The Galactic Times Newsletter #15 - December 16 - 31, 2021
This Just In--A Planet Around Two Stars, A Bite of Corona, Space Smoke; When IS the Shortest Day?; Sky Events in December--and 1st Two Weeks of January; Galileo's House for Sale--"Half Price!".
Cover Photo - Finding b Centauri
In This Issue:
Cover Photo — Finding b Centauri
This Just In —
Have a Corona, NASA!
Speaking of Coronal Activities…
Earth’s Weight Gain
b Centauri, the Unusual Planetary System (Cover Story)
Sky Planning Calendar —
* Moon-Gazing - A Brief Four-Planet Line-Up in the Evening;
* Observing—Plan-et — Hello, Mercury, Farewell, Venus; And When IS the Shortest Day of the Year, Really?
* Border Crossings — Just for three days…
* For the Future (January 1-16) — So you don’t go cold turkey….
Astronomy in Everyday Life —Galileo’s House for Sale—Half Price!
The Classroom Astronomer Inbox Magazine Issue 15 Highlights
Welcome to the last 2021 Issue of The Galactic Times Inbox Magazine, #15!
The Galactic Times will take a Holiday Hiatus. The next issue after this one will be January 16th, not January 1st. Have a Happy Holiday, whatever Holiday makes you Happy! (We’re looking forward to a Super Saturnalia, but that’s just us…)
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This Just In—
* Have a Corona, NASA!
A staple of science fiction is a spacecraft diving into a star’s corona until an enemy’s spacecraft veers away or disintegrates. But until now, no Earthly spacecraft has actually been inside our Sun’s corona. The Parker Solar Probe has finally done it.
The Sun’s diameter is approximately 865,000 miles, give or take; its exceeding hot but also exceeding tenuous outer atmosphere, the corona, can reach out at least 20 times that amount, and that’s at solar minimum, a time we are at or just past now. It can be larger at solar maximum. At some distance, called the Alfvén Critical Surface, the Sun’s gravity and magnetic field can no longer hold the gases in and they are powerfully expelled into the solar system as the solar wind. This is the ultimate origin of space weather events that interact with the Earth’s own geomagnetic field and atmosphere. Being able to predict space weather is one ultimate goal of exploring the Sun.
But where exactly that Surface is has been a mystery, only estimated from images at 4-9 million miles from the photosphere, the yellow visible solar surface. Parker has been slowing spiraling inwards, metaphorically trying to dip its metallic toes into the corona to find the coronal surf. In April of this year, it found it. And like surf, it came in wavy form. Parker slipped in and out of the corona several times during its encounter, indicating that the Surface is not spherical but corrugated like an ocean surface, with troughs and peaks.
At one point it flew into a region dominated by the Sun’s magnetic field rather than the flow of gaseous particles. Things got…quiet…proving the probe was actually inside the corona, inside a ‘superstreamer,’ something actually visible in the corona from Earth during eclipses. As the sunspot cycle gets more active, the corona will enlarge and Parker will not only spend more time in the corona, it will get even closer to its lower surfaces, down to less than 4 million miles above the photosphere. Shields up!
* Speaking of Coronal Activities….
Space weather has been in the news recently, with forecasts and scenes of auroral activity farther south than usual. These happen when solar flares cause coronal mass injections (CMEs) properly timed to be aimed to directly hit the Earth.
Flares of various kinds have been known to occur on other stars, and some are considerably more massive than anything launched by our Sun. Indeed, these flares would seriously harm earthly life if they did! What has not been seen from these stellar superflares are any evidence that they have caused filaments or prominences that create CMEs around their stars as happens with regular flares/CME connections with the Sun. Until now.
Japanese astronomers using optical spectroscopy monitored an active but otherwise solar twin-like star, EK Draconis, that has frequent ultraviolet flares, and detected such a filament following a superflare that seemed to send a CME towards us, observed via a blue-shifted spectral change. The CME was befittingly ten times larger than any seen from our Sun. The astronomers look at this as an opportunity to explore how they affect young exoplanets and young Earths, and stellar mass and system angular momentum evolution over time.
