Innehållsförteckning för No. 155 från All About Space

SCAN HERE TO GET OUR DAILY NEWSLETTER Did you know that some planets wander the universe without a parent star? These sunless worlds, known as rogue planets, are estimated to exist in huge numbers - for every star, there are supposedly 20 of these exoplanets. This issue, you can learn all about them: from how we find a rogue planet to what would happen if one of them wandered into our Solar System. As I write this, we are on the other side of the March equinox, marking the beginning of spring for those in the Northern Hemisphere and autumn in the Southern Hemisphere. While those in the Southern Hemisphere have the darker evenings to look forward to, those of us in the Northern Hemisphere lose some hours of night…

Ever since astronomers first began discovering planets outside of the Solar System, dubbed ‘exoplanets’, in the mid-1990s, our picture of the Solar System as a ‘typical’ arrangement of planets and stars has been turned on its head. Among the 5,600 or so exoplanets that we have discovered over the course of the last three decades are scorching hot worlds bombarded by so much stellar radiation that they rain molten metal, planets that race around their stars so fast they can fit several years into a single day and planets squashed by the gravity of their stars so much they have flattened discs. While all of these discoveries have changed our perspective of the Solar System and its planets being ‘typical’ and may have even made our corner of the Milky…

Recent observations of Betelgeuse, a star located in Orion, have created a mystery about the red supergiant. They suggest that it’s spinning much faster than a star its size should be able to. A team from the Max Planck Institute for Astrophysics, led by PhD student Jing-Ze Ma, may have an explanation for why Betelgeuse appears to be spinning so utterly fast – perhaps it’s an illusion created by the star’s violently boiling surface. Ma and his colleagues think the star’s bubbling surface could be mistaken for rotation, even by the most advanced telescopes. This mistake could lead to observers believing that Betelgeuse, which is located around 642.5 light years from Earth, appears to be rotating faster than should be possible for a star of such enormity. “For most people,…

1 Messier 81 (Bode’s Galaxy) Constellation: Ursa Major Type: Spiral Minimum optical aid: 10x50 binoculars A good place for beginners to start is with the famous group of stars known as the Big Dipper. It forms part of the constellation Ursa Major (the Great Bear). Locate the four stars that make up the ‘bucket’ and then take the bottom-left star, Phecda, and the top-right star, Dubhe. Now extend the line between them upwards until it has roughly doubled in length. You should find Bode’s Galaxy lurking very close by. As it is quite big and bright, it shouldn’t be too tricky to hunt down with binoculars. 2 Messier 82 (Cigar Galaxy) Constellation: Ursa Major Type: Starburst galaxy Minimum optical aid: 10x50 binoculars This is very close to Messier 81 –…

If you’ve observed all of the events this month has to offer, or you’re in between astronomical events, why not take a tour of April’s star patterns? The constellations of Hydra I (the Water Snake), Leo (the Lion) and Ursa Major (the Great Bear) contain a fascinating selection of Messier objects, including a large number of spiral and irregular galaxies. Ursa Major’s famous planetary nebula, known as the Owl Nebula (Messier 97), is particularly easy to observe for those with a telescope and a selection of filters. With sunset not occurring until around 20:00, observers will need to be patient in waiting for the twilight to fade. When the skies have darkened, the wait will be worth it as spring’s offering of planets, dwarf planets, star clusters and nebulae come…

12 March 2024 Record-breaking image of a dead star’s scattered remains This billowing mass of dust filaments and gas tendrils stretching across 100 light years of space is the Vela supernova remnant – the scattered ashes of a star that exploded about 11,000 years ago. The image was acquired by the Dark Energy Camera (DECam), mounted on the Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile. DECam was originally designed to conduct a survey of distant galaxies to measure the strength of dark energy as it accelerates the universe’s expansion and draws those galaxies away from us. On completion of that survey, however, DECam has been used in a more general fashion. It is one of the most powerful wide-field instruments ever built, and this image…

Interstellar distances are difficult to conceive. Our nearest star is Proxima Centauri, a red dwarf that lies 4.3 light years away – that’s more than 266,000 times the distance from Earth to the Sun. Even if our fastest spacecraft, Voyager 1, which is flying at 18 kilometres (11 miles) per second, were headed that way, it would still take 80,000 years to get there. For humans to be able to explore the galaxy, we are going to need another way to travel, but while the focus has been on the propulsion side of the puzzle, equally challenging is how we power such journeys. But there’s a strange concept that might solve both problems: the Schwarzschild kugelblitz, a craft powered by a black hole. To make interstellar journeys in a reasonable…

In February 2024, reports of a planned Russian nuclear space weapon renewed Cold Warera fears of the militarisation of Earth orbit. The furore began when US House Intelligence Committee chair Mike Turner issued a public statement asking President Joe Biden to declassify all information relating to a space-based nuclear weapon that Russia is reportedly developing. White House national security communications advisor John F. Kirby assured the public that “though Russia’s pursuit of this particular capability is troubling, there is no immediate threat to anyone’s safety. We are not talking about a weapon that can be used to attack human beings or cause physical destruction here on Earth.” It remains unclear if the potential Russian capability concerns a nuclear warhead in space or a nuclearpowered anti-satellite weapon of some kind. Nevertheless,…

