Table of contents for No. 112 in All About Space

WELCOME This month All About Space returns to the concept of dark matter, hailed as the most mysterious substance in the universe next to dark energy. There’s a plethora of questions astrophysicists are posing and working to solve in order to get closer to understanding it once and for all. What (we think!) we know about dark matter is how much comprises the cosmos and how it behaves. What we’re still trying to figure out is what it’s made of and where it actually came from. This issue, you’ll discover that a team of astronomers at the University of Houston, Texas, and the University of Melbourne, Australia, has an idea in mind – it could have been forged by ballooning cosmic bubbles, which led to its abundance in the universe.…

Newfound ‘Kraken merger’ may have been the biggest collision in Milky Way history Words by Brendon Specktor © ESA/NASA/ESO The Milky Way has more than 100 billion stars, but it didn’t come by them all honestly. At least a dozen times over the last 12 billion years, the Milky Way collided with a neighbouring galaxy and devoured it, swallowing up that neighbour’s stars and mixing them into an ever-growing stew of pilfered suns. With each galactic merger, the shape, size and motion of our galaxy changed forever, ultimately becoming the iconic spiral we recognise today. Now researchers have attempted to unwind that spiral. Using artificial intelligence (AI) to match distinct clusters of stars by their ages, motions and chemical compositions, the team found evidence of five large- scale galactic mergers…

Jupiter’s ocean moon Europa may spout water plumes Words by Mike Wall Jupiter’s moon Europa may cough water into space from small pockets in its icy crust, a new study suggests. Europa, one of Jupiter’s four big Galilean moons, harbours a huge ocean of salty water beneath its ice shell and is widely regarded as one of the Solar System’s best bets to host alien life. NASA’s Hubble Space Telescope and other instruments have spotted evidence of sporadic plumes of water vapour that rise perhaps 200 kilometres (120 miles) above Europa’s frigid surface. This water may be coming from the buried ocean, raising the exciting possibility that a spacecraft could sample this potentially life-supporting environment without even touching down on the moon. Those apparent big plumes may have smaller cousins,…

Dark matter WHERE DID DARK MATTER COME FROM? BUBBLES IN THE EARLY UNIVERSE MAY HAVE SOLVED THE MYSTERY 1 Big Bang occurs The universe begins as an extremely hot, dense state. 2 Inflation happens At 10-36 seconds the universe expands with unimaginable speed in a period known as inflation This cools the universe further. 3 Thermal freeze out Very quickly, the subatomic particles of ordinary matter ‘freeze’ out of the dense plasma as it cools. So does dark matter. 4 Bubbles form A particle called phi starts a phase change in the universe. These act as nucleation sites, growing as expanding bubbles. 5 Filtering of matter Despite particles freezing out, they’re still hot, including dark matter. Some of the latter pass into the bubbles and gain mass. 6 Bubbles merge…

Dark matter THE BIGGEST UNANSWERED QUESTIONS ABOUT DARK MATTER Is there more than one kind? Could there be an entire family of dark matter particles as opposed to just a single type? The Standard Model of particle physics says that ordinary matter is composed of electrons as well as the quarks that make up protons and neutrons. It also includes the fundamental force-carrying particles, such as photons, gluons, bosons and some other short-lived matter particles. Could there be a similar but separate model for dark matter? Are there corresponding ‘dark forces’? Forget horror and fantasy here. If there are a range of dark matter particles, could they experience their own dark matter forces? If so, could that also sometimes affect ordinary particles? This is the hope of a collaboration working…

PERSEVERANCE NASA’S NEW MISSION TO MARS The rover that’s about to begin a fascinating hunt for life on the Red Planet Reported by Jonathan O’Callaghan © NASA/JPL-Caltech For decades, we have sent spacecraft to Mars. Our neighbouring planet has held an allure over scientists for a long time, because we think it was once like Earth. Billions or perhaps even just hundreds of millions of years ago, the Red Planet likely had oceans and seas on its surface, providing potential habitats for life. Over time, however, it lost its atmosphere, the water boiled away, and today the surface is a barren, desolate wasteland. Thanks to numerous missions sent to Mars, however, we know that was not always the case. NASA’s Viking 1 and 2 landers, which arrived at the planet…

