Tabla de contenidos para October 2025 en BBC Sky at Night

For cellular life to exist, it must separate itself from its surrounding environment by forming a membrane – a barrier that maintains the right internal conditions for life, despite external changes. NASA research now suggests the hydrocarbon lakes on Saturn’s moon Titan contain the complex organic chemistry needed to form such protocells – primitive, cell-like structures that could represent an early step towards life. Titan is the only place apart from Earth known to have liquid on its surface, with rivers, lakes and rain made not of water, but of hydrocarbons like methane and ethane. This moving liquid, combined with Titan’s freezing atmosphere, creates ideal conditions for molecules called amphiphiles to form. These molecules have two ends: one that interacts with liquid (hydrophilic) and one that repels it (hydrophobic). Amphiphiles…

If there’s one thing I love, it’s a misnomer. Shooting stars, planetary nebulae, guinea pigs… none of them does what it says on the tin. Another great example is the term ‘physical constant’. These are quantities that are so fundamental that they have the same value throughout the Universe, and have done since the dawn of time. Or so we think! Buckle up, readers: for one night only, I’m activating my long-dormant Physics Teacher Mode. I have tremendously fond memories of my teaching days, and one particularly endearing thing my A-Level students did was show off to one another (and to me) how many physical constants they had memorised. I often pointed out that this was a legitimately pointless skill; after all, professional physicists have access to the internet. But…

According to a growing number of scientists and doctors, many of us are no longer getting enough darkness in our lives. As human animals, we rely on the dark just as much as the light – it keeps our circadian rhythm in balance. That rhythm is our natural sleep–wake cycle. It’s why we feel alert in the morning and drowsy in the evening. Darkness stimulates the pineal gland located deep in the brain to produce melatonin, which acts to slow down our body’s systems and prepare us for sleep. Maybe you’ve felt this: a rise in ‘sleep pressure’, usually about two hours before bedtime, as melatonin levels build. As you can imagine, there are a number of consequences to our health when our circadian rhythm slips out of kilter. And…

Scroll back 10 years from Venera 9 and we reach the very first detailed images of (as opposed to from) another planet’s surface, returned during Mariner 4’s fly-by of Mars in July 1965. As one of the earliest missions to carry television technology beyond Earth orbit, Mariner 4 was able to produce images directly in the form of varying electric signals. Light gathered by the onboard telescope was directed onto a camera tube, forming an image on a metal ‘storage plate’. Brighter areas generated stronger electric charges. An electron beam then scanned across the plate, discharging it to produce a stream of electrical signals, 200 rows of 200 pixels each. Mariner 4 returned 21 images of Mars in total, but with 40,000 bits of data per image, it took eight…

Aries isn’t the most dramatic constellation in the night sky, its main pattern consisting of three mid-brightness stars in a bent line. The brightest of the trio, to the east, is mag. +2.0 Hamal (Alpha (α) Arietis) – a star so unexciting and ‘normal’ it’s used as a baseline for comparing others. The middle star is mag. +2.7 Sheratan (Beta (β) Arietis). Its name means ‘the two signs’, referring to the time several thousand years ago when Sheratan and mag. +3.8 Mesarthim (Gamma (γ) Arietis) marked the point where the ecliptic and celestial equator intersected. The Sun crossed this position, known as the First Point of Aries, south to north at the Northern Hemisphere’s vernal (spring) equinox. Due to precession of Earth’s orbit, this location has since shifted into the…

The VLT (Very Large Telescope), comprising four 8.2-metre-diameter telescopes constructed in the 1990s, is one of ESO’s most famous instruments in the Atacama Desert. Located near the coast, 120km (75 miles) south of the port city of Antofagasta and a four-hour drive from San Pedro de Atacama, it’s among the world’s most advanced visible-light observatories. Visiting the VLT is free, with tours kicking off with a brief overview of the Paranal site. From the base of the telescopes, you’re introduced to the area and can admire views of the Andes to the east before entering one of the domes. The tour concludes with a quick stop at the astronomers’ residence, made famous as a location in the James Bond film Quantum of Solace. Tours last between two and three hours.…

1. Southern highlands crater Tycho is 85km (53 miles) wide and 5km (3 miles) deep, and has the longest rays of any lunar crater – up to 1,500km (930 miles)! 2. Copernicus, lying near the centre of Oceanus Procellarum, is 93km (57 miles) wide and sits at the centre of an elaborate, almost cobweb-like splash of rays. 3. Kepler, to the west of Copernicus, is a small, young crater surrounded by a roughly circular spray of bright rays. 4. Small Aristarchus, forming a neat triangle with Kepler and Copernicus, has a striking splash of bright impact debris on one side that looks stunning under higher magnifications. 5. Proclus was blasted out of the shore of Mare Tranquillitatis by a shuddering asteroid impact millions of years ago. This bright crater has…

