Tabla de contenidos para December 2024 en BBC Sky at Night

The mission to make solar eclipses Solar scientist Huw Morgan discusses the probe that will engineer eclipses to enable better study of our Sun. Download and print observing forms Keep track of your observations of the Sun and the planets through the eyepiece with our printable forms. Comet C/2023 A3: best readers’ images C/2023 A3 Tsuchinshan –ATLAS was a comet photographer’s dream come true. View our pick of the best images. The Virtual Planetarium FREE BONUS CONTENT Find it at www.skyatnightmagazine.com/bonus-content…

BULLETIN Mars’s long-lost atmosphere may have been hiding in plain sight all along. A recent study suggests as much as 80 per cent of Mars’s missing air could be trapped in the planet’s red clay soil, captured inside a mineral known as smectite. Mars was once a much wetter world, its surface water kept in place by a thick carbon dioxide atmosphere. Then, around 3.5 billion years ago, both the water and the atmosphere disappeared. Planetary geologists have studied Mars for years trying to discover where its atmosphere went, but the answer may finally have come from those looking at our own planet, and a group of researchers at MIT who were investigating smectites. Each grain of the minerals contains multiple folds that can trap carbonbearing molecules for billions of…

One of the biggest mysteries in cosmology has deepened after new results from the James Webb Space Telescope (JWST) suggest that the Hubble tension remains in full effect. This tension is caused by the fact that the expansion of the Universe appears to change speed depending on whether it’s measured by looking at the current, local Universe or at the distant, early Universe. Measured using a value known as the Hubble constant (sometimes referred to as H0), some recent measurements of the expansion rate had seemed to ease this apparent tension. JWST discovered three bright points of light in galaxy cluster PLCK G156.7+67.0 which aren’t visible in Hubble images from 2015. They appear to all be from a single supernova event that has been gravitationally lensed – a foreground object…

Our experts examine the hottest new research CUTTING EDGE One oft-discussed possibility for the planet Mars is the large-scale transformation of its planetary environment to become more Earth-like – a process known as terraforming. Extensive geological evidence indicates that Mars once had a much thicker atmosphere and a warmer climate that allowed liquid water to flow across its surface. In this sense, terraforming would represent an effort to wind back the clock of planetary time to return Mars to a warmer, wetter world. The first step in the terraforming process would be to pump up a more substantial atmosphere for the planet and so warm the surface by trapping heat through the greenhouse effect. Mars today is so cold that a significant amount of its carbon dioxide air has frozen…

Many fine works capture the spirit of sea voyages in the days of sail, such as Sea-Fever, in which the British poet laureate John Masefield (1878–1967) wrote the line: “And all I ask is a tall ship and a star to steer her by.” But for that image of a full-rigged ship cutting a foamy ocean swathe to become reality, the crew needed the knowledge and skill to determine the ship’s position at sea and the direction of the next port. There are many accounts from around the globe of humankind’s early sea excursions. In the Mediterranean, the Minoans, Phoenicians and ancient Greeks are documented as making numerous ocean voyages using simple coastal navigation – keeping the shoreline in sight, for fear of becoming lost. However, even then – going…

One of the simplest ways to watch Earth’s protective atmosphere defend us from what space throws our way is to look for a shooting star. These bright white lights, streaking through the darkness are not stars at all, but meteors, tiny specks of space dust or rocks called meteoroids that have broken off from larger bodies in the Solar System. Fabulous meteor showers like the Perseids or Geminids are attributed to debris from comets or asteroids left in Earth’s path. This enters our atmosphere at speeds of around 150,000km/h (90,000mph). At those speeds, even a meteoroid the size of a grain of sand can punch through metal plates and cause significant injury if it were to hit a person. Fortunately, friction in Earth’s atmosphere causes the space rock to heat…

