Indholdsfortegnelse for November 2023 i BBC Sky at Night

NOVEMBER HIGHLIGHTS Interview: Intelligent life beyond Earth? Astronomer Adam Frank on the search for alien life, what it would mean and what he really thinks about UFOs. Sky at Night meets the Very Large Telescope Maggie travels to Chile’s Atacama Desert to explore one of the most advanced observatories in the world. Download our planet observing forms Download and print out our observing forms to record your observations of the Sun and planets throughout the year. The Virtual Planetarium Pete Lawrence and Paul Abel guide us through the best sights to see in the night sky this month.…

Over three decades after they were first discovered, astronomers have finally managed to observe the dark spots in Neptune’s atmosphere from the ground. Ever since they were first seen by Voyager 2 in 1989, the spots have mystified planetary scientists. They have since been monitored by space telescopes like Hubble. Unfortunately, they disappear and reappear every few years, making them difficult to study. When a new spot was discovered in 2018, astronomers used the Very Large Telescope to not just see the spot but also take a spectrum of the light reflected from the planet. As different wavelengths of light pass through different layers of the atmosphere, the spectra allowed them to examine the spot in three dimensions. This revealed that the spot is in the hydrogen sulphide condensation layer…

I use some of the highest-resolution observing facilities on Earth to study how stars and their planets form. Five of the questions I’m frequently asked about my research are: How long does it take to form a star? The process starts with an initial collapse of material in a molecular cloud, trigged by gravity, and ends when hydrogen fusion ignites in the star’s core. How long this process lasts depends on the mass of the star. For stars like the Sun, it takes a few tens of millions of years, while higher-mass stars are formed much more quickly and lower-mass stars take much longer. Regardless of the mass, the process is rapid in proportion to a star’s lifetime: if you condensed the lifetime of a star down to the lifetime…

Astronomy Photographer of the Year 2023 National Maritime Museum, Greenwich, until August 2024 The National Maritime Museum once more plays host to some of the finest astro images you’ll ever see, as it presents its annual display of the best entries submitted to this year’s Astronomy Photographer of the Year competition. You might have seen the winning photos in BBC Sky at Night Magazine or online already, but the exhibition showcases all the shortlisted images from all the different categories and more, making it a must-visit, whether you’re an astrophotographer yourself or just a space nut generally! Admission is £10 for adults, concessions £6.50, kids aged 4–15 £5, under 4s free. rmg.co.uk/whats-on/astronomy-photographer-year/exhibition…

planetary atmosphere It may be one of the most capable exoplanet investigators ever devised, but there are many planets JWST can’t see, including those like our own. Earth is far too small for direct imaging, and while JWST can see Earth-sized planets via the transit method, it can only do so around dim stars. To find our planet against the bright Sun would require observing as many as 100 transits. Given that Earth transits the Sun only once a year this would mean a century of observation, just for one planet. Even if JWST could see our planet, astronomers would struggle to understand what they were seeing. “If we could measure our Solar System we would see Earth and Venus and make the assumption they were both the same, when…

All through the 21st century it has been above us, growing larger with the passing years. As the sunlight catches it, the sprawling structure becomes the brightest star of dusk or dawn. The International Space Station’s first segment was launched 25 years ago, on 20 November 1998. Since then, 15 further modules have been added to the initial foundation of Russia’s Zarya FGB block and the ISS has grown into a 400-tonne behemoth. At 109 metres across, it is longer than a football pitch. Continuously occupied since 2 November 2000, more than 260 people from 21 countries have lived and worked on the Space Station. But it was originally designed for just 15 years in orbit. It can’t last forever. So what happens next? The ageing station has generated negative…

THE BIG THREE The top sights to observe or image this month BEST TIME TO SEE: Before sunrise on 9 November, through to 11:00 UT From the UK, the Moon appears to hide Venus on the morning of 9 November, an event occurring during daylight. Unlike the very tricky daylight lunar occultation (or close pass, depending on your location) of Jupiter back in May of this year, this month’s event should be easier to see. The Moon appears as a 15%-lit waning crescent on 9 November. Venus will be just past dichotomy and showing as a 58%-lit gibbous disc, 20 arcseconds across through the eyepiece. It’ll be bright too, shining at mag. –4.2. Given clear skies, Venus will be visible to the naked eye and easy to see through binoculars.…

