This month look for the star Betelgeuse or Alpha Orionis in the constellation of Orion the Hunter. Betelgeuse is the second brightest star in Orion, which is one of the most recognizable constellations in the winter sky. Betelgeuse is located in the upper left corner and is orangish in color. Betelgeuse and Orion are located high in the southeast on January nights after sunset.

Betelgeuse comes from the Arabic for “hand of the central one”. The central one is a female Arabic character. Feminine names in Orion the hunter are not unusual, one of the constellation’s other bright stars is named Bellatrix, which is also has a female connotation. The light you see from Betelgeuse left the star in the year 1371.

Betelgeuse (the name sounds like beetle juice) is one of the largest stars in our galaxy. If it replaced our sun, its vaporous surface would reach over half way to Jupiter, engulfing the planets Mercury, Venus, Earth, and Mars in the process. That’s 600 times larger than our sun! Betelgeuse is a giant cool red star today; but in its stellar youth was a massive white hot star. Being seven times more massive than the sun, Betelgeuse burned through its main supply of hydrogen faster than the sun. Today, deep in its core, nuclei of helium atoms are fusing into carbon and oxygen. Outside that core is a shell of fusing hydrogen. Since that helium is denser than hydrogen, the helium created by the fusion of hydrogen sinks into the star’s core where it is fused into more carbon and oxygen. The increased heat generated by star’s fusion of hydrogen and helium has puffed up its atmosphere. The expanded atmosphere is a cool red-orange color as a result. However, because of its great size, Betelgeuse over 40,000 times brighter than our sun even though its surface is cooler.

Betelgeuse is so massive that it may eventually fuse the atoms in its core all the way to iron. When it does, the star will face an energy crisis that pales to anything we’ll ever see. That’s because iron is a dead end element and it’s impossible to fuse it into heavier elements to release energy. Since stars need that energy to support their weight, they collapse when their cores contains too much iron. The inward collapse of a massive iron core squeezes subatomic protons and electrons into neutrons and an immense blast of neutrino radiation that will outpace the emission of light from the dense core of the star. Betelgeuse’s blast of neutrino radiation will arrive at earth some 643 years after the core collapses, signally that the star is beginning to exploding as a supernova. When it goes, Betelgeuse will shine as brightly as the crescent moon and be visible in broad daylight.

Transcript for December 21st to 27th

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

RACHEL
...and Rachel.

BRING DOWN MUSIC

PAUL
The sun reaches its southernmost declination at 5:00 PM on the 21st.

RACHEL
That means it appears overhead to anyone residing at 23 degrees south latitude.

PAUL
That makes it the first day of summer in Australia and the first day of winter for us in the Northern hemisphere.

RACHEL
Ahh, just imagine, spending Christmas on an Australian beach.

PAUL
The distance between the sun and Earth has nothing to do with the seasons.

RACHEL
That’s right; the seasons are solely the result of Earth’s tilt with respect to its orbital plane around the sun.

PAUL
As a result of this tilt, the sun crosses the sky at its lowest path on the first day of winter.

RACHEL
And the hours of daylight are at their shortest length.

PAUL
The result is that the sun’s light is less intense and provides warmth for least number of hours.

RACHEL
Adding insult to injury, the night lasts it longest.

PAUL
Therefore, the ground has even more time to radiate its warmth back into the sky.

RACHEL
The combination of these three effects creates the coldest days of the year.

PAUL
However, its takes the ground and atmosphere another month to catch up to all that cold.

RACHEL
A minor meteor shower peaks on the night of December 22nd and morning of the 23rd.

PAUL
It’s the Ursid meteor shower and you can see it radiating out of the high north, near the Little Dipper or Ursa Minor.

RACHEL
Usually we don’t see more than 10 meteors per hour from this shower.

PAUL
However, it once produced an outburst of 100 meteors per hour.

RACHEL
The moon is only a day old tonight, so its light won’t interfere if you choose to watch the Ursid meteor shower.

PAUL
The 23rd presents us with the opportunity to observe a two-day old moon.

RACHEL
This is such a thin crescent moon that most people won’t chance upon it unless they know to look for it.

PAUL
So begin your search low in the southwest at around 6:15 PM.

RACHEL
You might find a pair of binoculars helpful.

PAUL
But please, please only use them after the sun has set.

