TGT #24V- Planets in Opposition - Watching Geminids Fly - Jupiter and Kepler's Third Law, & More!
TGT 12/1/24: TCA: Observing Jupiter to Determine P^2 Really Does Equal A^3; AEL: More Cosmic Tiki Drinks; SPC:Meteor Shower and Occultations, The X of Taurus, View 5 Brightest 'Stars'; Holiday Sales!
Cover Photo - 70th Anniversary
In This Issue:Â
Cover Photo — 70th Anniversary
Welcome to Issue 24V!
Sky Planning Calendar —
* Moon-Gazing - Moon Passes or Covers Up Four Brightest Planets* Observing—Plan-et - All the Brightest ‘Stars’, Some in Opposition to Each Other; Solstices and Other Days
* Border Crossings - Four Days of MatchingTCA - Towards Cosmic Awareness - Jupiter and Kepler’s Third Law
Astronomy in Everyday Life - Tiki Me, Elmo!
Welcome to The Galactic Times Newsletter-Inbox Magazine #24V!
Greetings, Galactic Timers!
Holiday schedule note: TGT usually publishes on the 1st and mid-month days (16th or 17th, depending on how many days the month has) but this month our second issue will be around the solstice, the 21st to as late as the 23rd time frame. Two reasons—first, yours truly will be on the tail end of a Fall book tour—three gigs (one astronomy, two historical) and attending a ceremony for a new park in Georgia that is located where this author found the site of a place that the Marquis de Lafayette spent some time on a day too stormy for travel. It had been lost for 200 years. Second, the end of year holidays arrive and I will be taking some time off until around the 17th of January, before the BIG spring book tour on Lafayette begins, from late January until early April.
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Here I was yesterday, November 30th, at the Comer Museum in Sylacauga, AL, talking on the actual anniversary date for the Meteor That Hit a Mrs., back in 1954. A very active and engaged audience ranging from around age 5 to around 80 included Mr. Billy Fields who witnessed the event at age 6 and talked about the participants and events from interviews he did later (and to our delight, a woman who also witnessed the bolide’s explosion). The monitors showing a PowerPoint did not reflect green laser pointer light well so a rarely used, long telescoping pointer with a red tip was in hand—was not conducting an orchestra :)
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The evening planets are in a divisive election cycle? No, just the use of similar word, opposition. In this case we’re talking about objects being opposite in the sky to each other, 180 degrees, half a circle around from each other. Jupiter and the Sun reach opposition this month, Mars next month, and Venus and Mars are in opposition to each other. Plus, the four brightest planets plus the brightest star are visible all at the same time, just in time for year-end needs for a star…. See the Sky Planning Calendar.
With Jupiter at opposition, its best observing season begins, and for both amateurs and teachers who want a science demonstration, we can use the four Galilean moons around the largest world as a project to determine that Kepler’s Third Law of Motion works also with planets and moons, not just Sun and planets. See the TCA column.
It may not be the season for cold drinks, but more planetary-named drinks came to our attention. See Astronomy in Everyday Life.
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A Patreon account has been set up for The Galactic Times. Right now, the one tier is simply a $2.50 monthly support for your kindness, since The Galactic Times is a free newsletter now. There are plans afoot for some additional benefits —outreach info, education resources—to be set up there for paid members, resource materials that can’t be housed on Substack. During the break mentioned above I plan to move a lot of The Classroom Astronomer newsletter articles over to the Patreon site, for paid Patrons; that Newsletter will then be shut down and taken off Substack.
To support TGT, please head over to our Patreon for The Galactic Times site.
* Not a Subscriber? Please hit the link..right… below:
* A Black Friday, Plus and Minus, Sale!
Visit Hermograph Press online or the Hermograph Facebook marketplace and get discounts on several astronomical and historical merch! All discounted heavily, and the sale has begun and runs until December 5th!
Enjoy!
Publisher — Dr. Larry Krumenaker Email: newsletter@thegalactictimes.com
Sky Planning Calendar
Moon-Gazing
Moon passages by a star, planet or deep sky object are a good way to find a planet or other object if you’ve never located it before.
December 1 It is a New Moon but only if you are in the eastern half of the United States, Canada, and points eastward. Otherwise, to the West, your New Moon was yesterday, November 30th.
December 4 A bright pair in the sky! Glowing inspiringly for cameras, Venus is just 2-degrees North of the Moon (to the Moon’s upper right).
December 8 The Moon reaches First Quarter and in the pre-dawn you’ll find it 0.3-degrees South of Saturn. On this occasion, if you are in very high North latitudes, you’ll see that Moon cover up the rings and planet. Mostly Pacific Rim nations get to see that but far North Alaska (a trip to Barrow, anyone?) can view it, too.
December 12 Perigee. A Super-Gibbous Moon. When these happen, we’re halfway from one eclipse season to the next one, i.e. in about another 3 months.
December 13 The Moon passes through the Pleiades star cluster. Bad luck for those Seven Sisters (and the few hundred other relatives seen in a telescope), but would you expect any less from the Moon on Friday the 13th?