CAUTION Never observe or image the Sun with the naked eye or any unfiltered optical instrument As the latest solar cycle reached its peak, many amateur imagers took their first solar snaps, capturing fascinating and dynamic activity on the Sun’s surface. One popular method is to use a solar hydrogen alpha filter such as an etalon that, if coupled with a monochrome camera, unveils the Sun’s chromosphere and delicate details such as prominences and flares. Once you’ve teased out these features through processing, you can easily convert your monochrome images into the familiar redorange hues of our nearest star. Here we’ll walk you through the two key techniques – inverting and then colourising – you can use to achieve this. We’ll use ImPPG and GIMP, two capable image-manipulation programs you…

What is normal or ‘ordinary’ matter? When astronomers talk about normal matter, we’re referring to baryons. By that, we just mean ‘the stuff of atoms’ – things like protons and neutrons. How did we find out some of the Universe’s ordinary matter was missing? We can see leftover light from the Big Bang; we call this the cosmic microwave background radiation or CMB. Fluctuations in the CMB give us a snapshot of how things were around 400,000 years after the Big Bang – a kind of ‘baby photo’ for the Universe, which tells us how much matter there was, both normal and dark. All those atoms should still be here 13.8 billion years later. But, if you count the stars and planets and dust you can see with your telescope,…

HUBBLE SPACE TELESCOPE, 28 JULY 2025 Spiral galaxies are among the most common in the Universe, making up around 60–70 per cent of all galaxies. One, NGC 1309 in the constellation of Eridanus, lies 100 million lightyears from Earth and has been imaged several times by the Hubble Space Telescope. The reason? Though otherwise unremarkable, it’s drawn attention for hosting not one but two supernovae since the turn of the millennium: the rather typical Type Ia SN 2002fk in 2002 and the rarer Type Iax SN 2012Z in 2012. Hubble showed that this second explosion left behind a partially destroyed white dwarf, a so-called ‘zombie star’. FREE BONUS CONTENT Explore a gallery of these and more stunning space images www.skyatnightmagazine.com/bonus-content Compare and contrast HUBBLE SPACE TELESCOPE, 14 JULY 2025 This…

Professor Michele Dougherty has been appointed England’s Astronomer Royal, following the retirement of her predecessor Lord Martin Rees. She is the first woman to be appointed since the role was established in 1675. The Astronomer Royal is now a largely honorary position, serving as the official advisor to the British monarch in astronomical matters. When it was created 350 years ago, its primary purpose was to determine how to calculate longitude using the stars, an urgent endeavour to improve navigation at sea. It’s no surprise King Charles III chose Professor Dougherty for the role. She’s internationally recognised for leading uncrewed space missions to Saturn and Jupiter, and for her contribution to the discovery of water on Saturn’s moon Enceladus. Her expertise lies in designing instruments to measure magnetic fields in…

New Horizons was the first mission sent to explore Pluto, conducting a fly-by in July 2015. It was then redirected for a close pass of a much smaller Kuiper Belt object, Arrokoth, in January 2019. Today, it’s over 61 AU away – almost twice as distant as Pluto – and racing from the Sun at around 50,000km/h (31,000mph), meaning that it covers the equivalent of the Earth–Sun distance every four months. It’s the fifth robotic spacecraft that we humans have launched on an escape trajectory that will ultimately leave the Solar System altogether and enter interstellar space. Indeed, the craft is already so remote that nearby stars appear to shift in position when viewed from the spacecraft, compared to how we see them from Earth. This displacement in the apparent…

Brits in Space In this episode, The Sky at Night team find out how Britain is contributing to the space sector in the modern era, from engineering and innovation to the talented astronauts training to travel into space. We catch up with three British astronauts in training with the European Space Agency and find out what it takes to make the journey into Earth orbit. BBC Four, 13 October, 10pm (first repeat will be on BBC Four, 15 October, 11.30pm) Check www.bbc.co.uk/skyatnight for more up-to-date information…

On 20 July 1976, NASA’s Viking 1 lander transmitted the first picture from the surface of the Red Planet. The lander (and its identical twin, which landed several weeks later) was fitted with two advanced solid-state video cameras. These used a movable scanning mirror to direct light from a very narrow field of view onto 12 silicon-based diodes. Six of the diodes were sensitive to wavelengths of visible and infrared light, while others captured monochrome images focused at different distances. Initial processing failed to correct for light conditions on Mars, resulting in images of a blue sky and pinkish landscape. It was only after proper calibration that the rusty terrain and pink-hued sky were properly revealed. In total, the Viking landers returned some 4,500 images of their surroundings, but this…

