Indholdsfortegnelse for August 2024 i BBC Sky at Night

EYE ON THE SKY HUBBLE SPACE TELESCOPE, 27 MAY 2024 This image shows NGC 4731, a barred spiral galaxy that lies 43 million lightyears from Earth in the constellation of Virgo. Created by applying six different filters, the picture clearly shows the galaxy's vast clouds of dust, its bright pink regions of star formation and, most clearly of all, its central bar, the long streak of light running from top left to bottom right. Barred spirals make up 60 per cent of all known galaxies – there are more of them than there are non-barred spiral and elliptical galaxies put together – but the mechanisms behind bar formation aren't yet fully understood, so despite their near-ubiquity, they remain an area of keen scientific interest. FREE BONUS CONTENT Explore a gallery…

A trio of galaxies dating from when the Universe was only a few hundred million years old have surrounded themselves with gas that will grow future stars, according to new images from the James Webb Space Telescope (JWST). The gas reservoirs are the first to have been observed around such young galaxies. The trio of galaxies are so far away that we see them as they were when the Universe was just 400 to 600 million years old. They appear as little more than red smudges: their true nature only becomes apparent when observed with JWST's near-infrared spectrometer, NIRSpec, which can pick out the light absorbed or emitted by gas within the galaxies. These spectra showed that the galaxies are surrounded by dense clouds of almost pure hydrogen and helium,…

Our experts examine the hottest new research CUTTING EDGE Researchers searching for life beyond Earth spend a lot of time thinking about what telltale signs might be detectable astronomically. Forms of unambiguous evidence for the presence of life on another world are known as biosignatures. By extension, technosignatures are indicators of activity by intelligent, civilisation-building life. SETI, the Search for Extraterrestrial Intelligence, focuses on picking up signals that could be alien communication, but other approaches include observing traces of industrial air pollution on an exoplanet; observing the emission of artificial light from cities on the planet's night side; or even detecting evidence that a highly capable civilisation has constructed a shell around its star, known as a Dyson sphere, to capture its emitted energy. Ravi Kopparapu at the NASA Goddard…

Do you remember the Icelandic volcano eruption of 2010? Millions were forced to make alternative travel plans as air traffic restrictions came into force. Now just imagine if all flights around the world were cancelled at the same time. And, for added drama, unlike the Eyjafjallajökul eruption, you couldn't phone home or find information on the internet about what was going on. In fact, you might be sitting in darkness, because the electricity has gone down. It's not as outlandish as you may think. The space physics community agrees that the next once-in-100-year solar storm might be coming soon. The last big one occurred in 1859, and we know this because a British amateur physicist, Richard Carrington, had been drawing a big sunspot using specialist equipment to monitor the Sun…

DON'T MISS Disappearing Saturn There's a rare lunar occultation of the planet Saturn visible from the UK on the morning of 21 August. A lunar occultation occurs when the Moon's disc appears to cover a more distant object, hiding it from view. Although the Moon looks impressive and dominant in a dark sky, its apparent size is actually only half a degree across. The Moon is able to move around the sky in a relatively narrow corridor approximately 10° wide, centred on the ecliptic. The main planets also stay near the ecliptic, but the width of the Moon's corridor means planetary occultations are infrequent. There are three types of lunar occultation event: disappearance, reappearance and a graze. The third type is a special kind of occultation where, from your position,…

PICK OF THE MONTH Saturn Best time to see: 31 August, 01:45 BST (00:45 UT) Altitude: 30° Location: Aquarius Direction: South Features: Rings, banded atmosphere, brighter moons Recommended equipment: 75mm scope or larger After the June solstice, the lengthening period of night really aids in the visibility of Saturn. On 1 August, the planet reaches its highest position in the sky due south, with an altitude around 30° up under deep twilight. However, by 10 August it reaches this position at 03:30 BST (02:30 UT) under truly dark conditions. Excitingly, Saturn will be occulted by a 97%-lit waning gibbous Moon on the morning of 21 August. This occurs just as the sky is becoming brighter with the onset of dawn. Saturn will be at mag. +0.3 on this date, disappearance occurring at 04:28 BST (03:28…

