For all the chaos going on down here on Earth, it’s easy to forget that we live in a volatile galaxy full of formidable dangers. 

From space rocks flying at thousands of miles per hour, to black holes that could rip our planet apart, sometimes it’s best not to think about them. 

But what would actually happen to the human body if we perished at the hands of these wild astronomical phenomena? 

MailOnline spoke to experts to find out – and to see if there’s any chance of them actually occurring while humanity still exists. 

Before any of them happen, Homo sapiens could be responsible for their own demise – likely by creating dangerous AI or the emission of greenhouse gases.

WHAT IF THE SUN DIED OUT?

Scientists estimate that our sun is about 4.5 billion years old – about halfway through its anticipated 9 billion or 10 billion year-long lifespan. 

When it starts to die, the sun will expand into a red giant, becoming so large that it will engulf Mercury and Venus, and possibly Earth too. 

Of course, in another 4 or 5 billion years’ time humans will likely be long gone, likely wiped out by a climate disaster or an asteroid impact.

However, in the event that we’re still here when the sun dies, the effects would be felt immediately and we would suffer a speedy demise. 

‘Assume the sun decide to quit, we would follow very quickly,’ Albert Zijlstra, a professor of astrophysics at the University of Manchester, told MailOnline.

‘The bottom line answer is you’d freeze to death.’ 

According to Professor Zijlstra, the closest Earth has seen to such an event was the era of ‘snowball Earth’, some 700 million years ago.

‘The entire world was frozen and the sea was covered in a kilometer thick ice from pole to pole, lasting 50 million years,’ he said.

‘Not much survived life that – and that was with the sun almost as bright as it is now.’ 

Even if we somehow survived the cold for a few days, plants and crops would die due to the lack of sunlight for photosynthesis – and we would surely starve. 

Thankfully, the sun is ‘remarkably stable’ and in no danger of disappearing, Professor Zijlstra added – and is actually very slowly getting brighter. 

‘It is not perceptible on human timescales, but give it a billion years and it becomes very noticeable,’ he said. 

WHAT IF EARTH FELL INTO A BLACK HOLE?

Perhaps one of the scariest features of the universe are black holes – regions of spacetime where gravity pulls so much that even light can not get out.

Black holes act as intense sources of gravity that hoover up surrounding dust and gas, as well as planets and even other black holes. 

They are often described as ‘destructive monsters’ because they tear apart stars, consuming anything that comes too close, and hold light captive. 

With light unable to escape black holes, Earth would have little chance either. 

Xavier Calmet, a professor of physics at the University of Sussex, said the gravitational force of a black hole would become so strong that we would experience ‘spaghettification’.

‘Your body will be stretched into a shape similar to that of a long pasta until it is reaped apart by the strong gravitational force,’ Professor Calmet told MailOnline. 

‘I can’t imagine that this would be pleasant – it would happen rather quickly, so if painful, it is unlikely to last long.’ 

Dr David L Clements, a senior lecturer at Imperial College London’s physics department, said ‘the end would likely be quick’ if falling into a black hole.  

‘It could come from asphyxiation if the atmosphere is stripped, or from the process called spaghettification where tidal forces stretch everything out into long strings – maybe briefly painful.’ 

Thankfully, the chances of Earth ever being swallowed by a black hole are ‘nearly zero’, according to Dr Clements. 

‘The fact that we’re still here shows that this hasn’t happened over the whole history of the Earth,’ he told MailOnline.

‘So the chances are at least less than once every 4.5 billion years and likely much much less.’ 

The closest black hole to Earth, called Gaia BH1, is around 1,600 light years away and is 10 times the size as our sun, experts recently revealed. 

WHAT IF OUR SUN COLLIDED WITH ANOTHER? 

You may not be aware that our Milky Way galaxy is on a collision course with another galaxy called Andromeda, which is currently around 2.5 million light years away. 

The two galaxies have a strong gravitational attraction and will merge in approximately 4 billion years’ time to create one new super galaxy, referred to by astronomers as ‘Milkdromeda’. 

Eric Bell, professor of astronomy at the University of Michigan, said ‘very likely nothing’ will happen to us in the event of the galaxy collision.

As the merger occurs, it’s likely the sun will be flung into a new region of our galaxy, but Earth and the rest of the solar system won’t be in danger of being destroyed. 

However, one potential danger of a galaxy merger would be a collision (or near collision) between our star with another star, although there’s an extremely small chance that would happen. 

‘There is a considerable uncertainty in when [the galaxy merger] will happen, roughly several billion years from now,’ Professor Bell told MailOnline. 

‘But galaxy collisions would only be dangerous because of a slightly increased chance of star collisions.’ 

Even a near collision with another star – a ‘close pass’ – would affect our orbit, which Professor Bell said would be ‘very bad’. 

‘The close pass changes the orbit, bringing us closer to the sun, or bringing us further away. 

‘What our fate would be depends on exactly how our orbit changed. 

‘So we would either escape the solar system (in which case we’d slowly freeze to death over months), or get cooked by the sun (which may be very fast, or take months, depending on the orbit we ended up in).’ 

WHAT IF AN ASTEROID HIT EARTH? 

A massive asteroid hitting Earth was famously the cause of the extinction of the dinosaurs around 66 million years ago. 

The so-called Chicxulub rock, around six miles in diameter, slammed into a shallow sea in what is today the Yucatán peninsula in Mexico. 

