The Galactic Times Newsletter #11 - October 17-31, 2021
Venus in the Sky and by Probes; This Just In--Jupiters and Moons Everywhere!, and Where is Planet 9?; Sky Events, plus a look at the Sea Goat; Watch Your Head! and More...
Cover Story - Probes to Venus
In This Issue:
In the sky, this is Venus’ time to shine. It reaches its maximum distance from the Sun, is getting much more interesting in a telescope, and passes through the most dramatic part of Scorpius. And scientists are setting up probes to explore it even closer. Jupiter and Saturn, an outstretched hand apart, take up the slack the rest of the evening….and dawn is planetar-ily quiet.
Cover Photo — The Neighborhood as it Once Was?
This Just In — Exploration of Hot Venus Heating Up
How our Solar System Will Look in 5 Billion Years Plus
Moons Around an Exo-Jupiter, and Water Around One of Ours
Where is Planet 9?Sky Planning Calendar — Moon-Gazing; Observing—Plan-et —Two planets visit the Sea Goat; a dim view of bright meteors; Border Crossings; For the Future
Astronomy in Everyday Life — Ouch!; Signs of the Times?
The Classroom Astronomer Newsletter Highlights
The Black Friday/End of Year/Holidays Sale with Ever-Increasing Discount Sale
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This Just In—
* Exploration of Hot Venus is Heating Up
One mission already on station and three more in development are making Earth’s size-twin, Venus, as much a target as Mars. At the most recent Division for Planetary Sciences meeting, members of the various mission teams gave summaries of the status of the Akatsuki, DaVinci, Veritas and Envision missions to Sol II.
The first, Akatsuki, pronounced A-kats’-key, is already at Venus. This Japanese probe has discovered that the winds are quite zonal, i.e. they move from equator to pole during day hours (and recall that Venus’ day is very very long) and do the reverse during the Venusian night. There is also a mountain wave; when the moving air apparently hits some elevation, it gets quite massively disrupted, and this happens during the Venusian afternoon.
DaVinci (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging), a NASA-Lockheed Martin mission, will launch later in the decade. Among its various explorations, it will measure noble gases like argon from the top of the atmosphere to the surface. It is also exploring the composition of the planet to determine if elements exist that indicate that Venus once was an ocean world, through not only atmospheric analysis but also 3D imagery. Its studies are expected to complement the exoplanet studies of the James Webb telescope, which is biased towards Venus-like worlds. It has a ‘lander’ of sorts, doing that measurement layer by layer as it descends, but it is not expected to actually survive landing on the surface, though they are hopeful.
VERITAS (Venus Emissivity, Radio science, InSAR, Topography And Spectroscopy) is run by the Jet Propulsion Laboratory, and one of its main goals is to look for evidence of continents on Venus. For example, low iron and high silicon values would indicate that there was once water. They will be looking at heat flow and evidence of subduction (plates sinking under other plates), and trying to determine if that is active or past history. What kind of volcanism is there on Venus, and is there water in the volcano emissions?
Finally, the ESA’s EnVision probe will look at processes using imaging radar, including ground penetration and SAR radar to within a few hundred meters below the surface.
- - - - - - - - -
In an opposing view of sorts, especially to DaVinci’s hopes, a climate model from French astronomer purports to show that Venus could never have had oceans. Although an earlier American study hypothesizes that Venus did, a paper published on the October 14, 2021 Nature, involving scientists from the CNRS/University of Bordeaux and University of Versailles-Saint Quentin-en-Yvelines claim that shortly after 4.5 billion years ago, the young Venus was covered with magma. To form oceans, the temperature of its atmosphere would have had to decrease enough for water to condense and fall as rain over a period of several thousand years, as happened on Earth. However, although the Sun at that time was 30% fainter than it is now, this would not have been sufficient to reduce the young planet's temperature to a point where oceans could form. Such a fall in temperature would only have been possible if the surface of Venus had been shielded from solar radiation by clouds. The researcher's climate model, however, showed that clouds would have preferentially formed on the night side of Venus, but not the day side. Data collected by future space missions to Venus should make it possible to test these theoretical results. How science works…..
* How our Solar System Will Look in 5 Billion Years Plus
(Credit Keck Observatory)
We all know that one day the Sun will become a red giant and probably expand out to at least the orbit of Earth, killing off the inner two-three worlds. What about the rest of the System? It has been surmise up to now.
Astronomers from Australia’s University of Tasmania and also the University of Maryland discovered a Jupiter-sized exoplanet by the oddest way, using gravitational microlensing. But not of the planet.
