatures greater than 850 degrees

RACHEL
Ouch! That’s hotter than your oven.

KRIS
Even though Venus is cloud shrouded, some sunlight filters through the clouds. At its surface, it looks like a typical overcast day here on earth.

PAUL
Saturn is close to the moon for a second time this month.

RACHEL
Look for the ringed planet less than one degree south of the moon on the 28th.

KRIS
Closest approach between Saturn and the moon takes place at ten PM.

PAUL
Alpha Leonis is just over a degree from the moon’s right on the evening of the 29th.

RACHEL
Don’t know who alpha Leonis is? Why that’s the star Regulus, the brightest star in Leo the Lion.

KRIS
This is another astronomical sight for your binoculars.

PAUL
April first is the 300th anniversary of the launch of the first space mission to land on the sun

RACHEL
Their goal was the return to Atlantis with samples of sunspots.

KRSI
Tragically the mission failed because they forgot to land after sunset and were instantly vaporized.

PAUL
The moon is full on April second. And that’s no foolin’

RACHEL
And no foolin’, the moon is at apogee on the third at eleven AM.

KRIS
Since the moon is full close to apogee this month, the full moon of April is the smallest full moon this year. And that’s no foolin’ either.

PAUL
That’s Idaho Skies for the fourth week of March. Join us next month for the space and astronomy news for Idaho and beyond. For Idaho Skies this is Paul…

KRIS
..Kris..

RACHEL
.. and Rachel.

Our sound engineer this month was Gwen Sanchirico.

ALL
No foolin'

Transcript: March Week 2

PAUL
Welcome to Idaho Skies on Radio Boise. This is the second week of March. We’re your hosts,

Paul..

RACHEL
..Rachel..

KRIS
..And Kris

PAUL
At one PM on the 18th the moon reaches perigee, or its closest distance from earth.

KRIS
This month the moon’s perigee has a distance of 222 thousand miles.

RACHEL
At a speed of 75 miles per hour, the fastest legal speed in Idaho, it would take a car 396 days to drive to the moon at perigee. But wait, there’s another lunar event today.

PAUL
That’s right. The moon is also new today.

KRIS
The moon is new when it lines up with the sun, from the earth’s perspective.

RACHEL
Did you know we’ll have higher than average high tides today because of this?

PAUL
Higher than average? Why?

KRIS
Well perhaps we should first learn why the sun and moon raise tides.

RACHEL
Sure. Tides occur when the gravitational attraction of the sun or moon is not the same on opposite sides of the earth.

KRIS
Since the force of gravity weakens as you move away from the sun and moon, their attraction is stronger on the near side of the earth than it is on the far side.

PAUL
Oh so I see. When the moon pulls more strongly on the near side of the earth, it lifts the oceans into a high tide. And then on the earth’s far side, the moon’s weaker gravity pulls the oceans less strongly, so more water is left behind to form a high tide their.

RACHEL
Not quite. The difference in gravity between the near and far side reduces the ocean’s pressure on the sea floor at those two spots.
KRIS
And as a result, water in the world’s oceans flow to these opposite points of low pressure. And that’s where you find the high tides.

PAUL
But you also said we’d have larger than average tides today. Why is that?

RACHEL
Since the moon is new and therefore aligned with the sun, the moon’s gravity pulls in the same direction as the sun’s.

KRIS
When they pull in the same direction, the sun’s high tides are added to the moon’s high tides. These higher than average tides are called spring tides.

RACHEL
But wait, there’s more. This month’s spring tide is larger still

PAUL
Larger still?

KRIS
Yes, larger. Remember that lunar perigee occurred just nine hours before new moon. So the new moon is at its closest to earth.

RACHEL
So the moon’s gravity is stronger on the near side of the earth and relatively weaker on the far side. The greater difference in gravity across the earth raises even larger tides.

KRIS
So this month’s perigean spring tide may be between 33 and 45 percent larger than the usual spring tide.

RACHEL
But tidal heights involve more than just solar and lunar gravity.

KRIS
Changes in atmospheric pressure and the shape of the ocean bottoms and bays can strongly effect the variation in tides.

RACHEL
The most extreme tides take place in Canada. You’ll be surprised to hear how much low tide and high tide can vary in the Bay of Fundy.

KRIS
Over fifty feet at times.

RACHEL
That’s Idaho Skies for the second week of March. Next week Idaho Skies talks about the Vernal Equinox and the V-2 missile.

For Idaho Skies this is Rachel.

PAUL
..Paul..

KRIS
.. and Kris.

Transcript: March Week 1

PAUL
Welcome to Idaho Skies on Radio Boise. This is the first week of March. We’re your hosts, Paul..

RACHEL
..Rachel..

KRIS
..And Kris

PAUL
Beginning on the evening of the sixth, the Zodiacal Light becomes visible in the evening again.

RACHEL
It’s visible because the moon is past full. So we have dark skies to see the Zodiacal Light.

KRIS
And each night the moon rises later, giving you a better opportunity to see the Zodiacal Light.

RACHEL
March is a particularly good month to look for the Zodiacal Light because it rises so steeply with respect to the horizon.

KRIS
So shortly after it gets dark, look for a faint glowing pillar of light rising in the west.

RACHEL
From a dark location the Zodiacal Light can be seen rising half way up to the zenith, or overhead.

KRIS
When you see it, you’re seeing sunlight reflecting from dust in orbit around the sun.

PAUL
Until the late 1970’s, the only planet known to have rings was Saturn.

KRIS
That changed 30 years ago on March 8th, 1977.

