Indholdsfortegnelse for September 2024 i BBC Sky at Night

VÍCTOR M BLANCO 4-METER TELESCOPE, 19 JUNE 2024 “T hings fall apart; the centre cannot hold,” wrote the great Irish poet WB Yeats. This new image of unbarred spiral galaxy NGC 3981 seems to prove him right. It was captured by the Dark Energy Camera (DECam) instrument on NSF NoirLab's Víctor M Blanco 4-meter Telescope in Chile, and clearly shows that the spiral arms of this galaxy, which lies 65 million lightyears from Earth in the southern constellation of Crater, the Cup, seem to be unfurling outwards into space. It's believed this unravelling is the result of the gravitational influence of one of NGC 3981's galactic neighbours – though as it's a member of the densely packed NGC 4038 Group, which contains at least 13 and possibly as many as…

A nearby exoplanet could be a water world with a nitrogen atmosphere similar to Earth's, according to new data from the James Webb Space Telescope (JWST). Exoplanet LHS 1140 b orbits a red dwarf star 48 lightyears away. The planet is in the star's habitable zone, meaning the climate of the planet could be temperate enough for liquid water to exist. Detailed observations have revealed that the density of the planet is consistent with a rocky world that's 10–20 per cent water, enough to cover the entire surface in water or ice. Recent measurements taken by the JWST have also hinted that the planet has a nitrogen-rich atmosphere, just as our own planet does. “This is the first time we have ever seen a hint of an atmosphere on a…

What do you do as NASA's head of science? I manage, look after and nurture all the science missions for NASA – anything that's not human space exploration falls under the Science Mission Directorate. Right now, we have about 144 missions. Some are still on PowerPoint charts; some have been in space for 47 years, like Voyager. We have a lot of medical research science that's on the International Space Station. There are missions to study the Sun, the planets of the Solar System and obviously our favourite planet, Earth, plus we study the Universe with our astrophysics telescopes. I get very involved in the missions, especially as they're preparing to launch. The technology is really inspiring when you hear about what the missions are going to do. But I…

No one knows why there are four different fundamental forces of nature: gravity, the electromagnetic force, and the weak and strong nuclear forces. Then again, there may be only one. In the very first moments after the origin of the Universe, this single force would have ‘split' into the four we now know. Indeed, in the 1970s, Sheldon Glashow, Abdus Salam and Steven Weinberg successfully formulated the electroweak theory, a unified description of the electromagnetic force and the weak nuclear force. In the future, physicists hope to also include the strong nuclear force, in what's known as a grand unified theory, or GUT. The ultimate dream is a single overarching Theory of Everything that would describe and explain all particles and forces of nature, including gravity. For many years, 10-dimensional…

Deslandres Type: Walled plain Size: 235km Longitude/latitude: 5.6° W, 32.5° S Age: Older than 3.9 billion years Best time to see: First quarter (11–12 September) or six days after full Moon (24–26 September) Minimum equipment: 10× binoculars Deslandres is a large, ancient and time-worn feature located just to the southeast of 750km Mare Nubium (the Sea of Clouds). A day after the first quarter Moon, there are two extremes visible in this region: the young, bright 86km crater Tycho and the dark, lava-filled 98km crater Pitatus on the southern edge of Mare Nubium. Centre to centre, Pitatus lies 410km north of Tycho. Head three-quarters of the way along this connecting line starting from Tycho, then head east for 200km and you'll be at the centre of Deslandres. Unlike either Tycho…

1. Alpha Persei Moving Cluster 10x50 Melotte 20 extends nearly 4° southeast from mag. +1.8 Mirfak (Alpha (α) Persei), with its hot, young, blue and blue-white (spectral types O and B) stars sparkling like diamonds on black silk. The colour of the stars hints at the relative youth (60 million years old) of this stunningly beautiful cluster. It's called ‘moving' because all the stars share a similar proper motion (motion relative to the celestial sphere). ☐ SEEN IT 2. Kemble's Cascade 10x50 During late summer evenings, Kemble's Cascade is approximately vertical in the sky, so you get the full effect of a ribbon waterfall falling into a splash pool (the open cluster NGC 1502). To find it, extend a line from mag. +2.3 Caph (Beta (β) Cassiopeiae) to mag. +3.3…

It now looks certain that samples of Phobos returned to Earth by JAXA will be the first ever obtained from the Mars system. Until recently, it had been hoped that NASA's Mars Sample Return mission would see a lander and a fleet of Ingenuity-style drones dispatched to the Red Planet's Jezero crater to join its Perseverance rover. The plan was for Perseverance and the drones to bring samples to the lander, where they would be placed in a rocket-equipped Mars Ascent Vehicle. After being fired into orbit, they would rendezvous with an Earth Return Orbiter spacecraft built by the European Space Agency, which would dispatch a capsule to travel back to Earth and land in Utah in the 2030s. However, NASA revealed in April 2024 that budget constraints meant it…