The microlensing was being done by a foreground star of a more distant object, but when trying to find the closer star, the astronomers initially could not do so. The planet was changing the lensing as it whizzed by the closer star in its orbit! As reported in the journal Nature now we have at least one example that planets can survive a star’s red giant phase and into the white dwarf stage. It might not be the best, and certainly not the warmest, environment for the future of mankind, but it is better than extinction, yes?
* Moons Around an Exo-Jupiter, and Water Around One of Ours
A variable star visible from Earth’s skies, GQ Lupi, 500 light years away, has been found to have not only a Jovian-sized exoplanet, but that exoplanet has a disk around it that has formed, or is forming, its own Galilean moon system. Dutch astronomers aren’t sure—it could be a central cavity in the ring system around the exoplanet, or just an effect of a magnetic field from the star. It needs observations from the soon-to-be-launched (we hope) Webb telescope to solve the mystery.
Meanwhile, our Jove’s Europa, already suspected to have an subterranean ocean and showing 60-km geysers, now seems to have a water-vapor tail as it orbits giant Jupiter.
* Where is Planet 9?
Having demoted Pluto but still thinking there is ‘something out there’ (shades of the X-Files), some astronomers are actively trying to find that something. Sessions and papers at the Division for Planetary Sciences meetings gave statistical evidence to try and pin down what it (or some in-the-Kuiper Belt planet) could be, and where. Some of the evidence for Planet 9 (P9) might be…
Among the many Trans-Neptunian Objects (TNO), there is a large gap in their perihelions, notably between 50-70 AU (astronomical units) that could be a resonance with P9’s orbit.
There are some peculiar orbital distributions, especially in inclinations of the orbits, that may help constrain the location of P9, possibly to 75-200 AU, but more likely <150 AU.
There are also resonances with Neptune itself to accommodate with TNOs to eliminate possible P9 locations.
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.
October 16 Jupiter is a bit to the right of the Moon, which passed it yesterday.
October 20 Full Moon. Though sometimes the October Full Moon is the Harvest Moon, being closer to the September Equinox, this one isn’t. More a Hunter’s Moon. The next Full Moon will be a nearly total lunar eclipse Moon….
October 24 The Moon’s at apogee, its farthest distance in its orbit from Earth.
October 25 The waning moon is less than two degrees from an easy open cluster to view, bouncing off the top edge of one of the Gemini twin’s feet like a soccer ball, M35. Look under the Moon in binoculars for the cluster of stars.
October 28 Last Quarter.
October 30 About an hour before dawn breaks, look in the East for the crescent moon about to cover up (occult) the moderately bright star Epsilon Leonis, the star in the Sickle or Question Mark head of Leo the Lion where the vertical part of the Sickle/QM/Head ends and the circular part begins. If you can line up a telescope on the star and follow it after the Sun comes up, you can watch Moon ‘eclipse’ it during mid-morning North American time, and some time later, reappear in a blink of an eye on the darkened and mostly-invisible-in-daylit-sky part of the Moon from minutes to about an hour later, depending on where north or south in the hemisphere you are.
Epsilon, by the way, is closely solar in temperature but way more in luminosity, nearly 300 times as bright as our Sun. It is actually brighter in reality than nearby Regulus, the brightest star in Leo.
Observing---Plan-et….
Venus reaches its maximum angular distance from the Sun, 47 degrees, on the 29th, but that doesn’t mean Venus’ show goes downhill from here. Yet. It IS at the longest time different point between end of twilight and Venus’ setting time this apparition, a mere ~one hour ten minutes, far below the 4 hours it can have. During this two weeks, Venus sets its latest clock time, around 8:25 PM local daylight savings time. After this it starts slowly closing back in towards Sol, setting earlier, and closer to twilight’s end in a few weeks before it does its hail-and-farewell act. Not quite at its maximum brightness it still is brilliant, magnitude -4.6, the third brightest object in the whole sky after the Sun and Moon.
At the start of this newsletter’s two weeks, you’ll find it near reddish Antares. It then cruises rapidly to the other end of the Scorpion, ending the month just passed its Stinger. which contains a neat pair of stars also called the Cat’s Eyes, for obvious reasons as you’ll see. Telescopically, it will be a half-moon shape at month’s end, and growing in diameter (‘taller’), but shrinking in crescent width.
Saturn officially becomes a pre-midnight-only object on the 29th, when it sets only during PM hours. It lies more than an outstretched-fingers-on-one-hand’s width to the right of brighter Jupiter which temporarily stops moving on the 18th as we finish passing the giant planet and we head at about a 90 degree angle away from it in our orbit. Jupiter then stars to move the normal eastward way, like a good planet should.