Jupiter Best time to see: 3 November, from 00:00 UT Altitude: 51° Location: Aries Direction: South Features: Complex atmosphere, Galilean moons Recommended equipment: 75mm or larger Magnificent Jupiter reaches opposition on 3 November and is currently a dominant night-time planet. Shining at mag. –2.8 at the start of the month, it dims only marginally to –2.7 by the end of November. It reaches a peak altitude of around 50° when due south and manages this under dark-sky conditions all month. This puts it in an extremely favourable place for observing through the eyepiece or imaging with a camera, as the planet will be above the turbulent atmosphere found closer to the horizon. A bright, almost full Moon (also at opposition) sits near Jupiter on the evenings of 24 and 25…

Minor planet 18 Melpomene reaches opposition on 5 November when it can be found in the northwest corner of Eridanus, the River, shining at mag. +8.2. At this brightness, it’s within binocular range and as it doesn’t move an enormous distance throughout the month, it should be relatively easy to keep tabs on. Melpomene is a large main-belt asteroid that fits within a triaxial ellipsoid measuring 170 x 155 x 129km. Its orbit brings it as close as 268.5 million km (1.8 AU) from the Sun at perihelion and out as far as 418.4 million km (2.8 AU) at aphelion. It takes 1,270.6 days (3.5 years) to complete each orbit. Melpomene is an S-type, silicaceous asteroid with a stony composition. It’s relatively bright and varies in magnitude between +7.5 at…

Jupiter is a gas giant with a thick, detailed and banded atmosphere. Any textbook typically shows a diagram identifying which bands are which. However, the view though the eyepiece doesn’t always match what you’d expect. In this challenge, we’re asking you to identify as many of Jupiter’s belts and zones as possible. Why doesn’t Jupiter’s atmosphere always resemble how it’s depicted in books? Well, being a dynamic entity, the visibility of the belts and zones can vary. Turbulence can create conditions where they become indistinct from one another and sometimes disappear completely. As a result, it’s best to use any diagram as a guide, first identifying the main features and then using these to navigate to the less obvious regions. The best place to start is with the North and…

The Great Red Spot (GRS) is Jupiter’s most famous feature, a vast storm that has been observed continuously for almost 200 years and was probably first spotted in 1665. Sitting on the edge of the South Equatorial Belt, it is confined between a strong westward jet stream to its north and a weaker eastbound one to its south. Winds along the edge can exceed 430km/h as it spins counter-clockwise (turning once every six Earth days), but the central eye of the storm seems largely stagnant. While most of Jupiter’s darker features are lowerlying than the pale clouds of the zones, the top of the GRS soars to 8km above its surroundings. The source of its colour (which can vary from intense red to a salmony-pink and sometimes disappears completely, leaving…

ASTROPHOTOGRAPHY PROCESSING Expert processing tips to enhance your astrophotos When using a hydrogenalpha (Ha) telescope or filter, we view a layer above the Sun’s whitelight photosphere called the chromosphere. The features that are revealed in Ha, like sunspots, prominences and filaments, can be very active, often changing extremely quickly. The Sun becomes a living, breathing and very exciting star, and is amazing to watch and image in fantastic detail. It’s important to emphasise that, of course, any observing or imaging of the Sun should always be done with the correct safety filters in place. Taking images of the Sun is akin to planetary imaging. A camera, using video-capture software, captures a video composed of hundreds of individual frames. This is stacked using videostacking software (AutoStakkert!, RegiStax or AstroSurface, for example)…

Nowadays you can download image data even from Hubble or the JWST, or pay for time on, and take images with, telescopes around the world. The difference with FLO’s Remote Observatory is that you get true and total control over what the telescope and camera does. From choosing the session start time, selecting the target and framing to your tastes, setting an appropriate filter and exposure duration, to gathering calibration frames, everything can be tuned to suit individual preferences. With total control of what the telescope did, a cheeky Messier or NGC marathon, flitting from target to target getting dozens of snapshots from a deep-sky tour, was entirely possible, but we decided to stick to our plan to capture three targets. The resulting images really feel like they belong to…

HUBBLE SPACE TELESCOPE, 7 SEPTEMBER 2023 Lying some 15,000 lightyears from Earth in the constellation of Sagittarius, the globular star cluster Terzan 12 is one of the Milky Way’s more peripheral members. Unlike their open cluster cousins – which are found between the Galaxy’s spiral arms – he Milky Way’s 150 globular clusters, made up of very ancient stars, orbit the Galactic centre far above and below the Galactic plane, like bees swarming around a hive. Confusingly, Terzan 12 was the last of 11 such clusters to be discovered by Turkish-Armenian astronomer Agop Terzan in the 1960s and 70s, its name deriving from the fact that the previously identified Terzan 5 and Terzan 11 turned out to be the same object. It’s also worth noting that the larger, brighter blue…

