All About SpaceNo. 119的目錄

WELCOME What if there was an equal but opposite to everything in the universe? That’s one thing that scientists are faced with, as we discover this issue: could there be galaxies peppered throughout space and time that are equal and opposite to each other, creating a symmetry throughout the cosmos? Let me introduce you to antimatter galaxies. Not long after the Big Bang, there were roughly equal amounts of matter and antimatter, with a bit more of an excess of the former. When the two crashed together, they annihilated, or ‘cancelled’, each other out. In our cover feature, we take a look at whether galaxies can be made up of antimatter – and the plans to find them. Turn to page 16 for the details. Elsewhere in the issue, we…

‘MISSING LINK’ EXPLOSION ON THE SUN COULD UNRAVEL LONG-STANDING SOLAR MYSTERIES Words by Chelsea Gohd ©NASA An explosion on the Sun is helping uncover new information about what causes powerful solar eruptions. In March 2016, scientists used NASA’s Solar Dynamics Observatory and the Solar and Heliospheric Observatory, a joint mission of NASA and the European Space Agency (ESA), to observe an explosion on the Sun. The event showed characteristics of three different types of solar eruptions that usually happen separately, but occurred together this time. “This event is a missing link where we can see all of these aspects of different types of eruptions in one neat little package,” said Emily Mason, a solar scientist at NASA’s Goddard Space Flight Center in Maryland. There are typically three different varieties of…

BOULDERS ON ASTEROID RYUGU ARE SURPRISINGLY FLUFFY, HAYABUSA2 FINDS Words by Charles Q. Choi Boulders on asteroids can be three-quarters hollow or more, a discovery that could help yield insights on how Earth and other planets formed. The earliest stage of planetary formation started with building blocks known as planetesimals, chunks of rock ranging in size from asteroids to dwarf planets. Research suggested planetesimals began as very porous, fluffy clumps of dust that heat, gravity and impacts compacted over time. Japan’s Hayabusa2 spacecraft found that Ryugu, a diamond-shaped near-Earth asteroid, is covered with rocks that are about 30 to 50 per cent porous. Now scientists have found that those boulders may be more than 70 per cent empty space, or about as porous as prior work suggested ancient planetesimals were,…

Antimatter galaxies LARGE HADRON COLLIDER Inside the most famous particle accelerator ©NASA ALPHA The Antihydrogen Laser PHysics Apparatus makes, captures and studies atoms of antihydrogen and compares them with hydrogen atoms 1 ANTIPROTONS Antiprotons enter through one end of the device. 2 POSITRONS Positrons enter through the other end. 3 COLLISION COURSE Antihydrogen is made when they collide. 4 WALLED IN The device delays annihilation with the walls of the detector. 5 PRESERVATION Antihydrogen can be kept for 16 minutes and studied. x3 illustrations © Adrian Mann AD The Antiproton Decelerator is a source of antiprotons for use in other antimatter experiments at the LHC BEAM TO BLOCK 6 A powerful proton beam is fired into a block of metal. PARTICLE PRODUCTION 7 A shower of particles is produced, including…

Solar System EVERYTHING YOU NEED TO KNOW ABOUT… THE SOLAR SYSTEM Join us on a tour through our current understanding of the planetary system we call home Reported by Giles Sparrow © Nicholas Folder INTRODUCING THE SOLAR SYSTEM Our Solar System consists of the area influenced by the Sun and, apart from occasional stray visitors from interstellar space, everything it contains. Aside from the Sun, its main components are the eight major planets, their moons and rings, a handful of worlds classified as dwarf planets and vast numbers of smaller bodies made of varying amounts of rock and ice, which are broadly termed asteroids and comets. Most of these objects orbit in a plane roughly in line with the Sun’s equator and in the same direction as the Sun’s rotation…

Solar System THE EIGHT MAJOR PLANETS © Getty MERCURY Diameter: 4,879 kilometres (3,032 miles) Mass: 0.055 Earths Distance from the Sun: 46 to 69.8 million kilometres (28.6 to 43.4 million miles) Orbital period: 88 days Rotation period: 58.65 days Axial tilt: 0.03 degrees Satellites: Zero VENUS Diameter: 12,104 kilometres (7,521 miles) Mass: 0.815 Earths Distance from the Sun: 107.5 to 108.9 million kilometres (66.8 to 67.7 million miles) Orbital period: 224.7 days Rotation period: 243.02 days Axial tilt: 177.36 degrees Satellites: Zero EARTH Diameter: 12,742 kilometres (7,918 miles) Mass: 5.97 billion trillion tonnes Distance from the Sun: 147.1 to 152.1 million kilometres (91.4 to 94.5 million miles) Orbital period: 365.256 days Rotation period: 23 hours and 56 minutes Axial tilt: 23.44 degrees Satellites: One MARS Diameter: 6,779 kilometres (4,212 miles)…

