The Moon is New on August 4th, Full on August 19th.. The very young crescent Moon is close to Venus on August 5th. The Moon occults Saturn on August 21st between 4.28 and 5.21 a.m., varying by a few minutes according to location, and on the same day at 10,30 p.m. the Moon is close to Neptune. On the morning of the 26th the Moon passes through the lower part of the Pleiades, occulting Atlas, one of the Seven Sisters, and on 27th and 28th, the Moon is near Jupiter, Mars and Aldebaran in the Hyades cluster.
More results have been published from the ongoing mission of China’s Yutu-2 rover, on the far side of the Moon, confirming that in the first 130 feet below the Farside surface at its location there are at least five layers of lava, increasing in thickness with depth. Below that may be the remains of a very large impact crater (unless they’re talking about the rim of the huge Aitken Basin, tangential to the south pole, which Yutu-2 is near). The broken material between the layers supports the hypothesis that the Farside was resurfaced, over the following 200 million years, by debris from impacts on the side facing the Earth. (Harriet Brewis, ‘”Hidden Structures” Discovered Beneath the Dark Side of the Moon’, Indy 100 online, 23rd July 2024.)
After the crash landing of Intuitive Machines’ IM-1 (Nova-C) Odysseus in February, the IM-2 mission later this year will repeat the attempt to land near the lunar south pole, and to deploy NASA’s PRIME ice and rock drill (Fig. 1). The laser altimeter system which failed last time has received major improvement, and the landing gear has been beefed up in hopes to survive the touchdown if it has to be controlled optically as before – though a new Canadian optical system is being prepared and will be flown if ready. IM-2 will also carry a hydrazine-fuelled ‘Hopper’ called Micro-Nova. After initial short flights to demonstrate the technology, like Ingenuity’s first ones on Mars, Micro-Nova will fly into the permanently shadowed crater Marsden, and back out (Fig. 2). It has been suggested that it could do the same with a nearby lava tube, if there is one, but that is probably too ambitious.
Talking about ambition, though, the IM-3 lander in 2026 (Fig. 3) is scheduled to tackle a major lunar mystery which goes back to the Lunar Orbiter programme before the Apollo missions. The Orbiters found mysterious swirls, ‘lunar tattoos’, which were flush with the surface but very large – Reiner Gamma, one of the most prominent, needed three frames to capture its hundreds of kilometres’ length (Fig. 4). Although the Moon has no intrinsic magnetic field, the sites show residual magnetism, with Reiner Gamma the most intense on the Moon, and the swirls may be due to dust moved by disturbance to the Solar Wind, perhaps in the aftermath of cometary impacts. Ilmenite, a common form of titanium oxide found across the Moon, contains iron crystals which can readily be magnetised at high temperatures, for instance by shocks (Fig. 5). Previous studies of ilmenite brought back by the Apollo astronauts have concentrated on formation at the surface, but if due to subsurface action, the swirls could be due to magma containing ilmenite. IM-3 is going to release a NASA rover called Lunar Vortex (Fig. 6); given the size of Reiner Gamma, the claim that it may solve the mystery seems ambitious to say the least, but direct measurement on the surface will undoubtedly be valuable, if not surprising.
The planet Mercury is not visible this month, too near the Sun and at inferior conjunction on the 19th. The August edition of Astronomy Now suggests it might be seen with binoculars, 35 minutes before sunrise in southern England, but it’s much less likely to be seen in Scottish summer twilight.
An extraordinary idea has been proposed to explain anomalous features of Mercury, one of which is that its magnetic field is unusually strong for such a small body, rotating so slowly. The surface of Mercury is dark, containing high levels of graphite, and scientists in China and Belgium now suggest this is because at the time of its formation Mercury had a surface ocean of magma which was rich in carbon. As graphite formed it floated to the surface, while diamond formed and sank, now forming a layer of diamond between the mantle and the core, 15-18 kilometres thick, which modifies the transfer of heat from the interior and helps to maintain the magnetic field (Fig. 7). Presumably the diamond layer is not rigid, or not continuous, because there is plenty of evidence that Mercury’s core has contracted over time, particularly in the form of giant scarps which have formed due to wrinkling of the crust.
