Transcript: 21 -27 March

PAULWelcome to Idaho Skies on Radio Boise. This is the fourth week of March. We're your hosts, Paul..

RACHEL..Rachel..

KRIS..And Kris

PAULLast week we talked about the German astronomer William Herschel.

RACHELOn the night of March 13TH, 1781, William Herschel was observing the stars with his telescope when he found a small disk shaped object. At first he thought it was new comet.

KRISBut after watching it move across the sky over several nights, Herschel decided that he had found a new planet instead of a comet.

PAULIn the 18TH century, scientists often named their discoveries after potential sponsors.

RACHELHerschel was no different. And so he named his new planet after the current king of England.

KRISIf Herschel had his way, we'd be calling the seventh planet of the solar system, Georgium Sidus, or George's Star.

RACHELInstead the astronomical community decided to name the new planet after the father of the Roman god Saturn.

KRISSo today we know this planet as Uranus. Umm, perhaps George's Star would have been a better name.

RACHELUranus is our solar system's third largest planet with a diameter of 32,000 miles. That's four times larger than Earth.

PAULUranus is nearly two billion miles from the sun. This vast distance means the sun's gravity is much weaker at Uranus than it is at Earth.

KRISAs a result, it takes Uranus 84 years to orbit the sun.

PAULLast week was the 80th anniversary of the first launch of a liquid fueled rocket.

RACHELSince he was a teen, Robert Goddard had wanted to design a device that could travel to Mars. But Mars was impossibly distant for late 19TH century technology.

KRISSo Goddard knew he'd have to design a machine that could generate tremendous speeds while carrying its own oxygen.

RACHELBurning gasoline with pure oxygen would create the large amount of energy he would need. But safely generating and directing this energy was something no one knew how to do.

KRISAfter several studies of solid fueled rockets, Goddard finally settled on using a liquid fueled rocket.

PAULBut where could Goddard test his contraption?

RACHELHe launched his first rocket at his Aunt Esther's farm in rural Massachusetts. Needless to say, the neighbors where none to pleased.

KRISFor the first 20 seconds the rocket just sat on its launch stand. The rocket was too heavy to lift itself.

RACHELBut after 20 seconds the rocket had burned off enough fuel to lift itself. The rocket rose to an altitude of 41 feet before arcing over and returning to the ground without a parachute.

KRISThe rocket's flight took less than three seconds and achieved a maximum speed of 60 miles per hour. Today, rockets achieve altitudes in excess of 100 miles and speeds greater than 17,000 miles per hour.

PAULSpring begins on the 20TH at 11:26 AM.

ALLYippee!!!!

RACHELAt that time, the sun stands directly over Earth's equator. This makes our day and night twelve hours long that day.

KRISActually the day lasts a few minutes longer because the atmosphere refracts light and makes the sun appear a bit higher near sunrise and sunset.

PAULThat's Idaho Skies for the fourth week of March. Join us next week to hear about the planet Venus. For Idaho Skies this is Paul...

KRIS..Kris..

RACHEL.. and Rachel.

Transcript: 28 March - 3 April

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

RACHEL..Rachel..

KRIS..And Kris

PAULThis week our solar system's second planet reaches its greatest distance from the sun.

KRISThe average distance between Venus and the sun is 67 million miles, or about two-thirds the distance between Earth and the sun.

RACHELThis means Venus can appear at a maximum of 46 degrees away from the sun.

KRISSince the earth rotates 360 degrees in 24 hours, Venus could rise or set three hours before the sun.

RACHELHow much earlier Venus rises before the sun depends not just on its distance from the sun, but also the angle the ecliptic rises above the horizon.

PAULThe ecliptic is the path that the sun and planets travel around the heavens.

KRISThe sun travels low across the sky in the winter. This means the ecliptic must rise at its smallest angle above the horizon.

RACHELThis month Venus is also located on that part of the ecliptic. So even though Venus is far from the sun, it only rises two hours before the sun.

PAULGreco-roman cultures have associated Venus with their goddess of love.