* Earth’s Weight Gain
There’s a VERY old song…..”16 tons, whaddya get? Another day older and deeper in debt.” In our planet’s case, it may be 25 tons of weight gain every day from cosmic dust.
As you possibly watched the Geminids this past week, and maybe the Ursids next week, you can imagine that some of that material maybe makes it to the Earth’s surface. Each rock burns up by friction in the atmosphere, but it is exceedingly rare to have one of them survive their passage into the air all the way to the ground. Sporadic fireballs, yes, but shower meteoroids, no.
What about those everyday bits of cosmic fluff that the Earth goes through that are just not big enough to even make a meteor flash through the sky? How much of that does the Earth get, how much floats down to the surface every day?
Cosmic dust, from the space environment and leftovers from shower meteors that just ended up floating in the atmosphere, ultimately do fall to Earth, but simply by gravity. Yet their mass is clearly tiny, and it has been speculative for decades how much has been landing on soil, rooftops, and oceans. In fact, rooftop collection has been a bit of a niche meteoric hobby for some, using gels in collection units. They’ve been collected from polar ice cores. Short-duration rockets collect tiny particles in various atmosphere layers. They also are believed to be the nucleic particles that ice condenses on to form the highest clouds on Earth, the noctilucent clounds. And now a small NASA satellite called SOFIE measures the atmosphere for signs of the effects of this “cosmic smoke.”
Yes, smoke. SOFIE both takes light intensity through the atmosphere layers and can detect certain chemicals spectroscopically. What it has found has narrowed the composition of atmospheric-born cosmic smoke to that of olivine, an iron-rich compound, adding up to about 25 tons of it landing on Earth per day.
* b Centauri, the Unusual Planetary System (Cover Story)
It has been in the news for a while, a planet orbiting a double star, something not seen before. The planet is orbiting the equivalent of 500-550 AU (Astronomical Units) from the two stars, which are the hottest and most massive central stars ever seen to host a planet, unlikely targets. But the star is also an unusually named light in the sky. Not named with a Greek letter like Alpha or Zeta but a small Roman letter “b”, the name goes back to the days when certain constellations had so many naked eye stars that cosmographer J. Bayer simply ran out of Greek letters and began using Roman ones. Which is confusing because the modern tradition is to name the exoplanets around stars with lower-case letters, too, starting with…. “b”. So this planet’s name is “b Centauri b”. To make nomenclature-pain worse, the main star is a B-type star, blue and hot and emitting copious ultraviolet light which should make any surrounding gas both glow and be ejected from the system, making planetary formation all but impossible, but there it is, a planet. Probably not one to harbor life, and at only an estimated 15 million years old, not likely to have had the time, either.
The planet is calculated to be at least 10 Jupiter masses in size so its gravity would be immense. No information seems to be available on the smaller companion star.
Still, this binary is bright enough even at over 300 light years away to be visible to the naked eye in Earth skies. It currently rises in the dawn, to the far right of Mars and red giant Antares, in Scorpius, and below the diamond-shape of Libra. The magnitude 4.0 star is marked on the chart in our Cover Photo.
Sky Planning Calendar
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 16 The Moon is near the Pleiades star cluster. In fact, it is within the boundary of Taurus the Bull tonight and the next two nights.
December 17 The nearly Full Moon is at apogee, the far point of its elliptical orbit, so it is the smallest size in the sky it will be this month.
December 18 Full Moon AND, by the next morning, back to being Castor’s, the western Gemini twin’s, second soccer ball, the star cluster M35 being the first one. Of course, the Full Moon light drowns out that star cluster’s stars, but you can use the Moon’s location tonight to note where this nice cluster is, and when the Moon gets kicked aside, look for it with binoculars. If you have a telescope, look closer to the southwest side of M35 for a smaller, fuzzy star cluster, NGC 2158, that may or may not resolve into stars, depending on the size of your scope.