There are other possible locations for large residues of diamond in the Solar System and beyond. Conditions inside Uranus and Neptune may favour the formation of diamonds up to the size of the Earth, though no evidence has been found for them. In 2010, the sequel to 2001, A Space Odyssey, Arthur C. Clarke suggested there was one such at the core of Jupiter, but that has never been detected and is ruled out by the tracking data from the current Juno orbiter, which has established that Jupiter is gaseous hydrogen all the way to its heart (though compressed there into metallic form). It has been suggested that ‘carbon planets’ could form around white dwarf stars, or at an earlier stage, from pre-planetary discs rich in carbon rather than oxygen. Such planets might have oceans of graphite, and mountains of diamond thrown up from denser layers within. I was caught on the hop with that one, because the BBC asked me for a comment on it in 2005 before I got to hear of it. In particular, since 2012 the nickname ‘diamond planet’ has been applied to the exoplanet 55 Cancri-e, formally known as ‘Janssen’, but the identification isn’t absolutely certain.
Venus is back in the evening sky, setting around 9 p.m., but needing binoculars to find it in the twilight. As always, take great care if searching for it before sunset. Venus is near the Moon on the 5th, as above.
Mars passes the Hyades Open Cluster in Taurus and is to the right of Jupiter in early August, though much fainter, and is in close conjunction with Jupiter on the morning of the 15th. The planets are less than a degree apart for a week (less than half a forefinger’s breadth at arm’s length), and only quarter of a degree apart at their closest. Both planets rise soon after midnight BST.
On Mount Sharp in Gale crater, the Curiosity rover is exploring mounds formed by landslides and deposits in the Gediz Vallis river which once ran down the mountain. Many of the rocks show ‘halos’ where groundwater has penetrated them, billions of years ago (Fig. 8). But then Curiosity accidentally crushed a pebble and revealed bright yellow crystals of pure sulphur inside (Fig. 9). Such finds are normally associated with volcanoes, but Mt. Sharp is the central peak of an impact crater. (‘Researchers shocked by hidden contents of Martian rock’, NASA, July 18th 2024, updated as ‘Martian rock crushed by Curiosity hides a surprise!’, EarthSky, online, July 26th.) Was there volcanic activity inside the mountain? Patrick Moore believed many of the central peaks in lunar craters showed signs of volcanic activity, and I think he might even be right about the central peak of the crater Tycho. Or was the pebble ejected from a volcano elsewhere? The plot thickens, but it may be overshadowed by another sulphur-related discovery.
Almost immediately after its organic compounds sampler was restored to life (see ‘Space Notes’, ON, July 7th 2024), on 21st July the Perseverance rover found a calcium sulphate-bearing rock in the Neretva Vallis river valley, rich in organic compounds and containing black-ringed ‘splotches’ like leopard spots, bearing concentrations of iron and looking for all the world like the remains of microscopic life (Fig. 10). The rock has apparently been immersed twice in water, during floods of the river in the remote past, forming out of the organics-bearing mud from upstream and then penetrated and moulded in the second episode. Already, the find has sparked new discussion about how to get the Perseverance samples back to Earth for more detailed analysis. (Sharmila Kuthunur, ‘NASA’s Perseverance Mars rover finds possible signs of ancient Red Planet life’, Space.com, online, 25th July 2024.)
Jupiter in Taurus rises at 00.30 a.m., forming an equilateral triangle with Aldebaran and Mars, close to Mars mid-month as above, and still close to them and the Moon on the mornings of the 27th and 28th.
Now and again, a fresh look at data from previous space missions turns up something that wasn’t suspected at the time. One example was that in 2012-14, Hubble Space Telescope studies found possible evidence of water plumes escaping from Jupiter’s icy moon Europa. Looking back through the records for any other possible instances, it was found that in 1997 the Galileo Jupiter orbiter made a close flyby of Europa and experienced an unexpected drop in readings, possibly due to passage through a similar plume. The chance of future such encounters has influenced the choice of instrumentation and the mission profiles for Europe’s Jupiter Icy Moons Explorer, now in flight, and for NASA’s Europa Clipper mission, due for launch this Autumn. The James Webb Space Telescope is looking at Europa from time to time as well.
