The Galactic Times Newsletter #10 - October 1-16, 2021

News from the Planets and Beyond; Venus to the Max, Passing Two Interesting Stars; Mobile's Starry Streets, and We're are NOT Passing Mercury!

Cover Story - The Molten Ring

In This Issue: 

We like to think we put a magnifying glass to the universe, but in this issue, we get a lot of usage out of gravitational lenses! Those are one way to get a glimpse of the farthest reaches of the universe, albeit distorted. Another common topic this issue is —um—gas. Interstellar gas. The Milky Way is full of it, and two research groups have found interesting results mapping them….one in plastic and in 3-dimensions. In other gaseous news, Venus delicately tiptoes around a star known for…um…passing gas (sorry…). Mars’ water may have been trapped in several places useful for future astronauts, and in the past it may have flooded at least 25% of its valleys, while our own Jupiter has its hurricane-like Great Red Spot spinning tighter and faster.

In the sky, this is Venus’ month to shine. It approaches its maximum distance from the Sun, is getting much more interesting in a telescope, and passes through the most dramatic part of Scorpius. 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 Molten Ring

  • This Just In — Predicting a Supernova 16 Years From Now
    3D Printing of Molecular Interstellar Clouds
    You Think YOU Have Flooding Problems??
    Getting Breezy on Jupiter
    A Nearly Complete Einstein Ring
    A Whole Lot of Gas, or a New Spiral Arm?

  • Sky Planning Calendar — Moon-Gazing; Observing—Plan-et —Venus’ phases, and conjunction with Delta Scorpii—a gas blowing star; Border Crossings; For the Future

  • Astronomy in Everyday Life — The Starry Streets of Mobile; Mercury’s NOT Retrograding THAT Way!

  • The Classroom Astronomer Newsletter Highlights


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Dr. Larry Krumenaker.


This Just In—

Predicting a Supernova 16 Years from Now

Scientists at the Hubble Telescope, a.k.a. Space Telescope Science Institute, are known for making hyperbolic statements (probably justifiably) about their photos, but not usually for predictions. But they’ve made one now, for a future supernova. Unlike, say, periodic comets or eclipses, supernovae are not known for clockwork precision, but there is one that these scientists want to stake a claim to for a date. This exploding star, dubbed Supernova Requiem, is predicted for 2037 (hedging plus or minus a couple of years…), though only Hubble and maybe some other telescopes will view it.

How can they be so sure? Because they’ve seen it before.

Lead researcher Steve Rodney of the University of South Carolina in Columbia notes that this will be “the fourth-known view of the same supernova, magnified, brightened, and split into separate images by a massive foreground cluster of galaxies acting like a cosmic zoom lens. Three images of the supernova were first found from archival data taken in 2016 by NASA's Hubble Space Telescope.” Multiple images are produced when a foreground galaxy cluster's gravity distorts and magnifies light from any supernova far behind it, a process called gravitational lensing. The third image captured by Hubble, from the cluster, MACS J0138.0-2155, took about 4 billion years to reach Earth. The light from Supernova Requiem needed an estimated 10 billion years for its journey, based on the distance of its host galaxy.

The team's prediction of the supernova's return appearance is based on computer models of the cluster, which describe the various paths the supernova light is taking through the maze of clumpy dark matter in the galactic grouping. Dark matter is an invisible material that comprises the bulk of the universe's matter and is the scaffolding upon which galaxies and galaxy clusters are built.

"Whenever some light passes near a very massive object, like a galaxy or galaxy cluster, the warping of space-time that Einstein's theory of general relativity tells us is present for any mass delays the travel of light around that mass," Rodney said. He compares the supernova's various light paths to several trains that leave a station at the same time, all traveling at the same speed and bound for the same location. Each train, however, takes a different route, and the distance for each route is not the same. Because the trains travel over different track lengths across different terrain, they do not arrive at their destination at the same time.

In addition, the lensed supernova image predicted to appear in 2037 lags behind the other images of the same supernova because its light travels directly through the middle of the cluster, where the densest amount of dark matter resides. The immense mass of the cluster bends the light, producing the longer time delay. "This is the last one to arrive because it's like the train that has to go deep down into a valley and climb back out again. That's the slowest kind of trip for light," Rodney explained.

3D Printing of Molecular Interstellar Clouds

(Orion B Molecular Cloud, photo from ESA)

Among the least understood, and hardest to visualize, structures in the universe are the molecular clouds that float between the stars, and that ultimately form into the nebulae and stars in the galaxy. They are cold, dark, and amorphous, and are detected mostly through radio telescopes, and visualized mostly through arduous plotting in two-dimensions. Researchers at the University of California-Santa Cruz, the Center for Astrophysics in New York City, and Harvard University managed to take data and convert it into 3-dimensional lattices and turn that into visual representations with a 3D plastic printer.