KRISTo the Greeks the planet was named after Aphrodite and to the Romans the planet was Venus. To the Mesopotamians, the star was their goddess Ishtar.

RACHELBut in Mesoamerica, Venus was their plumed serpent god, Quetzcoatl.

PAULJust over a century ago, astronomers developed a scientific view of the planet.

KRISIn their telescopes, Venus appeared as a dazzling featureless disk or crescent.

RACHELAstronomers understood they were looking at a cloud enshrouded world that was about the same size as our Earth.

KRISAstronomers believed the clouds were made from water. Therefore the planet must have been water rich.

RACHELAstronomers speculated that the planet could be either a humid swamp or a global ocean.

PAULThanks to radar studies and spacecraft launched by the United States and Russian, today we know the surface of Venus very well.

KRISThe atmosphere of Venus is a thick blanket of carbon dioxide. The air pressure at the surface of the planet is 90 times greater than Earth's air pressure.

RACHELThis dense carbon dioxide atmosphere creates a greenhouse effect on a massive scale. Surface temperatures on the planet reach 900 degrees Fahrenheit.

KRISThat's hotter than your oven.

PAULOnly two spacecraft have transmitted images of the planet's surface.

RACHELImages from the Russian Venera landers shows the surface to be rocky. The chemical composition of these rocks matches basalt, or lava rock.

KRISThere are very few craters on Venus. This is partly due to the protection its thick atmosphere provides.

RACHELBut it's also due to the fact that Venus resurfaces itself with volcanic eruptions. Over a few hundred million years, Venus recoats its entire surface in fresh lava.

KRISAny craters that may have formed since the last time Venus was resurfaced are buried in the new lava flows.

PAULSo the surface of Venus is not very pleasant, but what about those attractive clouds?

RACHELAttractive is definitely relative here. The clouds of Venus consist almost entirely of sulfur compounds, including sulfuric acid.

KRISSo the weather report of Venus occasionally calls for sulfuric acid rain. But because of its broiling surface temperature, the rains never make it to the ground.

PAULThat's Idaho Skies for the fifth week of March. Join us next month and hear about the astronomical events visible from Idaho. For Idaho Skies this is Paul.

RACHEL..Rachel..

KRIS.. and Kris.

Transcript: 14 - 20 March

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

RACHEL..Rachel..

KRIS..And Kris

PAULOur next spacecraft to Mars will arrive at the red planet on the tenth..

RACHELThis is the Mars Reconnaissance Observer, or MRO. MRO is a spy satellite for Mars.

KRISThe cameras on MRO are so good that they can see objects on Mars as small as one yard across.

RACHELThe stated goal of MRO is to follow the water. If we want to find life, or past life, on Mars, we’ll need to look where the water is located. This is what MRO can do with its camera.

KRISYou can read more about this mission at its website, marsprogram.jpl.nasa.gov/mro

PAULLet the moon be your guide to Saturn and the Beehive star cluster.

RACHELOn the evening of the tenth you’ll find the Beehive sandwiched between the moon and Saturn.

KRISSaturn is the pale yellow star just to the west of the gibbous moon.

RACHELTo find the Beehive star cluster, place the moon on the left side of your binoculars and Saturn on the right side. Between them will be a splash of star dust called the Beehive star cluster.

KRISThe moon’s light will wash out some of the stars in the cluster. So let your eyes adapt to the dark for several minutes before looking for the Beehive.

RACHELThen once you find the Beehive, move your binoculars away from the moon until it leaves your field of view. This let’s you see fainter stars in the cluster.

PAULThe moon is at apogee on the night of the 12TH.

KRISRecall that apogee means the moon is at its greatest distance from Earth for the month.

RACHELThis month lunar apogee is at a distance of 252 thousand and 450 miles. That’s equivalent to 84 trips across the United States.

KRISIn terms of distances in the solar system, this is pretty short. So its no wonder that it takes months to fly to Mars and years to reach the outer solar system.

PAULA discovery that doubled the size of the known solar system occurred 225 years ago on the 13TH.