A star that was caught being devoured by a giant black hole in a nearby galaxy turned out to have been one of the largest stars seen being consumed in this way, a recent study has found. The event, called ASASSN-14li, was spotted in a galaxy located 290 million lightyears away in 2014, but astronomers have been studying the aftermath ever since. It occurred when the star strayed too close to a black hole and was torn apart – what is known as a tidal disruption event. Much of the star’s gas left over from the event remained in orbit, but a portion was blown away by strong winds created by the black hole’s accretion disc. To study this ejected gas, astronomers used X-ray observatories such as NASA’s Chandra and…

CUTTING EDGE Our experts examine the hottest new research The trans-Neptunian objects (TNOs) are icy bodies orbiting in the dark, outer recesses of the Solar System beyond the orbit of Neptune. In recent years, astronomers have noticed a number of oddities about the orbits of some TNOs, which cannot easily be explained by any single current model of Solar System development. For example, there are a significant number of TNOs with high orbital inclinations, but they lie too far out to have been gravitationally nudged by Neptune. Theories such as the close pass of a rogue planet are also unable to properly explain their presence. Additionally, several ‘extreme’ TNOs have been discovered on exceptionally elliptical orbits at extreme distances from the Sun – such as the dwarf planet Sedna, which…

while astronomers may not typically lead in the fashion stakes, there is one closely linked sphere that has moved with the times – that of spaceflight, the astronaut and, in particular, the spacesuit. The basic template for the early spacesuit would have been drawn from attire affording protection for those working in similarly testing environments, such as the deep-sea diver and the aircraft pilot. Clothing for both of these roles was functional and robust, with a proven track record of achieving what the suit was designed to do. However, after rigorous testing of suits like these, doubt must have crept into the mind of even the most disciplined of astronauts. A leaky diving suit could potentially see its wearer pulled up from the watery depths quickly enough to save them,…

It’s one of humanity’s biggest questions, but could JWST be the telescope to tell us the answer? Unfortunately… no. To be observed using the transit method, a planet must orbit close into its star, where it will be bombarded by deadly radiation. Even if some organism did manage to evolve despite this onslaught, JWST is only able to identify the gases within a planet’s atmosphere. The limitations of this have already been highlighted by the potential sighting of dimethyl sulphide on K2-18b that was announced in September 2023 (read the full story on page 12). On Earth, the only known source of dimethyl sulphide is from living organisms, such as marine phytoplankton. However, K2-18b is a sub-Neptune planet, a category of exoplanet that’s not well understood at all. We don’t…

The ISS, equivalent in volume to a Boeing 747, has been occupied continuously for more than 22 years. So what does it smell like? American astronaut Scott Kelly told Wired magazine: “I was touring the Harris County Jail [in Texas], and there’s this room that smells like space station – combination of antiseptic, garbage, and body odour.” He added that in the absence of gravity, bodily smells – such as farts – tend to linger. UK astronaut Tim Peake said it smells “like a barbecue that’s gone wrong”, while Italian astronaut Samantha Cristoforetti mentioned a “peculiar odour” she had to adjust to. Any odour can’t be too bad, because of the ISS’s atmospheric quality control: module air is circulated by fans through a filtration system that includes activated charcoal beds…

Cassiopeia is an easily identifiable circumpolar (never sets) constellation for UK viewers. The central star is Gamma (γ) Cassiopeiae, sometimes known by the unofficial name ‘Navi’, a name given to it by the American astronaut Virgil ‘Gus’ Grissom, first because it’s an easy to spot ‘navi’gational star and second because it’s Grissom’s middle name, Ivan, spelled backwards. Listed as mag. +2.5, it’s an eruptive variable, its brightness varying between mag. +1.6 and +3.0 at irregular intervals. It’s fairly distant at 560 lightyears and was once thought to be a rare example of an octonary system, eight gravitationally bound stars. It’s a rapid rotator at 472km/s, which means it’ll be bulging noticeably at its equator. A hot circumstellar gaseous disc is believed to have formed around the star and this is…

Studying Jupiter’s magnetic field in detail presents a huge challenge, not only because of the difficulty of sending probes to the giant planet, but also because the field itself traps a series of doughnutshaped radiation belts around the planet (similar to Earth’s Van Allen belts, but far more intense). For the Galileo mission (1995–2003), the first spacecraft to orbit Jupiter, these belts were a hazard to avoid, since bombardment with their high-energy particles could damage sensitive instruments. When Juno arrived in July 2016, on a mission to specifically study the magnetic field and interior, it therefore took up an unusual elongated orbit over Jupiter’s poles. For most of the time, the probe remains at a safe distance well beyond the radiation belts (up to 8 million kilometres from Jupiter). However,…