WHAT’S UP WITH THE MILKY WAY? A fast radio burst was detected from Within our galaxy for the first time. Are we closer to uncovering their origin? Reported by David Crookes On 28 April 2020, two ground-based radio telescopes detected an intense pulse of radio waves. It only lasted a mere millisecond but, for astonished astronomers, it was a major discovery, representing the first time a fast radio burst (FRB) had ever been detected so close to Earth. Located just 30,000 light years from our planet, the event was firmly within the Milky Way, and it was, to all intents and purposes, almost impossible to miss. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) and the Survey for Transient Astronomical Radio Emission 2 (STARE2) certainly had no problems picking it up.…

GREAT SPACE IMAGES OF 2020 FROM THE STUNNING WESTERLUND 2 TO THE MIGHTY JUPITER, OUR EYES IN THE SKY HAVE SEEN SOME SPECTACULAR SIGHTS THIS YEAR. HERE ARE JUST A FEW OF THEM Reported by Baljeet Panesar © NASA, ESA, Hubble Heritage Team WESTERLUND 2’S COSMIC FIREWORKS Westerlund 2 is one of Hubble’s most visually striking images, a sight that resembles a magnificent fireworks display. Thousands of stars call the stellar nursery Gum 29 home. Yet astronomers have found that stars in the centre haven’t accumulated enough dust clouds that could become planets in a few million years. At the centre of the cluster are at least 30 massive stars, some weighing 80-times more than the Sun. In this region, extreme quantities of ultraviolet radiation and stellar winds disperse the…

STARGAZER This month’s planets Mercury will glide past Jupiter and Saturn, which remain close together after their great conjunction last year Planet of the month Our Planet of the Month for January is the smallest planet of them all: Mercury, the closest world to the Sun. As Mercury is the nearest planet to the Sun it never strays far from it in the sky. We never see it shining brightly in a dark sky, only for a short time after sunset or before sunrise. Because of this proximity, many people – even amateur astronomers – have never seen this fascinating world, but by mid-month it will be very well placed for observation by everyone, looking like a copper-coloured star low in the southwest after sunset. The good news is that…

LAUNCH PAD YOUR FIRST CONTACT WITH THE UNIVERSE A split sky The Moon, Saturn and Mercury are all captured in this image, but can you identify where they are? The dusty area at the top of the frame is the Milky Way, which looks as if it cuts the sky in two horizontally. There you can identify the Lagoon Nebula, Cat’s Paw Nebula and Trifid Nebula. But where are those celestial bodies? In the centre is a bright object - it’s not the Sun, but the Moon reflecting our star’s light. Saturn is positioned slightly to the upper right and Mercury is to the lower left. As for the objects on the ground, these are the telescopes making up the European Southern Observatory’s Very Large Telescope at the Paranal Observatory…

Dark matter WHAT IS DARK MATTER? It’s not really ‘dark’, but it has some properties It’s the majority of matter Invisible dark matter makes up 80 per cent of the mass in the entire universe. It affects light Because of general relativity, dark matter acts as a gravitational lens and ‘bends’ light. It could be a new particle Dark matter could be an undiscovered particle that hardly interacts with normal baryonic matter or radiation. It could be a WIMP Weakly Interacting Massive Particles, formed after the Big Bang, could be one explanation. It could be an axion Evidence for WIMPs is weakening, giving ground to axions as a possible alternative. Newton’s laws may need modifying One alternative to dark matter is tweaking Newton’s laws so that they behave differently at…

Future tech Venus rover EXPLORING HELL Needing to navigate mechanical rovers on Venus, NASA offered a prize As recently illustrated in the announcement of potential life signs, Venus harbours the most benign off-Earth environment in the Solar System. Some 30 kilometres (18.6 miles) high in the clouds it is one Earth atmosphere pressure and between 15 and 30 degrees Celsius (59 and 86 degrees Fahrenheit), yet the surface is the most hostile place in the Solar System. The dense carbon dioxide atmosphere, which produces the benign conditions higher up, traps in solar heat through the greenhouse effect. The surface temperature is hotter than the surface of Mercury, and hot enough to melt lead. The density of the atmosphere also makes the su pressure 92 times that of Earth’s, equivalent to…