December 19th …and the next two nights, the Moon travels straight up and through the Twins, a pair of parallel lines of stars lying fairly horizontally in the East so the Moon is pretty much going mostly from feet to just to the left of Pollux’ head!
December 22 The waning Gibbous Moon passes above (north) of the Beehive star cluster in Cancer the Crab.
December 26 Last Quarter Moon, near the border of Leo and Virgo.
December 28 The Moon is near bright star Spica, of Virgo.
December 31 Mars is 0.9 degrees north of the Moon in the morning sky. For observers in Asia and Oceania, the Moon will pass in front of Mars.
The highlight of the month occurs on the 22nd, when the evening twilight has a line-up of four planets. As brilliant Venus rapidly dives towards the Sun, a big, thin crescent in good binoculars and any telescope, up from below comes little brother Mercury, bright though nowhere near that of big sister Venus. On this date, they make a near perfect straight line with Saturn to their upper left, and Jupiter further upper left-er. Don’t look any later than 40 minutes after sunset! Mercury will be gone in just a few more minutes, and any sooner will probably require some Christmas binoculars to find those two inner planets anyway.
Let’s review the solar system schedule for these last two weeks of 2021.
Mercury pops into view as Venus exits stage right (west) and will stick around into January. On the 29th, the pair make one last easy-to-find (‘easy’ is a matter of opinion) when Mercury is 4 degrees due South (left) of Venus; the next day they’re level in altitude as seen from mid-latitudes at 40 minutes after sunset. They set together about 20 minutes before twilight ends…which for Venus shows you how fast it is disappearing from view since on the 26th it set as twilight was ending! Hail and farewell, Evening Star, it is gone from view by the 3rd of January, in solar conjunction by the 8th.
Saturn is still up when twilight ends but not for long, an hour more only by New Year’s Eve. Not a party planet. On December 16th, Venus got to within 14 degrees of it before it turned around and headed in the direction of the Sun.
Though Venus’s thin crescent is perhaps the most gorgeous planetary view of the month, Jupiter’s system and disk is the easiest to view, still high and bright in the southwest.
Mars, for now, has the dawn to itself, but will share it starting early January with Venus (and later with Saturn). Find Mars with the Moon in the dawn on the 31st as the latter dives down on the former from above. That bright star to Mars’ right is literally its rival, Antares, which means ‘rival of Mars’ though Mars is only feebly competing with it on the far side of its orbit, just half as bright as the red giant star in the heart of Scorpius. It lies 5 degrees away from its rival on the 26th.
The Sun ‘reaches’ its solstice point on the 21st at 9:59AM Central Time. Of course, the Sun has nada to do with it; it’s Earth’s tilt and revolution positioning. You would expect the latest sunrises and earliest sunsets on this date, making it the shortest day of the year, right?
I looked at the sunrise and sunset times in the Royal Astronomical Society of Canada’s Observer’s Handbook which indicates that the latest sunrise and earliest sunset times aren’t at the winter solstice dates everywhere. At latitudes 45N and higher, the latest sunrise is during the last days of the year. The latest occur by the solstice only when you get above 60N, too. But near the Equator, the latest sunrises are a month after the solstice! The earliest sunsets in the tropics occur in November, around the American Thanksgiving holiday. So the shortest days are nowhere near the solstice during your Christmas holiday basking in the Caribbean…..and, of course, there are no days at all in the Arctic this time of year.
There’s a meteor shower on the 21st, the Ursids, coming from the Little Dipper. But with a Moon just three days past Full, you’ll have a bright sky most of the night. The Ursids last less than half a day, and this year’s peak isduring the day North America time, at only 10 meteors per hour anyway. You might see a few of these coming out of the northern sky during the hour or two after moonset and before morning twilight begins, but you probably have to be an ardent meteor lover to want to.
Traditional Zodiac calendar—Sun in Sagittarius until December 21 after which it is in Capricorn, and it stays there a month.
Reality—As discussed in the last two issues, the Sun is in….Ophiuchus, the Serpent Bearer! And it will be there until December 18. Then it enters Sagittarius and remains there for an entire month, until January 18th. Thus, for a whole whopping three days, astrology will match astronomy. Wow…..
