Monday, June 30, 2014

Idaho Skies Transacript for July 27 - Aug 2

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

RACHEL
...and Rachel.

PAUL
Like the vast majority of orbits in our solar system, the moon’s orbit around Earth is not a perfect circle.

RACHEL
Closed orbits that are not perfect circles are called elliptical.

PAUL
You can think of them as perfect ovals, but not like an egg.

RACHEL
At its closest to Earth, the distance between the center of the moon and the center of Earth is 225,291 miles.

PAUL
At its greatest distance, the moon is 26,619 miles father away.

RACHEL
Perigee is the term for the closest distance and apogee is the term for the greatest distance.

PAUL
Due to its gravitation interaction with the sun, the distances of lunar apogee and perigee varies from month to month.

RACHEL
On the 28th, the apogee of the moon’s orbit is its greatest for the entire year, about 700 miles farther away than usual.

PAUL
At its greatest distance, it would take you over 9 ½ years to walk to the moon.

RACHEL
On July 30, 1610, Galileo became the first astronomer to observe Saturn’s rings through a telescope.

PAUL
Unfortunately, Galileo’s 20-power telescope was not good enough to show the true nature of the rings.

RACHEL
He thought he was seeing handles on opposite sides of Saturn.

PAUL
Later on, he thought he was seeing two very large satellites.

RACHEL
Things got more confusing for Galileo when two years later, when these objects disappeared altogether.

PAUL
It took decades before Cassini finally figured out that astronomers were seeing rings around Saturn.

RACHEL
Fortunately, you can see Saturn’s rings tonight though a small telescope or even spotting scope and you won’t suffer the confusion Galileo did.

PAUL
The Southern Delta Aquarid meteor shower peaks on the night of the 29th and morning of the 30th.

RACHEL
It’s a pretty good meteor shower and you can expect to see up to 20 meteors per hour in dark skies.

PAUL
Better still, the moon is young and it sets before midnight.

RACHEL
So its light won’t interfere with watching the fainter meteors.

PAUL
Adding to the number of meteors is the fact that July and August contain many overlapping meteor showers.

RAHCEL Any Southern Delta Aquarids will appear to originate from the southeast.

PAUL
So dress warmly and enjoy a shower, meteor shower that is.

RACHEL
That’s Idaho Skies for the last week of July. Join us next month for the space and astronomy events for Idaho.

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.

Idaho Skies Transcript July 20-26

RACHEL
Welcome to Idaho Skies for the third week of July. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
We celebrate two important spacecraft landings this week.

PAUL
And they both occurred on the 20th of July

RACHEL
Thirty-eight years ago, the spacecraft Viking 1 landed on Mars.

PAUL
It was a good thing that JPL engineers placed Viking 1 in Martian orbit before it attempting a landing.

RACHEL
That’s because when the spacecraft arrived at Mars, the initial landing site was found to be too rocky and dangerous for the lander.

PAUL
After JPL found a safer location, Viking 1 successfully touched down on Chryse Planitia, or the Plain of Gold on July 20, 1976.

RACHEL
The Viking 1 lander was nuclear powered and operated on Mars for six years.

PAUL
It determined that Mars had no obvious signs of life.

RACHEL
As a result of the negative findings, there was some reluctance in NASA to go back to the planet for further study.

PAUL
Our second landing celebration is Apollo 11.

RACHEL
Forty-five years ago on the 20th, Armstrong and Aldrin landed on the moon.

PAUL
After six hours of rest, they climbed out of their lander and spent 2-1/2 hour exploring the moon.

RACHEL
Do you remember the name of their lunar lander?

PAUL
Sure, it was Eagle.

RACHEL
Yep, and Columbia was the Apollo capsule that remained in lunar orbit with astronaut Michael Collins.

PAUL
Armstrong, Aldrin, and Collins safely returned to Earth on the 24th.

RACHEL
And they brought back 47 pounds of lunar rock and dust.

PAUL
It was the fulfillment of Kennedy’s pledge to put a man on the moon before the end of the decade and bring him back safely.

RACHEL
Speaking of the moon, it moon passes close to the Pleiades star cluster on the morning of the 21st

PAUL
And the Hyades star cluster on the morning of the 22nd.

RACHEL
The Pleiades and Hyades are examples of loose groupings of stars called galactic star clusters.

PAUL
The stars in a galactic star cluster tend to be young, only on the order of tens to hundreds of millions of years old.

RACHEL
Because of their recent birth, they are rich in elements heavier than helium.

PAUL
That increases their chances of having planets containing the raw materials of life.

RACHEL
We just need to wait a billion years or so to find out if life developed.

PAUL
That’s Idaho Skies for the third week of July. It’s the start of meteor shower season and next week we’ll tell you about the first one to watch.

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.

Idaho Skies Transcript for July 13-19

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

RACHEL
...and Rachel.

PAUL
Idaho has several opportunities to see the innermost planet this week.

RACHEL
The best morning is the 16th.

PAUL
To find Mercury, you’ll first need to find the Morning Star.