The Sun and Moon play a crucial part in the existence of life on Earth. Almost all animals on Earth have a circadian clock, an internal clock regulated by light that helps us navigate the 24-hour day. But there are some animals that depend on the lunar cycle too. Many marine animals rely on the tides, and so their feeding and reproductive cycles are tied to the Moon. Coral, for instance, uses the waning Moon as a signal to spawn, while reef fish forage for food more intensely around the full Moon. Terrestrial life also relies on our celestial satellite. Insect activity has long been shown to fluctuate in step with the phases of the Moon. Ephedra foeminea, the Werewolf plant, takes advantage of this fact by secreting a sugary…

Many astronauts have experienced incredible views of our Blue Planet suspended against the blackness of space, a sight that most of us can only dream of. Two of the most famous and inspiring photographs that capture that moment are ‘Earthrise’, taken in 1968 by Apollo 8 astronaut William Anders as he orbited the Moon, and the ‘Blue Marble’, a photograph of Earth taken aboard the Apollo 17 spacecraft in 1972. Capturing the vulnerability of our planet against the vastness of space, they influenced the birth of environmentalism. Viewing Earth from space has resulted in astronauts reporting a change in their emotions, an overwhelming sense of beauty and stronger connections to people and to Earth as a whole. This phenomenon is known as the Overview Effect, a term coined in the…

DON’T MISS Lunar occultation of Mars BEST TIME TO SEE: Morning of 18 December at 09:05–10:25 UT This month, we get another rare planetary occultation when the Moon will move in front of the planet Mars. The event occurs during the morning of 18 December, with the catch (there’s always one!) that the Sun will be up – in other words, it’ll be daylight. Although this may sound difficult, Mars will be at mag. –0.9 at the time and the Moon will be at a large and bright phase, appearing as an 89%-lit waning gibbous, so it should be pretty easy to locate in a clear sky. Look for it in plenty of time before the start of the event, above the west-northwest horizon. Once you’ve located the Moon, you’ll…

Phocylides Type: Walled plain Size: 114km Longitude/latitude: 57.3° W, 52.8° S Age: 3.9 billion years Best time to see: Five days after first quarter (12–13 December) or four days after last quarter (26–27 December) Minimum equipment: 10× binoculars We head south for this month’s Moonwatch target, the 114km crater Phocylides. Appearing as a rim surrounding a flat floor, with no evidence of a central mountain complex, Phocylides is a classic example of a walled plain. From Earth, it sits relatively close to the Moon’s southwest limb, close enough to change appearance over time due to the effects of libration – the apparent rocking and rolling exhibited by the Moon. Despite the Moon being tidally locked to Earth and always presenting the same familiar face, the Moon’s orbit causes it to…

1. The Pisces Parallelogram 10×50 Use the chart to find this parallelogram of coloured fifth-magnitude stars. The northeast corner is 29 Piscium, a brilliant blue-white star, while, diagonally opposite, is the stark contrast of orange 30 Piscium. The other two corners of the parallelogram are a muted yellowish colour. Can you see how the northern part of the parallelogram seems to be empty? Very dark skies show this to be an illusion, as a smattering of fainter stars become visible. □ SEEN IT 2. Neptune 10×50 Just west of the parallelogram is mag. +5.5 20 Piscium, and less than a degree east-northeast of this, shining at mag. +7.9, is outermost planet Neptune. It’s very easy to see in binoculars, as long as you know exactly where to look. It moves…

People once thought that stars were static and unchanging. It’s only in the past 100 years or so that we have understood that while stars of a similar mass to our Sun are pretty uneventful, massive stars end their lives in a far more dramatic fashion. After burning hydrogen and helium, they start to burn heavier elements until their cores collapse, producing an enormous explosion that astronomers call a supernova. When this happens, the explosion can outshine an entire galaxy as the star returns its heavier elements back to the cosmos. Observing supernovae is a great activity for beginners to familiarise themselves with popular galaxies. Supernovae do sometimes occur in our own Galaxy, but they are rare and so astronomers wanting to observe these objects survey lots of external galaxies…