Mini-moons THE MAKING OF EARTH The nebular hypothesis is the most widely accepted theory of how our planet formed at roughly the same time as the rest of our Solar System’s worlds © Nicholas Forder 1 A protoplanet is formed 4.6 billion years ago Gravity caused the Solar System, then a cloud of gas and dust, to collapse in on itself, forming the Sun. Some of the remaining material accumulated to form the Earth’s rocky core. 2 The giant-impact hypothesis 4.5 billion years ago A Mars-sized rocky object known as Theia smashed into the proto-Earth, catapulting pieces of the young planet’s mantle into space. Some of these pieces merged to form our Moon. 3 Meteorite collisions 4.5 to 3.8 billion years ago Earth developed into a solid sphere after being…

Focus on GALEX SOLVES BLUE RING NEBULA MYSTERY A stellar collision is the culprit behind the strange ultraviolet phenomenon Scientists have uncovered new evidence in the mysterious fluorescent debris of the Blue Ring Nebula that may explain how the strange structure formed. The nebula harbours a central star, TYC 2597-735-1. An unusual ultraviolet ring surrounds the star, which astronomers first observed in 2004 using NASA’s now-defunct Galaxy Evolution Explorer (GALEX). The formation of this peculiar ring - which is actually invisible ultraviolet light that has been colour-coded blue in the telescope images - has largely remained a mystery. “Every time we thought we had this thing figured out, something would tell us, ‘No, that’s not right,’” said Mark Seibert, an astrophysicist with the Carnegie Institution for Science. Using the W.…

WHAT HAPPENS ON TITAN’S SURFACE? 1. Nitrogen & methane leave the surface These two gases percolate up from the surface of Titan, eventually reaching its outer atmosphere. 2. The gases combine Once in the outer atmosphere, the nitrogen and methane react to form small organic molecules such as cyclopropenylidene. 3.They react again These organic molecules then grow larger by reacting with each other, and also other nitrogen and methane. 4. Again and again These reactions keep happening, producing a soup of different organic molecules. 5. The molecules sink The heavier molecules then sink towards the surface, clumping together as they do so. 6. On the surface Eventually the clumps of molecules come to rest on Titan’s surface. Their appearance is like that of sand. 7. Forming new life? Once on…

A MYSTERY SOLVED? The detection of an FRB in our galaxy has led astronomers to conclude such bursts involve a magnetar At long last, astronomers can now say with great certainty that fast radio bursts, or FRBs, have a magnetar as their source. It had long been theorised that these dead magnetic stars – spinning remnants resulting from the explosion of a massive star – were a potential source. But only now, with the discovery of FRB 200428, has there been firm evidence for such a theory. Being able to place this FRB in the same area of sky as magnetar SGR 1935+2154 was the breakthrough needed, particularly when an X-ray burst occurred simultaneously. Now astronomers will work to find out if magnetars are behind every FRB. ©ESO…

User Manual Arecibo Observatory Inside the Arecibo Message A letter to the cosmos, beamed from the huge dish towards globular star cluster M13 in Hercules Source: Wikipedia Commons ©Mutante Source: Wikipedia Commons ©Johannes Rossel…

ASK Space Our experts answer your questions SPACE EXPLORATION Will the International Space Station ever be replaced? ©Getty The short answer? Yes, most definitely. The components for the ISS were designed to last for only 15 years; it is 20 years old now and NASA is talking about keeping it in service until 2024. After that NASA may sell the rest, Russia will most likely disconnect from the ISS and eventually it could be jettisoned back into the atmosphere. This, of course, is hugely wasteful, so it could be recycled in low-Earth orbit. That, I believe, is a better use of a space mass that cost $150 billion (£113 billion) to get there. Personally, I would break down all the mass into its molecular components then reuse them in space…

STARGAZER The Northern Hemisphere Get stuck into a plethora of galaxies, nebulae and star clusters Winter offers a selection of targets not just for the beginner to whet their stargazing appetite, but for seasoned sky-watchers to get truly stuck into a tour of the heavens. Mid-January through to February offers a selection of star clusters, galaxies and nebulae for those armed with or without an optical aid. These views compliment the readily available planets, which observers will see make their grand appearances at dusk and dawn through the coming weeks. A selection of galaxies, including the Cigar Galaxy (Messier 82) bursting with star formation in the constellation of Ursa Major, as well as Messier 106, Messier 94 and Messier 63 in Canes Venatici, and the star clusters of Gemini, Orion…

