We have a real potpourri of current astronomy news and sights in this column. Amazing news includes the finding of 20 more moons of Saturn and the discovery of the first interstellar comet. Sights for this week and next that we’ll discuss today include stronger volcanic twilights, a scheduled rocket launch from Delmarva, and a fine pairing of the crescent moon and Jupiter on Halloween.
Strengthening volcanic twilights: We’ve discussed volcanic twilights recently. They are enhanced colorful glows after sunset and before sunrise, caused by the sun shining on very high altitude clouds of sulfuric acid droplets produced by volcanic eruptions. These clouds of aerosols from two volcanoes on the opposite side of the world from the U.S. are possibly getting denser for us in recent weeks. On Monday of last week I saw the strongest of these twilights in many years. Starting at sunset (actually sooner) the glow from the west lit up the landscape intensely. Then a vivid spot of rose appeared partway up the west sky and soon turned wider and more purple. Long streaks of thicker volcanic aerosols became visible. And finally, more than a half-hour after sunset, all sank into a very intense band of dayglo orange then red down near the horizon.
I suspect these twilights will be visible for weeks or even a few months longer. But don’t forget that on any given day the twilight will only be strong if the atmosphere is free of ordinary clouds for a few hundred miles west of you (at dusk) or east of you (at dawn).
Antares rocket launch scheduled: The launches of the large Antares rocket from Wallops Island in Virginia can produce puffs of fire and glowing trail visible from as far away as South Jersey. To see something impressive from this, however, we do need a launch at twilight or night. But the next launch is set for 9:59 a.m. on Nov. 2. Keep checking the website of the Wallops Island base and especially their Twitter feed to see, as often happens, if the date of the launch gets delayed and the time therefore changed. If we’re lucky the launch time will be backed up to before sunrise and the launch will look spectacular.
A celestial pairing for Halloween: Rain hid the very tight pairing of the moon and Jupiter back on Oct. 3. The next one, though not as compact, takes place on the evening of Thursday, Oct. 31 — and therefore should be a special treat for the holiday of Halloween. The lunar crescent will be quite slender and appear to the upper left of the bright planet Jupiter. A good time to look is about 7 to 8 p.m., fairly low in the southwest.
20 new moons and an interstellar comet: When I was a kid, Jupiter was known to have 12 moons and Saturn to have nine moons. But the rate of discovery of moons has picked up greatly in recent decades due to the work of space probes and more advanced technology at ground-based observatories. Now, just the other week, the most amazing finding yet, the announcement of 20 new moons of Saturn.
Jupiter has always held the title for most moons — until now. The totals have now reached 82 for Saturn and 79 for Jupiter. The sum for all moons of major planets in our solar system has at last exceeded 200.
Another remarkable discovery recently announced was the first comet entering from another solar system. Actually back in 2017 a strange object — possibly a new kind of asteroid — was discovered entering our solar system. But it definitely wasn’t a comet. Our current object is, releasing a cloud of dust and gas for a “head” and a trail of dust and gas for a “tail.” Interestingly, this object, Comet Borisev, was discovered by an amateur astronomer. Unfortunately, it will likely remain too dim to see with amateur telescopes.
Next column: In two weeks, this column will be about the Nov. 11 “transit of Mercury” — a planet passing in front of the sun.