STEP 1 First locate the Moon. It’ll be positioned 17˚ above the westnorthwest horizon at 09:00 UT. Try to find it as early as possible to give yourself plenty of time to locate Mars. The Sun will be up, so take care when sweeping the sky, although the Moon will be in approximately the opposite direction to the Sun. STEP 2 Once you’ve located the Moon, point your planetary imaging setup at it. Initially, we’d recommend using a low image scale, one that will allow you to capture the whole Moon or perhaps a large portion of it in one go. Align the camera equatorially, so the Moon moves horizontally when you slew in RA. STEP 3 If you have an IR-sensitive camera and an IR pass filter, fit the…

VICTOR M BLANCO 4-METER TELESCOPE, 1 OCTOBER 2024 Seen here is Caldwell 49, also known as the Rosette Nebula or, sometimes, the Skull Nebula – though the latter name is also used for planetary nebula NGC 246. Caldwell 49 is a 130-lightyear-wide region of ionised hydrogen that lies some 5,000 lightyears from Earth, at one end of a molecular cloud in the constellation Monoceros. The star cluster at the heart of the Rosette, NGC 2244, is only about 2 million years old and powerful radiation from these young stars is carving out the cavity at the Rosette’s core. This colourful image was captured using the Victor M Blanco 4-Meter Telescope’s Dark Energy Camera, and its release marks the fifth anniversary of the founding of the USA’s NOIRLab (National Optical-Infrared Astronomy…

In an unprecedented landing on 13 October 2024, SpaceX successfully caught the booster stage of its massive new Starship spacecraft with a giant pair of mechanical arms as it hovered in mid-air next to its launch tower. It was the fifth test flight for Starship, a 71-metre-tall (233ft) heavy-lift launch vehicle that SpaceX hopes will one day take humans to the Moon and perhaps onwards to Mars. The system is designed to be reusable, meaning each section of the spacecraft needs to be able to land safely after each use. Like SpaceX’s other rocket series, the Falcon, Starship uses thrusters to guide its booster stage back down to Earth. But while the Falcons are able to deploy landing legs, these would be unfeasible on the much larger and heavier Starship.…

The festive season is upon us, and along with the gift lists and packs of Christmas cards, there may be an Advent calendar waiting to have its first door opened. Let’s hope Advent brings with it some clear nights to enjoy, because once the mince pies have been made, there are lots of fascinating and beautiful things to see in the night sky throughout the month of December. We’ve picked 10 glittering delights for you here, all of them visible to the naked eye, so you don’t have to worry if you’re waiting to unwrap your first telescope on the 25th. Some of our 10 treats will only be clearly visible if you’re out under a dark sky on a night with no Moon blazing; for these, avoid the five…

Not only is Earth blanketed under a protective atmosphere, but our planet is also surrounded by a colossal magnetic field that extends out into space, a region known as the magnetosphere. It’s created by Earth’s molten iron outer core, which is constantly churned around by the planet’s rotation and convection currents within the red-hot liquid. This constant movement generates large, fast-moving electrical currents which in turn create Earth’s magnetic field. It is as if Earth has a huge magnet at its centre. The magnetosphere shields us from a constant barrage of charged particles called the solar wind and particle radiation from coronal mass ejections, massive ejections of plasma and magnetic fields emitted from the Sun. Most of this solar energy is trapped within the Van Allen belts, two belts of…

Gravity is all around us, not just here on Earth, but throughout the Solar System. It holds the planets in their orbits, keeps the Moon in its circuit around Earth and even helps new stars to form. The proximity of the Moon to Earth – on average 384,400km (238,855 miles) away – creates a gravitational pull on our planet’s oceans, creating the tides. Tides are the regular rise and fall of the oceans caused by the gravitational pull of the Moon and to a lesser extent, the Sun. As Earth spins on its axis each day, the oceans are affected by two forces. The side of Earth closest to the Moon experiences a high tide caused by the gravitational pull of the Moon. On the opposite side of Earth, furthest…