Meanwhile dark matter continues not to appear in detectors, on the International Space Station for instance, although the evidence for its existence on large scales in the Universe continues to mount. But now, scientists at Princeton and at the National Accelerator Laboratory in California are suggesting that evidence for its existence may have been found by the Cassini spacecraft, when it flew past Jupiter on its way to Saturn in 2000. Looking at production of trihydrogen cations (H3+) in Jupiter’s upper atmosphere due to solar ultraviolet light (Fig. 11), they found an excess of those ions on the nightside of the planet, either side of the midnight meridian. Something other than solar radiation must be causing the heating which generates them, and the suggestion is that because of its huge size and mass, Jupiter may be acting as a dark matter collector. (Dave Adalian, ‘Do Dark Matter Collisions on Jupiter Glow in the Infrared?’, EarthSky, online, 10th July 2024.) As I said in ‘Jupiter’ (ON, 5th September 2021), if we could see Jupiter’s gravitational field, it would dominate a large area of sky. It will be interesting to see if there’s confirmation of the anomaly from the New Horizons Jupiter flyby of 2007, because New Horizons went out from Jupiter straight down the shadow cone, as it happens. Neither the HST nor the JWST can tell us more, because they can’t see the nightside of Jupiter from here or from the Sun-Earth L2 point, but JUICE and Europe Clipper may be able to when they’re not looking at the icy moons – and the Juno orbiter is still good to circle Jupiter for at least another 14 months, so it may be able to help.
Saturn in Aquarius rises about 9 p.m., moving westward before opposition in September, and is occulted by the Moon on the 21st (see above), for the first time since 2007 as seen from the British Isles. Its largest moon Titan will be occulted just ahead of it, a minute earlier. As the August issue of Astronomy Now points out, with diagrams, such events can only occur when the rings are nearly edge-on to Earth, as they are now.
Another case of new information coming from old data is a report from Cornell University about reprocessing radar studies of Titan. In 2016 radar from the Cassini orbiter was bounced back to Earth from the huge lakes or seas in Titan’s northern hemisphere (Fig. 12). One of the big questions has been whether they consist of methane, ethane or a mixture; what has been found is that pure methane enters the lakes from the rivers which feed them, so confirming that it’s methane which falls as rain. As seasons advance on Titan, methane evaporates from the lake surfaces, releasing hydrogen which escapes and leaving ethane behind. (Robert Lea, ‘Before plunging to its death, NASA’s Cassini spacecraft saw secrets in the seas of Saturn’s moon Titan’, Space.com, online, 22nd July 2024.)
It’s nice to get confirmation and details of these processes: the Huygens lander of January 2005 found that the mountains were water ice, and the rivers which flowed down them were almost certainly methane (Fig. 13). What I found amazing was that the Space.com article was accompanied by an irrelevant diagram of Titan’s interior, showing a water-clathrate crust, a water ocean at least as deep as the one on Jupiter’s water-moon Europa, an ice-6 solid layer below that, and a water-silicate core below all. This was stated with confidence to be ‘A diagram showing the interior of Saturn’s moon Titan, including its deep ocean’, from A. D. Fortes of University College London and the Science & Technology Facilities Council (Fig. 14). I’ve seen those ideas suggested before, probably from the same researchers, but for them to be proven comes as news to me. In 2005 and 2006 Cassini did find possible indications of cryovolcanic activity (Fig. 15), driven by liquid water from below, but to quote Wikipedia, ‘The identification of cryovolcanic features on Titan remain controversial and inconclusive, primarily due to limitations of Cassini imagery and coverage’. To go from there to confident identification of a three-layered ocean much larger in volume than Europa’s (Titan is larger than the planet Mercury) would be a huge leap, and my guess is that this image is of a hypothesis, and has been lifted from a different article or folder and inserted in the Space.com article almost at random.
Uranus in Taurus rises at 11.30 p.m., near the Moon on the 26th. Studies by the James Webb Space Telescope of Uranus’s brightest moon, Ariel, have discovered surprising amounts of carbon dioxide ice, and even carbon monoxide, on the trailing hemisphere of Ariel where it was not expected to be. There’s a strong possibility that it’s coming from a subsurface liquid ocean, which ties in with geological features imaged by Voyager 2 in 1986 (Fig. 16), and makes the case which I’ve previously mentioned for a new mission to Uranus even stronger. (Mark Thompson, ‘Now Uranus’ Moon Ariel Might Have an Ocean too’, Universe Today online, July 25th 2024.)
Neptune in Pisces rises about 9.30 p.m., and is close above the Moon on the 21st, as above. It will be occulted by the Moon as seen from south-east Europe, and north and central Africa.
The Perseid meteors peak on the night of 12th/13th August, and this will be an excellent chance to see them after the Moon sets at 11 p.m., with more becoming visible as the Earth turns into the shower after 1 a.m. BST.