AMAZING MUONS Muons are the cousins of electrons, but what else do we know about them? ©Getty 1 THEY DON’T LIVE LONG Muons have an average lifetime of just 2.2 microseconds. To put that into perspective, there are a million microseconds in a second. 2 THEY CAN PASS THROUGH OBJECTS And that includes you! Muons have strong penetrative power, and about 10,000 of them pass through our bodies every minute. 3 THEY CAN BE MADE IN A LAB Although muons were discovered in 1936 as a product of cosmic rays hitting the atmosphere, they can also be made in particle accelerators. 4 THEY ARE RATHER HEAVY In comparison to electrons, at least. Although muons have the same negative charge as electrons, they have 207 times the mass. 5 THEY DECAY…

Focus on Accurate clocks MORE ACCURATE CLOCKS MAY ADD MORE DISORDER TO THE UNIVERSE All clocks create entropy, but accuracy might come at a higher cost Reported by Ben Turner Entropy – or disorder – is created every time a clock ticks. Now scientists working with a tiny clock have proven a simple relationship: the more accurate a clock runs, the more entropy it generates. “If you want your clock to be more accurate, you’ve got to pay for it,” said Natalia Ares, a physicist at the University of Oxford. “Every time we measure time, we are increasing the universe’s entropy.” As we go forwards in time, the second law of thermodynamics states that the entropy of a system must increase. Known as the ‘arrow of time’, entropy is one…

ASK Space Our experts answer your questions © NASA/JPL-Caltech, ESO ASTROPHYSICS Do all galaxies have a black hole at the centre? It sure seems that way! The centre of every galaxy we’ve been able to examine in detail has proved to be the host of a supermassive black hole. The most famous recent addition to our understanding is the directly imaged shadow of the supermassive black hole in the centre of Messier 87. At 6 billion times the mass of our Sun, M87’s black hole is a tremendously large object. But what of other, more distant galaxies where we can’t go look directly? M87 gives us a clue. In addition to being able to see the shadow of the black hole directly, its supermassive black hole also drives a thin…

STARGAZER MOON TOUR EARTHSHINE See the beautiful ‘old Moon in the new Moon’s arms’ ©ESO Take a quick look at any map of the Moon and you will see that it is covered with many fascinating features, some even visible to the naked eye. On any night when our planet’s natural satellite is visible in your sky, you will be able to look at it through a telescope, or even just a pair of binoculars, and peer down into the dark depths of its dramatic craters, see sunlight bathing the jagged peaks of its magnificent mountain ranges and, of course, roam its dark seas of ancient, frozen lava. Sometimes though, the Moon itself is the star of the show. The sight of a bloated full Moon rising from behind the…

LAUNCH PAD YOUR FIRST CONTACT WITH THE UNIVERSE ©NASA 16 JUNE 2021 Against the clock European Space Agency (ESA) astronaut Thomas Pesquet was manoeuvred by the Canadarm2 robotic arm during a spacewalk to install new roll-out solar arrays on the International Space Station. Pesquet was joined by NASA astronaut Shane Kimbrough on the spacewalk, which lasted just over seven hours. Despite initially making good progress, an interference issue with another piece of equipment prevented the pair unfolding the solar array fully, running out of time. The pair resumed their efforts four days later with a six-and-a-half hour spacewalk, and the arrays were successfully deployed. © ESA/Hubble & NASA 21 JUNE 2021 Rich galactic tapestry The heart of the Milky Way is captured here in unprecedented detail. Ribbons of superheated gas…