Jupiter, the king of the planets, reaches opposition on 7 December. Around that time, the gas giant is shining at its brightest and visible throughout the night, in the constellation of Taurus, the Bull – which makes now a great time to observe and find out about the planet’s four largest moons. Discovered in 1610 by Italian pioneer Galileo Galilei, the four moons were soon all named after lovers of Zeus, the Greek name of Jupiter. For another 360 or so years, the quartet remained nothing more than specks of light, until Jupiter was visited by NASA’s unmanned Voyager 1 and Voyager 2 in the late 1970s and the Galileo mission in the 1990s. Their close-up images revealed stunning details on the four worlds, each of which has its own…

PICK OF THE MONTH Jupiter Best time to see: 7 December, 00:00 UT Altitude: 59° Location: Taurus Direction: South Features: Complex atmosphere, Galilean moons Recommended equipment: 75mm scope or larger Magnificent Jupiter is ablaze in the December night sky. Reaching opposition on 7 December, the planet shines brightly at mag. –2.7 located against the stars of Taurus the Bull and is visible all night long. December’s long nights offer an opportunity to observe a full rotation of Jupiter, the planet spinning once on its axis in just under 10 hours. It’s a bit of a marathon to do this, but fascinating to devote an entire night to observing Jupiter. It really allows you to connect with the planet, your eyes noticing every nuance of its complex atmosphere delivered by your…

Minor planet 15 Eunomia reaches opposition on 13 December, when it can be found shining at mag. +8.1 among the stars of Auriga. At this brightness, it’s best viewed using a small or medium telescope. Its monthly track has it starting just east of the Cheshire Cat asterism, a pattern that consists of a smiling mouth and two stars representing the eyes and, if you have a good imagination, a tail too. 15 Eunomia initially passes between mag. +6.0 M36 and mag. +6.4 M38, heading along a track that takes it over the diffuse nebula IC 417 adjacent to mag. +5.1 Phi (φ) Aurigae. It scrapes past the southern corner of the Cheshire Cat’s mouth around opposition, thereafter heading southwest along the stars of the cat’s tail. This is good…

The peak of a meteor shower can be a delicate thing to observe, even for showers with good rates. For the best views, you need the shower radiant at a decent altitude, clear weather and no Moon to interfere. For this year’s Geminid peak on the night of 13/14 December, only one of these conditions will be certain and that’s the height of the radiant. This month’s challenge is to try to photograph a Geminid trail under skies heavily illuminated by moonlight. We can’t predict what the weather will be, but we can predict that the Moon will definitely be a nuisance. Virtually full throughout the nights when Geminid activity is highest, the Moon is also positioned fairly near the radiant. If there is any haze or mist present, this…

Phosphine is a compound comprising the elements phosphorous and hydrogen, with the chemical formula PH3. On Earth, at room temperature and pressure, when pure it exists as a colourless, odourless gas that is actually extremely toxic to nearly all life. Indeed, as well as finding uses in the chemical production and semiconductor industries, it is a very effective pesticide, commonly used to fumigate insect-infested food stores. Yet the possible presence of this poisonous gas in Venus’s atmosphere is actually taken by some as a potential sign of life. This is because although natural processes occurring on Venus can produce it – volcanism, lightning, and chemical reactions in the atmosphere or on dust grains in clouds – they do not produce such significant quantities that its presence in the atmosphere would…

Step 1 Choose a couple of bright galaxies to observe. The Pinwheel Galaxy in Ursa Major and the Andromeda Galaxy are good winter targets and have produced supernovae in recent years. Pick a galaxy suitable for the limiting magnitude of your setup. Step 2 Use a star chart or planetarium software such as Stellarium to see where the galaxy is located and its magnitude. Zoom in on the region. Spend some time familiarising yourself with the area surrounding the galaxy, including background stars. Step 3 Use a weather app such as Clear Outside to find out when the Moon is out of the way. Try to observe on transparent nights, as galaxies are faint targets and easily lost in haze. Allow 30 minutes before observing so your eyes are fully…

