The Night Sky Tonight

Tonight,  May 21, 2015, Venus is quite clear near the waxing crescent moon in the western sky. Venus is the third-brightest celestial object in our view, after the sun and moon.

The fourth-brightest celestial body is Jupiter and it is above the moon and Venus and can also be seen at dusk. If it is a clear night for you, you will see, as the darkness deepens, the bright star Regulus above Jupiter, and the Gemini stars, Castor and Pollux , will come out above Venus.



The Precession of the Equinoxes: Spring

Spring has arrived – even if there is still snow on the ground in Paradelle.

I have been writing about the changing of the seasons for a few years now and there is only so much you can say about the spring equinox, autumn equinox and the solstices of summer and winter. I try to find a new path into them and for this season I am thinking about spring in music and in the sky.

As a quick review, “equinox” is derived from the Latin aequus (equal) and nox (night), because the night and day are approximately equal in length on that day.  We experience an equinox in spring and fall when the tilt of the Earth’s axis is inclined neither away from nor towards the Sun which is vertically above a point on the Equator.  An equinox actually occurs at a specific moment in time (for 2015, today, March 20 at 6:45 pm EDT), but commonly people refer to the entire day as the equinox or first day of the season.

It is very “northern” of me to say it is the Spring Equinox, because in the Southern Hemisphere this celestial observation means the start of autumn. Being that autumn is my favorite season, I have often thought that I should travel between the two hemispheres to get two autumns each year. Unfortunately, the Sun doesn’t allow me to live in a three-season world and avoid winter.

The Four Seasons (Italian: Le quattro stagioni) is a set of four violin concertos by Antonio Vivaldi (1720) and his best-known work. My knowledge of classical music is shallow, but I was reading about this piece and discovered a few interesting nuggets.

I like that Vivaldi provided some additional instructions with the music, such as “The barking dog” in the second movement of “Spring.”

It seems that there is some debate as to whether or not the concertos were written to accompany four poems (sonnets) or if the sonnets were written to accompany the music. It doesn’t seem to be known who wrote these sonnets,and some say that Vivaldi wrote them himself. Either by plan or coincidence, each sonnet is broken down into three sections, nicely corresponding to a movement in the concerto.

The Four Seasons is sometimes classified as “program music,” instrumental music that intends to evoke something extra-musical. For me, the four pieces, especially “Spring,” does evoke the season.

If you listen to the music tonight, I suggest that you turn your eyes to the sky and look for Arcturus. It is one of the brightest stars. Due to its northerly location on the sky’s dome, it is visible for much of the year in the Northern Hemisphere and its appearance in the evening sky heralds the coming of the spring equinox.

Like other stars, Arcturus rises four minutes earlier every day and now Arcturus will appear at dusk (instead of nightfall or early evening) which is its signal of spring in our hemisphere.

Arcturus is the brightest star in the constellation Boötes the Herdsman. It is not one of the best-known constellations. The name comes from the Greek Βοώτης, meaning herdsman or plowman (literally an ox-driver; from boos, related to the Latin bovis, “cow”). It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, but it was first used by Homer in his Odyssey as a celestial reference point for navigation.

Homer described it as “late-setting” or “slow to set.” It is not clear exactly whom Boötes is supposed to represent in Greek mythology is not clear. The story I will go with is that he was a son of Demeter, twin brother of Plutus, a ploughman who drove the oxen in the constellation Ursa Major. The ancient Greeks saw what we call the “Big Dipper” as a cart with oxen.

It seems a nice match with the spring that one myth associated with Boötes is that he invented the plow which certainly is associated with spring and planting. If you think of him as a “herdsman,” that works too, as those who watch over a herd of cows, sheep or other animals leads a nomadic life very much guided by the seasons. Spring is the time to move to those areas that were snow-covered and the tain and melting turns the land green again.

If staring up at the big sky makes you feel small and timeless – a good feeling, I believe – then also consider this: even the equinoxes are constantly changing. They are not fixed points but move westward along the ecliptic, passing through all the constellations of the zodiac in a period of 26,000 years. This motion is called the precession of the equinoxes. And we think that the 5000 year Mayan calendar was looking at a long period of time…

Sirius White and Black

This is about two Sirius topics. Not so serious and not very well connected, except for the name.

Sirius is the brightest star in the nighttime sky tonight and most of the winter. (Venus and Jupiter outshine Sirius this month but I’m not considering planets.) And Sirius is easy to find in that sky full of stars.  Almost everyone can find Orion’s belt of three stars (if that is no longer true, please don’t tell me. It would depress me immensely.), and if you follow the imaginary line of that belt of medium-bright stars in Orion’s Belt, you will arrive at this bright white Sirius.

sirius black

That other Sirius is Sirius Black,  a pure-blood wizard in the wizarding world of Harry Potter. He is the older son of Orion (Aha! A star connection!) and Walburga Black (from Saint Walpurga and that Walpurgis Night of witches?) , and the brother of Regulus (also named for a bright star).

Sirius parted ways with the Black family and their belief in blood purity. He was sorted into Gryffindor instead of Slytherin at Hogwarts.  According to the, he attended that school from 1971 to 1978, which coincides with my own college years.

I like Sirius. My favorite line of his is probably when he tells Harry “We’ve all got both light and dark inside us. What matters is the part we choose to act on. That’s who we really are.”  I agree and I would certainly have joined the Order of the Phoenix with him, Harry’s father, James, and Lupin. (I would have had my doubts about letting Pettigrew join.) I would have been happy to be a Marauder against Voldemort.