For the Future (January 1-15)
Since there will not be a January 1st Galactic Times, here is what you can look forward to for Sky Events in the first half of January, to keep you from having withdrawal symptoms from a lack of sky information:
January 1 Perigee. That big crescent you see in the dawn isn’t due to your New Year’s celebrating….the Moon really is close to us, and will be again, on the 30th.
January 2 New Moon
January 3 The crescent Moon passes by Mercury.
January 4 Very low in the West, last possible glimpse of Venus in the evening sky?
The slightly fatter crescent Moon passes Saturn.
Earth is closest to the Sun, perihelion, 0.98 Astronomical Units or 91.4 million miles. For those ‘chilling’ in the Northern Hemisphere, this should prove conclusively that distance to the Sun is NOT the reason for the seasons!
January 5 The now distinctly thick crescent Moon passes Jupiter.
January 8 Venus in solar conjunction, passing a few degrees north of the Sun (don’t try to find this with eye or optics!).
January 9 First Quarter Moon
January 12 Mercury and Saturn are only 3.5 degrees apart in the evening twilight (though obviously this is perspective and they are nowhere near each other in real space!).
January 14 Apogee. Yep. That gibbous moon is not as big as it could be….
January 15 Back from its break! By now you might just be able to see Venus low in the Eastern sky in the dawn, and a mere 2% in thickness as a crescent moon shape.
Astronomy in Everyday Life
* Galileo’s House for Sale—Half Price!
Times are tough everywhere. Misfortune frowns on even the best of us. A few years ago, the house in Padua that Galileo Galilei lived in for the first half of his time there was purchased by an investment firm. They planned to turn it mostly into apartments, some commercial uses, and an underground garage, with a section apparently dedicated to the historical parts. Then…they went bankrupt. Over the past two years the variously partitioned structure, for centuries owned by the Jesuit church, has attempted to be auctioned off for as high as 8 million Euros. It is now available for less than half that, that is, 3.7 million Euros. A steal at half the price….
This was the residence where the famous astronomer lived when he was teaching but before he created and used his telescope and got into a world, indeed, a universe, of trouble. According to the article from the newspaper Corriere della Sera (December 1, 2021) that I was sent by my good friend Dario Tiveron of Padua and Fulldome Database, a planetarium program company, it was in this building that a large library owned by the landlord enticed Galileo with massive numbers of astronomy and physics books. Here, too, he met nightly with many Jesuits for discussions, and where he corresponded with Johannes Kepler over his mathematical laws and hunches about Copernican doctrines.
I am pleased to say I’ve actually been there. In 2017, before returning to the States for a book tour (not realizing that it was going to be a permanent return) while living in Germany and before going to the Italian Planetarium Association) PlanIt meeting to give workshops on teaching astronomy, Dario gave me a tour of various sites in Padua and elsewhere, and one of them was this place, apparently about the time the original buyers made their investments. I am not pleased that I am a bit short of the amount of money needed to purchase The Master’s apartment, or even one of the other ones nearby (and, no, these are definitely not one of the famous buy-for-a-dollar-homes-in-Italy that are all the rage these days). Sigh….
The Classroom Astronomer Newsletter Issue 15 Highlights
This premium Inbox Magazine is a subscribers-only publication, though a free Lite version is available. Starting in January, it becomes a 30 issues per year publication, and the Lite version becomes an end-of-month digest.
Cover Photo - Smartphone Universes
Welcome to Issue 15!
Sky Lessons - Ecliptic Pachinko
Astronomical Teachniques -
Smartphone Astronomy Simulations
The Inverse Square Smartphone
ASP Notes—What Kids Think Are Scientific Activities; Learn by Teaching
Connection to the Sky -
Massively Resourceful Collections
All the Moon’s Motions
The RAP Sheet – Research Abstracts for Practitioners -
- Why and how teachers make use of drawing activities in early childhood science education
- Deciding on drawing: the topic matters when using drawing as a science learning strategy
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