All About Space 107 (Sampler) by Future PLC

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HISTORY OF NASA • EVENTS THAT CHANGED THE WORLD • 60 SECOND SCIENCE

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INSIDE MET YOUR COE IMAGES NEOWIS

ON BOARD A TOP-SECRET SPACE SHUTTLE

THE CRASH THAT MADE

New image space’s biggest star Instant Expert WHAT IS ZODIACIAL LIGHT?

Secrets of a Solar System collision that sparked life on Earth

ISSUE 107

REVEALED

APOLLO 11’S FIRST MAN

The story of Neil Armstrong’s daring astronaut training

ALIEN CONTACT ACTION PLAN EINSTEIN CHALLENGED

IS SPACE-TIME THEORY WRONG?

NASA PHOTOS OUR SUN AS YOU’VE NEVER SEEN IT BEFORE

End of space and time

IS THIS THE END OF SPACE AND TIME? To better understand the universe we may need to kill off Einsteinâ&#x20AC;&#x2122;s long-standing theory

End of space and time

Above: Black holes bend space and time with their great masses

cat hinges on that measurement, but quantum physics says that until such a measurement is made the particle is simultaneously in both states, which means the vial is both broken and unbroken and the cat is alive and dead. Such a picture cannot be reconciled with a smooth, continuous fabric of space-time. “A gravitational field cannot be in two places at once,” says Sabine Hossenfelder, a theoretical physicist at the Frankfurt Institute for Advanced Studies. According to Einstein, space-time is warped by matter and energy, but quantum physics says matter and energy exist in multiple states simultaneously – they can be both here and over there. “So where is the gravitational field?” asks Hossenfelder. “Nobody has an answer to that question. It’s kind of embarrassing,” she says. Try and use general relativity and quantum theory together and it doesn’t work. “Above a certain energy you get probabilities that are larger than one,” says Hossenfelder. One is the highest probability possible – it means an outcome is certain. You can’t be more certain than certain. Equally, calculations sometimes give you the answer infinity, which has no real physical meaning. The two theories are therefore mathematically inconsistent. So, like many monarchs throughout Do

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Below: Newton came up with his ideas on gravity after seeing an apple fall

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s in history, revolutions are the lifeblood of science. Bubbling undercurrents of disquiet boil over until a new regime emerges to seize power. Then attention turns to toppling the new ruler. The king is dead, long live the king. This has happened many times in the history of physics and astronomy. First we thought the Earth was at the centre of the Solar System – an idea that stood for over a thousand years. Then Copernicus stuck his neck out to say we are just another planet orbiting the Sun. Despite much initial opposition, the old geocentric picture buckled under the weight of evidence from the newly invented telescope. Then Newton came along to explain that gravity is why the planets orbit the Sun. He said all objects with mass have a gravitational attraction towards each other. According to his ideas we orbit the Sun because it is pulling on us, and the Moon orbits Earth because we are pulling on it. Newton ruled for two-and-a-half centuries before Albert Einstein turned up in 1915 to usurp him with his general theory of relativity. This new picture neatly explained inconsistencies in Mercury’s orbit, and was famously confirmed by observations of a solar eclipse off the coast of Africa in 1919. Instead of a pull, Einstein saw gravity as the result of curved space. He said that all objects in the universe sit in a smooth, four-dimensional fabric called space-time. Massive objects such as the Sun warp the space-time around them, and so Earth’s orbit is simply the result of our planet following this curvature. To us that looks like a Newtonian gravitational pull. This space-time picture has now been on the throne for over 100 years and has so far vanquished all pretenders to its crown. The discovery of gravitational waves in 2015 was a decisive victory, but like its predecessors, it too might be about to fall. That’s because it is fundamentally incompatible with quantum theory. The quantum world is notoriously weird. Single particles can be in two places at once, for example. Only by making an observation do we force it to ‘choose’. Before an observation we can only assign probabilities to the likely outcomes. In the 1930s Erwin Schrödinger devised a famous way to expose how perverse this idea is. He imagined a cat in a sealed box accompanied by a vial of poison attached to a hammer. The hammer is hooked up to a device that measures the quantum state of a particle. Whether or not the hammer smashes the vial and kills the