On 14 July 2015, NASA’s New Horizons mission delivered some of the most ambitious of all space-based imaging to date, returning pictures from a twilight zone beyond Neptune. At Pluto’s distance, sunlight is 1,000 times weaker than on Earth, so the probe’s cameras were designed to sweep up as much light as possible. The CCDs used pixels 100 times larger than those in a typical Earth-based device. A narrow-angle instrument called LORRI captured highly magnified views on a square array 1,024 pixels wide, while the wide-angle camera Ralph – with a resolution of 5,024 by just 32 pixels – built larger images by scanning the surface continuously throughout the high-speed fly-by. Pluto was widely expected to be a deep-frozen ice ball with ill-defined patchy features. Instead, the cameras revealed a…

PICK OF THE MONTH Jupiter Best time to see: 31 October, 05:15 UT Altitude: 58° Location: Gemini Direction: South Features: Complex atmosphere, moons Recommended equipment: 100mm or larger Jupiter skips opposition in 2025. Its last opposition occurred on 7 December 2024, and the next will take place on 10 January 2026. This gap is a normal part of the planet’s roughly 13-month opposition cycle. The good news is that this currently puts the planet in an excellent position for observation and imaging. Jupiter is in Gemini at present, near the stars Castor (Alpha (α) Geminorum) and Pollux (Beta (β) Geminorum), a spot that Mars passed through last spring. The planet is bright at the moment, shining at mag. –2.0 at the start of October and brightening slightly to mag. –2.2…

1. NGC 6940 Let’s start the tour with open cluster NGC 6940, which deserves to be far better known. To find it, use the chart to identify mag. +4.2 52 Cygni and pan 3.5° to the southwest to an oval patch of light about 0.5° across. You should be able to resolve about eight or so stars within this patch. NGC 6940 is about 2,700 lightyears distant and is thought to be about 800 million years old. □ SEEN IT 2. The Dumbbell Nebula Our next target is the first planetary nebula ever discovered, and the easiest to spot with binoculars from UK latitudes. Put mag. +3.4 Gamma (γ) Sagittae at the south of your field of view and M27, the Dumbbell Nebula, will be just north of centre: a…

We had been driving for most of the day across the rugged terrain of the Atacama to reach our wild camp spot for the night. Shades of rusty orange coated the landscape. Volcanoes loomed among the jagged peaks that protruded from the horizon. As the Sun started to set and a pink hue flooded the sky, the dazzling stars started to reveal themselves. I couldn’t imagine the beauty I was about to witness. I was fortunate to visit the Atacama earlier this year and was welcomed with some of the best skies I have ever seen. After three weeks of traversing the Moon-like terrain, I found that the best places for stargazing were in the true heart of the Atacama region. The Atacama Desert isn’t merely great for stargazing, it’s…

Following post-O4 upgrades, observing run O5 is planned for 2028–31, after which even more significant upgrades will be made. At the start of the next decade, the plan is for a fifth detector, LIGO-India, to join the search for gravitational waves. Plans are also proposed to construct two brand-new detectors in the US and Europe: Cosmic Explorer, with arms 10 times longer than LIGO’s, and the Einstein Telescope, with 10km (6.2-mile) arms built underground and cooled cryogenically. These aim to detect virtually all mergers of stellar-mass black holes in the observable Universe. The 2030s will also see the launch of the first space-based gravitational wave observatory. The Laser Interferometer Space Antenna (LISA) is led by ESA in collaboration with NASA and an international consortium, and comprises three spacecraft millions of…

One of the greatest draws of astrophotography is how it blends science and creativity. Once you get to know your camera’s settings, you’ll unlock a plethora of ways to image the night sky. Even a humble DSLR offers plenty of target choices, from complex deep-sky objects like galaxies and nebulae to beautiful landscapes that celebrate our Milky Way. While DSLRs aren’t typically ideal for lunar or planetary photography due to their low frame rates, they’re perfect for letting your creativity flow. A great example is capturing the Moon’s ascent from the horizon. This involves shooting your foreground and Moon frames separately, then combining them in post-processing. As you can see from our image, not only can you capture lovely lunar surface details with a humble kit lens, you can also…