Asteroid 16 Psyche will be at opposition on 6 August when it can be found among the stars of Capricornus, shining at magnitude +9.6. At this level of brightness you'll need a telescope to find it, but it doesn't need to be a large one. Psyche begins its August track across the stars from a location 2.4° north of mag. +4.1 Theta (θ) Capricorni. The star is sometimes referred to by the unofficial name Dorsum, which means ‘the back’ in Latin, referring to the back of mythological sea goat Capricornus. From this location, Psyche tracks in a more or less straight path southwest, ending the month 4.7° west of Theta Capricorni. Psyche's magnitude stays within small-telescope range throughout August, starting at mag. +9.8, brightening to +9.6 at opposition on 6…

Planetary nebulae are amazing objects to track down and observe. The glow of the ejected outer layers of an intermediate- or low-mass star reaching the end of its life forms an object that resembles a faded planet through a telescope. The star that sheds the outer layers remains at the nebula's centre. This month's challenge is to try to see the central star of several famous summer planetary nebulae. Thanks to the presence of the Milky Way, the summer sky is littered with planetary nebulae, some easy to find, others more challenging. The central stars of these objects tend to be rather faint, but some are within small-telescope range. Let's start with the Dumbbell Nebula, M27, an easy object to locate and observe as it's big and relatively bright. Its…

With four sovereign nations and multiple commercial players set to ply their trade in space over the coming years, significant opportunities lie ahead. SpaceX's Dragon and Boeing's Starliner are tasked with exchanging crew members aboard the International Space Station until the sprawling orbital complex is retired and deorbited sometime after 2030. Additional plans call for Dragon to fly independent flights for Jared Isaacman's Polaris Program and resupply and visit Vast's commercial space station from 2025. With AxiomSpace building a suite of pressurised modules for scientific research, educational outreach and entertainment, to be added to the ISS after 2026 and operated as an independent ‘Axiom Station’ beyond 2030, commercial providers will undoubtedly be called upon to deliver astronauts to and from the new outpost. SpaceX's Dragon is likely to be one…

In these times of high-tech telescopes and astro cameras, you might think the days of scientific contributions from simple visual observing are over. Well, think again! The night sky is full of stars that vary in brightness, and many hundreds of these ‘variable’ stars can be observed and their light variations plotted with basic equipment. This data can then be sent to the British Astronomical Association (www.britastro.org) for study. All you need to get involved are a few basic tools, patience and, of course, a clear sky. The stars to study At some stage through their evolution, most stars will probably vary in brightness to some extent. Changes within a single star are generally caused by pulsation – as the star changes in size over a period, its luminosity changes…

PHOTO OF THE MONTH The Cat's Eye Galaxy, M94 Alex Battu and Luca Barcaro, Castilléjar, Andalusia, Spain, 10–14 April 2024 Alex says: “M94 is a spiral galaxy with two distinct zones: an inner ring and an outer ring, measuring 30,000 and 45,000 lightyears in diameter respectively. It took a lot of work at the processing stage to get best balance between the luminance of the inner galaxy and the outer ring.” Equipment: ZWO ASI6200MC camera, Tecnosky AstroGrafo Fast 300 reflector, ioptron CEM120 mount Exposure: R 46× 900”, G 43× 900”, B 49× 900”, Ha 24× 900”, total 40h Software: PixInsight Alex's top tips: “When photographing M94, special attention has to be paid to its bright core and outer ring structure. Combining short exposures (to prevent core over-exposure) and long ones…

BULLETIN Humanity now has its first ever sample of material from the far side of the Moon, with the return of China's Chang'e 6 spacecraft to Earth. The craft touched down in Mongolia on 25 June, just a few hours before this month's issue went to press. Chang'e 6 launched from China's Hainan Island on 3 May 2024. A month later, on 1 June, the spacecraft landed on the lunar surface in the South Pole–Aitken Basin, a 2,500km (1,550 mile) wide impact crater. This was only the second time that any nation has landed on the far side, following China's previous mission, Chang'e 4, in 2019. After landing, Chang'e 6 swiftly gathered around 2kg of rock and dust from the surface, along with samples from up to 2m underground, collected…

Astronomers were recently able to confirm the presence of two black holes lurking at the heart of galaxy OJ 287, after a bright flash of light revealed the presence of a second, smaller companion to its larger singularity. The galaxy has long been thought to contain a pair of black holes at its centre, one 100 times larger than the other, but the opportunity to confirm the theory didn't arise until 2021. Several years earlier, Pauli Pihajoki from the University of Turku, Finland, had predicted that in late 2021 the smaller companion would swallow gas from the larger black hole's accretion disc. This would create a jet that would temporarily outshine its larger sibling, and also cause the usually red-tinted system to appear more yellow. When this event duly occurred…