RACHEL
That’s Venus and it appears in the low northeast at 5:15 AM.

PAUL
Look below and left of Venus for a fainter star.

RACHEL
That will be Mercury.

PAUL
Mercury will be easy to find if you have a clear horizon.

RACHEL
Unfortunately, Mercury doesn’t climb very high above the horizon this month.

PAUL
Do you know how Mercury got its name?

RACHEL
It got its name because it travels very quickly around the sun.

PAUL
The Greeks and Romans thought it had the speed and mobility of the Roman god, Mercury.

RACHEL
Did you know that a year on Mercury lasts only 88 Earth days?

PAUL
However, from our perspective on the moving Earth, it appears Mercury’s year lasts 116 days.

RACHEL
Still, that’s shorter than any other planet.

PAUL
So Mercury really does deserve its name.

RACHEL
The moon is located just below Aries the Ram on the morning of the 19th.

PAUL
To locate Aries, follow the terminator of the moon northward.

RACHEL
In a short distance, this path will take you to a flat triangle of three stars.

PAUL
Those three stars form Aries.

RACHEL
Astronomers call the brightest star of Aries, Alpha Arietis.

PAUL
But you can call it Hamal.

RACHEL
Hamal is just about 50 light years away.

PAUL
This means that if you were born in 1964, then Hamal is your birthday star this year.

RACHEL
The fact that we can see Hamal 50 light years away means that it’s much brighter than the sun.

PAUL
At a distance of 50 light years, the sun would be invisible except in a telescope.

RACHEL
Hamal is an orange star, which indicates its cooler than our sun.

PAUL
However, since it’s brighter than the sun overall, its must be a giant star.

RACHEL
In fact, astronomers have determined that Hamal is about 15 times larger than the sun.

PAUL
That’s Idaho Skies for the second week of July. We celebrate two American planetary landings next week.

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 July 6-12

RACHEL
Welcome to Idaho Skies for the first week of July. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
It’s a shame we don’t live in Chile or Argentina.

PAUL
Why?

RACHEL
Because they get to see the moon pass over Saturn on the afternoon of the 7th.

PAUL
So what do we get to see instead?

RACHEL
We’ll see the moon and Saturn with a separation of 1.3 degrees between them.

PAUL
Since the moon has an apparent diameter of ½ of a degree, they’ll be separated by less than three times the moon’s apparent diameter.

RACHEL
And that’s bound to be an attractive sight, so get you binoculars out.

PAUL
When an astronomical body like the moon covers another object, astronomers call it an occultation.

RACHEL
That’s right and occultations are important tools in astronomy.

PAUL
Because when the time of the occultation is carefully measured, astronomers can accurately measure positions of bodies, like asteroids.

RACHEL
And by measuring the time of the occultation for telescopes in many locations, astronomers can determine the size and shape of an asteroid.

PAUL
New planetary rings and asteroid satellites have been discovered using occultation timings.

RACHEL
Hey, there’s a Super Moon on the 12th.

PAUL
That’s because the moon becomes full just a few hours before reaching its closest point to Earth.

RACHEL
As a result of its closeness this month, the full moon will be slightly larger and brighter than usual.

PAUL
You probably won’t notice this difference with your eye, but you can if you take a picture of the full moon.

RACHEL
After taking a picture of the full moon, record your camera settings.

PAUL
Then take an identical picture six months from now.

RACHEL
And be sure you used the same camera setting for both photographs.

PAUL
When you compare the two images, you’ll see that July’s full moon was both the larger and brighter full moon.

RACHEL
Don’t worry if you can’t record this month’s Super Moon, we’ll get three more Super Moons this year.

PAUL
That’s Idaho Skies for the first week of July. Mercury is visible next week, but not for long. Listen in to learn where you can find it.

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.

This month look for the Keystone of Hercules. The Keystone consists of four stars arranged in a keystone, or truncated triangle shape. The Keystone represents the body of the hero Hercules. His arms and legs are arranged such that he is upside down and kneeling.

Find the Keystone by first locating Vega, the brilliant blue-white star located nearly overhead just after dark. From Vega, look 16 degrees to the west-southwest for keystone pattern of four stars. Sixteen degrees is about the width of your hand and extended thumb when viewed from your outstretched arm.

The stars of the Keystone, clockwise from the upper left are Pi, Eta, Zeta, and Epsilon Herculis. Although the Keystone appears flat against the sky, it’s actually three-dimensional. Pi is 370 light years, Eta 112 light years, Zeta 35 light years, and Epsilon 163 light years away. However, these distances pale in comparison to the distance to the fuzzy cloud located between Eta and Zeta (the side of the keystone away form Vega). That fuzzy cloud is M-13, the Hercules Globular Cluster and its located 25,000 light years away. In a pair of binoculars, M-13 looks like a fuzzy star. You’ll know you’re looking at it when all the stars appear as sharp pin points of light, except for this one. M-13 is more impressive through a telescope though. A good telescope will resolve the cluster into a ball of tiny stars immersed in fog. In a large telescope, M-13 looks like a pile of salt on blackest velvet.