Interview Dr Nour Raouafi

INTERVIEW BIO

Dr Nour Raouafi

Raouafi is a Tunisian astrophysicist at Johns Hopkins Univerisity’s Applied Physics Laboratory (APL) in Maryland and the project scientist for NASA’s Parker Solar Probe mission. He is an expert in many solar and heliospheric topics, including solar magnetic fields, coronal plumes and jets, coronal mass ejections (CMEs), solar wind, solar energetic particles and many other areas. For the last two years the Parker Solar Probe has been beaming back unique data sets while breaking records when it comes to how close a human-made object has been to the Sun and how fast it travels. Its latest encounter reached within 18.7 million kilometres (11.6 million miles) of the Sun and sped past at 393,000 kilometres (244,225 miles) per hour.

Dr Nour Raouafi

PARKER SOLAR PROBE: TWO YEARS ON

“THIS COMING DECADE WILL BE THE GOLDEN AGE OF SOLAR AND HELIOPHYSICS RESEARCH” All About Space catches up with the project scientist for NASA’s incredible Parker Solar Probe mission, Dr Nour Raouafi – a spacecraft continuously breaking records and surpassing all expectations as it orbits the Sun Interviewed by Lee Cavendish

What is the major mystery surrounding the Sun and its corona that astronomers are desperately trying to solve, and are hoping the Parker Solar Probe will help shed light on? There are a few phenomena that were discovered decades ago, but we are still struggling to understand. I think the one that is most puzzling is what we call the ‘coronal heating problem’. The corona, which is the outermost layer of the solar atmosphere, is 300-times hotter than the solar surface. And we know that all the energy is coming from inside the Sun, so in a way it’s counter-intuitive that the source is cooler than the environment around it. But the Parker Solar Probe is giving us clues and hints as to what might be causing excess heating there. Another phenomenon, which is very closely related to coronal heating as well, is what we call the acceleration of solar wind. The solar wind is a flow of charged particles – electrons, protons,

ionised helium and heavy elements – that are constantly flowing away from the Sun to the rest of the Solar System. The issue with the solar wind is that low down [within the solar atmosphere] these particles are flowing at very slow speeds, but they get accelerated to hundreds of kilometres per second in a very short distance. We don’t know exactly what is the physical mechanism that gives them the energy to accelerate to these high speeds. The third phenomenon, and we are impacted by it every day, is big explosions on the Sun. Whenever there is a flare or a coronal mass ejection (CME) erupting on the Sun, there is a population of particles that get accelerated to almost the speed of light. We call them solar energetic particles. The Parker Solar Probe was built specifically to be able to shield its instruments in a really dangerous environment. How has its heat shield been constructed so that it can withstand such dangerous temperatures and radiation while remaining relatively lightweight? The heat shield is basically made of carbon foam. Most of it is a vacuum. It’s like a sponge made out of carbon that is sandwiched between two sheets, which are also compressed carbon. The other thing that is specific to the Parker Solar Probe is a plasma spray that is white and is on top of the heat shield. The goal here is to reflect as much light from the Sun as possible. When we are closest to the Sun in 2024, that side of the heat shield will be more than 2,500 degrees

Fahrenheit [1,371 degrees Celsius]. 4.5 inches (11.5 centimetres) inward, which is the other side of the heat shield, will be at almost 700 degrees Fahrenheit [371 degrees Celsius], so there we have already lost a lot of heat. And from that backside of the heat shield to the bus, where the instruments are mounted, it is at room temperature.

Right: The closest-ever approach to the Sun planned for the Parker Solar Probe will occur in 2024.