December 14 The Moon passes the second brightest planet, Jupiter, just past opposition (see below), by a comfortable 5-degrees.
December 15 Full Moon.
December 18 Before dawn, watch the Moon pass by the third brightest planet, Mars, by 0.9-degrees to the planet’s North. Again, in high latitudes including North Alaska, the Moon covers the planet up for a bit, so the further North you are, the closer the two objects appear.
Observing---Plan-et
==Is it an Election? Planets and Sun in Opposition to Each Other ==
==Geminid Meteors and When to See Them==
==Jupiter Centers an X, and Its Moons Find Planetary Laws==
==Solstices, Early Days, Twilight Times, Oh My!==
Mercury has vanished from the evening sky, but re-appears quickly in the dawn. In fact, it is visible at least 40 minutes before Sunrise by the 9th and actually rises before dawn(!)—technically in darkness—from the 17th until month-end.
Venus can’t be missed all month, setting well after twilight ends, in the western half of the sky. The Moon makes a photogenic appearance nearby on the the 4th.
Earth has some key dates this month.
December 4—Earliest End of Evening Twilight
December 21—Shortest day for latitude 40 degrees North…AND….Solstice occurs at 3:20 AM US Central Time.
The peak of the Geminid meteor shower occurs on December 13th and usually has 60-100 meteors per hour. This is the rare shower that actually is better in the evening rather than just before dawn, because the radiant point, where all the meteors seem to radiate from, is already up and high in the sky. The Moon, approaching Full, will drown out many of the meteors, though you might get a numbers boost in the last few hours before dawn when the Moon has set. The shower can be seen a couple days before and after the peak, though not as high in numbers, of course.
Mars rises about 1 hour after twilight ends in the evening. It isn’t a ‘wandering star’ right now, becoming temporarily motionless on the 7th, its first ‘stationary point’ where the faster-orbiting Earth starts to lap past slower Mars. Midpoint of the passage? In January, when Mars is 180 degrees opposite the Sun at opposition. The Moon passes it on the 18th. Use Mars to find the very scattered star cluster, the Beehive or Praesepe, nearby, with binoculars best.
Speaking of opposition, that 180-degree thing, Jupiter rises at Sunset on the 8th. The light you see then took 34 minutes to arrive here from the planet orbiting 4.1 astronomical units beyond Earth (An A.U. is the Earth-Sun average distance) and is second only to Venus in brightness, magnitude -2.8. Large enough to be seen as a disk even in some binoculars, its four bright Galilean moons, Io, Europa, Ganymede and Callisto, are also at their brightest (some above naked eye brightness limit) and could be seen without a telescope if Jupiter wasn’t so bright and close. They make a good binocular project for determining or supporting Kepler’s third law of motion. See below.
On opposition night, Jupiter makes a big X (no relation to the social media company) in the space between Taurus the Bull’s head and eyes, and the tips of its horns. The face of the Bull is made up of the V-shaped star cluster, the Hyades. Extending the V eastwards gets to the horn tips. Interestingly, the tip stars are both B-giants, hot and blue. The lower horn star, Zeta or Tianguan (a rare official Chinese star name), is a binary star with its companion orbiting in 134 days or so, too close for telescopes to see but far enough for spectroscopes to detect. Just a tiny bit above Zeta is the ghostly (literally and figuratively) Crab Nebula, a faint cloud of gas left over from the supernova of 1066. The upper horn star, El Nath, Alnath, or Beta Tauri, is actually shared with Auriga, the Charioteer, the constellation North of it. The ends of the Hyades-V, the constellation’s brightest star Aldebaran (the Bull’s Eye) and the dimmer northern eye star Ain, are both orange-y K stars, cooler than the Sun. But Aldebaran is an interloper and is just coincidentally in the right place, but it is not at all in the actual Hyades star group but about half the distance to it from Earth. Also, both orange stars have an exoplanet but the blue stars do not.
The Moon passes nearby to Jupiter on the 14th. Our only all-nighter of a planet, at least until month-end.
Saturn sets before local midnight. The Moon passes it on the 8th. The planet’s rings are nearly edgewise as we approach the ring plane passage in March of 2025.
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You can see all four brightest planets and the brightest star Sirius (the five brightest ‘stars’ in the night sky—the brighter Moon is not star-like and doesn’t count her) in the sky at the same time from about December 20th onward for a while.
Border Crossings
As explored in last issue’s article, the Sun actually entered the 13th sign of the Zodiac, Ophiuchus, the Handler of Snakes on November 30th. It remains there through to the 17th. The next day finds it in Sagittarius, where it will remain for a rare full month (only Gemini also gets that distinction). All other constellations go from a smallest size of 7 days (Scorpius) in duration to the largest amount of days, 45—Virgo.
In the fake future, the Sun is in Sagittarius already, until our issue expires on the 21st. So there is a 4 day overlap between reality and fantasy.