SCIENTISTS 3D PRINT HUMAN LIVER TISSUE IN A LAB AND WIN TOP PRIZES IN NASA CHALLENGE Words by Chelsea Gohd Scientists have grown liver tissue capable of functioning for 30 days in the lab as part of NASA’s Vascular Tissue Challenge. In 2016 NASA put forth this competition to find teams that could ‘create thick, vascularised human organ tissue in an in-vitro environment to advance research and benefit medicine on long-duration missions and on Earth’. On 9 June the agency announced two winners of the challenge. The teams, both made up of scientists from the Wake Forest Institute for Regenerative Medicine (WFIRM) in North Carolina, won first and second place in the competition with different approaches to creating lab-grown human liver tissue. The winning teams both used 3D-printing technologies to…

RELATIVITY SPACE UNVEILS FULLY REUSABLE, 3D-PRINTED TERRAN R ROCKET Words by Mike Wall A fully reusable, 3D-printed rocket will be launching satellites into orbit three years from now – if all goes according to plan. Relativity Space has revealed details of Terran R, a new two-stage rocket expected to launch for the first time in 2024. The engines, which burn liquid oxygen and methane, are 3D printed, just like the rest of the rocket. This manufacturing strategy allows Relativity Space to build rockets with 100 times fewer parts than those of its competitors and churn out a completed vehicle in less than 60 days. Terran R will be 66 metres (216 feet) tall by 4.9 metres (16 feet) wide, with the ability to lift more than 20,000 kilograms to low-Earth…

Future tech Orbital service station ORBITAL SERVICE STATION If rockets could be refuelled in space, it could open up interplanetary travel © Adrian Mann Following SpaceX’s first successful landing of its Starship test vehicle and the award of a NASA contract for a lunar lander based on Starship, it’s looking increasingly likely that a Starship will reach orbit in 2021. When launched on its booster stage ‘Super Heavy’, it will become the largest launch vehicle yet, capable of placing up to 150 tonnes into orbit. But once it has done that it will have exhausted its propellants, and the driving purpose of Starship, and indeed SpaceX itself, is to provide cost-effective transport to Mars. The first challenge was to dramatically reduce the cost of reaching space, and SpaceX set about…

AN ACQUIRED TASTE While the choice of refreshments for astronauts has grown considerably in recent years, they continue to crave the spicier things in life – specifically hot sauce. Since the 1960s astronauts have noted that their taste buds don’t work as effectively in space, and it’s not uncommon for astronauts to find themselves enjoying cuisines in space that they couldn’t eat at home, and vice versa. As such, a lot of work has gone into researching the science behind this and coming up with meals that satisfy the astronauts’ hunger as well as enjoyment of the food itself. Despite the continually updated menus and food choices, nothing seems to beat a good spicy sauce, or really any condiment that can add that extra kick of flavour. Former astronaut Peggy…

Muons HAVE SCIENTISTS DISCOVERED A FIFTH FORCE OF NATURE? REVOLUTIONARY EXPERIMENTS MAY POINT TO A NEW FORCE, OR AN UNDISCOVERED SUBATOMIC PARTICLE ©Alamy For over 50 years, scientists have found that the Standard Model of particle physics has performed well in the face of rigorous testing. It has been able to accurately predict the behaviour of the universe’s fundamental particles, as shown in numerous experiments, and has proven more than capable time and time again of explaining three of the four known forces of nature. Even so, scientists have long known that it isn’t perfect. The rule book describes electromagnetism as well as weak and strong interactions, yet it lacks a description of gravity. “It does not explain how the universe we live in is made of matter when presumably…

SOLVING CASES What could the potential discovery tell us about the universe? WHY IS THERE SO MUCH DARK MATTER? About 68 per cent of the universe is made up of dark energy, while dark matter – which is thought to be the stuff that binds galaxies together – makes up about 27 per cent, the rest being everything we can observe. But why is there so much dark matter out there, causing galaxies to rotate faster than the gravity generated by their observable matter? It’s a mystery that has occupied scientists for many years, yet the possibility that new particles exist may provide a connection that goes some way to explaining what dark matter is and how it functions. WHERE HAS ALL THE ANTIMATTER GONE? As the name suggests, antimatter…

STAR PROFILE MIRA This variable star is the queen of hide and seek ©Getty From one of the brightest stars in the entire sky to one of the dimmest, Mira’s dazzling qualities have been fascinating scientists for centuries. Located 350 light years away in the constellation of Cetus (the Whale), Mira – officially designated Omicron Ceti – lies on the celestial equator, and can therefore be seen from the entire Earth, but only when it is visible, which is not very often. This intriguing celestial object is an intrinsic variable star, meaning it differs in brightness, and this variety is caused by the fundamental structure of the star. Mira’s brightness fluctuates on a regular schedule, with a peak in luminosity roughly every 11 months. At its dimmest, Mira is a…

