Celebrating Saturnalia

In Ancient Rome the winter solstice festival of Saturnalia began today, December 17.  It was a festival that lasted for seven days.

Created to honor Saturn, the father of the gods, it was interestingly celebrated by suspending discipline and a reversal of the usual order.

It was said that this was the time to suspend grudges. Businesses, courts, and schools were closed. Some accounts say that even warfare was suspended for the week.

Want to celebrate Saturnalia? If you need another reason to have a party, here are some suggestions from the Romans.  Masquerades were common. Traditional gifts were real or imitation fruit (fertility), dolls (symbolic of the custom of human sacrifice), and candles (small symbols of pagan solstice bonfire celebrations).

I have read that a mock king would be chosen. It would probably be a slave or criminal. It sounds like a good thing since this king was able to run wild for the week, but unfortunately, the king was usually killed at the end.

As with much of the Roman empire, Saturnalia degenerated into a week of debauchery and crimes. Today the word “saturnalia” means a period of unrestrained license and revelry.

You can go out this week and look at the sky and see Saturn. In the Northern Hemisphere, if you look at the constellation Gemini which rises above the eastern horizon, a bit west of Gemini is the brilliant planet Jupiter looking like a star to most people.  Just before sunrise, Saturn, Venus, and Mercury appear above the southeastern horizon.

A Christmas Star That Is Not a Star

The conjunction that appears as a “star” – Image: NASA

Popularly known as the “Christmas Star,” at this time of 2020 you can observe this “star” that is actually the planetary conjunction of the bright planets Jupiter and Saturn.  The conjunction culminates on the night of December 21, but is visible in the evening sky now.

We know that Galileo Galilei in 1610 discovered the four moons of Jupiter – Io, Europa, Ganymede, and Callisto. He also saw in his telescope a strange oval surrounding Saturn. Later that halo would be seen in better telescopes as Saturn’s rings.

In 1623, our solar system’s two giants, Jupiter and Saturn, moved together until Jupiter caught up to and passed Saturn. This astronomical event is known as a “Great Conjunction.”

The planets regularly appear to pass each other in the solar system. Jupiter and Saturn align in the sky about once every 20 years.

You can imagine ancient skywatchers seeing this conjunction as a bright star at this time of solstice or Christmas as something miraculous.

But this year has several additional celestial wonders. First, it has been almost 400 years since the planets passed this close to each other in the sky. Astronomers tell us that it has been nearly 800 years since the alignment of Saturn and Jupiter occurred at night so that people around the world can see this conjunction.

The 21st is also the Winter Solstice. These two planets will be so close (a tenth of a degree apart)  and will appear on the long solstice night to be one “star.” No telescope needed to observe the conjunction. Actually, the naked eye will blur the two together more than an optical view.

If you believe in coincidences, this is an interesting one. If you don’t believe in coincidences, this is more interesting.

Like many celestial events when viewed from Earth, these giants will appear close together, but they will remain hundreds of millions of miles apart in space.

On this snowy night, I will venture out to an unobstructed view of the sky, an hour after sunset, and look to the southwestern sky. Jupiter will look like a bright star and Saturn will be slightly fainter and will appear slightly above and to the left of Jupiter. At the solstice, Jupiter will overtake it and they will reverse positions in the sky.  If you do have a telescope or good binoculars you might see Jupiter’s four large moons. The Moon will be at its First Quarter tonight with 45% of it illuminated.

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You might want to watch the NASA Science Live episode on the conjunction live at 3 p.m. EST today on NASA Television and the agency’s website, along with the NASA Facebook, YouTube, and Periscope channels.

Our solar system –  Image by Comfreak from Pixabay

 

Venus, Saturn, Jupiter and a Crescent Moon

If you were up early this morning you would have seen a lineup in the morning sky of Venus, Saturn and Jupiter on a line with the morning crescent moon. The lineup will be around for the next few mornings, so if there is a clear sky and you are up more than an hour before sunrise, it will be easy to spot.

Look east to the sunrise and the Moon will slide its way up past the three planets.

The planetary lineup – via earthsky.org

This morning the waning crescent moon was right next to Jupiter. (This is best viewed from North America.)