STARGAZER In the shops The latest books, apps, software, tech and accessories for space and astronomy fans alike Telescope Meade Instruments StarPro 102 Cost: £174.89 / $239 From: B&H The StarPro 102 is a classic telescope that’s both simple to use and assemble. If you know someone who is happy to spend hours under the night sky, learning their way around without the aid of technology, then we fully recommend this well-built instrument. This refractor makes use of an alt-azimuth mount as well as slow-motion cables for fine movements that allow the observer to accurately lock onto a target. Some mounts cause telescopes to jump from one positioning extreme to another, but we were pleased to discover that we could make incremental adjustments to the tube’s orientation with ease. It’s…

LAUNCH PAD YOUR FIRST CONTACT WITH THE UNIVERSE IN COOPERATION WITH SPACE.COM China’s Chang’e 5 lands on the Moon, collects first lunar sample Words by Mike Wall ©CCTV China has landed on the Moon again, and this time the country plans to bring home some souvenirs. Chang’e 5, China’s first sample-return mission, successfully touched down on 1 December near Mons Rümker, a lunar mountain located in the Ocean of Storms, or Oceanus Procellarum. The probe deployed its solar array and antenna soon after to begin its work. Two pieces of the four-module Chang’e 5 mission hit the grey dirt after descent - a stationary lander and an ascent vehicle. If all goes according to plan, the lander will spend the next few days collecting about two kilograms of lunar material,…

LAUNCH PAD YOUR FIRST CONTACT WITH THE UNIVERSE Faint ‘super-planet’ found by radio for the first time Words by Samantha Mathewson © ASTRON/Danielle Futselaar Scientists have discovered a cold, faint ‘super-planet’ that has remained elusive to traditional infrared survey methods. Observations from the Low- Frequency Array (LOFAR) radio telescope revealed a brown dwarf, designated BDR J1750+3809 and nicknamed Elegast. Brown dwarfs are sometimes referred to as failed stars or super-planets because they are too small to be considered stars, yet too big to be considered planets. Generally, brown dwarfs are discovered by infrared sky surveys. Elegast, however, represents the first substellar object to be detected using a radio telescope, according to a statement from the University of Hawai’i. Since brown dwarfs are too small to become stars, they don’t undergo…

DARK MATTER WHERE DID IT COME FROM? It’s eluded us for decades, but bubbles could be the answer to the universe’s most mysterious substance Reported by Kulvinder Singh Chadha © Tobias Roetsch If something cast a shadow but you couldn’t see it, you’d be intrigued. If it did that on the scale of the universe, you’d be perplexed. If you then couldn’t find it despite your best efforts, you’d likely be frustrated. This is the situation that scientists looking for dark matter find themselves in. But dark matter doesn’t even cast shadows; it’s invisible to all electromagnetic radiation. And yet we have solid evidence that it exists. In fact, current calculations show that it comprises 80 per cent of all of the mass in the universe. Now a new study…

Dark matter DARK MATTER VS DARK ENERGY Even more mysterious than dark matter is a phenomenon in the universe called dark energy Invisible matter Scientists think that dark matter may be like ordinary matter, only invisible and non-interacting. However, we don’t know. We could be completely mistaken, and it could be something else entirely, yet to be theorised. It has a gravitational effect Like ordinary matter, its dark counterpart has a gravitationally attractive effect on its surroundings. This can be seen in the gravitational lensing of large galaxies and galaxy clusters. It was seen in the 19th century Lord Kelvin first noted the peculiar motions of stars in the Galactic Centre, concluding in 1884 that a large number of ‘unseen dark bodies’ were present and causing the gravitational effects. Voyager…

Mini-moons EARTH’S LITTLE MOONS Our Solar System’s planets have more than one moon - even ours on occasion 1 Temporary visitors A typical mini-moon will orbit the Earth for around nine months, although some could stay in orbit for decades or more before being recaptured into orbit around the Sun. 2 More than one moon The Moon isn’t our only natural satellite. Asteroids orbiting the Sun can temporarily become mini-moons, following a complex path around Earth. 3 A complex journey As they are tugged in different directions by the Earth, Moon and Sun, mini-moons follow complicated paths rather than neat elliptical orbits. 4 A confirmed mini-moon In 2006 the car-sized mini-moon ‘RH120’ was discovered. It orbited Earth for less than a year before returning to the Sun’s more powerful gravity.…