A rare exoplanet has somehow kept hold of its atmosphere, even though the ravaging radiation of the red giant it orbits would normally have stripped it away. The discovery could provide us with new insights into the fate of our own Solar System. The planet, nicknamed Phoenix, is a ‘hot Neptune’, meaning it has many similarities to the ice giant in our own Solar System although it is much closer to its star – so close, in fact, that it takes just 4.2 days to orbit. The scorching temperatures and intense radiation that close to the star would normally be expected to have stripped away the planet's atmosphere – yet recent measurements by NASA's Transiting Exoplanet Survey Satellite (TESS) have found the planet has a density 60 times lower than…

Chile's Elqui Valley hides a secret door to the stars. A narrow highway heads east through the region's fertile carpet of green dedicated to producing grapes for both wine and Chile's famous Pisco brandy. I found myself making my way along a dirt road beside one of the region's many vineyards. After using the proper paperwork to pass through the checkpoint, I travelled along 20 miles of mountain passes to the summit of Cerro Pachón. Here is the Gabriela Mistral Dark Sky Sanctuary, which numbers among the darkest and driest places on Earth. On a mountain ridge 2,700m above sea level is the new home to one of astronomy's most important new facilities, the Vera C Rubin Observatory. It's been taking shape here since 2015 and, from next year, is…

When the James Webb Space Telescope (JWST) launched on Christmas Day 2021, we knew its groundbreaking capabilities had the potential to rewrite the astronomy textbooks. And this incredible spacecraft has not disappointed. The deployment of its giant segmented mirror and sun shield went without a hitch, its science instruments are operational and exceeding expectations, and the launch trajectory was so precise that there's fuel to maintain its orbit for many years to come. Right from its first observations, the space telescope has given astronomers new puzzles to solve and new questions to pursue. In particular, it is challenging what we thought we knew about the early evolution of galaxies. ‘Impossible’ galaxies JWST's intriguing deep-field observations of faint light from the early, distant Universe reveal stars and galaxies that seem to…

PARTICLE PHYSICS 101 When you read the word ‘antimatter’ in the title, you'd be forgiven for thinking that we've slipped into the realms of science fiction. Chances are that you first encountered the concept of antimatter in Star Trek, where it's used to propel spaceships. Or maybe you've read Dan Brown's novel Angels and Demons, in which antimatter makes the ultimate bomb. If so, it may come as a surprise that antimatter really does exist. So, what is it? Simply put, every type of elementary particle in nature has its own antiparticle. Particles and corresponding antiparticles are very much alike, except they have opposite electrical charges. For instance, the antiparticle of the electron – known as the positron – has the same tiny mass, but while electrons carry a negative…

Thursday 1 Just after it rises this morning, the 11% waning crescent Moon sits 4.2° north-northwest of open cluster Messier 35 in Gemini. Friday 2 Io and Ganymede's shadows form a double shadow transit on a low-altitude Jupiter between 00:23 and 01:46 BST (23:23 on 1 August to 00:46 UT). Sunday 4 Dione's shadow is in transit across Saturn's disc between 00:27 and 03:25 BST (23:27 UT on 3 August to 02:25 UT). Monday 5 A 1%-lit waxing crescent Moon sits 1.8° northwest of Venus, low in the evening twilight, over the west-northwest horizon shortly after sunset. Regulus appears 1.2° southwest of Venus and Mercury 6.2° south of Venus. Tuesday 6 From around 02:00 BST (01:00 UT) mag. –2.0 Jupiter, +0.9 Mars and +0.8 Aldebaran form a right-angled triangle, with…

By the time you read this, our star choice for this month may have become visible to the naked eye. T Coronae Borealis (T CrB) is a variable in Corona Borealis, the Northern Crown, a backward-C-shaped constellation east of Boötes. T CrB is a recurring nova, a star that brightens due to a physical interaction between two stars in a binary system, one a red giant and one a white dwarf. Material accretes from the red giant onto the white dwarf until enough mass has transferred to set off a thermonuclear detonation. This causes T CrB to brighten significantly, possibly as bright as second magnitude; that's on a par with Polaris (Alpha (α) Ursae Minoris) and Gemma (Alpha (α) Coronae Borealis). Gemma isn't far from T CrB, 1° south-southeast of…