Scientists have taken an instrument originally designed to study huge celestial objects in the cosmos and repurposed it to investigate the world on an infinitely smaller scale. With this instrument, they managed to probe the heart of an atom. The team wanted to understand quantum-scale changes that occur within unstable atoms and realised there’s a state-of-the-art gamma-ray polarimeter they could tap into. This device, known as a Compton camera, can measure the polarisation of highenergy light waves. In other words, it can dissect what direction such high-energy light is oriented towards. This instrument was built for deep-space astronomy, not atomic investigations. In fact, scientists constructed it because they wanted to place it on the Hitomi satellite to make observations of high-energy cosmic processes. Yet the camera has now proven its…

Jargon buster Conjunction An alignment of objects at the same celestial longitude. The conjunction of the Moon and the planets is determined with reference to the Sun. A planet is in conjunction with the Sun when it and Earth are aligned on opposite sides of the Sun. Declination (Dec) How high an object will rise in the sky. Like Earth’s latitude, Dec measures north and south in degrees, arcminutes and arcseconds. There are 60 arcseconds in an arcminute and 60 arcminutes in a degree. Opposition When a celestial body is in line with Earth and the Sun. During opposition, an object is visible for the whole night, rising at sunset and setting at sunrise. At this point in its orbit, the celestial object is closest to Earth, making it appear…

1 Messier 92 This magnitude +6.3 globular cluster looks like a fuzzy star in binoculars. Some 26,000 light years away, it’s over 12 billion years old and contains around 300,000 stars. It’s often overlooked since bigger and brighter Messier 13 is so close. 2 Great Globular Cluster in Hercules The most beautiful globular cluster in the northern sky, Messier 13 is just visible to the naked eye as a faint star, making it best seen through binoculars and telescopes. It contains around a quarter of a million stars tightly packed together. 3 The Keystone of Hercules This trapezium shape, comprising the stars Pi, Eta, Zeta and Epsilon Herculis, is one of the northern sky’s most famous asterisms. Once located, it will help you find the pretty globular star clusters Messier…

R ubin was always fascinated by the stars. After earning her undergraduate degree at Vassar College, Rubin attempted to enrol at Princeton University, where she hoped to continue her dreams of becoming an astronomer. However, the institution refused her based on the fact that she was a woman, despite her obvious talent. This extremely unfair ruling wouldn’t be lifted until 1975. Rubin wasn’t put off and refused to let Princeton dictate her career path, instead applying to Cornell University. Encouraged by her supervisors, Rubin completed her studies in 1951. During this time, and unknown to her, she would make one of the first observations of the motions of galaxies. At this point, it was suggested that galaxies moved outwards in accordance with the Big Bang theory, but Rubin figured that…

Just how big can a star get? The biggest stars in terms of diameter are red supergiants J that swell to enormous sizes as their lives come to an end. As they begin to exhaust their fuel and go through internal changes, these stars brighten, swelling in size as their surfaces become cooler and redder. But if by defining the biggest star you simply mean the most massive, the answer is very different. The most monstrous stars of all are hypergiants, with many times the mass of the Sun. The most massive of all was discovered in a neighbouring galaxy of the Milky Way in 2010 – a hypergiant star with up to 230 times the mass of the Sun, called R136a1. Fittingly, this stellar bruiser is a resident of…

A stronomers have spotted the closest visiblelight example yet of a supermassive black hole ripping apart and devouring a star. This star’s gory death can be blamed on a black hole with a mass equal to around a million Suns. The event occurred in the active star-birthing galaxy NGC 3799, which is located about 160 million light years from Earth in the constellation of Leo. The scientists, who hail from the University of Hawaii Institute for Astronomy, discovered the stellar murder, referred to as a tidal disruption event, or TDE, when they spotted the sudden brightening and rapid fading of the barredspiral galaxy within which it occurred. The discovery was made with the All Sky Automated Survey for SuperNovae (ASAS-SN) system on 22 February 2023. “While black holes destroying stars…

here was a time when we thought that our Milky Way galaxy was all there is. In the 18th century, when astronomers like Charles T Messier began spotting faint, fuzzy patches of light between the stars, it was thought they must be clouds within our own galaxy. The alternative didn’t bear thinking about, that they were faint because they were incredibly far away, much further away than the astronomers of the day could reconcile with their idea of the scale of the universe. This belief was widely held right up until the early 20th century. Eventually, Edwin Hubble was able to show that these foggy smudges were indeed incredibly far away – many millions of light years from us, in fact. Fast-forward to the modern day and amateur observing equipment…

Uranus is a truly fascinating world – a slow-moving, faraway ‘ice giant’ planet much larger and colder than our own lush, green Earth. Because it’s so faint, many amateur astronomers and skywatchers have never actually seen it themselves, but this month you will be able to find it very easily in the sky because it will be snuggled up close to one of the brightest planets visible in the sky: Jupiter. At the start of our observing period you’ll find the planetary pair low in the west after sunset, just below the well-known and beautiful Pleiades star cluster, also called the ‘Seven Sisters’. They’ll set two hours after the Sun. You won’t be able to see Uranus very clearly with your eye – even if you are blessed with very…

Many amateur astronomers think that Cassiopeia is a rather barren constellation, and perhaps compared to its more glitzy neighbours it is. For example, nearby Perseus has the stunning and famous ‘Double Cluster’ of NGC 869 and NGC 884, Taurus has its show-stopping Pleiades cluster and Andromeda holds the stunning Andromeda Galaxy, Messier 31. But if you take the time to look a little more closely at Cassiopeia, the Vain Queen of the sky, you’ll find quite a few attractive deep-sky objects hidden within the folds of her royal robes. First of all, Messier 103 positively demands that you look at it through as big a telescope as possible. It might have been the last object Messier put in his catalogue, but it’s far from the least attractive. Close to…

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