How’s the Parker Solar Probe doing? Are there any updates that we should be aware of? The Parker Solar Probe is doing great. We are going through our fifth encounter and recently we were the closest we’ve ever been to the Sun. After a period of five days where we could not communicate with the spacecraft, it sent us a signal that it’s healthy and it’s doing what it’s supposed to do. In terms of science, it’s just amazing. Whenever the spacecraft gets closer to the Sun, we are learning new things that we’ve never seen before.

Antares

HOW

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ANTARES?

Antares

Using the best radio telescopes in the world, this local red supergiant star has recently been mapped in extraordinary detail Below: ALMA currently holds the title of the world’s largest radio telescope

Reported by Lee Cavendish

he night sky, especially when viewed from an area with low to no light pollution, can reveal a beautiful array of celestial gems – twinkling stars that generations before have marvelled at. The difference between then and now is that our generation has the capability to map these stars with precision. New research has taken this to a whole new level by mapping the famous star Antares, learning more about its atmosphere and how this can be applied to other red supergiant stars. Throughout the years people have gazed upon ruddy Antares, the brightest star in the constellation of Scorpius and one of the brightest stars in the night sky, which lies 554 light years from Earth. As telescopes, spectroscopy and multi-wavelength observations have become more advanced, we have been able to learn more about the stars. Scientists have been able to categorise Antares as a red supergiant star that has swollen as it approaches the end of its life, despite it being only 11 million years old. By comparison the Sun is 4.6 billion years old. This is because Antares weighs 12 solar masses – 12 times the mass of our Sun – and with stars the biggest and brightest burn out the quickest. Astronomers have deduced over many years of visible-light observations that Antares is approximately 700-times wider than the Sun, and previous research into its climate has suggested that the temperature of the red supergiant star’s chromosphere should be between 5,700 and 12,700 degrees Celsius (10,000 and 22,900 degrees Fahrenheit). Now the plot has thickened as researchers have been able to map the atmosphere of Antares with unprecedented levels of precision, revealing unusually cool regions residing in localised bubbles in addition to highlighting the true extent of the star’s impressive stellar wind. This research was only made possible by utilising two of the

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The wavelength range that Antares was observed in using the two radio telescopes.

Alien contact Upcoming projects like the Square Kilometre Array will further our knowledge and bring us closer to a discovery that many think is on the horizon. To look for signals, astronomers point telescopes to distant stars and listen for irregular patterns on a particular frequency, focusing on radio waves. If an anomaly is found the signal is observed again, and if it disappears it was likely just interference from something on Earth, like a satellite. If the signal is heard five times from the same point of sky, then things get interesting. At this point the signal would appear to be of alien origin. The SETI Institute uses an automated system to sift through thousands of signals per hour, just ten per cent of which pass the first cut. None of these, of course, have ever passed the final cut, but there have been an estimated 300 million interesting signals found over the years.

SETI’s strict protocols usually mean a signal is ruled out as being sent by aliens before the information is leaked to the public. But one day a signal may very well pass these tests. Despite the far-reaching ramifications of this discovery, it will almost certainly be treated like any other scientific finding. Gradually various institutions and organisations will be alerted, and then the fun can begin. “It would be a race to see who would be the first to make sense of the signal,” says Harp. “There’s a Nobel Prize in unlocking that language.” The first step will be to determine if the signal is just generic noise, like the radio transmissions we send out daily, or a directed message containing a signal. If it’s the former then the message will serve simply to tell us that we are not alone, and perhaps we could pick up more errant signals from this distant civilisation. If it’s the latter, however, there