And finally: the James Webb Space Telescope has captured a far-infrared image of a galaxy NGC (New General Catalogue) 2936, which looks very like a penguin (Fig.17), to be eating a fish in mid-infrared (Fig. 18), and previously to be wearing dark glasses in a 2023 Hubble telescope image (Fig. 19). The penguin is a spiral galaxy being distorted by an encounter with the elliptical galaxy NGC 2937 (bright green in the HST image), 25-75 million years ago. Everything in the images is extragalactic except for the two nearby stars at top right, one of them apparently at the rim of the edge-on spiral NGC 1237172, itself about 100 million light-years closer to us than the penguin, and which appears bright to a high rate of stellar formation.
The penguin and egg are together # 124 on a list of unusual objects compiled by Halton Arp, The Atlas of Peculiar Galaxies, whose opposition to the Big Bang and to the standard theory of redshifts eventually cost him his place at the Mount Palomar Observatory in 1983. He appeared on Patrick Moore’s The Sky at Night to make his case, and soon afterwards I met his daughter Jennifer Tifft in California. She gave me her poem ‘The Astronomer’s Daughter’, and the Scottish spaceflight society ASTRA published it in 1990. Funnily enough, I’m expecting a visit in August from a member of the family who introduced us. to Earth
The Astronomer's Daughter
Jennifer Gail (lferion)
Work Text:
My father sails the galaxies on glass and steel and light
My mother paints us pictures of bright things beyond our sight
My books tell me of marvels - of elves and ships and stars
I sit entranced as Voyager launches off toward Mars
Telescope, spectrascope, antenna-dish
Red-shift and blue-shift and galactic drift
Luminous measures, mechanics of lift
The Astronomer's Daughter has only one wish
Heinlein told of torch-ships, of tunnels in the sky
Goddard built us rockets to show that we could fly
Apollo 7 launches men, 11 lands them safe
Why must I be stuck on Earth, in gravity's pull and chafe?
Pulsar and quasar and hydrogen glow
Infinity squared and physics says "Go!"
Mathematic equations, mirrors just so
The Astronomer's Daughter thinks we're going too slow
*I'm younger than the Space Age - spaceflight? But of course!
*My father taught me magnitude, star names, black hole's force
*Velocity and red-shift, zero kelvin, fahrenheit
*He would have been an astronaut, but something stayed his flight
*Sputnik and Skylab and Mariner 3
*Grissom and Armstrong and fractions of C
*Jupiter, Saturn and Pioneer's free
*The Astronomer's Daughter cries "Will they let me?"
They've cancelled the Apollo flights, petitions all in vain
Will they let the shuttle fly or ground us once again?
Now I'm old enough to know the tragedy of this
We've climbed too high to cut so short our trek through the abyss
Stellar equations and venturi thrust
Silicon wafers and microdot rust
Fragile heat-tiles that crumble to dust
Astronomer's Daughter, hold fast to your trust
My father studies redshifts of the distant galaxies
Stuck on Earth we can but look out at the starry seas
But the promise of my childhood was of Space within our reach
The rocked flamed and thundered as we watched upon the beach
Venus and Neptune and Pluto and Mars
Asteroid, planetoid, meteor scars
LaGrange point stations and shuttlecraft cars
The Astronomer's Daughter asks "What of the Stars?"
*The Shuttle's named Columbia, she's NASA's joy and pride
*We finally convinced them and they sent up Sally Ride
*But still we've only got three ships, they range not very far
*What happened to the dreams we had of reaching to the stars?
*Rukbat and Algol, Rigel and Altair
*Castor and Pollux, the twins are a pair
*Betelgeuse bloodly and Procyon fair
*The Astronomer's Daughter cries "Do we not care?"
The planets still await us, the moon within our sight
The authors and the telescopes push back the rim of night
Our ships would span the distance out to Pluto and beyond
The Universe awaits us, and I would we'd carry on
Parsecs and lightyears and Pisces the fish
Helium, hydrogen, oxygen-gift
Telemetry, physics, molecular shift
The Astronomer's Daughter yet holds to her wish
Notes (Jennifer Tifft, 1986):
Written as a filk/song, this has yet to acquire a tune. The *verses are the ones I occasionally leave out for time when performing.
All the star-names in the second-to-last verse are real, including Rukbat (Alpha Sagittarii), which is indeed in the constellation Sagittarius.
Works inspired by this one:
Astronomer's Daughter — Luinasolmë Elentiriel by lferion
You can download a copy of August’s Sky Map here