July Overview

  • The length of the day shortens by 46 minutes this month
  • Mercury and Venus make a close, but low approach on the morning of the 17th
  • Earthshine on the moon is visible in the evening on the 1st and again in the morning starting on the 22nd
  • The moon approaches Venus the morning of 24th
  • The moon approaches Mars the evening of the 5th.
  • The moon approaches Saturn the evening of the 7th.

Transcript for June 29 to July 5

RACHEL
Welcome to Idaho Skies for the last week of June. We’re your hosts, Rachel...

PAUL
...and Paul.

RACHEL
Earth received an interplanetary wake up call 106 years ago on the 30th.

PAUL
June 30, 1908 started out as just another day for the Tungus people in Siberia.

RACHEL
The morning was interrupted at 7:14 when they saw the sky split in two by a great meteor.

PAUL
It was bright; glowing more brightly than the sun as it fell from the sky.

RACHEL
This meteor didn’t go out with the whimper like most meteors.

PAUL
Nope, the tremendous heat of its reentry vaporized the space rock and it exploded some 5 miles above the ground.

RACHEL
The 50 foot diameter meteoroid or comet exploded with the force of a 10 to 15 megaton nuclear bomb.

PAUL
People over one hundred miles away where knocked off their feet and their windows were shattered.

RACHEL
No one has ever found a crater or meteorite fragments at Tunguska because the destruction of the meteor was total.

PAUL
What people did find however was the remains of a forest with its trees knocked over in a pattern radiating away from the center of the explosion.

RACHEL
Events like Tunguska occur naturally on Earth.

PAUL
And they point out the need to monitor the skies regularly for approaching extraterrestrial threats.

RACHEL
Earth reaches aphelion at 8:00 PM on the 3rd.

PAUL
Aphelion is the point in Earth’s orbit farthest from the sun.

RACHEL
On the 3rd, Earth will be 94.5 million miles from the Sun.

PAUL
It would take nearly 144 years to traverse that distance in a car traveling at 75 miles per hour.

RACHEL
It would take over 3.1 million gallons of gas if the car had a gas mileage of 30 miles per gallon.

PAUL
It’s the 960th anniversary of the Crab Nebula supernova on July 4th.

RACHEL
A supernova marks the end of the massive star’s life.

PAUL
And when it explodes, people can see bright star appear in the sky where once there was none.

RACHEL
Chinese astronomers reported that the new star remained visible for a year before finally fading out of sight.

PAUL
Today we understand that some supernova explosions lead to the formation of a rapidly rotating neutron star or pulsar.

RACHEL
The neutron star then makes the expanding as cloud of the supernova glow brightly.

PAUL
And that’s what astronomers see today when they look up at where Chinese astronomers reported a guest star 960 years ago.

RACHEL
That’s Idaho Skies for the last week of June. Join us next month for the space and astronomy events for Idaho.

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.

Sunday, June 22, 2014

Transcript for June 22 to 28

RACHEL
Welcome to Idaho Skies for the fourth week of June. We’re your hosts, Rachel...

PAUL
...and Paul
.

RACHEL
Some of our listeners know that Aries represents the ram with the Golden Fleece in Greek mythology.

PAUL
Have you ever wanted to know how to find the constellation of Aries the Ram?

RACHEL
Well, at 4:00 AM on the 22nd the constellation is located just above the moon.

PAUL
Aries appears as the small 3-star constellation with a squat triangular shape sitting above the moon.

RACHEL
The triangle has a base several times wider than the moon and it points nearly straight up.

PAUL
Pluto’s first moon was discovered 36 years ago on the 22nd.

RACHEL
For 48 years after Pluto’s discovery, the outermost world remained an enigma to astronomers.

PAUL
That changed however when astronomer Jim Christy discovered that Pluto had a satellite.

RACHEL
The new satellite was named Charon, after the ferryman of the dead.

PAUL
The gravitational interaction between Pluto and Charon and a fortunate set of eclipses taught astronomers a lot about Pluto.

RACHEL
For one, they learned that Pluto had a diameter of 1,400 miles.

PAUL
Charon’s orbit told astronomers that Pluto must consists of a large rocky core and thinner coating of ice.

RACHEL
Since Charon’s discovery, astronomers have discovered four other satellites orbiting this distant world.

PAUL
All five satellites have densities close to that of water.

RACHEL
Therefore, it’s known that they are predominately composed of ice.

PAUL
It’s most likely the five satellites formed as the result of a collision between Pluto and another icy body.

RACHEL
There were a lot of these collisions during the formation of the solar system and our moon is most likely a product of one.

PAUL
The moon makes a call on Venus, the Morning Star on the 24th.

RACHEL
At 5:00 AM, look very low in the east for this attractive pair.

PAUL
Their distance apart is a scant two degrees, so they will fit well together in your binoculars.

RACHEL
That’s Idaho Skies for the fourth week of June. Be sure to listen in next week to learn about the Tunguska event.

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
.

RACHEL
Dark skies and bright stars.