“ The question of whether we are alone is arguably one of the greatest unsolved mysteries, and the impact of an answer would be far-reaching”

may very well be some sort of key, or crib, hidden within that can help us decipher it. “If it has a crib, a directed message, maybe a hello from someone else, then we have a very good chance of deciphering it,” says John Elliott from Leeds Beckett University, who is a member of the UK SETI Research Network and has spent much of his research career working out how we’d decipher an alien signal. “It’s a bit like meeting someone in the Amazon rainforest who is from a tribe that has never had contact from the outside world. You’ve only got to point at a tree and say ‘tree’, or point at a rock and say ‘rock’, for them to understand that word means that object. That’s what the crib would have to do.” Assuming we could decipher it, then things get truly interesting. A heated debate is almost certain to spring up on whether we should respond or not. Many have argued either side of the coin, with some worrying that revealing our presence could invite hostile aliens to come here, pillage our land and destroy humanity. Others are more optimistic, noting that the distances involved would likely be too great to travel over. And if we’ve spent so much time discovering we’re not alone, why would we not respond? “I’m firmly in the camp of yes, we should reply,” says Elliott. “I honestly think not to do that would be a waste. The whole point is we want to

Above: China’s Fivehundred-meter Aperture Spherical Radio Telescope is a sensitive listening device

Alien contact

An alien discovery

How do we know if we’ve made contact?

How the detection of a signal might change life on Earth Politics

Religion

There will be discussions on how humanity should be represented – if we even respond.

Gerry Harp, director of the Center for SETI Research, reveals what we would expect to see

Some religions may deny the discovery. Others may embrace it within their beliefs.

What are we looking for? We’re looking for signals that are clearly artificial. We have lots of ways we communicate using radio on Earth, and in principle ET might use the same. But the interstellar medium – the gas between stars – messes up signals, so we look for narrow-frequency bandwidth signals. How would we verify a signal is real? The signal has to persist. You have to look away and back with telescopes several times, until there have been five cycles. This tells you if it really is from that direction in the sky, or just scattered radiation.

Culture

Conspiracies Science Perhaps the message would contain explanations of advanced scientific concepts, furthering our knowledge.

If people can believe the Moon landings were faked, you can be sure some will not believe this news either.

Golden Record

Our signals into space

Pioneer plaques

The primitive attempts we’ve made so far to initiate contact Cosmic Call 1

Teen Age Message

Sent: 1999

Sent: 2001

Sent by: Yevpatoria RT-70 telescope

Sent from a radio telescope in Crimea, the signal targeted four separate Sun-like star systems.

Six Sun-like stars were targeted with a recording of a theremin – an early electronic musical instrument.

Sent: 2003 Sent by: Yevpatoria RT-70 telescope The second phase of Cosmic Call transmitted photos and multimedia files to five stars.

A Message From Earth Sent: 2008 Sent by: Yevpatoria RT-70 telescope A signal was sent to the exoplanet Gliese 581c, which is 20 light years from Earth.

Sent: 1977 Sent by: Voyager 1 and 2

Sent: 1972/1973 Sent by: Pioneer 10 and 11

The two Voyager craft have a vinyl record on board with sounds and images of Earth.

The twin Pioneer spacecraft carried a pair of plaques with information about humanity.

Arecibo message

Across the Universe

Sent: 1974

Sent: 2008

Sent by: Arecibo radio telescope

Sent by: Deep Space Network

A 210-byte image detailing numbers, the chemistry of DNA, the shape of humanity and the Solar System.

The Beatles’ song Across the Universe was sent by NASA towards Polaris, some 430 light years away.

RuBisCo Stars Sent: 2009 Sent by: Yevpatoria Deep Space Network The genetic code for a protein involved in photosynthesis was sent to three stars.

Discovering that we are not the only life in the universe would likely have a large impact on our culture.

Cosmic Call 2

Have we ever had a promising signal? There has only been one that passed all our automated testing. That was in 2015, and it was exciting. We’re always very sceptical, but we took a look and it was a very interesting signal almost designed to fool our system. It had all the right properties to look like something from outer space, but it was interference.