DIY ASTRONOMY Practical astronomy projects for every level of expertise Seeing the aurora borealis (Northern Lights) or aurora australis (Southern Lights) is at the top of many people’s bucket lists, but you don’t need to travel to the polar regions to see or photograph a display. Armed with forecasting data, you can be ready and waiting when the conditions are right. On 1 September 1859, Richard Carrington and Richard Hodgson recorded the first visual observation of a solar flare. Less than 18 hours later, the largest geomagnetic storm ever recorded, the Carrington Event, began. Aurorae were seen all around the world, even in equatorial locations. It was the first definitive proof that aurorae are directly linked to solar activity. When charged particles from the Sun, the solar wind, interact with…

More ONLINE A gallery containing these and more of your images PHOTO OF THE MONTH The Lagoon and Trifid Nebulae Antoine and Dalia Grelin, captured remotely via Utah Desert Remote Observatories, Utah, USA, 1–2 August 2023 Antoine and Dalia say: “This shows a widefield view that includes both objects in the same frame. A large amount of nebulosity is visible even without the use of any filters, thanks to a very fast telescope (f/2) and dark skies (Bortle 2).” Equipment: ZWO ASI2600MC Pro camera, Celestron 8-inch Rowe-Ackermann Schmidt astrograph, 10Micron GM1000 HPS mount Exposure: 96× 300”, 8h total Software: PixInsight Antoine and Dalia’s top tips: “Fitting two nebulae in the same frame is both exciting and challenging for beginners. To achieve something like this, use a scope with a wide…

What is a dark star? Dark stars are candidates for the first stars that formed in the Universe, around two hundred million years after the Big Bang. They would be made only of hydrogen and helium from the Big Bang, but unlike stars that are powered by nuclear fusion, would be powered by dark matter. Because there’s no fusion happening inside them, they aren’t very hot, and this means they can grow until they reach perhaps a million times the Sun’s mass and a billion times its brightness. A single dark star from the early Universe could be as bright as an early galaxy containing many more standard stars. How can a star be powered by dark matter? The first stars formed in a very dark-matter-rich environment, at the centres…

After an eight-year journey of almost four billion kilometres, NASA’s OSIRIS-REx spacecraft has finally delivered a precious sample of space dust it collected from asteroid Bennu. The pristine space rocks will help planetary geologists examine what our Solar System looked like as the planets were forming. OSIRIS-REx has spent almost two years studying the asteroid Bennu. On 20 October 2020, the craft collected an estimated 250g of material from the surface, stowing it inside a sample-return capsule. On the morning of 24 September 2023, OSIRIS-REx released this capsule when it was 102,000km away from Earth. After entering the atmosphere at 44,500km/h, the capsule was safely slowed down by aerobraking and parachutes, before landing just outside Salt Lake City, Utah at 14:52 UT. It was found by NASA’s recovery team about…

Though you might not be able to feel it, there is a magnetic field running through our entire Galaxy. Now, astronomers have managed to detect the most distant example of a galactic magnetic field ever spotted. “This discovery gives us new clues as to how galactic-scale magnetic fields are formed,” says James Geach from the University of Hertfordshire, who led the study. The field was observed in the galaxy 9io9, which was discovered with the help of the BBC’s Stargazing Live viewers in 2014. The light from 9io9 has been travelling for 11 billion years, meaning we are viewing it as it was when the Universe was just 2.5 billion years old. Some of this light was emitted from dust grains that were aligned along the galaxy’s magnetic field, meaning…

In the 1980s, as NASA was putting the finishing touches to the Hubble Space Telescope, discussions began to turn to what the agency’s next grand orbital observatory would be. The design they came up with was a huge, 6.5m-wide infrared observatory that could peer back through distance, dust and even time to view the dim light of the earliest galaxies, and which we now know as the James Webb Space Telescope (JWST). At the time of those first discussions, humanity had yet to even find a hint that there were planets orbiting around other stars. That changed in 1992, when it was announced that the first-ever confirmed alien world had been found around PSR B1257+12, sparking three decades of exoplanet exploration. Astronomers have now catalogued over 5,000 verified exoplanets, with…