Comets and asteroids are the minor bodies of the Solar System. Like planets, they orbit the Sun, but they're far smaller and often more difficult to find. Today, most are discovered by large, automated survey telescopes when they are very faint. In the past, though, many were discovered by amateur astronomers, either visually or photographically, and it's still an interesting, fun activity to use the same technique to ‘discover' these objects for yourself. Asteroids are rocky objects, usually in almost circular orbits. They resemble slow-moving stars, even through large telescopes, and range from small rocks just a few metres across to 940km-wide Ceres. Meanwhile, comets are dusty, icy objects that generally have elongated orbits. The solid part of a comet is called the nucleus, which is often a few kilometres…

FREE BONUS CONTENT Find our extended Gallery at www.skyatnightmagazine.com/ bonus-content The Lobster Nebula Mohammed Dawoud, Al Kharrara, Qatar, 21 June 2024 PHOTO OF THE MONTH Mohammed says: “Being in the Northern Hemisphere, I don't often image southern constellation targets, but with the Lobster Nebula, aka The War and Peace Nebula, 31° above the meridian, I decided to try. I'm so pleased how the image turned out, in spite of limited exposure time and low altitude.” Equipment: ZWO ASI2600MM camera, Celestron RASA 8 astrograph, iOptron GEM 45 mount Exposure: Ha 20× 180”, OIII 17× 180”, SII 17× 180” Software: Astro Pixel Processor, PixInsight, Photoshop Mohammed's top tips: “The most important thing in astrophotography is planning. Good planning is the key to getting a nice image, including deciding what telescope to use,…

BULLETIN For almost two centuries, astronomers have been arguing over whether the Great Red Spot we see on Jupiter today is the same feature as a similar mark first observed by Cassini in 1665. Now a new set of simulations may have settled the debate once and for all, suggesting our spot and Cassini's are two separate things. After Cassini first noticed what he referred to as the Permanent Spot, he and others observed the feature continuously until 1713, when it vanished from the record for 118 years. Then in 1831, astronomers again started to see a clear, oval structure on the planet, at the same latitude as the Permanent Spot. This Great Red Spot (GRS) has been continuously monitored for over 190 years and is now known to be…

The first crewed test of Boeing's Starliner crew vehicle has been dogged with problems, making its stay at the International Space Station a month longer than intended. Starliner – a vehicle for carrying astronauts to and from the ISS – launched on its first crewed test on 5 June, with experienced NASA astronauts Sunita Williams and Butch Wilmore on board for what was initially a 10-day mission. The test flight appeared to be going well, until the propulsion system sprang multiple helium leaks. When the spacecraft began to approach the ISS for docking, five of the 28 control thrusters went offline. Four were later recovered and the spacecraft successfully docked on 6 June. Though Starliner was soon determined to be capable of a return journey, it has remained at the…

It's rare that discovering a place that smells of rotten eggs is a cause for celebration, but that's the case with exoplanet HD 189733 b. Observations of the planet's atmosphere by the James Webb Space Telescope (JWST) found traces of hydrogen sulphide, the chemical which gives bad eggs their odour and which is an important ingredient in the formation of life. “We're not looking for life on this planet – it's way too hot,” says Guangwei Fu from Johns Hopkins University, who led the study. “But finding hydrogen sulphide is a stepping stone for finding this molecule on other planets and gaining more understanding of how different types of planets form.” HD 189733 b is far from a pleasant place to visit, quite aside from its odour – the temperature…

Our experts examine the hottest new research CUTTING EDGE Binary craters are something of a curiosity. They're much more than two craters that happen to have formed side by side. Instead, they're believed to have been created simultaneously by the impact of a binary asteroid – a larger body being orbited by a natural satellite. About 15 per cent of all small asteroids are believed to be orbited by their own little moon, so dual craters, formed by the impact of both an asteroid and its moon at the same time, are actually relatively common. As such, double craters can also tell us something very useful about the population of binary asteroids. Binary asteroids in space are currently detected directly using radar, but this is only possible for the closest,…

The possibilities that lay in the early crackles and hisses of radio were only too clear for those who could envisage the real potential the invention possessed: what began as a revolutionary new method of communication would eventually reach to the stars. But at its birth in the late 19th century, no one expected that we would find radio waves rippling through space towards Earth; it would take decades to construct a mechanism to hear them. Two great minds jostled for notoriety in the early days of radio: Serbian-American engineer Nikola Tesla (1856–1943) and Italian inventor and engineer Guglielmo Marconi (1874–1937). After a serious off-air kerfuffle between the two, it was Marconi who eventually gained the patent for the invention of the radio in 1896. However, it was the brilliance…

