My Guiding Star

star spin

Anyone who looks up at the night sky and can identify a few stars, constellations or planets knows that everything is always moving.

Or is everything moving? Maybe we are the one who is moving.

There is an expression that your “North Star” is the thing that guides you. The actual North Star or Pole Star – which is named Polaris – is known for holding nearly still in our sky while the entire northern sky moves around it.

It really was a guiding star for ancient travelers and sailors. Like a compass, it showed you due North.

Polaris is located nearly at the north celestial pole which is the point around which the entire northern sky turns. If you painted stars on the ceiling of a room and had your own Pole Star at the center of the room and stood right below it, you could spin like a top and all the stars would circle over your head. Except for that Pole Star.

In my lifetime, the stars have been essentially fixed relative to one another, but over time they are moving around the center of the galaxy.  I wrote earlier about how even the North star has moved and the Pole Star has not always been Polaris.

The universe is still at times unimaginable.

The Return of the Dog Days

dog days
Once again, we enter the Dog Days of summer. These 40 days of especially hot and humid weather often have little rainfall, but here in the Paradelle Northeast of the U.S. we have been getting a lot of rain with our 90+ degree days and humidity.

The ancient Greeks believed that Sirius, the “dog star” was rising with the Sun at this time was adding to the Sun’s heat. After all, since Sirius is the brightest star in the sky, they assumed it would be a second Sun and give off heat like our nearest star.

Sirius is called the Dog Star because it’s part of the constellation Canis Major (Greater Dog).  Sirius means sparkling or scorching which is certainly what it seemed like to early astronomers. Sirius is almost twice as bright as Canopus, the next brightest star.

Those ancients also believed that the weather made dogs go mad. The Romans unfortunately tried to appease Sirius by sacrificing a brown dog at the start of the Dog Days.

Ancient Egyptians saw this time of Sirius arriving with the Sun as the beginning of the Nile’s flooding season. It was also their time for New Year celebrations.

“Dog Days” has become in modern times a term for any period of stagnation or inactivity. Wall Street marks this period as a generally slow and sluggish time for the markets (though earnings do create some heat).

star chart
via Etsy

The Importance of Darkness

night sky
Watcher of the Skies | Image by Pete Linforth

My friend Patricia, who is currently living in the American southwest, sent me an article about programs there to get out to places with dark night skies and see the stars. This is a new kind of travel that is known as astrotourism. There are travel companies and also national and state parks doing these programs.

This is not a time for travel, but I continue to do my stargazing here in Paradelle which definitely is not a dark-sky location. I was looking up at Orion the Hunter at the beginning of this year, but now I note that it has moved very low in the western part of the sky when the sun goes down.

Soon, Orion will disappear into the sun’s glare because, like all the stars, it shifts westward as we pass through the seasons.

In the daytime, I observe the Sun as it moves in the morning from one of my family room windows to another marking winter and summer for me.

Stars have to be in the far northern or southern sky (circumpolar) to avoid movement.  And all the stars and their constellations move westward in the course of a single night. Not that they are actually “moving” but because the Earth is spinning.

Orion is no exception. That motion, though, is due to Earth’s spin. Add to that spin our orbit around the Sun and things are constantly moving out there – from our point of view.

Indigenous peoples have always had a deeper connection to nature, the seasons, and the changes in the Moon, stars, and night sky. I was not surprised to read that Shash Diné, an off-the-grid bed-and-breakfast in the northeast tip of the Navajo Nation in Arizona has become an astrotourism place for night sky observations.

In The End of Night: Searching for Natural Darkness in an Age of Artificial Light, Paul Bogard writes about the loss of the dark night sky which has influenced our science and art.

The International Dark-Sky Association (IDA) is an organization that monitors light pollution and certifies “dark-sky places.”  In the United States, the densest concentration of these locations is found at the Four Corners where New Mexico, Arizona, Utah, and Colorado meet.

Light pollution makes it difficult to see things in the night sky, but it has other impacts on us. It disrupts wildlife, impacts human health, wastes money and energy, and even contributes to climate change. And it is increasing at twice the rate of population growth. Now, 83% of the global population lives under a light-polluted sky.

A Star to Mark a New Year

Sirius (bottom) and the constellation Orion (right) with its 3-star “belt.”                        (Hubble European Space Agency Image by Akira Fujii – spacetelescope.org)

Sirius is the brightest star in the sky.  Its common name is the Dog Star because it’s part of the constellation Canis Major (Greater Dog). “Sirius” means sparkling or scorching – a name given for its brightness in the night sky.  Sirius is almost twice as bright as Canopus, the next brightest star.

It reaches its highest point in the sky around the stroke of midnight every year and so tonight we can think of it as the New Year’s Star. Astronomers call this a midnight culmination of Sirius. What a cosmically strange coincidence it is that as we ring in the New Year, Sirius peaks in the sky. Is it a coincidence?

To find Sirius, I look North in Paradelle but at midnight I’m really looking up above. You should be able to find Orion’s three belt stars. Follow the belt’s line down to the left (west) and there is bright Sirius.

Like the sun, the stars rise in the east and travel westward across the sky.  Midway between rising and setting, the sun or any star reaches its highest point in the sky. Tonight, for Sirius, it will be at midnight.

At a distance of 2.64 parsecs (Yes, that’s a real thing), the Sirius system is one of Earth’s nearest neighbors. Sirius is gradually moving closer to our Solar System, so it will slightly increase in brightness over the next 60,000 years and then the distance will increase, and it will become fainter. Even then, astronomers say that it will still be the brightest star in the Earth’s night sky for the next 210,000 years.