Explosion fingers Only 500 to 1,000 years ago, an explosion occurred in the heart of a dense cloud of gas known as Molecular Cloud 1. The explosion sent out waves of material which struck the surrounding gas, heating it and causing it to glow, creating these bright ‘fingers’. The red colour indicates areas of molecular hydrogen, but the green tinge seen at the tips of the fingers shows areas of hot iron gas. Piercing the veil JWST observes at various wavelengths to show different aspects of the nebula, such as these expanding fronts driven by forming stars. The shorter wavelengths, on the left, best show discs, outflows and stars. Meanwhile, longer wavelengths, seen on the right and in the main image, highlight the intricate filaments of dust. Neither star, nor…

1. The Cosmic Question Mark 10x 50 Use the chart to identify mag. +4.9 Nu (ν) Ceti and hold it at the bottom half of the field of view. You’ll see that it is the dot at the bottom of the 2.25°-long question mark asterism (an informal group of stars). This is a good star-party object, both because of its shape and the colours of the fainter stars that make up the rest of the asterism. ■ SEEN IT 2. The Pisces Parallelogram 10x 50 If you follow a line up from mag. +2.0 Deneb Kaitos (Beta (β) Ceti; also known as Diphda) through mag. +3.5 Iota (ι) Ceti, you will find four stars of fifth magnitude (or so) that form a 3° x 1° parallelogram. The northeast corner is blue-white 29…

Step out under the stars this month and you won’t be able to miss Jupiter. As well as being the largest planet in our Solar System, it is also at opposition this month, meaning it lies directly opposite the Sun as seen from Earth. That means the giant planet is not only visible all night but is also at its closest to us, giving backyard astronomers a great chance to observe its colourful cloud bands. These ever-changing patterns have fascinated sky-watchers for centuries, but now an international team of scientists say they’ve come a big step closer to understanding what drives their behaviour. Jupiter is a bloated gas giant that could swallow 1,300 Earths, but it’s composed almost entirely of the lightweight gases hydrogen and helium. The uppermost layers of…

On a recent trip to London, my family and I had a chance to visit the Royal Observatory in Greenwich. I’ve always been fascinated by the challenges faced by sea-faring explorers of the 18th century, who needed accurate methods to track a ship’s location on the ocean but hadn’t cracked the problem until John Harrison perfected his marine chronometer in 1759 (which is on display in the observatory). We can draw direct parallels between space-based observatories – seeking answers to the big questions about our place in the Universe – and those intrepid oceanic explorers who set sail with the goal of exploring the unknown reaches of the world. The James Webb Space Telescope, with its huge sun shield deployed like the sail of a cosmic ship, is the latest…

EXPLAINER The fundamentals of astronomy for beginners When we think about light, most people only think in terms of what our eyes can see. But this ‘visible’ light is just a fraction of the light, or electromagnetic radiation, suffusing the cosmos. The entire range of this radiation is called the electromagnetic, or EM, spectrum. Electromagnetic radiation is described as a stream of massless particles, called photons, travelling in a wave-like pattern at the speed of light. Each photon contains a certain amount of energy, and different types of radiation are defined by the amount of energy found in those photons. Radio waves have low energies, microwave photons have a little more energy, infrared photons have still more. Then comes visible, ultraviolet, X-rays, and finally the most energetic of all, gamma…

Our experts review the latest kit VITAL STATS • Price From £349/month • Minimum subscription 1 month • Optics StellaMira 90mm triplet refractor • Camera ZWO ASI2600 colour or mono • Software Sequence Generator Pro • Supplier First Light Optics • Email contact@remoteobservatory.com • www.remoteobservatory.com Rather than a piece of astronomy equipment, this month we’re reviewing the new Remote Observatory package from First Light Optics (FLO), which offers subscribers the chance to directly control an observatory and take their own astrophotos using familiar software and equipment that is typical of a decent home setup. The observatory itself is situated in Granada, southern Spain, within the excellent PixelSkies complex. Although sited in the middle of nowhere, with superb crystal-clear skies unblighted by light pollution, accessing the Windows mini PC that controls…

WIFD stands for William Optics Internal Focus Design. Instead of placing the focuser at the rear of the tube, in this design the focuser is internal and moves the optical assembly. Rotating the focuser knob moves the optical setup inside to achieve focus. It is roughly in the centre of the tube, which also aids in balancing the setup while your camera gear is attached to the rear of the telescope. This arrangement eliminates potential tilting due to the weight of camera gear that can sometimes occur on traditional focusers. A window on one side shows a graduated scale so you can note the position of sharpest focus for later sessions. We found the focusing very smooth, with no slippage. The focusing mechanism is dual-speed, with coarse- and fine-focus on…