DON'T MISS Partial lunar eclipse BEST TIME TO SEE: 18 September, 01:41-05:47 BST (00:41-04:47 UT) There's a small partial lunar eclipse taking place in the early hours of 18 September, when a portion of the Moon's surface will be covered by Earth's shadow. The full Moon that's involved will be the Harvest Moon for 2024, as it occurs nearest to the Northern Hemisphere's autumn equinox (the equinox itself occurs on 22 September). Unlike its solar counterpart, a lunar eclipse can be seen from anywhere on Earth where the Moon is above the horizon. Fortunately, this will be the case from the UK for this particular eclipse. Earth's shadow in space has two components: a weak, outer penumbral shadow and a dark, inner umbral shadow. If you were in a spacecraft…

PICK OF THE MONTH Saturn Best time to see: 8 September, 01:15 BST (00:15 UT) Altitude: 29° Location: Aquarius Direction: South Features: Rings, banded atmosphere, brighter moons Recommended equipment: 75mm scope or larger Saturn reaches opposition on 8 September, when the planet is presented at its best to us viewing from Earth. Shining at magnitude +0.2 among the stars of Aquarius, Saturn reaches around 30° altitude when due south, which is much better than it has managed over recent years. This lifts it above a lot of the lowaltitude turbulence that has ruined the UK's view for a number of years. Having said this, Saturn's rings are currently only tilted to our line of sight by 3.7°, which makes them appear extremely thin and somewhat less impressive than when they…

Comet C/2023 A3 Tsuchinshan–ATLAS is causing a bit of a stir because it has the potential to be visible to the naked eye, from the UK at least, from mid-October when it re-emerges from the Sun's glare into the evening sky. With a nucleus 20–40km across, C/2023 A3 is interesting because it's an Oort cloud comet that will reach perihelion on 27 September, when it swings past the Sun at a distance of 58.6 million kilometres. Perihelion also takes place with the comet moving between us and the Sun, giving rise to some difficult viewing conditions through September and early October. Minimum distance from Earth is achieved on 12 October, at 70.6 million kilometres. After solar conjunction on 9 October, when C/2023 A3 will be just 3.5° from the Sun,…

The planets are coming back in droves. After their poor performance in the first half of 2024, they are now moving out of the Sun's glare into the expanding autumn darkness. Not only that, but those that have been horizon-huggers in recent years are now able to reach higher altitudes. This is great news, because it lifts them out of the turbulent atmospheric murk lower down. To celebrate this, our challenge this month – and it's a tough one – is to capture details on planetary moons. It will require good seeing and preferably a large scope. The contenders here should be fairly obvious, as many of the Solar System's moons are physically too small and too far away for amateur equipment. This leaves the larger contingent, namely the four…

Don't ever go for a run on Phobos. With only one thousandth as much gravitational pull as on Earth, there's a danger you'll accidentally launch yourself into space and begin orbiting Mars. Phobos, one of Mars's two moons (the other being Deimos), is a dangerous place to try to land, which makes the Japan Aerospace Exploration Agency's (JAXA) Martian Moons eXploration (MMX) mission particularly daring. Planned to launch atop JAXA's new H3 medium-lift rocket in 2026 and go into orbit around Mars in 2027, the 4,000kg (8,820lb) MMX spacecraft will do something no other mission has yet attempted: return a sample from the Mars system to Earth. Phobos and Deimos were discovered in 1877 by American astronomer Asaph Hall and named after the sibling Greek gods of fear and panic,…

This month sees a small but welcome partial lunar eclipse. The event occurs on the morning of 18 September, when a maximum of 3.5 per cent of the Moon's surface (8.5 per cent of its diameter) will be covered by the darkest umbral part of Earth's shadow. Here we look at how to extract colour from the shadow. A total lunar eclipse is a colourful affair. The dark part of Earth's inner shadow isn't totally dark, but infilled with sunlight refracted through the thin ring of atmosphere at the edge of Earth. The blue component is scattered, leaving predominantly reddish hues to infill the shadow. Depending on things like the amount of cloud cover on Earth at the time of the eclipse, the shadow can appear a deep brownish colour,…

BULLETIN Drawing on 18 years of Hubble observations, astronomers have created the most precise map ever of how stars move in a dwarf galaxy. The new survey could be a huge boost to understanding how dark matter holds galaxies together. Most galaxies are spinning so fast that, if they only contained the stars that we see, they should fly apart. To explain why they don't, astronomers have theorised that galaxies are held together by the mass of an invisible substance they call dark matter. Currently, the presence of dark matter can only be inferred from the effect it has on the motions of stars and galaxies around it, which makes accurate tracking of its distribution within a specific galaxy difficult. While telescope observations suggest dark matter is relatively evenly distributed…