Shooting for the Moon

SHOOTING FOR THE MOON A INED ITS HOW NA SA TR A POL L O A STRONA UTS

From battling river rapids and weathering sandstorms to scaling walls and flying spacecraft propelled at eyewatering speeds, preparing to be the first on the lunar surface wasnâ&#x20AC;&#x2122;t for the faint-hearted Reported by Gemma Lavender

Shooting for the Moon

All Images ÂŠ NASA

Left: Three months after this photograph was taken, Armstrong was walking across the Moon

Top-secret space shuttle

An X-37B has been sent into orbit for its sixth mystery mission. All About Space uncovers what the ex-NASA spacecraft has really been up to Reported by David Crookes

ÂŠ Adrian Mann

Top-secret space shuttle

ASK

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Our experts answer your questions

EXOPLANETS

How does a planet’s colour influence its habitability? Much like a white shirt keeping you cool on a bright summer day, a planet’s colour plays an important role in keeping a planet’s temperature just right for life. Our search for life is currently focused on finding exoplanets with temperatures in a range that allow for liquid surface water. An exoplanet with a dark surface like ocean or basalt will absorb a lot of the incoming stellar energy and heat up. A brighter surface like snow or sand will reflect stellar energy and prevent the temperature from rising. Because colour plays such an important role in temperature, there are sweet spots in the interaction between type of starlight, exoplanet colour and exoplanet-star distance

that allow for liquid water to exist. Having a better understanding of this complex system of interactions will help us find a habitable planet. In the coming decade we will be able to assess the habitability of exoplanets with direct measurements. Until then we need to model many different scenarios so we are prepared for a wide range of possible environments. By modelling the way exoplanet colour influences habitability, we can focus our search on the exoplanets that show the most promise for life. This gives us a way to compare real observations with the physics we expect. Dr Jack Madden is an astrophysicist at Cornell University, New York

Left: Asteroids can fragment from a parent body, but they no longer form via accretion

Above: Darker exoplanets typically absorb more heat than lighter reflective ones

SOLAR SYSTEM

Could asteroids still be forming in the Solar System? Originally asteroids formed in the early phases of the Solar System when the Sun was surrounded by a disc of gas and dust particles, which collided together to form larger bodies. These objects are the leftovers of the planetary building blocks that now mostly reside in the asteroid belt between Mars and Jupiter. There is no creation of asteroids by this mechanism anymore because the relative speeds between existing asteroids are too high; therefore when they collide with each other the outcome cannot be an accretion anymore, but rather a disruption. However, collisions occurring between asteroids sometimes cause the disruption of a large asteroid. Asteroid families, which are identified groups of asteroids sharing the same orbital characteristics and composition, are evidence of such disruptions. Each family is the product of the disruption of a parent body, and family members are the fragments produced by such a disruption. In this sense asteroids

are still forming as fragments of larger ones that are disrupted by a

collision. In fact, based on our current understanding, most asteroids smaller than 50 kilometres (31 miles) in diameter are believed to be at least of the second generation. Dr Patrick Michel is the director of research at the French National Centre for Scientific Research

Did you know? ASTROPHYSICS

Gravitational waves are ripples in space-time caused by collisions of massive objects – like black holes – somewhere in the universe.

Left: The first gravitational wave detection occurred in 2015

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Ask Space

Gravitational waves should travel at the speed of light, but in science we can never truly say that two things are exactly the same. We can only compare our measurements and say how much room they have to possibly be different. In the case of light and gravitational waves, you want to have an event that gives off both at the same instant, and then measure when both signals arrive. If a light wave and a gravitational wave were to race to us from Proxima Centauri, the nearest star after the Sun – a distance of a little more than four light years away – they would arrive at the finish line within a few nanoseconds of each other. Perhaps even closer, but that’s as good as our measurements have gotten up to now. We think that gravitational waves should travel at the speed of light because that is what Einstein’s theory of general relativity predicts. But Einstein may not be the final word on gravity – just as Newton’s ideas on gravity had to be modified by Einstein. That’s why we make measurements, to find out all the cool stuff our theories can’t yet explain! Dr Kathleen E. Saavik Ford is an astrophysicist at City University of New York Graduate Centre, the Borough of Manhattan Community College and the American Museum of Natural History