Sirius is Harry’s godfather – a title some might find odd for families of wizards.

sirius whiteThere are brighter stars than Sirius in absolute magnitude, but they are much farther away. Sirius is in the constellation Canis Major (the Greater Dog) and appears very bright because it is only 8.6 light-years away. Right in that constellation, Aludra and Omicron 2 are probably brighter but are also about 3,000 light-years away.

Sirius Black is an Animagus – a wizard who has learned to morph into an animal at will. Sirius becomes a massive black dog, like his brother star in Canis (dog) Major.

Imagining A Cosmic Year (and failing)

Our nearest star, the Sun, seems to move, rising and setting. But most people think of it as fixed at the center of our solar system as Earth and the other planets orbit around it.  We have this model in our head from a textbook or animation of them clustered like a children’s crib mobile.

Our Sun is moving. Everything in space moves. It circumnavigates the Milky Way galaxy that is made up of several hundred billion stars.

Numbers for calculating the sun’s journey aren’t very exact.  The Milky Way has a diameter of about 100,000 light-years. Can you imagine that? I can’t.

The Sun is traveling through the galaxy at about 140 miles per second. At that equally unimaginable speed, it would take about 230 million years for the sun to complete one circuit of the galaxy.

solarsystem hand

That’s what I am trying grasp today. A cosmic year – the length of the sun’s orbit around the Milky Way’s center

Where is the sun headed on this incredible journey? Astronomers say that our sun (and Earth and our little family of planets) are moving toward the star Vega and away from that brightest star, Sirius.

Poor Sun. It doesn’t even have a proper name like the other stars. Capitalize Sun to show some respect.

I can see Vega appearing over the northwest horizon in the early evening.  I look at it and then at Sirius towards the southeast during winter.

I try to imagine the path between them. It runs through me, but it is like imagining infinity.


We Are Stardust


“We are stardust.
Billion year old carbon.
We are golden.”
  – Joni Mitchell, “Woodstock”

Did you ever really wonder where you came from? Not relatives and ancestors and family trees, but the stuff that’s inside your body. And I mean even deeper than bones, organs, and muscles. Down to the molecules and atoms.

Where did those come from and how were they created?

It very early in the morning as I write this. It’s raining and the sky is dark and cloudy. But the stars are out there and I am traveling back in my mind to a time when the universe was very different.

Big bang. About 3 seconds long. And then that new universe expands and cools to a state where subatomic particles assembled into atoms. Or at least, so say most physicists. I’ll take it on faith for now, like knowing that those stars are out there tonight even though I can’t see them.

Hydrogen atoms formed first and then after a mere 300 million years, they clump together under the force of gravity, the pressure increases, they heat up (15 million degrees F) and fuse their nuclei together.

Now we move to number two on the periodic table of elements. Helium. That fusion releases a lot of energy, some is converted into light energy (see E=mc2 ) and we have a star.

I am simplifying to a ridiculous degree, but allow me for the purposes of telling the story.

A star produces all of the elements up to iron in the periodic table . Iron has 26 protons in its nucleus and to make higher elements, fusion requires more energy than it produces.  So, that star creates, fusion ceases and the core begins to cool. Eventually, that cooled core no longer expands and gravity quickly collapses the star.

It implodes. Supernova. What happens is not totally known but there is enough energy to now fuse some atoms into Nickel, Krypton, Gold, Uranium and other higher elements.

The stardust travels throughout the universe. One day it will clump together with other stardust and give birth to a new star. Circle.

Aside from hydrogen, all the elements can be viewed as stardust. The parts of our body that are not hydrogen are stardust. That is estimated to be about 40%.

Wish upon a star. Think of them as ancestors.

Want to know more about the science here? Want to know the math to arrive at that 40%? Check out

You can Download the “How much of the human body is made up of stardust?” poster illustrated above format_pdf  and order other posters

The Dog Days of Summer

Welcome to the dog days of summer, the days of especially hot and humid weather with little rainfall.

The name comes from the ancient Greeks. They believed that Sirius, the “dog star,” which rose along with the sun at this time of the year, was adding to the sun’s heat. They also believed that the weather made dogs go mad.

“Dog Days” (Latin: diēs caniculārēs) are the hottest, most sultry days of summer. In the northern hemisphere, they usually fall between early July and early September. (Not to forget our southern hemisphere friends – there it is usually between January and early March.)  The days will vary from place to place because of latitude and climate.  The general definition of the Dog Days is a time period that is very hot or stagnant, or marked by dull lack of progress.

Sirius is the brightest star in the night sky. It is almost twice as bright as Canopus, the next brightest star. The name “Sirius” is derived from the Ancient Greek Σείριος Seirios (“glowing” or “scorcher”). What we see with the naked eye as a single star is actually a binary star system (a white main sequence star – Sirius A – and a faint white dwarf companion – Sirius B).

The Romans tried to appease Sirius by sacrificing a brown dog at the start of the dog days.

The Egyptians marked the arrival of dog days as the beginning of the Nile’s flooding season, as well as their New Year celebrations.

The modern French term for both this summer period (and for heat waves in general) “canicule“, derives from this same term.  It means “little dog”, again referring to Sirius.

Icelanders refer to the Danish adventurer Jørgen Jürgensen as Jörundur hundadagakonungur (“Jørgen the dog-days King” in Icelandic).

“Dog days” has been adopted by the American stock market, because the markets tend to be slow and sluggish during these summer months, as a period of stagnation or inactivity.

There are many popular culture references to Dog Days. Perhaps the best known is Dog Day Afternoon, the1975 film directed by Sidney Lumet, with Al Pacino and John Cazale in which a bank robbery goes a bit mad during a hot NYC afternoon.