Picking a first telescope for a young astronomer can be challenging. Your choice should be simple to use, to encourage absolute beginners, yet it should also return some rewarding views. If you don’t meet both criteria, the telescope could end up simply gathering dust. We think Bresser has struck a good balance with this budget introductory setup, marketed for ages 8 and above. The Bresser Junior 70/400 refractor telescope comes with a suite of accessories to provide astronomy newcomers with a complete one-stop shop, from eyepieces to a smartphone adaptor, plus even a small backpack to transport everything on astronomy adventures. Available in a range of colours, for our review we received the blue version which arrived in a single package. Assembly couldn’t have been easier; the compact refractor arrived…

A newly discovered planet could provide a window into Earth’s future, billions of years from now. The planet is 4,000 lightyears away in the constellation of Sagittarius and has around the same mass as Earth, but it orbits its white dwarf star twice as far out. In around one billion years, our Sun will begin the long transition into becoming a white dwarf. Initially, it will swell to a red giant, consuming Mercury and Venus during its expansion. There’s a chance, however, that Earth could be spared. As it swells, the Sun will start losing mass, which will cause the planets to migrate outwards, meaning Earth could outrun the growing star. If Earth survives, it will end up at double its current orbital distance, while the Sun will continue to…

A giant asteroid that smashed into Earth 3.26 billion years ago may have helped life flourish rather than snuffing it out, according to a recent study by a team of geologists. It’s thought the asteroid, dubbed S2, was 40–60km (25–37 miles) wide, giving it a mass as much as 200 times greater than the space rock that killed the dinosaurs. A team of geologists, led by Nadja Drabon from Harvard University, investigated the impact by gathering samples from the Barberton Greenstone Belt of South Africa, analysing the sedimentary layers laid down before, during and after the impact, to build a timeline of events. They found that S2 generated enough heat to boil the surface layer of the ocean, while the shock of the impact created a huge tsunami. The racing…

The European Southern Observatory (ESO) has released one of the most detailed infrared maps of the Milky Way ever published. Comprised of over 200,000 images taken by the Visible and Infrared Survey Telescope for Astronomy (VISTA) over 13 years, the map covers a sky area equivalent to 8,600 full Moons. The map includes many newborn stars, which are obscured from visible-light telescopes by dust from the stellar nurseries they grow in. The maps also reveal many cold objects, such as brown dwarfs and free-floating planets, which don’t emit optical light but glow at infrared wavelengths. “We made so many discoveries, we have changed the view of our Galaxy forever,” says Dante Minniti from Universidad Andrés Bello in Chile, who led the project. You can explore the data yourself at archive.eso.org/scienceportal/home.…

As the Sun begins its slow descent over Carn Galver in west Cornwall, I stand at the triangular viewing stone at Little Galver, surrounded by a small group of observers on the evening of the spring equinox. We’ve gathered to witness a sunset alignment, a phenomenon meticulously crafted by the ancient inhabitants of this landscape thousands of years ago. As an archaeoastronomer and historian of astronomy, this is both a professional study and an opportunity to share the significance of such moments with others, encouraging reflection on the relationship between ancient peoples and the skies, and highlighting the ongoing need to protect the darkness of our night skies. The precision of this alignment is remarkable. The stone was placed here to interact with the path of the Sun, marking a…