RACHEL
After all these months, Mars is still visible in our night sky.

PAUL
Yep. And you can find the red planet on the 24th.

RACHEL
You first need to find the moon in the low southwest.

PAUL
Mars will be the slightly yellowish star located to the moon’s left.

RACHEL
Mars is not really red; its surface is more orange in color.

PAUL
That color comes from the oxidized iron in its soil.

RACHEL
So the surface of Mars is actually rusty.

PAUL
Because its soil doesn’t contain organic material, we actually call the soil of Mars its regolith.

RACHEL
That’s Idaho Skies for the fourth week of December. You can use your Christmas binoculars to observe a star cluster 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.

Transcript for December 14-21

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

PAUL
...and Paul.

RACHEL
The brightest star of Virgo the Maiden is located below the moon on the morning of the 16th.

PAUL
The star’s name is Spica and it represents a wheat stalk in the hand of Virgo.

RACHEL
Look for the moon in the low southeast as you drive to work this morning.

PAUL
Spica is the brightest star below the moon.

RACHEL
Double stars are fun astronomical objects.

PAUL
They are excellent tests of an astronomer’s visual acuity and the optical quality of his or her telescope.

RACHEL
Astronomers and physicists have even used the motion of double stars around each other to prove that gravity works light years away just like it does on Earth.

PAUL
So take some time to look for an easy double star on the morning of the 18th.

RACHEL
Its name is Zubenelgenubi and it’s located below the moon.

PAUL
Zubenelgenubi means Southern Claw of the Scorpion in Arabic.

RACHEL
Wait, isn’t Zubenelgenubi is the brightest star in Libra the Scales?

PAUL
It is today, but over 2,000 years ago, Libra was actually the claws of Scorpius.

RACHEL
This changed after precession carried the sun to the claws of Scorpius on the first day of autumn, otherwise known as the autumnal equinox.

PAUL
Because the equinox is a time when day and night are equal in length, the Greeks and Romans declawed Scorpius and turned its starry claws into a scale.

RACHEL
Listeners with sharp eyes are capable of seeing Zubenelgenubi as two closely spaced stars without using binoculars.

PAUL
Use your binoculars however and you’re sure to see two unequally bright stars next to each other.

RACHEL
This stellar pair is 77 light years away.

PAUL
Saturn is a morning planet this month.

RACHEL
You can locate it on the 19th if you look for the brightest star below the moon at 7:00 AM.

PAUL
That may be a bit early to look for this planet, but you’ll be the first on your block to see Saturn.

RACHEL
If you have a telescope or spotting scope handy, then point it at Saturn.

PAUL
A telescope magnification of 25-power is enough to see its rings.

RACHEL
Which means even a spotting scope is up to the task.

PAUL
The distance across the rings is slightly larger than the distance between Earth and its moon.

RACHEL
Saturn is not the only planet to have rings.

PAUL
That’s right; all the large planets have their own rings.

RACHEL
However, Saturn’s are the most wonderful and stunning.

PAUL
That’s Idaho Skies for the third week of December. The winter solstice occurs next week.

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.

Transcript for December 7 - 13

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

RACHEL
...and Rachel.

PAUL
The constellation of Gemini the Twins consist of two rows of stars

RACHEL
The two rows of stars are horizontal in the eastern sky during December evenings, but become more vertical at around midnight.

PAUL
You can locate Gemini on the 7th by looking for the two rows of stars located to the moon’s left.

RACHEL
One row is higher than the moon and the other is lower.

PAUL
The two bright stars at the left end of the row of stars are named Castor and Pollux.

RACHEL
You can tell the difference between them because Pollux is slightly brighter than Castor.

PAUL
In Greek mythology, Castor was the mortal twin and Pollux his immortal brother.

RACHEL
The light of Pollux left 34 years ago, so if you’re 34 this year, Pollux is your birthday star.

PAUL
And Castor is the birthday star of everyone 51 years old.

RACHEL
New Horizons is scheduled to wake up from its hibernation on the 7th.

PAUL
New Horizons is an American spacecraft bound for Pluto.

RACHEL
The spacecraft’s closest approach to Pluto occurs on July 14th next year.

PAUL
This will be the first time humans have ever been able to see Pluto as more than just a few pixels or a faint smudge.

RACHEL
And who knows what we’ll discover, perhaps geysers of liquid nitrogen.