Saturn and Venus are east of Jupiter and the line they seem to all be on is the ecliptic, or Earth-sun plane. This is the plane on which the other planets in our solar system and the moon all orbit, so we view them as being on this line.

Would You Live on Titan?

Settler as imagined in the National Geographic Mars series.

In our movies and novels, the Moon or Mars is usually the other place for humans to live in our solar system. It seems more fiction than reality, but they are closer and more hospitable compared to Mercury and Venus.

I’m watching the Mars series on the National Geographic channel now. Turns out, despite movies, books and TV shows, the Moon and Mars have no protective magnetosphere or atmosphere and that makes them lousy choices for colonies. Galactic Cosmic Rays (GCR), the energetic particles from distant supernovae, bombard both places and humans just can’t live long-term under those conditions.

I was surprised to see an article at scientificamerican.com that says that beyond Mars, the next best potential home is among the moons of Jupiter and Saturn. There are dozens of those and it seems that the best option is Saturn’s largest moon Titan. It is the most Earthlike body  in our system.

 

Composite infrared image of Saturn’s moon Titan from NASA’s Cassini spacecraft. Credit: NASA/JPL/University of Arizona/University of Idaho. Public Domain via Wikimedia Commons.

Titan is the only other body in the solar system with liquid on the surface. These are not watering or fishing holes though. They are lakes of methane and ethane. It rains methane on Titan.

Titan has a nitrogen atmosphere 50 percent thicker than Earth’s for protection. There are vast quantities of hydrocarbons in solid and liquid form on the surface that can be used for energy.

No oxygen in the atmosphere, but water ice just below the surface could be used to provide oxygen for breathing and to combust hydrocarbons as fuel.

You’ll need warm clothing with your respirators. It’s cold on Titan. How does  -180°C (-291°F) sound? But the plus of that thick atmosphere is that if you are a Titanian you won’t need pressure suits.

We can build shelters of plastic produced from the plentiful resources there. Nice domes inflated by warm oxygen and nitrogen would give us huge indoor spaces.

Titan’s weak gravity and thick atmosphere would allow you to leap easily and maybe even fly with some type of wings on your back. Falling would be gentle.

But don’t pack your suitcases just yet. Currently, we can’t really get to Titan or even Mars. We need faster propulsion to limit the time in space and those doses of GCR. The trip currently would take seven years.

As Charles Wohlforth and Amanda Hendrix, authors of Beyond Earth: Our Path to a New Home in the Planets, say:

There is no quick way to move off the Earth. We will have to solve our problems here. But if our species continues to invest in the pure science of space exploration and the stretch technology needed to preserve human health in space, people will eventually live on Titan.

 

Saturn Tonight

Tonight and tomorrow night (October 5 and 6, 2016) if you look at the waxing crescent moon, the brightest starlike object near the moon will be Saturn. Looking golden to the eye, Saturn looks very cool through a telescope. I only use a good binocular to bring it in closer, but all you need are your eyes to spot it.

You should look as soon as the sun sets, find the moon in that same general direction of sunset and Saturn will below and a bit to the left (tonight) or right (tomorrow).

Below Saturn, the other bright point is a star – the reddish Antares. It’s the “heart” of the constellation Scorpius.  Stars “twinkle” but planets show steady light.

By October 7, the moon will be near Mars.

Yes, everything is always moving.

A cool place to check online is the U.S. Naval Observatory site. Want to see what our Moon looks like today? Click over to http://aa.usno.navy.mil/imagery/moon

Saturn seen during equinox

The sixth planet outward from the sun, Saturn is the most distant world that you can easily see with the unaided eye.

Before darkness falls, in that first hour after sunset, you can also see our brightest planet, Venus, near the sunset point on the horizon.

Moon and Saturn

Tonight, shortly after sunset (4:40 ET), look for the sliver of the waxing crescent moon. From mid-northern latitudes, the illuminated points direct you to the setting sun and to Saturn. The planet is between the sunset and moon and from there it will follow the sun below the horizon before nightfall. It will do its own setting about an hour after sunset and will be very difficult to see in the glare of evening twilight.