At the heart of our Solar System lies the Sun, a massive yellow dwarf that has a diameter of 1,392,000km (864,950 miles) and sits 149,597,870km (92,955,807 miles) away from Earth. The electromagnetic radiation that we receive from the Sun comprises infrared radiation, visible light and ultraviolet radiation, all of which are produced by nuclear fusion at the star’s core. It is the most important energy source for our planet, providing us with the heat and light we need to survive, driving our ocean currents, seasons and weather. Earth’s atmosphere acts as an insulating layer, helping to stop that heat escaping, but it also plays an important role in keeping us safe from some of the most harmful rays, including gamma rays and some ultraviolet radiation waves. Our atmosphere absorbs and…

Betelgeuse (Alpha (α) Orionis) is one of the most famous stars in the night sky. Located in the northeast corner of the main pattern within Orion, it’s an easy naked-eye object, typically being the 10thbrightest nighttime star. We say ‘typically’ because it’s a semi-regular variable which changes in magnitude between 0.0 and +1.6. Its spectral type is M1–M2 Ia–ab, indicating a red supergiant, and visually it shines with a glorious orange hue. Betelgeuse’s distance isn’t precisely known, lying somewhere between 400 and 600 lightyears away. Its diameter has similarly been tricky to pin down, but it’s currently thought to be around 640 times larger than the Sun and 14–19 times more massive. Betelgeuse has been around for 8–14 million years and is now getting near the end of its life.…

Venus is often referred to as Earth’s twin, because the two planets are of similar size, mass, composition and structure. Analyses of the Venusian atmosphere, together with climate-modelling tools suggest that Venus may have had just as much water as Earth and a potentially habitable climate earlier in its history compared to the inferno we see today. It is thought the divergence in the evolutionary paths of these two planets could stem from their relative distances from the Sun. When the Sun was younger and less luminous, Venus sat within its habitable zone – that is, within the range of distances from a star at which liquid water could exist on an orbiting planet’s surface. As the Sun aged and increased in luminosity, Venus heated up and any water it…

Many were fortunate enough to see the last lunar occultation of Mars visible from the UK on 8 December 2022. Seeing the Moon pass in front of a planet or star is always fascinating to watch and photograph. It places two familiar but normally separated worlds together in the same frame and highlights just how quickly the Moon appears to move. Lunar occultations of planets can often push your skill levels too. Last August saw the Moon occulting Saturn under brightening twilight conditions, when the first eye-opener was the large difference in brightness between the Moon’s surface and Saturn. The scene required great care to deal with such a significant dynamic range. This month, the Moon will occult Mars once again. The event occurs on 18 December, when Mars will…

Abell 85 supernova remnant Michael Caligiuri, Descanso, California, USA, 31 August 2024 PHOTO OF THE MONTH Michael says: “I knew this object had a trace of OIII in its shell, so I spent two full nights capturing Ha and OIII data, then added a little RGB for the star colours. Excellent conditions with several hours of OIII made all the difference.” Equipment: ZWO ASI294MM Pro camera, Takahashi FSQ-106N refractor, Losmandy GM8 mount Exposure: RGB 8× 5’ each channel, OIII 10× 15’, Ha 15× 15’ Software: CCDStack, PixInsight, Photoshop Michael’s top tips: “For very faint supernova remnants, the more data the better. Use 3nm narrowband filters, which will sharpen the filaments more than wider bandwidths. I captured as many long subs as the night allowed, revealing a bright blue edge to…

What is the Nadir crater? The Nadir crater is a scar left by an asteroid or comet impact on Earth. It’s a 9km-wide (6-mile) impact crater on the Guinea Plateau off the west coast of Africa. Nadir’s impact occurred into an ocean, affecting the crater’s shape. We think it occurred around 66 million years ago, at the same time as the Chicxulub impact. What was the Chicxulub impact? It’s believed that a massive asteroid impact 66 million years ago killed around 75 per cent of life on Earth, including the dinosaurs. It formed the Chicxulub crater on the Yucatán Peninsula in Mexico. Compared to Nadir’s 9km diameter, Chicxulub is around 200km (124 miles) across. When the asteroid that formed Nadir hit, it would have caused local devastation. For Chicxulub, the…