Voyager 1 is back conducting scientific observations and transmitting data after spending more than six months offline. In November 2023, Voyager 1's data transmissions suddenly became nonsensical. The Voyager team finally discovered the fault was caused by a corrupted memory chip and were able to reprogramme the spacecraft to avoid the problem component. “This is the first flight software update made to a spacecraft in interstellar space,” says Linda Spilker, Voyager's project scientist. “We are now getting science data back from all four Voyager 1 science instruments.” Following the update on 19 May, two instruments immediately came back online. The other two required more work, but have now resumed their tasks of measuring plasma waves, magnetic fields and particles. No craft has gone further out into space than Voyager 1,…

PARTICLE PHYSICS 101 The previous installments of this series all dealt with well-established facts and known particles and forces. However, this month we'll take a look at a much more speculative idea: supersymmetry (also known as SUSY). It's an as-yet unproven theory that could solve a number of nagging problems in particle physics, such as why gravity is so weak compared to the other forces in nature, or what the nature is of dark matter. However, it comes at a cost: if supersymmetry is right, nature should host a large number of additional particles, beyond the many we already know. Currently, physicists know of two families of elementary particles: fermions and bosons. Fermions are particles of matter, like quarks, electrons and neutrinos, which make up the material world. In contrast,…

Lyra is one of the iconic constellations of summer. Its brightest star, Vega (Alpha (α) Lyrae), is easy to find, being one of the vertices of the large Summer Triangle asterism. Hanging southeast of Vega is a squashed diamond pattern, the body of the harp-like instrument represented by the constellation. In its southeast corner is Sulafat (Gamma (γ) Lyrae), at mag. +3.3 the second-brightest star in Lyra after mag. +0.0 Vega. The name Sulafat comes from the Arabic for turtle, ancient harps being traditionally made from tortoiseshell. Sulafat is a B9 III star, indicating it's a blue-white giant. It is estimated to be 15.4 times larger and 2,430 times more luminous than our Sun, and has a mass 5.8 times greater. It's a dying star, having ceased hydrogen fusion approximately…

There are traditionally two theories about where the Martian moons came from. One suggests that both moons are merely captured asteroids. The albedo (reflectivity) of Phobos supports this. “The albedo of Phobos is very low, making the moon very dark,” says Tasker. “Examination of the wavelengths of reflected light from Phobos gives a result very similar to that of [low-albedo] asteroids.” This suggests the moons may have initially formed in the main asteroid belt between Mars and Jupiter and were later snagged by Mars's gravity to become captured moons. The idea that Phobos and Deimos are two halves of a trapped comet is a twist on this theory. However, Phobos and Deimos orbit Mars's equator in a very circular path. “This is hard to achieve with capture,” says Tasker, “but…

Astronomy Photographer of the Year Advice from the 2023 winner in the ‘Planets, Comets and Asteroids' category Venus often goes unappreciated in the planetary imaging community. However, when we venture past the visible spectrum, a wealth of detail within its upper atmosphere is revealed. This is where ultraviolet (UV) and near-infrared (nIR) filters shine. To achieve a similar image to my Astronomy Photographer of the Year entry, ‘Suspended in a Sunbeam', we should first consider equipment. You'll need a suitable UV or violet filter. While dedicated UV filters can be expensive, they do provide the best image contrast. For my image, I used the Bessel (U)BVRI photometric UV filter. For near-infrared, almost any infrared (IR) pass will suffice. To gain greater magnification, adding optical glass is not kind for ultraviolet,…

VITAL STATS • Price £39 each • Focal length 3.5mm, 5.5mm, 7.5mm, 10.5mm, 15.5mm, 19mm, 25mm • Lens design Flatfield • Apparent field of view 60° and 65° • Eye relief 15mm (3.5mm), 16mm (5.5mm-15.5mm), 20mm (19mm), 23mm (25mm) • Optical elements 5 or 6 • Barrel size 1.25-inch • Extras Cleaning cloth, dust caps • Weight 80g-110g • Supplier First Light Optics • Email questions@firstlightoptics.com • www.firstlightoptics.com Most beginner telescopes include an eyepiece or two to get users started, often a wide 25mm or 30mm version plus a higher-magnification option. While these can offer new astronomers some memorable first views, often it's not long before you'll want to expand and upgrade your eyepiece collection. The variety available can be daunting, as can the cost, so we're seeing how the…

How did you first become aware something unusual was happening in galaxy SDSS1335+0728? For two decades, the galaxy showed no changes. However, in December 2019 it started showing significant optical variability, detected by the Zwicky Transient Facility (ZTF) – the galaxy was starting to shine. It was later classified as an active galactic nucleus (AGN), meaning it's emitting a lot of radiation from its central region, which is believed to be produced by matter falling into the supermassive black hole at its centre. Since the discovery, the galaxy has continued showing random optical variations. The fact that the galaxy didn't show any previous activity and now varies like an AGN is very puzzling. Normally transient events related to the galaxy's central supermassive black hole show very smooth variations and only…