KRISSince ancient times, humans had only known about five stars that traveled around the night skies. The Greeks called these stars wanders, or planets.

RACHELThere were still only five known planets in 1781 when the German astronomer William Herschel was a church musician in England during the reign of King George the third.

KRISAt night Herschel scanned the sky with his many telescopes. Herschel’s telescopes were among the best in the world at that time.

RACHELSince many objects still remained to be discovered in the heavens, he often let the stars drift through his telescope. Herschel watched at the eyepiece as the earth’s rotation brought objects through the field of view of his telescope.

KRISTo maintain his eyes’ sensitivity to faint light, Herschel called out his observations to his sister, Caroline. Caroline sat near the light and recorded her brother’s observations in his observation book.

RACHELCaroline was an accomplished astronomer herself. She was the first woman to discover a comet and eventually discovered a total of eight comets. This was a record for women in the 18TH century.

KRISOn the night of the 13TH, Herschel found a small circular object in his telescope. At first he thought he had discovered a new comet.

PAULWe’ll have more to say about Herschel’s discovery and the anniversary of modern rocketry next week. That’s Idaho Skies for the third week of March. For Idaho Skies this is Paul...

RACHEL..Rachel..

KRIS.. and Kris

Transcript: 7 - 13 March 2006

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

RACHEL..Rachel..

KRIS..And Kris

PAULThe moon is our guide to Mars, the Pleiades, and Hyades on the night of the fifth.

KRISFrom west to east, you’ll see the Pleiades, the moon, Mars, and the Hyades.

RACHELThis grouping spans an angle of ten degrees, or about the width of your fist when you fully extend your arm.

KRISThat’s a little wider than your binocular’s field of view. But still, they’ll make an attractive sight.

PAULThe moon is at first quarter the next day, the sixth.

RACHELTake advantage of the warmer March evenings to observe the first quarter moon with your binoculars or telescope.

KRISYou’ll see lots of lunar craters in the moon’s south and several mountain ranges in the north.

RACHELAt the moon’s two o’clock position, you’ll see a dark oval shape.

KRISThis is a lunar maria called the Mare Crisium, or the Sea of Crises.

RACHELThe lunar maria are flat lava plains that formed after large meteoroids, called planetesimals, impacted the moon.

PAULThe resulting large crater is called an impact basin and the lunar crust within the basin is deeply fractured.

KRISThree point eight billion years ago magma, or molten rock, welled up from below the lunar surface. The magma filled the basin in dozens of thin lava sheets.

RACHELIf you had been on the moon at this time, you would have even seen fountains of lava shooting into the black lunar skies.

KRISToday the moon is cold, so there are no more volcanic eruptions. Now the lunar surface is very quiet geologically speaking.

RACHELThe constant rain of meteor impacts has broken up the lava sheets creating a dark dusty plain.

KRISOn Earth plate tectonics has destroyed the signs of the great impacts Earth must have suffered over three point eight billion years ago.

PAULSo if we want to study the impact record of the solar system, we must send robots and humans to places like the moon.

PAULSputnik 9, or Korabl-Sputnik 4, was launched 45 years ago on the ninth.

KRISSputnik 9 carried a dog named Chernushka on a single orbit around Earth. In addition to the dog, there were also mice and a guinea pig onboard.

RACHELThe last passenger was Ivan Ivanovich, a mannequin.

KRISIn Russian, the name Ivan Ivanovich is similar to John Doe in the United States.

RACHELIvan and his companions were launched in preparation for the first launch of the human into space. Ivan and his comrades returned safely to Earth, giving the Soviets confidence in their spacecraft, Vostok.

KRISThe flight was so successful that the Soviets only launched one more test before they made space history. Next month we’ll talk about their cosmonaut, Yuri Gagarin.

PAULThat’s Idaho Skies for the second week of March. Join us next week when we’ll tell you how you can find the Beehive star cluster and about astronomer William Herschel. For Idaho Skies this is Paul.

KRIS..Kris..

RACHEL.. and Rachel.

Idaho Skies is a production of NearSys and Boise Community Radio. Dark skies and bright stars.