The two planets are in Capricornus the Sea Goat, a Greek mythological creature. Jupiter is near the tail of the Goat, the stars Delta (left, brighter) and Gamma Capricornii. In binoculars, drop a line from Jupiter between the two stars, past the first nearly equally bright star, and a little more than the same distance further down. until you’ll see a faint fuzzy blob. That’s Messier 30 (M30), a globular cluster of thousands of stars in a tight ball. BTW, that’s pronounced Mess-ee-yay, not mess-ee-yer.) The light from Jupiter is about 40-50 minutes old coming at you. M30’s took about 26,000 years. Meanwhile, Saturn has been swallowed by the beast and is inside the usual triangular star pattern of the constellation. To Saturn’s right is a small triangle of dim stars; the lowest one is named Omicron Capricornii and it is a decent double star of nearly equal in brightness stars, needing a telescope to split and see. Further to the upper right is a brighter pair of stars, wider apart, and the star on the right is a double star as well, enough most people can see them as separated with the naked eye, Alpha-1 and Alpha-2 Capricornii, the head of the Sea Goat.
Mercury is in the morning sky and doing a pretty nice show. In solar conjunction in early October it reaches maximum elongation from the Sun October 25-26th depending on which side of the Earth you are on. That elongation is far enough that if you are actually in a dark enough sky, and have a LOW unblocked East-Southeast horizon, you can actually see Mercury rise in a DARK sky October 21st to 26th! It will be among the brightest stars anywhere, magnitude -0.7 so you’ll know it very low if you see it.
Earth’s meteor season is in full swing, but though you’ll hear a lot about it, you probably shouldn’t lose any sleep over the Orionid meteor shower that peaks on the 21st and runs best for a day on either side of that. Normally an exciting morning spectacle, this remnant of a comet’s debris gets pretty swamped out by the one-day-past full Moon. Yes, you’ll see a few of the brightest of the roughly 20 per hour max, and you might get a decent show during that last hour before morning twilight starts. Remember, though, the best meteors aren’t seen looking at Orion; look 45 to 90 to 120 degrees from Orion, so that you are looking along the sides of the glowing meteors’ paths, not head-on.
Mars——Come back with a telescope or binoculars next month….
For the Future…
We have a (very nearly) total Lunar Eclipse in a month. Details coming soon.
No Halloween moon for you this year unless you trick-or-treat in the dawn….
Border Crossings
Traditionally, the Sun splits from Libra the Scales to Scorpius the Scorpion the 22nd/23rd. In reality, it is still in Virgo that whole time…and stays there until it enters Libra on Halloween. Boo….
Astronomy in Everyday Life
* Ouch!
There’s a parody Christmas song—Grandma Got Run Over by a Reindeer. In Canada, it might now be Grandma Almost Got Conked by a Meteor!
Yes, the rarity of contact with the universe got real for one Canadian family this past week, when an elderly British Columbian woman woke up to a loud boom. Getting up, she checked around, thought it might be a fallen tree on her house. Nope, but saw a hole in the roof. Tracked THAT to her bedroom ceiling, and amazingly, found nestled next to the impression her head left on the pillow a near-3kg meteorite (and a few small fragments haloed around her—don’t ask me how she missed it thumping next to her—sound sleeper?). She has sent it to a meteoritics lab, but only under the condition they return it to her when done. Estimates are that her dense sleeping companion will earn her up to 100,000 dollars, which should more than cover any repairs not paid for by any insurance….
(credit R. Hamilton, via Twitter)
* Signs of the Times?
Screenshot from a PowerPoint slide, but perhaps a red slash or red ‘NOT’ is needed for ol’ Eratosthenes here?….
…whereas this sign is regrettably truer than we’d like….
The Classroom Astronomer Newsletter Issue 11 Highlights
This premium newsletter is a subscribers-only publication, though a free Lite version is available.
Cover Photo - Cosmos + 41
Dawning Words (Cover Story)
Astronomical Teachniques - IAU-Shaw: Just Look Up; Solar Motions
Astronomy Remotely - 1. Remote Observing, Generally
The RAP Sheet – Research Abstracts for Practitioners - Programming Ozobots for Teaching Astronomy
The Galactic Times Newsletter Highlights
The Black Friday/End of Year/Holidays Sale with Ever-Increasing Discount Sale
The Black Friday/End of Year/Holidays Sale with Ever-Increasing Discount Sale
Every year, Hermograph Press tries to clear its inventory shelves with an End of Year Etc. sale, in which a discount coupon nets you a discount off the sale. Sort of like Hermograph Roulette. With each issue of The Galactic Times and The Classroom Astronomer, the discount increases, but historically, the inventory goes down on some items so quickly that if you wait too long, there isn’t any inventory on an item you want to buy at a greater discount!
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