Sopdet
A bust of Sopdet, the Egyptian goddess of Sirius

The heliacal rising of a star occurs annually when it briefly becomes visible above the eastern horizon at dawn just before sunrise after it has spent a season behind the sun rendering it invisible. Historically, the most important such rising is that of Sirius.

It was an important feature of the Egyptian calendar and marked the flooding of the Nile in Ancient Egypt. The ancient Egyptians worshipped the star as the goddess Sopdet, the guarantor of the fertility of their land. The Egyptian civil calendar was apparently initiated to have the New Year “Mesori” coincide with the appearance of Sirius.

Sirius (Spdt) in hieroglyphs

The rising meant the “dog days” of summer for the ancient Greeks. To the Polynesians, mostly in the Southern Hemisphere, the star’s rise marked winter and was an important reference for their navigation around the Pacific Ocean.

All hail, Sirius!

Everything Is Always Moving

Aldebaran
This photo of Aldebaran is cropped from one made of the Hyades star cluster, the nearest cluster to Earth.

Remember back in 2006 when the poor, old planet Pluto was demoted? A group of scientists decided that there are three main categories of objects in our solar system. There are Planets – 8 from Mercury to Neptune. There are Dwarf Planets – now to include Pluto and any other round object that “has not cleared the neighborhood around its orbit, and is not a satellite.” And there are Small Solar System Bodies – all other objects orbiting the Sun.

PlutoI felt bad for Pluto – and so did a lot of other Earthlings.

In 2015, I read that the waxing gibbous moon outside my window was moving toward the star Aldebaran, the brightest star in the constellation Taurus the Bull. Nothing odd about that. Normal movement.

But what I had not known until then was that Aldebaran also had a kind of demotion. It used to be the North Star, also known as the Pole Star. How does a star lose its rather prominent name and place in the sky?

You probably learned that Polaris is the North Star, but a long time ago Aldebaran had that honor. That was 450,000 years ago.

Back then, it appeared several times brighter in the sky then than it does now. In a way, it shared the title because it was very close to another very bright star, Capella, so they served as a double pole star. (This was 447,891 BCE, if you like precision.)

That’s pretty amazing, but it was a long time ago. What really hit me was that in this little solar system of ours and in our beautiful galaxy and this almost unimaginable universe, everything is always moving.  The sky looked different hundreds of thousands of years ago.

sky chart
This illustration shows the view as seen from present-day Arizona in 447,000 BCE when Aldebaran and Capella served as double pole stars. Illustration via Carina Software and Instruments and earthsky.org

The identity of the pole star shifts over time. This is due to the 26,000-year cycle of precession. (read more)

Most people believe the stars essentially fixed relative to one another. Within the scale of human lifespans, that is true. But stars are moving through space in orbit around the center of the galaxy.

The Earth is spinning as I sit here typing. It is making our Moon and Aldebaran shift westward but the Moon is moving to the east relative to the “fixed” stars because of the Moon’s orbit around us.

It is all so amazing. Some people think that looking up into that giant night sky makes them feel so small. I disagree. It makes me feel a part of something so enormous and grand.

Hello, Aldebaran. We didn’t forget you.

 

Number the Stars

One of the birthday cards I received this week contained this list of firsts from my birth year of 1953. None of them connect in any way with me. Elsewhere I read that 1953 was the year that rapid eye movement (REM) was connected to dreaming. I feel connected to that. Looking at words that were added to the dictionary that year (including UFO, videotape, Medicare, road trip) gives you a sense of what was happening when I was born.  As looking at words that will be added this year will remind us (though most of us don’t need reminders) of what was new in 2020.

numbers

The card also had a string of stats that I assume are numbers based on averages. But I don’t think I am average. My heart beats a bit slower than average at 58 beats per minute. But even at that rate, I must be near 2 billion beats which is an impressive run for that organ.

I’m also not a great sleeper (night owl, insomniac, sleep apnea) so I don’t think I’ve hit 188,000 hours yet. But I guess I have been alive for about 35,000,000 minutes (though these numbers for 1953 must cover birthdays from January to December so…) and I still put milk in my coffee and on my occasional bowl of cereal, so that might be close.

My birthday is close to the days when the Orionid meteor shower peaks. On my birthday morning, I took a look but it was too cloudy. The next morning it was foggy. There is a waxing crescent Moon during the shower’s peak which would help darken the sky.

You should be able to see the meteors across the sky but they do appear to originate in the constellation Orion. You can find Orion with his well-known three-star belt if you look in the southwest sky (northern hemisphere) or the northwestern sky (southern hemisphere) or the western sky if you live on or near the equator. This Orionid shower’s radiant rises in the east in late evening and meteors appear but increase after midnight and peak in the hours before dawn.

These meteors are vaporizing bits of comet debris from Halley’s Comet. Because they look to us like streaks of light in the night sky, they are popularly called “shooting stars.”

Orion

We can’t number the stars. I’m sure some people have tried to at least estimate the number of stars, as someone has tried to number my breaths and heartbeats. Maybe it’s not the numbering or the naming that matters. Maybe it’s the attention we pay to the moments and the stars that really make a difference.

Number the Stars was a young adult novel by Lois Lowry that students of mine used to read. It’s told by a ten-year-old girl who chronicles German Nazi troops “relocating” Jews in her Denmark and the Danish Resistance smuggling almost all of that Jewish population to Sweden.

The novel’s title is taken from a line in Psalm 147:4 – “He telleth the number of the stars; he calleth them all by their names.” Maybe God has numbered and named all the stars.

stars
Starfield via spacetelescope.org