PAUL
The eighth brightest star in the sky is located to the moon’s right on the night of the 9th.

RACHEL
The star’s name is Procyon and it’s the alpha star of the constellation Canis Minor, the Little Dog.

PAUL
Procyon is so bright because it’s only 12 light years away from the solar system.

RACHEL
Hey, where’s Jupiter?

PAUL
Why it’s above the moon late on the evening of the 11th.

RACHEL
Through a good pair of binoculars or a spotting scope, you’re likely to see all four of its Galilean satellites.

PAUL
Starting from the bottom and going up, the moons are Ganymede, Europa, and Io.

RACHEL
Jupiter is next and through a spotting scope or small telescope, it will show a disk.

PAUL
Above Jupiter is Callisto.

RACHEL
You may have difficulty splitting Io and Europa in binoculars, but not through a spotting scope.

PAUL
Don’t forget that through an astronomical telescope, the order of the satellites is backwards.

RACHEL
One of the year’s best meteor showers peaks on the night of the 13th and morning of the 14th.

PAUL
Normally the Geminid meteor shower does not disappoint with its plentiful number of yellowish meteors.

RACHEL
In fact, when viewed from dark skies, you can expect to see more than a meteor per minute on average.

PAUL
Unfortunately, this week the moon is a waxing gibbous.

RACHEL
Therefore, its large and bright surface will wash out many of the fainter members of the shower.

PAUL
If you have some time and the inclination, dress warmly and spend a little time observing this shower.

RACHEL
That’s Idaho Skies for the second week of December. Next week we’ll tell you how you can observe Saturn’s rings.

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.

Transcript for November 30th to December 6th

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

PAUL
...and Paul.

RACHEL
The moon helps locate the seventh planet on the 1st.

PAUL
The 7th planet is named "your anus", although I prefer to pronounce it as Uranus to keep people from giggling.

RACHEL
To find Uranus, look for two stars on the right side of the moon that form a triangle with the moon.

PAUL
That means the moon is the left corner of the triangle.

RACHEL
The star closest the moon is the top of the triangle and it’s called 96 Piscium.

PAUL
Twice as far away from the moon is slightly fainter Uranus.

RACHEL
The moon, 96 Piscium, and Uranus will all fit within half of your binocular’s field of view.

PAUL
Do you want to find the constellation of Aries the Ram?

RACHEL
It’s the flat triangle of stars right above the moon on the evening of the 3rd.

PAUL
Many of our listeners are familiar with Aries; in Greek mythology, it’s the ram with the Golden Fleece.

RACHEL
Some of the best star clusters are among the closest ones to our solar system.

PAUL
And they’re visible to us in the Northern hemisphere.

RACHEL
Look for two of these star clusters above and below the moon on the evening of the 4th.

PAUL
The Pleiades is the small dipper-shaped cluster of stars above the moon.

RACHEL
The other is the Hyades star cluster and it’s the larger V-shaped splash of stars below the moon.

PAUL
Both are excellent objects for your binoculars.

RACHEL
The moon immerses itself within the Hyades star cluster on the evening of the 5th.

PAUL
When observed separately, the moon seems larger than the Hyades star cluster.

RACHEL
On the 5th however, you’ll be able to see how much larger the Hyades is than the moon.

PAUL
Be sure to use your binoculars on this attractive sight.

RACHEL
The moon is located above Orion the Hunter on the evening of the 6th.

PAUL
Orion appears as a tall rectangle of bright stars.

RACHEL
Going from left to right, the top two stars are named Betelgeuse and Bellatrix.

PAUL
The two bottom stars, also going form left to right are names Saph and Rigel.

RACHEL
Check out Betelgeuse.

PAUL
Betelgeuse has a reddish-orange tint because it’s a red giant star.

RACHEL
It’s a red giant because it is nearing the end of its life.

PAUL
Its core is now filling with the helium ash from its fusion of hydrogen.

RACHEL
Some day in the near future, it may accumulate enough helium to start fusing it for energy.

PAUL
Until then, it will remain a huge and bloated star.

RACHEL
Betelgeuse is so bloated that if it replaced our sun, the star would engulf all the inner planets out to Mars.

PAUL
Ouch!

RACHEL
That’s Idaho Skies for the first week of December. The moon passes by the Heavenly Twins next week.

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.