STARGAZER WHAT’S IN THE SKY? “DURING OPPOSITION, AN OBJECT IS VISIBLE FOR THE WHOLE NIGHT” 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 night. Declination (Dec) This tells you how high an object will rise in the sky. Like…

STARGAZER IN THE SHOPS The latest books, apps, software, tech and accessories for space and astronomy fans alike FOR YOUR HOME BAR GALAXY DUST RUM LIQUEUR Cost: £19.99 / $29 From: firebox.com 1 According to scientists, Sagittarius B2 – a giant c loud of gas and dust 390 light years from the centre of the Milky Way – ‘smells’ like rum and ‘tastes’ like raspberries. Why not treat yourself to a drink that captures the essence of our galaxy. Enjoy it neat or make your own cosmic cocktails – all in the name of science. Made from an exquisite blend of white rum and sweet tart raspberries, this liqueur shimmers like stardust when you give it a swirl. This vegan-friendly rum liqueur is a guaranteed crowd pleaser. The 50cl bottle…

LAUNCH PAD YOUR FIRST CONTACT WITH THE UNIVERSE EARTH’S CORE IS GROWING ‘LOPSIDED’, AND SCIENTISTS DON’T WHY Words by Brandon Specktor There’s a mystery brewing at the centre of the Earth. Scientists can only see it when they study seismic waves passing through the planet’s solid-iron inner core. For some reason, waves move through the core significantly faster when they’re travelling between the North and South Poles than when they’re travelling across the equator. Researchers have known about this discrepancy, known as seismic anisotropy, for decades, but have been unable to come up with an explanation that’s consistent with the available data. Now, using computer simulations of the core’s growth over the last billion years, a recent study offers a solution that finally seems to fit: every year, little by…

LAUNCH PAD YOUR FIRST CONTACT WITH THE UNIVERSE EARTH’S AURORA ORIGIN MYSTERY SOLVED BY ‘SURFING’ ELECTRONS Words by Daisy Dobrijevic ©Getty Earth’s aurorae are caused when electrons emitted from the Sun hurtle towards Earth and are funnelled down Earth’s magnetic field lines, where they collide with oxygen and nitrogen molecules in the ionosphere – the upper atmosphere between 80 and 600 kilometres (50 and 370 miles). The absorption of energy by these ions causes them to move to an ‘excited’ high-energy state. To relax, the molecules reradiate the energy as light, producing impressive auroral displays. Though scientists understand what causes aurorae, a mystery remains – just how do these electrons accelerate to speeds of up to 72 million kilometres (45 million miles) per hour on the last stretch of their…

Antimatter galaxies ANTIMATTER GALAXIES HAS THE IMPOSSIBLE EXISTENCE OF THESE OBJECTS JUST BECOME POSSIBLE? Reported by Colin Stuart © Tobias Roetsch You shouldn’t exist. That you do suggests something is very wrong with our best theories in physics. Yet there is a way to both explain your existence and save theorists’ blushes: if bizarre entities called antimatter galaxies also exist. In the beginning there was nothing, only energy. Our universe burst into existence 13.8 billion years ago in the Big Bang, and soon some of the energy was converted into particles. The kind of particles that are the building blocks of atoms, which in turn are the building blocks of you. We call this stuff matter. Except that’s only half the story. The process of converting energy into stuff is…

Focus on Gamma-ray burst WEIRD NEARBY GAMMA-RAY BURST DEFIES EXPECTATIONS This isn’t how they’re supposed to behave Reported by Meghan Bartels Scientists have gotten their best look yet at a gamma-ray burst, the most dramatic type of explosion in the universe. Astronomers think some of these explosions occur when a massive star – five or ten times the mass of our Sun – detonates, abruptly becoming a black hole. Gamma-ray bursts may also occur when two superdense stellar corpses called neutron stars collide, often forming a black hole. And, conveniently, a gamma-ray burst that scientists watched during a few nights in 2019 likely occurred only about 1 billion light years away from Earth, relatively close by for these dramatic events. “We were really sitting in the front row when this gamma-ray…