Given that investigating Titan's potential habitability is one of Dragonfly's primary goals, a major concern for the mission is planetary protection – that is, ensuring Dragonfly doesn't bring any biological stowaways from Earth to potentially contaminate Titan's environment. Fortunately, there's little concern of harming any life that might exist on Titan. On Earth, no organism has ever been found reproducing at temperatures colder than –20ºC (–4ºF). Titan's –180°C (–292°F) temperature would kill, or at least deactivate, any microorganism on the spacecraft. And even if there is life on Titan, it would almost certainly be in the subsurface ocean, separated from Dragonfly by 100km (62 miles) of ice. “Titan, like Ganymede, has a very deep interior water ocean,” says Turtle. “It's not like Europa or Enceladus, where the ice shell is…

Saturn is hidden by a rare and unmissable (unless you have clouds) lunar occultation on 21 August. The Moon will be in a 97%-lit waning gibbous phase at the time, so pretty much full. The occultation starts with dawn in progress. Despite brightening skies, from the UK the event is completely viewable from start to finish. Imaging it will be more challenging, due to the increasing brightness of the dawn, but with care, a great capture of this exciting event is perfectly feasible. The waning gibbous nature of the occulting Moon means it's the bright lunar limb that first encounters the planet (see page 46). The issues for this stage will be coping with the enormous dynamic range between Saturn and the illuminated lunar surface, but as this part of…

BULLETIN Human spaceflight took a step towards the future in June, with the successful test launches of two new spacecraft. On 5 June, Boeing's Starliner spacecraft finally embarked on its first crewed test flight, carrying experienced astronauts Sunita Williams and Butch Wilmore to the International Space Station (ISS). The spacecraft, which has been developed as part of NASA's Commercial Crew Program, will hopefully carry future astronauts back and forth from the ISS, but has had a history of problems. Starliner's first uncrewed test flight in 2019 failed to reach the ISS. A second uncrewed test flight then achieved success in 2022, only for issues with the parachutes and wiring to delay a test with humans on-board. This crewed test was delayed again when a helium leak in the control system…

The venerable Hubble Space Telescope will now use a single gyroscope to keep itself stable, extending its observations into the next decade. Hubble has been observing the Universe since 1990, and after 34 years the spacecraft is beginning to show its age. One recurring issue has been with its gyros, devices which allow the spacecraft to keep itself orientated. Six new gyros were installed during the last servicing mission in 2009, but only three remain active. Over the last six months, one of these gyros began to return faulty readings. Though the Hubble team was able to temporarily fix the issue, the problem keeps returning, and the gyro is now seen as too unreliable to use. Instead, the Hubble operations team decided to take a course of action they've been…

The list of known exoplanets numbers in the thousands. The most prolific method of finding these worlds orbiting around other stars is to watch the dimming of the star's light as the planet passes in front of it, known as a transit. I study the atmospheres of transiting exoplanets to better understand how their climate is affected by their environments. I'm most interested in hot gas giants: planets similar in size to Jupiter but orbiting their stars in just a few days, meaning they are baked under the intense radiation. These ‘hot Jupiters’ are tidally locked with a very hot permanent dayside facing the star, and a cooler nightside facing space. This dichotomy in temperature drives supersonic winds and changes the atmosphere's chemistry. One key driver of how an atmosphere…

Last year, physicists at CERN confirmed that antimatter falls down, just like normal matter. Particles and their corresponding antiparticles have equal but opposite electrical charge, but some other quantum properties are also ‘mirror-reversed’. This is all described in detail by quantum theory. However, our standard model of particle physics doesn't include gravity, so no one knew whether antimatter might fall up instead of down. The CERN team, led by Jeffrey Hangst, produced positrons and antiprotons in their huge particle collider. They slowed the antiparticles down and let them combine into atoms of anti-hydrogen. Using magnetic fields, they concentrated the anti-atoms in the centre of a small vacuum vessel, making sure they wouldn't touch the walls made of normal matter and annihilate. After switching off the magnetic field, detectors revealed that…

Albategnius Type: Crater Size: 136km Longitude/latitude: 4° E, 11.2° S Age: Around 3.9 billion years Best time to see: First quarter (11–12 August) or six days after full Moon (26 August) Minimum equipment: 10x binoculars Albategnius is a distinctive walled plain located just east of the famous north–south crater trio of 154km Ptolemaeus, 118km Alphonsus and 98km Arzachel. It's closest to Ptolemaeus, the two craters separated by a piece of rough highland terrain 70km wide. The 6km crater Albategnius G sits within this highland region. Albategnius is classed as a walled plain because it appears as a flat, lava-filled floor surrounded by a defined wide rim, widest in the west. It's pretty battered but holds its own quite well, with the exception of a section to the southwest that is interrupted by the lava-filled 45km…