TCA - Towards Cosmic Awareness: Jupiter and Kepler’s Third Law
Jupiter is in prime evening position and when school resumes in January it will be so for 2-3 more months, before it starts to get smaller and less visible as we gain distance on it. Start the year off with a good observational exercise, tracking Jupiter’s Galilean moons and deriving Kepler’s Third Law.
Now, a caution. Yes, you can find Jupiter moon simulators on the Web. There are labs that use computer programs, such as CLEA, or websites that simulate the experience. But these don’t teach how to do science the real way. Having to make real measures. How to deal with data gaps from when the sky is cloudy for a few nights. Interpolation and figuring out when the little moons were at their extreme positions—and you didn’t see that. Gathering data over a series of repetitive real cycles to minimize errors. Computer programs and simulators just don’t do that.
It is suggested that you use at least small telescopes so you can get all four moons. Binoculars do not always get the inner moons well, and they don’t always come with tripods to steady the image.
Finally, we aren’t going to get P-squared = k(=1)*A-cubed, because we aren’t going to be using years and AU for units. We are going to get the squared and cubed parts, and a linear relationship will be found, but the units are not going to be the same, and k won’t equal 1. In any case, it is a good graphing exercise, too, and Kepler’s Laws are a part of the Next Generation Science Standards.
Jupiter’s disk itself appears distinctly but still very tiny in smaller scopes. Binoculars are more likely to be found in students’ homes than telescopes, and the outer moons Ganymede and Callisto are better at determining the Third Law than the inner ones. Still, it helps to get observations of at least three of the four moons to get this right.
The moons appear to be shuttling back and forth from one side of Jupiter to the other. When observations are placed in order of time of observation, connecting each moon’s position during the shuttling would create wavy lines down the sheet. Try it a la the above partial example. You should, observing nightly, get something like the below….
One of the two key datum needed is the orbital period P for each moon—how long it takes in days to go from one side to the other and back to the same place as it started. The other key, A, the moon’s average (or here, maximum) distance from Jupiter, can be measured by using Jupiter’s diameter as our ruler, our ‘Astronomical Unit’ of distance. Estimate how many Jupiter diameters there are between the center of Jupiter and the spark of light of the moon. Do this for at least two weeks but better a full month or longer. You need to find the farthest each moon gets, and if there are several such maxima, average them, and for more accuracy, use both sides. The reason you want a long observing time is that the farthest moon takes about two weeks for one orbit and you want to have at least 3 repeating plots for that moon, to get a good measure of A and P. Plus you won’t have every night clear! Welcome to real-world science!
When you have your observations, plot them on a graph where the date is on the Y-axis and the distance is on the X axis. (Leave blank spaces for dates you did not get an observation!) You are seeking two values: how long it takes the moon to return to its maximum distance on one side of the planet (P) and the maximum distance itself in Jupiter radii (A).
Once you have determined the moons’ P and A values, calculate P-squared and A-cubed and plot each moon’s values in another X-Y plot, where the P-squared is on the X-axis (the horizontal axis). The slope of the line = k. Generally, k = ~ 0.12 in this system because of our units; in the real Kepler’s Law of real AU’s and years it would be k = 1.
Astronomy in Everyday Life
Tiki Me, Elmo!
After my story on the Saturn tiki cocktail, three other such drinks were given to me.
The first is called the Pluto. Being an icy world, it has lots of ice…and blue curacao liqueur, a kiwi slice for the green, and gin.
Pluto is low in sky, in Capricornus, and extremely dim and approaching solar conjunction in January.
The second is the Neptune, I guess a followup to last issue’s Neptunian business and parking lot sign. But I can’t recommend it. I have no idea how it tastes and it uses 8 ingredients, some of which I have never come across or even heard of:
lime juice
hot honey mix—using honey, simple syrup, absinthe, and orange blossom water
Sergio’s T-mix—tangerine juice and cinnamon syrup
pimento dram
Rum
Real McCoy 5
Wood’s Old Navy Rum
and Mystic Mango soda
But then, discovering Neptune in the 1800s, after noting that Uranus was gravitationally being pulled out of its predicted orbit by a then-unknown planet, took a lot of complicated math. So the drink is appropriate for all those students who have to calculate an orbit from observational data….using classical celestial mechanics mathematical tools and no computer program previously created.
Speaking of finding Neptune, the dim greenish world can be found, faintly, in Pisces, above and slightly left of Saturn in Aquarius. It is already up before Sunset, is highest in the sky around 8PM at mid-month, and sets around 2 AM. It shines at a dim, telescope-needed magnitude 7.9, and a pale green. It stays in the evening sky until around March next year.
The final one was the Full Moon. Made with just 5 ingredients—a blackberry, 1/2 cup Coconut cream, sugar, 1 oz of Vodka and 1/2 cup of water, it shines white as the Full Moon, which you can toast with this on the night of December 15th. Drown your sorrows as the near-Full Moon drowns out the Geminids…..
‘Til next issue,
Dr. Larry Krumenaker