PHOTO OF THE MONTH The Dark Shark Nebula Ron Brecher, Guelph, Ontario, Canada, 23–30 July 2025 Ron says: “Many celestial objects resemble animals, but perhaps none more so than the Dark Shark. Its snout, jaws, eye, dorsal fin and tail are all obvious in this sea of dust, gas and stars. It was great fun teasing out the details.” Equipment: QHYCCD QHY168C camera, Sky-Watcher Esprit 70EDX refractor, Sky-Watcher Wave 150i mount Exposure: 287× 300” Software: PixInsight Ron’s top tips: “Dark nebulae can be tricky to process. It’s important to make your image bright and boost contrast, but don’t ‘overcook’ it. I worked with masks to enhance the spiral galaxy on the Shark’s back and the blue van den Bergh nebulae. I decided not to suppress the glow around the brightest…

The number of planets discovered orbiting other stars stands at over 6,000 and counting, but that’s just the confirmed ones. Many more candidate exoplanets are awaiting verification, some of which are so promising that they warrant further investigation. One of these tantalising prospects is located in our nearest star system, Alpha Centauri, and – if confirmed – will be the closest exoplanet to Earth to also fall within its star’s habitable zone. At just four lightyears away from us, the planetary candidate is thought to be orbiting Alpha Centauri A, a star which is around the same size and age as our Sun. Before we get too excited, while it’s located in an orbit that could potentially support life – that is, one where liquid water could exist – the…

A supermassive black hole has been discovered that formed when the Universe was just 3 per cent of its current age – around 500 million years after the Big Bang, or 13.3 billion years ago. Found in the centre of a galaxy known as CAPERSLRD-z9, it’s the most distant black hole ever confirmed and a rare glimpse into the cosmic dawn. The black hole was spotted by an international team of astronomers led by the Cosmic Frontier Center at the University of Texas at Austin, using data from the James Webb Space Telescope. “When looking for black holes, this is about as far back as you can practically go,” says Anthony Taylor, a postdoctoral researcher at the centre. “We’re really pushing the boundaries of what current technology can detect.” The…

It’s been announced that by April next year, the UK Space Agency (UKSA) will be absorbed into the UK government’s Department for Science, Innovation and Technology, in a move to cut duplication, reduce bureaucracy and strengthen public accountability. The agency will keep its name and brand, and will be staffed by experts from both organisations. There will also be no immediate changes to the grants or contracts already in place. Space Minister Sir Chris Bryant explains: “Bringing things in house means we can bring much greater integration and focus to everything we are doing, while maintaining the scientific expertise and the immense ambition of the sector.” UK Space Agency CEO Dr Paul Bate adds: “Having a single unit with a golden thread through strategy, policy and delivery will make it…

Email us at inbox@skyatnightmagazine.com MESSAGE OF THE MONTH I looked out of the window before bed while on holiday in Orkney in mid-August and was delighted to see my first-ever noctilucent cloud display! The reflections in the still waters of the Bay of Firth were an added bonus, and even capture some of the delicate ripples in the clouds. Gareth Wilkes, via email What a fortuitous glance out of the window, Gareth! That’s a beautiful picture of an extensive display. Thanks for sharing. – Ed. Birthday treat My amazing partner got me a Dwarf 3 smart scope for my birthday recently and for the first time ever I have managed to take a zoomed-in picture of the Sun, thanks to its ability to also take solar pictures. Not managed a…

Some 17 years earlier than Viking 1, in October 1959, a far less complex mission delivered the first close-up pictures taken from space of another world: the hidden far side of the Moon. Even getting the target in the frame was a major challenge for the designers of the Soviet probe Luna 3. With computing in its infancy, and the precise star-based orientation used by later probes unimaginable, their ingenious solution was to use a light sensor to aim the spacecraft directly towards the Sun. Because the fly-by was timed for the new Moon (when the far side would be fully illuminated), the Moon therefore lay directly behind the spacecraft and lined up with its rear-facing camera. Once Luna 3 had passed the Moon, it looked back and captured a…

On 12 November 2014, ESA’s Philae lander became the first spacecraft to send back images from the surface of a comet. It was deployed by Rosetta, which had entered orbit around the comet 67P/Churyumov–Gerasimenko some three months earlier. A hazardous landing saw the 100kg (220lb) craft bounce twice in the comet’s weak gravity before coming to rest in the shadow of a cliff. With limited sunlight reaching its solar panels, its battery ran down after 57 hours – but not before it had sent back images, including a panoramic view of its final landing site. Philae’s cameras, like those of most modern probes, used modified versions of the same CCD (charge-coupled device) chips found in consumer digital cameras. Essentially an array of tiny light-sensitive diodes arranged on a silicon wafer,…