Perseverance MEET PERSEVERANCE AND INGENUITY Here’s how the rover and drone will operate on the surface of Mars 1 Mastcam-Z Used for: Imaging Mars Operated by: Arizona State University Located on top of the rover’s ‘mast’, this camera system will take high-definition videos and images of Mars, including images in 3D. 2 Mars Environmental Dynamics Analyzer (MEDA) Used for: Weather monitoring Operated by: National Institute for Aerospace Technology, Spain This instrument will measure the Martian weather, including wind speed, temperature, humidity and even dust particles in the surrounding atmosphere. 3 Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) Used for: Making oxygen Operated by: Massachusetts Institute of Technology MOXIE will take carbon dioxide out of the Martian atmosphere and see if it can turn it into oxygen, which could be useful…

Perseverance PERSEVERANCE VS PREVIOUS MARS ROVERS © NASA/JPL-Caltech © NASA/JPL-Caltech 1 Sojourner Weight: 11 kilograms Date launched: 1996 Size of rover: 65 centimetres (26 inches) long Still in operation?: No Notable achievements: First rover on Mars. Took hundreds of images 2 Spirit and Opportunity Weight: 180 kilograms Date launched: 2003 Size of rover: 1.6 metres (5.2 feet) long Still in operation?: No Notable achievements: Found evidence of water and past volcanic activity 3 Curiosity Weight: 900 kilograms Date launched: 2011 Size of rover: Three metres (ten feet) long Still in operation?: Yes Notable achievements: Found evidence for past habitable Martian environments 4 Perseverance Weight: 1,025 kilograms Date launched: 2020 Size of rover: Three metres (ten feet) long Still in operation?: Start date 18 February 2021 Notable achievements: N/A…

Titan WEIRD DISCOVERY ON TITAN A newfound molecule has raised hopes that Saturn’s largest moon hosts the building blocks needed for life Reported by Nina Notman © Tobias Roetsch Are we alone in the universe? Humanity has been pondering the answer to this question for many years now, but no evidence has been found that we aren’t - at least not yet. But it’s not for lack of trying. Recent decades have seen us employ increasingly sophisticated telescopes and space missions in the search for alien life. We use tools able to listen out for radio and light messages that may be being sent from intelligent life forms. And other instruments are able to hunt celestial bodies, in our Solar System and beyond, for molecules that could potentially indicate the…

User Manual Arecibo Observatory USER MANUAL Arecibo Observatory Prior to its decommissioning and sudden collapse, this huge dish made many invaluable contributions to astronomy THE SPECS Dish diameter: 305 metres (1,000 feet) Curvature radius: 265 metres (870 feet) Number of panels: 38,778 Transmission power: 20TW at 2380MHz Receiver weight: 900 tonnes Receiver height: 150 metres (492 feet) Official opening: 1 November 1963 Decommission order: 19 November 2020 Welcome to the National Astronomy and Ionosphere Center, better known as the Arecibo Observatory. The observatory’s 305-metre (1,000-foot) radio telescope dish was completed in 1963, but in November 2020 it was flagged for decommissioning and eventual demolition. Until 2016 it was the world’s largest singleaperture telescope, and it was involved in many exciting radio astronomy discoveries, as well as collecting data in an…

STARGAZER What’s in the sky? ESSENTIAL GUIDES AND ADVICE FOR AMATEUR ASTRONOMERS Red light friendly In order to preserve your night vision, you should read our observing guide under red light Jargon buster Conjunction A conjunction is 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. Right Ascension (RA) Right Ascension is to the sky what longitude is to the surface of the Earth, corresponding to east and west directions. It is measured in hours, minutes and seconds since, as the Earth rotates on its axis, we see different parts of the sky throughout the…

STARGAZER Astroshots of the month Get featured in All About Space by sending your astrophotography images to space@spaceanswers.com Warren Keller Location: West Virginia, US Telescope: 16-inch RCOS Ritchey-Chrétien owned by the University of North Carolina “A child of the 1960s – Star Trek, 2001: A Space Odyssey – I boldly went with my heroes ‘where no man [had] gone before’, and I never really touched down again. I began exploring the night sky at 15 with an eightinch Newtonian and I knew I would someday photograph the wonders of the heavens. “I started out using film in 1998, and then I switched to a charged-coupled device (CCD) in 2003. I am artistic by nature, so it’s less about the cosmology and more about the thrill of the hunt for the…