RACHEL
That’s when a telescope onboard an aircraft was monitoring the brightness of a star as it was occulted by Uranus.

PAUL
The occultation occurred when Uranus passed between the earth and a distant star, cutting off its light.

KRIS
Planetary astronomers like occultations because monitoring the star’s brightness during the occultation gives clues to the planet’s atmospheric structure.

RACHEL
But to their surprise astronomers detected several small decreases in the star’s brightness before and after it passed behind Uranus.

KRIS
Since the dips in the star’s brightness were symmetric with respect to Uranus, the dips were most likely created by a ring around the planet.

RACHEL
Had the dips in light brightness been due to one or more moons, the dips would not have been symmetric around the planet.

PAUL
Uranus is now known to have eleven dark and narrow rings.

KRIS
Instead of bright icy rings like Saturn’s, the rings of Uranus are made of rocky material and dust. The rings are between 1 and 60 miles wide.

RACHEL
Stacked together, they span a width of 8 thousand miles. Some of Saturn’s rings on the other hand span a width close to 200 thousand miles.

PAUL
Don’t forget to set your clock ahead one hour on the night of the 10th.

KRIS
Daylight Saving Time begins at 2 AM on the 11th. That’s four weeks earlier than usual.

RACHEL
Daylight Saving Time saves energy because more of our late day activities now take place while there’s still adequate sunlight.

PAUL
At 10 PM on the 11th the moon reaches the third quarter phase.

KRIS
The third quarter moon looks like a half moon. So does the first quarter moon, but unlike first quarter, the third quarter moon is visible after midnight, rather than before.

RACHEL
Also the moon’s western hemisphere is in sunlight, rather than its eastern hemisphere.

KRIS
So look after midnight for the last quarter moon. In binoculars you’ll see it’s covered with more lava plains and has fewer craters.

RACHEL
That’s Idaho Skies for the first week of March. Join us next week to hear about the moon and tides.

For Idaho Skies this is Rachel

KRIS
..Kris..

PAUL
.. and Paul.

Transcript: February Week 4

PAUL
Welcome to Idaho Skies on Radio Boise. This is the fourth week of February. We’re your hosts, Paul..

RACHEL
..Rachel..

KRIS
..And Kris

PAUL
This week the New Horizons spacecraft will fly past our largest planet, Jupiter.

RACHEL
Its Jovian flyby will accelerate the spacecraft so it will reach Pluto three years earlier than it would without Jupiter.

KRIS
Still, Pluto is so distant that it will take New Horizons another nine years to reach this world.

PAUL
Last year, astronomers adopted the first official definition of a planet.

RACHEL
The astronomical definition for planet leaves Pluto out. Instead, Pluto is the first Kuiper Belt object to be discovered.

KRIS
It was discovered in 1930 by a Kansas farm boy named Clyde Tombaugh.

RACHEL
For 65 years, it was the only Kuiper Belt Object, or KBO, known.

KRIS
Today, hundreds of them have been discovered and it’s believed there are thousands more waiting to be discovered.

RACHEL
The New horizons will be our first close up exploration of these small icy worlds.

PAUL
March 1st is the 25th anniversary of the 1982 landing of Venera 13.

KRIS
Venera is Russian for Venus. The Venera 13 was their 13th spacecraft to reach the planet Venus.

RACHEL
But it wasn’t the 13th launched. It appears Venera 13 was the Soviet’s 20th attempt to reach Venus.

KRIS
Venera 13 was a two part spacecraft, a flyby spacecraft and a lander.

RACHEL
Since the flyby spacecraft didn’t enter Venusian orbit, it didn’t need a heavy rocket engine and fuel.

KRIS
That saved weight for the Venera 13 lander. And since it had a thick Venusian atmosphere to slow it down, the lander didn’t need a rocket either.

RACHEL
The parachute for Venera 13 was released high in the atmosphere. The thick atmosphere let the lander drop safely to the ground from an altitude of 29 miles.

KRIS
Once on the surface at Phoebe Regio, Venera 13 drilled a surface sample for analysis and returned images from the surface of Venus.

RACHEL
The surface near Venera 13 was a flat rocky plain with very little loose dirt.

KRIS
Rocks near the lander were discovered to be made of basalt, a volcanic rock found in much of Idaho.

RACHEL
Venera 13 survived for over two hours before it was cooked by the furnace-like temperatures on Venus.

PAUL
Hey, there’s a close passage between the moon and Saturn on the evening of the second.

KRIS
So look in the east after sunset for the gibbous moon. To its upper right is a star.

RACHEL
That star is really the ringed planet. And the moon and Saturn are close enough together to be seen in a pair of binoculars.

KRIS
But if you have a telescope, the view is better. Use an eyepiece that gives your telescope a magnification of at least 50 power if you want to see Saturn’s rings.

RACHEL
In your telescope you’ll find Saturn’s largest moon to the planet’s upper right.

KRIS
That’s Titan. Titan is larger than our moon and covered in a thick atmosphere of nitrogen gas.

RACHEL
But it doesn’t have a nice climate. The surface temperature of Titan is close to 300 degrees below.

KRIS
That’s so cold that water freezes as hard as rocks on earth.

RACHEL
In fact, that’s probably the composition of the pebbles that the Huygens’ lander saw on the Titanian surface.

PAUL
That’s Idaho Skies for the fourth week of February. Join us next month for the space and astronomy news for Idaho and beyond. For Idaho Skies this is Paul…

KRIS
..Kris..

RACHEL
.. and Rachel.

Our sound engineer this month was Gwen Sanchirico.