Mercury Mercury is an evening planet during October. It reaches greatest eastern elongation on 29 October, when it’ll be separated from the Sun by 23.9°– but it’s poorly placed from the UK, and so probably won’t be visible this month. Venus Best time to see: 1 October, one hour before sunrise Altitude: 11° Location: Leo Direction: East The position of morning planet Venus worsens throughout October as it creeps nearer the Sun. On 1 October, Venus rises 2 hours and 20 minutes before sunrise, a mag. –3.8 beacon visible above the eastern horizon in the dawn twilight. On the morning of 19 October, a 4%-lit waning crescent Moon sits 6° west of Venus. By the end of the month, Venus rises 1 hour and 37 minutes before the Sun. Mars…

The minor planet 12 Victoria reaches opposition on 5 November, when it can be seen shining at mag. +9.9 within the borders of Aries, not too far from mag. +5.7 Mu (μ) Arietis. Victoria remains in Aries throughout October and November, appearing to travel along a straight line from northeast to southwest. You’ll need a small telescope to see it. On 1 October, Victoria will appear to shine at mag. +10.7 and can be found 9° to the west of mag. +2.9 Alcyone (Eta (η) Tauri), the brightest star in the Pleiades. That starting position is just west of the mid-point between mag. +5.4 52 Arietis and mag. +4.8 Zeta (ζ) Arietis. On 15/16 and 16/17 October, Victoria travels just to the north of mag. +4.6 Epsilon (ε) Arietis. Visually,…

Supermoons, micromoons and all the in-between Moons occur because the Moon’s orbit around Earth (or, more accurately, around the Earth–Moon barycentre) isn’t circular but elliptical. This means the Moon’s physical distance from Earth varies over the course of its orbit. As a result, its apparent diameter changes too. Recording these changes is surprisingly easy. All you need is a camera, preferably attached to a telescope or long-focal-length lens, that’s able to capture the entire disc of the Moon in one go. The larger the image, the easier it will be to see the effects, but the critical point is you must use the same equipment setup for every image. The Moon’s physical distance also varies slightly between rising, transiting past the south point and setting. That’s because when it’s rising…

With high temperatures during the day which quickly drop at night, the Atacama region can be challenging to navigate as a first-time visitor. You’ll likely start at the town of San Pedro de Atacama, the epicentre for stargazing in the Atacama Desert, and the place from which several tours operate. Many tours take you out of town and some even to the ALMA telescope. Generally, tours operate at night, with guides that bring a selection of telescopes along and point out constellations, planets and more to observe. It’s less common to find overnight tours, but there are several glamping sites that are well located for this. Look for local guides and tour operators based in San Pedro de Atacama. Warm layers, thermals, plenty of water, a good jacket and suitable…

While not the first to have the idea, it was Albert Einstein in 1916 who showed that gravitational waves are a natural consequence of his general theory of relativity. Gravitational waves are ripples in spacetime that are generated by accelerating masses – anything with mass, when it changes speed or direction, generates gravitational waves, ‘wobbling’ the spacetime around it. The effect is very weak, so to detect a gravitational wave we need objects of very large masses that move incredibly fast. Existing gravitational wave detectors, with arms a few kilometres long, are sensitive to the remnants of deceased massive stars, neutron stars and stellar-mass black holes, typically five or more times the mass of the Sun, sometimes up to 100 times. More massive black holes produce lower-frequency waves and require…

The worst time to look at the Moon is when it’s full, right? Not necessarily. It’s true that at full Moon, sunlight hits the surface head-on, flattening the appearance of its rugged landscape of deep craters, towering mountains and meandering valleys, showing only a flat, grey-and-white disc. But this direct lighting reveals something else: lunar rays – bright lanes of shattered rock and fine dust that fan out from impact craters. While these are hard to see when the Sun is low in the lunar sky (when we see the Moon as a crescent or a gibbous disc), when the Sun’s light strikes them from above during full Moon they shine. And with 2025’s first supermoon coming on 7 October, there’s never been a better time to see them. Imagine…

In recent months, we’ve highlighted how Titan and its shadow have been passing across Saturn’s disc, rare events that happen around Saturn’s equinox. That’s when the planet’s apparent tilt angle makes it appear sideways-on to the Sun (and to us), bringing Titan into play. A lot of the early crossings that resulted were compromised by bad weather, poor seeing conditions and unfavourable timings, but now there’s some good news – and some bad. The good news? Titan will be transiting Saturn a couple of times each month from October 2025 through to January 2026, and many of these events will be well-timed for UK viewing. The bad news is that – as conditions for these transits are right only every 15 years or so – after February 2026, the next…