FANCY SPACE TIPPLE? NOT ON NASA’S WATCH Booze is strictly forbidden on the ISS for a whole number of reasons. An inebriated astronaut in control of a billion-dollar space station hurtling through space isn’t a very good idea, but alcohol can also damage the ISS in other ways. Alcohol-containing products such as mouthwash and hand sanitiser are also banned, as the alcoholic compounds they contain affect the station’s water-recovery system. Ethanol is a volatile compound and could cause damage to valuable equipment on the ISS. Despite the dangers of alcohol in space, it wasn’t always taboo. At the start of the Space Race, alcoholic drinks were included in cosmonaut rations. Small amounts of cognac were said to be recommended by Russian doctors to help the immune system. The ban only…

Focus on JUPITER’S OCEAN MOON EUROPA MAY HAVE DEEP-SEA VOLCANOES Jupiter moon may be an even more promising abode for life than scientists thought Reported by Mike Wall A new study suggests volcanoes may lurk on the seabed of Europa, which harbours a vast ocean of salty water beneath its icy shell. Active volcanoes could power deep-sea hydrothermal systems, environments rich in chemical energy that potential Europa life forms could exploit. “Our findings provide additional evidence that Europa’s subsurface ocean may be an environment suitable for the emergence of life,” said Marie Běhounková of Charles University in the Czech Republic. “Europa is one of the rare planetary bodies that might have maintained volcanic activity over billions of years, and possibly the only one beyond Earth that has large water reservoirs…

MYSTERIES OF THE UNIVERSE Exoplanet size gap ARE EXOPLANETS SHRINKING WITH AGE? ASTRONOMERS MAY BE CLOSER THAN EVER TO KNOWING WHY SUPER-EARTH EXOPLANETS ARE SO SCARCE Reported by David Crookes ©Tobias Roe tsch As we all know, planets come in many different sizes, and you only have to look at our Solar System to see how varied they can be. Just take Mercury as the smallest, for example, and Jupiter as the most humongous. If you had enough Mercurys at your disposal, you could take 24,462 of them and pack them tightly into Jupiter. For comparison, you could do the same with 1,300 Earths. Interestingly, though, there is a size gap. Try as you may, you’re not going to find too many planets anywhere in the universe that are between 1.5…

THE THEORIES What could be causing mini-Neptunes to lose their atmospheres? EXOPLANETS ARE NOT LOSING THEIR ATMOSPHERES According to David, this theory suggests that super-Earths are not the product of planets that have lost their atmospheres. Instead the theory explains that they avoided accreting atmospheres to begin with: “In this theory, whether or not a planet becomes a rocky super-Earth or a gaseous mini-Neptune depends on whether or not the core formed early enough to accrete and hold onto a substantial amount of gas.” ©ESO IT’S CAUSED BY HIGH-ENERGY RADIATION This assumes that the exoplanets have accreted atmospheres. As David says, the accretion will have happened when the gaseous protoplanetary disc was still around – that is, in the first 10 million years. In this theory, X-ray and ultraviolet radiation,…

STARGAZER THIS MONTH’S PLANETS Jupiter takes pride of place in the dawn sky for early risers, while Mars and Venus grace the twilight PLANET OF THE MONTH JUPITER Constellation: Aquarius Magnitude: -2.7 AM/PM: AM Our Planet of the Month this issue is the largest planet in the Solar System: mighty Jupiter. Between mid-July and mid-August Jupiter will be visible all through the night. Rising in the ESE at around 22:00, looking like a blue-white ‘star’, it will then trace out a low arc across the southern sky during the night, eventually fading from view as the light of the approaching dawn washes it from the western sky. Though Jupiter will be shining at magnitude -2.7, at this time of year, thanks to summer’s late sunsets and early sunrises, the sky…

STARGAZER Deep sky challenge STARS, CLUSTERS AND NEBULAE OF SUMMER Glittering stellar groupings, a star’s corpse and a beautiful double star can be seen through any size of telescope © ESA/Hubble & NASA Many think the summer sky is too bright to allow observation of ‘faint’ and ‘fuzzy’ deep-sky objects, but if you stay up late the sky is just dark enough to let you see some lovely sights. Around one and two in the morning – providing the sky isn’t lit up with a display of bright blue and silver noctilucent clouds – a telescope will give you very pleasing views of some of astronomy’s most famous objects. Although the broad, frothy band of the Milky Way dominates the sky, running right through the centre of Cygnus (the Swan), or…