What they find are strong representations of the dynamics in three dimensions of shock features, self-gravitational activities, and magnetic field structures. It also shows how the clouds have sheet structures that are complex and which do not show up well in 2D representations. Lastly, they show that filaments actually bend and whirl and loop over much longer distances than presumed before and yet remain coherent throughout the cloud.

(Imari, Forbes and Weaver, The Astrophysical Journal Letters, 918:L3 (9pp), 2021 September 1 https://doi.org/10.3847/2041-8213/ac194e)

* You Think YOU Have Flooding Problems??

Okay, there have been a lot of tropical (and other storm system) flooding issues all over the world—the USA, Mexico, Europe (my once-residence in Erftstadt, Germany), Asia. Why should Mars be any different?

A significant amount – at least 25 percent - of Martian valley networks formed as a result of lake breach flooding, stated Planetary Science Institute Research Scientist Alexander Morgan in a recent Nature journal paper coauthored with University of Texas’ Timothy A. Goudge. Mars’ surface hosted large lakes about 3.5 billion years ago. Some of these lakes spilled over their rims, resulting in massive floods that rapidly formed deep canyons. Similar lake breach floods occurred in the northwest United States and central Asia at the end of the last glacial period more than 15,000 years ago. “We found that at least a quarter of the total eroded volume of Martian valley networks were carved by lake breach floods. This high number is particularly striking considering that valleys formed by lake breach floods make up just 3% of Mars' total valley length,” Morgan said. “This discrepancy is accounted for by the fact that outlet canyons are significantly deeper than other valleys.”

The paper helps shed light on historic climate change on Mars. For several decades there has been an ongoing debate about whether the early Martian climate should be better characterized as ‘warm and wet’ or ‘cold and icy.’ “Almost everyone agrees, however, that the early Martian environment underwent big climatic changes,”  Morgan said. “During dry eras, impact cratering and volcanism would disrupt previously developed rivers, essentially creating dams. When the climate warmed to a point where liquid water was stable on the surface, there would have been numerous floods as new flow paths had to be created across the cratered landscape,” Morgan said.

* More Martian Water….

An international team of researchers has used seasonal variations to identify likely sub-surface deposits of water ice in the temperate regions of Mars where it would be easiest for future human explorers to survive. The results were presented this week by Dr. Germán Martínez at the European Planetary Science Conference (EPSC) 2021.

Using data from NASA’s nearly 20-year-old Mars Odyssey, Martínez and his colleagues have identified two areas of particular interest: Hellas Planitia and Utopia Rupes, respectively in the southern and northern hemispheres. Seasonal variations in levels of hydrogen detected suggests that significant quantities water ice can be found in the first meter or so below the surface there. 

(Image modified from NASA map)

Martínez, of the Lunar and Planetary Institute, could not say '“whether this is in the form of water ice, which can readily be used as a resource, or locked away in mineral salts or in soil grains and minerals.” Seasonal variation, though, provides an important clue. As the coldest ground temperatures occur at the same time as the largest observed increase in hydrogen content, it suggests that water ice is forming in the shallow subsurface of these regions during the fall and winter seasons, and then sublimating into gas during the warm season of each hemisphere.’ 

Water ice in the shallow subsurface has been found in plentiful supply at the poles. However, the frigid temperatures and the limited solar light make polar regions a hostile environment for human exploration. The areas from equatorial to mid latitudes are much more hospitable for both humans and robotic rovers, but only deeper reservoirs of water ice have been detected to date, and these are hard to reach. 

To survive on Mars, astronauts would need to rely on resources already available in-situ, as sending regular supplies across the 55 million kilometres between Earth and Mars at their closest point is not an option.

‘Definitely, those regions too are interesting for future missions,’ added Martínez. ‘What we plan to do now for them, or Hellas Planitia and Utopia Rupes, is to study their mineralogy with other instruments in the hope of spotting types of rock altered by water. Such areas would be ideal candidates for robotic missions, including sample return ones, as the ingredients for rocket fuel would be available there too.’

* Getting Breezy on Jupiter

Jupiter’s Great Red Spot seems to be tightening…and rotating faster, or at least having faster winds circulating in the solar system’s fastest ‘hurricane’. In Jupiter’s Great Red Spot, a storm that has been roiling for centuries, its “outer lane” is moving faster than its “inner lane” and continues to pick up speed. Long-term data from the Hubble Space Telescope indicates that the high-speed ring has increased by up to 8 percent between 2009 and 2020.