1. Poniatowski's Bull The uppercase V formed by the fourth- and fifth-magnitude stars 66, 67, 68, 70 and 73 Ophiuchi is reminiscent of the Hyades cluster in Taurus. This led the 18th-century astronomer Marcin Odlanicki Poczobutt to propose it as a new constellation, Taurus Poniatovii, to honour Stanislaus Poniatowski, then king of Poland. Your binoculars will reveal many dozens more stars in this rich open cluster, more formally known as Melotte 186. ■ SEEN IT 2. The Summer Beehive Locate mag. +2.7 Cebalrai (Beta (β) Ophiuchi) and you'll see IC 4665 in the same field of view, looking like a slightly smaller version of Praesepe (the Beehive Cluster) just over 1° northeast of the star. Your 10×50s should reveal curved chains of white stars forming the word ‘HI’, as this…

Titan, Saturn's largest moon, is a contradiction: a world that's remarkably Earth-like and profoundly alien at the same time. Like our own planet, the moon has a nitrogen-dominated atmosphere over a landscape of mountains, deserts and even seas. Only on Titan, the mountains aren't made from rock, but ice. And rather than water, in its rivers flows liquid methane. Most captivating of all, the moon is rich with the organic chemicals that form the foundations of life on Earth. All this makes Titan an ideal place to investigate the evolution of the chemistry that makes our planet, and perhaps others too, habitable. In April this year, NASA confirmed that it intends to send the Dragonfly mission on its way to the mysterious moon in July 2028. When it arrives in…

Six decades ago, human spaceflight was a two-sided coin, as the United States and Soviet Russia competed for primacy in the Space Race during the Cold War. With global nuclear holocaust looming menacingly on the horizon, parallel space programmes arose on opposite sides of the Iron Curtain: Mercury versus Vostok, Gemini versus Voskhod, Soyuz versus Apollo and the Space Shuttle. Today, this East/West duopoly has ceded a few grains of its dominance to newer players. National actors like China and India have emerged like a whirlwind, along with a growing chorus of commercial entities from Boeing to SpaceX, and Blue Origin to Virgin Galactic, all hungrily eyeing the space domain. When Yuri Gagarin conquered space in April 1961, the door creaked ajar for others to follow. But initially, those ‘others’…

BEFORE Creating a detailed astrophotography image typically involves these steps: imaging the target (known as taking ‘light’ frames); gathering a series of calibration images (‘dark’, ‘flat’ and ‘bias’ frames); using software to stack these images together to remove noise and increase the data signal; and, finally, stretching this data to boost our target's delicate details and making colour and gradient adjustments to perfect the image. It's quite common to use multiple software programs to carry out the above steps – for example, stacking software followed by specialist processing software to do the rest. However, the free astrophotography processing software Siril is capable of supporting the entire workflow, from stacking data to managing background gradients and colour saturations afterwards. It comes pre-programmed with various scripts designed to automate many functions and…

VITAL STATS • Price £299.99 • Optics 114mm (4.5-inch) parabolic primary mirror, Newtonian reflector • Focal length 450mm, f/4 • Mount Altaz tabletop Dobsonian • App control StarSense Explorer • Focuser 1.25-inch rack and pinion • Extras StarSense smartphone dock, Star-Pointer red dot finder, eyepiece rack, collimation cap, 17mm and 10mm Kellner eyepieces • Weight 6kg • Supplier PicStop • Tel 01624 670005 • www.picstop.co.uk App-enabled telescopes have come a long way in recent years and are an excellent way of introducing newcomers to astronomy. Now they're joined by Celestron's smartphone-controlled StarSense Explorer 114mm tabletop Dobsonian, the smallest tabletop option in its StarSense series. With a respectable aperture contained within a portable unit, this reflector promises enough light-gathering power to bring out delicate details in a range of objects, including…

What is a rogue planet? Most people believe planets are objects that go around a star, just like Earth goes around the Sun. Rogue planets are objects that have mass similar to planets but are not orbiting stars. They're free-floating planets and there are lots of them. This study [using Euclid] found seven more rogue planets than those we knew of before and confirmed the existence of some previously discovered ones. Why did you opt to use Euclid to detect these rogue exoplanets? ESA's Euclid is a space telescope like JWST or Hubble, but it's unique because it covers a huge fraction of the sky – one third – and it's doing so at very great depths. Euclid can image an area of the sky 9,000 times larger than is…