The Sky Above You – November 2023 #Astronomy

By Duncan Lunan

The Moon will be New on November 13th, and Full on November 27th, very near Venus on the 9th and occulting it in daylight  (see below).  There’s some interesting news about Apollo 17 samples which have  (deliberately)  never been examined until now, waiting until new analytical methods were developed.  Researchers at Glasgow University have now used new techniques of electron microscopy to study zircons in the returned rocks.  Zircons are reckoned to be the first crystals to have formed as the Moon’s crust solidified from its molten state, after forming in a collision between the proto-Earth and a Mars-sized body now called ‘Theia’.  They’re also the oldest material found on Earth, dated to 4.3 billion years ago, yet formed in the presence of water, before the final bombardment phase in the origin of the Solar System.

The lunar zircons also formed in the presence of water, and with the new dating methods, it’s been established that they are 4.46 billion years old, setting a new date for when the lunar crust began to form.  Some articles wrongly said that the date was previously believed to be 4.95 by ago, which would made the new dating younger, not older;  but the correct previous figure was 4.42 by, so it turns out that the Moon’s crust is 40 million years older than we thought.  The formation of the zircons probably coincided with a major outbreak of water from within the Moon, due to developing volcanic activity below.

The planet Mercury is not visible this month.  When the ESA Bepi-Colombo spacecraft achieves orbit around Mercury in 2025, its Japanese Mercury Magnetospheric Orbiter  (MIO)  is intended to separate from the main probe in order to study the planet’s electromagnetic environment without interference  (Fig. 1).  But on the first two of the three Mercury flybys already performed, the instrument has already succeeded in mapping the magnetic field as never before, confirming that chorus waves, aka radio ‘whistlers’, are generated when the weak magnetic field is compressed on the sunward side of the planet by the outward flow of charged particles called the Solar Wind.

Fig. 1. Bepi-Colombo separation in Mercury orbit, scheduled for 2025

Venus in Virgo rises at 2.30 a.m. in early November, 3 a.m. later, very near the Moon on the morning of the 9th, and occulted by it later, in daylight, between 9.45 and 10.45 a.m., approximately.  Venus is near Spica in Virgo at the end of the month.   

Mars is still out of sight beyond the Sun, until next spring, at superior conjunction on the far side of the Sun on November 18th.  The Ingenuity helicopter had now performed its 63rd flight, the third longest to date, in support of Perseverance rover operations.  Perseverance itself recently caused a stir when it found circular markings in rocks which might indicate microbiological activity in the remote past;  sad to say, however, spectroscopic analysis failed to find any supporting evidence in the samples drilled out.  The hunt for evidence of past life on Mars continues.

The sample return capsule from the asteroid Bennu landed safely in Utah on September 24th, while the main body of the OSIRIS-REx spacecraft, now renamed OSIRIS-APEx, flies on to catch up with the asteroid Apophis, shortly after they both pass close to the Earth in 2029.  It was known from images of its closure that the return container was full to overflowing, and when the capsule was opened, 70 grams of dark material was found loose inside  (Fig. 2).  The original target was to return only 65 gms!  Preliminary analysis of the material found surprisingly large amounts of hydrogen and iron, indicating that fragments of many other asteroids have found their way into the ‘rock pile’ which Bennu proved to be.  According to on 26th October, the main sample canister TAGSAM (Touch-and-Go Sample Mechanism)  cannot be opened yet because two of its latches are not compatible with the tools designated to be used.  What the difficulty is wasn’t specified, but the canister has been removed from the glovebox with its sterile nitrogen airflow, and sealed in a temporary wrapper while the problem is addressed. 

Fig. 2. Dust on the outside of the OSIRIS-REX sample canister

On November 1st the Lucy mission, on its way to Jupiter’s Trojan asteroids, will pass close to asteroid (152830) 1999 VD57, ‘Dinkinesh’.  The spacecraft has been sending back images of the asteroid, but as it’s only 0.4 miles across, no detail will be visible until the flyby itself.

NASA’s latest asteroid probe, to the metallic object Psyche, was launched successfully on a Falcon Heavy rocket on October 13th.  Due to delays in some of the instruments the spacecraft missed its original launch date and will not reach its target until 2029, a busy year because that’s when asteroid Apophis buzzes the Earth and the former OSIRIS-REx spacecraft, now called OSIRIS-APEx, will catch up with it.

Jupiter in Aries rises about 4.30 p.m. and is visible all night in November, at its closest to us  (596 million km)  on November 1st, and at opposition on the 3rd, when it will be due south at midnight.  That night the ice moon Europa and its shadow will be close together as they cross the face of the planet, starting at 1.15 a.m.  Several of November’s events with Jupiter’s moons are highlighted in the November issue of Astronomy Now, along with the usual complete listing of them.  Our Moon passes Jupiter on November 25th.  

Analysis of the James Webb Space Telescope’s infrared images of Jupiter in June has revealed a previously unsuspected atmospheric feature, a 350 mph jetstream just north of the equator, 21 miles above the main cloud deck, explaining some mysterious features in the layers below  (Fig. 3).  Meanwhile the Juno orbiter is making successively closer approaches to the volcanic moon Io, and from 7500 miles it has identified 266 active volcanoes on its surface  (Fig. 4), with strong evidence for an underlying magma ocean, 50 km down and 50 km thick.

Saturn in Aquarius sets at 11.30 p.m., and the Moon is near Saturn on 20th November.  Saturn has been moving retrograde  (westward)  after opposition in August, but passes its ‘stationary point’ and resumes eastward motion on November 5th

Uranus in Aries is at opposition on the 13th following Jupiter.  Uranus appears near the Moon on the 26th.  Ultraviolet light from auroral displays on Uranus has been detected frequently since 1986, but scientists at the University of Leicester have now detected infrared emissions from aurora there, for the first time.  Distant though it is, new discoveries about Uranus continue to stack up, and the case for an orbiter mission, to study the planet, its rings, moons and magnetic field in detail, is steadily gaining strength.

Neptune is on the boundary of Aquarius, setting around 2 a.m., still moving retrograde after opposition in September.  Neptune is near the Moon on November 22nd.

Much further out, in interstellar space, the two Voyager spacecraft have had software updates to deal with ageing problems, and make the most of their last decade of life before their power supplies give out.

The long-drawn-out Northern Taurid meteor shower continues, peaking on November 12th to 13th.  The Leonid meteor shower from Comet Tempel-Tuttle peaks about 6 a.m. on the night of 17th-18th November, with no interference from moonlight after 7 p.m., and there are hopes of a slightly better show as we move towards the 33-year peak in 2032, though there’s a long way to go yet. 

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