[Ed. note—Just a guess on my part but the GRS has been shrinking. Could this be the cause of the increasing speed? That old conservation of angular momentum thing?]

(Image credit STSCI/NASA)

* A Nearly Complete Einstein Ring

Now known as the Molten Ring, this issue’s cover photo is seen as the most complete Einstein Ring ever photographed. Einstein Rings are light brought about by the gravitational pull of a massive intervening galaxy from a galaxy further behind it, and so centrally located that the light encircles the galaxy doing the ring-work. Yes, one galaxy to wind it all…around. Located in the constellation of Fornax the Furnace, the distorted lensed galaxy lies more than 9 billion light years away. Sorry, Sauron.

* A Lot of Gas, or a Whole New Arm?

Not talking biology here….four Chinese astronomers published a note in September 1st’s Astrophysical Journal Letters that they have found an indicator of what could be either the largest gas filament in the Milky Way galaxy, or a whole new spiral arm feature, on our side of the Milky Way. Chong Li, Keping Qiu, Bo Hu, and Yue Cao whimsically name this feature Cattail and note that it is a continuation of the Scutum-Centaurus Arm that begins on the other side of the galaxies central bulge from us.


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 3 The Moon lies to the left of Regulus, the heart of the Lion, just before the Sunrise point during dawn.

October 6 New Moon.

October 8 The Moon is at its perigee point; we have a Super-Thin Evening Crescent Moon!

October 9 Venus is 3 degrees to the North (right-ish) of the evening crescent, perhaps the most beautiful Venus--Luna conjunction of this year. Try to photograph it! At the same time, the planet passes its closest to the star Delta Scorpii, the brightest star in the T-shaped head of the Scorpion. See the full story below.

October 12-13 The midnight between these dates (roughly, depending on your time zone) is the exact moment of First Quarter. On the second of those dates, the Moon is also 4 degrees south of Saturn.

October 15 Jupiter is passed 4 degrees away by the Moon.

Observing---Plan-et….                                    

This is Venus’ month, or rather, its first of three prime months. First, as noted above, it passes very close by the star Delta Scorpii, the middle and brightest of the three stars that make up the T-shaped head of Scorpius the Scorpion. Delta has a bit of modern infamy. Two decades ago, it did something most of the so-called fixed stars don’t do….it changed. It got brighter—noticeably. Normally a middling second magnitude star, comparable in brightness to the North Star, it rose nearly a full magnitude, nearly 2.5 times its usual luminosity, to nearly the ranks of a first magnitude object, magnitude 1.6. This significantly changed the ‘face’ of the Scorpion! Cause? The throwing off of gas rings. It has faded back mostly, but watch it anyway.

The first half of October will have Venus gingerly approaching and then moving past and away from this explosive star….closest approach on the 9th.

On October 16th Venus passes a degree and a half from the Anti-Mars, a.k.a. Antares, the red giant heart of Scorpius. Easily note the color differences. By month’s end, Venus will have maxed out its angular distance from the Sun and will begin to dive back towards ol’ Sol, slowly but then with increasing speed.

Meanwhile, though low in our Northern Hemisphere skies (oh, to be observing in Sydney or Johannesburg!), drag out the telescope! Venus will not be just some amorphous disk but will be a half-moon shape starting around mid-month, and shrinking in width (but not size!) through year end.

Mercury does the reverse. It’s too close to the Sun right now, in solar conjunction on the 9th, but flies into the morning sky in just over a week. It rises more than 40 minutes before Sunrise after the 14th. More in the next TGT….

Earth gets visited by some meteoroids. There’s a strange meteor shower, called the Taurids, that is split between two equally wide streams, the Northern Taurids and Southern Taurids, that each give around 5 meteors per hour. The Southern Taurids strike us first, but the peak varies each year, NOT because the streams are lumpy or don’t know how to keep a schedule. Because the meteoroids are so sparse, the maximum you can view is highly susceptible to being washed out by the Moon! So this year, the best time for (some of) us is a peak around the 9th. Other years, it peaks in early November. Meanwhile, the Northern Taurids will peak later, see the next TGT. When both are active, you get lots more to see….and both are known not for numbers of meteors, but for fireballs!

Mars——still lounging in the Sun. Or at least near it, in the Earth’s sky, in solar conjunction on the 7th; won’t reappear in a dark pre-dawn sky until late December.

Jupiter—Still shining nicely in the Southeast to South at the end of evening twilight, but its motion amongst the stars is stalling out. Saturn, to its right, does stall out, on the 11th, and begins to move correctly, towards the east, after that. It sets around 1 AM-ish.

For the Future…

We have a (very nearly) total Lunar Eclipse in a month.

On the heels of the Southern Taurids, the rest of the meteor season (for northern hemisphere observers) begins, with more major and minor showers now than in most of the rest of the year! The more numerous Orionids are coming up later in October.

Mercury gives us its best 2021 morning show in late October, early November.

Border Crossings

None. The horoscope columns say the Sun’s in Libra. In reality it is in Virgo. The twain won’t meet until about a week before Halloween.


Astronomy in Everyday Life

The Starry Streets of Mobile, AL

Mobile, Alabama is a formerly French city. Well, it was about three centuries ago. It also was British and Spanish, long before it became American. Yours truly has been down there quite a few times, for research before and presentations afterwards on a non-astronomical book, on the Marquis de Lafayette, who came to Mobile in 1825 as part of his Grand Tour of the USA. Historical tourism is my other writing interest, and recently I was down by Mobile Bay giving a book presentation. As part of any tour I do as I travel, I am always keeping my eyes open for anything astronomical, especially things celestial where you don’t expect them. Mobile has no public planetariums or observatories. It does, however, have a subdivision where whoever designed the layout had an obvious interest in the sky.

As you can see by the photos here, the subdivision is primarily navigated by seven first-magnitude stars (meet me at Rigel and Vega!). What is a bit puzzling, given that there are far more than seven such stars, is that the remaining three streets are named for two zodiacal constellations and one second magnitude, though navigationally important, star, Polaris. The two zodiac streets, neighbors in the sky, are neigbord on the ground, intersecting, and Aldebaran Way does intersect its constellation, Taurus Drive. Polaris Drive somewhat acts as an outside perimeter navigational connector (not completely, but almost) so clearly the road labeler knew something about the constellations.

It is always fun to try and discern any patterns when one finds these cosmic puzzles on the ground!

* * *

Mercury’s NOT Retrograding THAT Way!

Normally, I like when mainstream media covers astronomy, but I’m not at all happy with the way CNN does it. Their usual reporter clearly LIKES astronomy and space, but hasn’t the background. Someone got them to discuss Mercury’s retrograde motion and ‘how it affects our lives'. I can’t tell if it was to be tongue-in-cheek, but one thing did push my button…..their explanation of what Mercury’s retrograde motion is…the Earth passing Mercury in our orbit. That’s usually the right answer….for planets further out in the Solar System. But NOT true here! In this case, it is Mercury passing Earth! Mercury and Earth, like all planets, move in the same direction around the Sun, but Mercury being faster, is currently rounding the Sun between it and us, and going into conjunction with the Sun. To do so, it appears to us to be moving from east to west—retrograding. But that is not because we’re passing IT. This is because IT is passing US.

Get it right, even if it is tongue in cheek. And if it is not t-i-c, don’t talk about it at all….

-LK


The Classroom Astronomer Newsletter Issue 10 Highlights

This premium newsletter is a subscribers-only publication, though a free Lite version is available.

  • Cover - Star Cluster HR Diagrams from Stellarium!

  • Connections to the Sky - 
    Testing Activities Online for the Rubin Observatory;
    SETI Institute Joins Unistellar & The Planetary Society to Inspire Girls to
    Discover Space During World Space Week;
    Virtual Goddard

  • Astronomical Teachniques - 
    The Sound of a Supernova’s Structure;
    Virtual Observations from Stellarium;
    An Additional Stellarium Exercise Resource;
    A Flat Moon?

  • The RAP Sheet – Research Abstracts for Practitioners - 
    Periodicity and Change: Talking about Time Inside the Planetarium Dome;
    The Gateway Science: a Review of Astronomy in the OECD School Curricula,
    Including China and South Africa;
    Physics for the Masses: Teaching Einsteinian Gravity in Primary School


Coming Soon!

Learning Astronomy Under The Northern Stars – A 365-Night Per Year Textbook

Use the stars that are ALWAYS visible to understand basic astronomy, stellar evolution, galactic structure, with the naked eye and common binoculars.  EBook and print book coming.  Detail description and advance orders link coming soon (sorry for the delay!).


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Thanks for reading. Until the next newsletter, stay safe.

Dr. Larry Krumenaker Questions, suggestions, comments? Email them to: newsletter@thegalactictimes.com Twitter: @TimesGalactic Facebook:The Galactic Times