For those not killed directly by the impact, the collision released a huge dust and soot cloud that triggered global climate change, wiping out 75 per cent of all animal and plant species. 

NASA scientists think it would take an asteroid 60 miles (96 km) wide to totally wipe out life on Earth – about 10 times bigger than Chicxulub. 

According to a 2022 research paper by Jean-Marc Salotti at the University of Bordeaux, a 60-mile asteroid would ‘kill all lifeforms’ if it hit Earth, with the possible exception of extremophiles, those tiny lifeforms that can survive high temperatures, acidity and radiation. 

Such an asteroid would ‘transform the Earth into an inhospitable planet’, causing the extinction of many life forms including the human species. 

But the bigger the asteroid that hits us, the quicker the end would likely be. 

If a small one hit Earth today, there would be a huge amount of dust thrown up into the atmosphere that could block out sunlight – freezing us to death, which would likely be more drawn out and unpleasant. 

If it hit water, then there would be an increase in water vapour in the atmosphere, which would result in an increase in rain resulting in landslides and mudslides.

Regionally there might be earthquakes, hurricanes and tsunamis due to the increase in kinetic energy. 

Dr Kelly Fast, program manager for NASA’s Near-Earth Object Observations initiative, said asteroids have hit Earth before and ‘it will happen again’. 

‘Finding them early is important for advanced warning and to mitigate against potential future impact threats,’ she said. 

WHAT IF EARTH’S ATMOSPHERE DISAPPEARED? 

Earth’s atmosphere is described as its ‘security blanket’ because it contains the oxygen we need to exist, making the air breathable. 

It also protects us from harmful ultraviolet solar radiation from the sun and creates the required pressure for liquid water to exist. 

If this precious multi-tiered atmosphere somehow disappeared, most vertebrates, including humans, would suffocate in seconds. 

Marine creatures, which rely on oxygen dissolved in the water, may last a little longer – although the seas would also boil into vapour due to the sun’s rays. 

In the event of the atmosphere disappearing, we may have to build radiation-shielded domes that provide a pressured environment and plentiful oxygen. 

But is there any chance of this actually happening? 

A 2021 study in Nature Geoscience concluded that Earth’s oxygen-rich atmosphere will be lost in about 1 billion years, but this will happen gradually as the sun gets hotter.

Carbon dioxide levels in the atmosphere will drop due to the gas absorbing the heat and breaking down, leading to death of plant life and in turn reduced oxygen production. 

All in all, it seems like the most realistic dangers to humanity are the ones of our own making – such as greenhouse gas emissions and killer robots. 

According to one academic, there’s a 50 per cent chance artificial intelligence will wipe out humanity, and it could happen in a similar way to how humans wiped out extinct animals such as the Dodo. 

MEMOIR 

Hidden Valley 

by Paul Richardson (Abacus Books £20, 288pp) 

Thirty years ago, journalist Paul ­Richardson left London to make his home on the island of Ibiza, where rents were cheap and life was idyllic. 

Within a few years, though, Ibiza had begun to change, becoming ‘a fiefdom of the super-rich’ and a raucous party destination. 

Dismayed by the transformation of their tranquil island, Richardson and his partner Nacho decided to move to the Extremadura, a rural region in the far west of Spain which couldn’t have been more different. 

They bought some land and set about pursuing their dream of a pared-down, self-sufficient lifestyle, where they could eat ‘clean’ food: ‘Not in the prissy Gwyneth Paltrow sense, but food that tastes vibrantly of itself and, importantly, doesn’t need to be paid for,’ Richardson writes. 

At first their new plot was nothing more than ‘a clearing in a forest of brambles, like something out of a fairy tale’, but they could imagine building their own house there and living surrounded by orchards of citrus fruit, cherries, peaches and apricots, with a vegetable garden and contented animals grazing nearby. 

This memoir is firmly in the mould of Peter Mayle’s A Year In Provence and Chris Stewart’s Driving Over Lemons: bumbling outsiders move into a rural area in southern Europe, make lots of mistakes, meet eccentric locals and are eventually embraced as part of the community. What makes Hidden Valley different is that Richardson is far more interested in the land than in the people. 

He revels in the beauty of the countryside, from the nightingale’s ‘peals of melody’ in spring to the ancient fruit trees which emerge from the brambles that had swamped them for years. 

As they get to grips with the terrain, Richardson writes lyrically of their increasingly bountiful harvests, ‘the year’s first lustrous black aubergines, the green peppers and courgettes, the strawberries and apricots, the French beans so fresh they squeaked as you bit them’. 

Be warned, there are also some graphic accounts of the despatching of the rabbits and pigs they raise. 

Richardson doesn’t shy away from the pitfalls of this lifestyle. Building their eco-friendly house takes forever, not least because the builders disappear for a whole year before returning, with no explanation, to complete the work. Drought and wildfires are a constant worry; one summer the fire races right up to their property, leaving the surrounding countryside blackened and scorched, yet miraculously sparing their house. A violent hailstorm wrecks the garden, wiping out that year’s harvest. 

Other disasters, amusingly, are self-inflicted. The couple’s attempts to make drinkable wine are an epic failure: ‘The harder we tried to correct our errors, the worse our wines became,’ Richardson laments. 

There is some compensation in the fact their vinegar, topped up with bottles of ‘failed wine’, is superb. 

Although there is much talk of living off the land, Richardson concedes that true self-sufficiency is almost impossible to achieve. They still have to buy salt, sugar, pasta, rice, tea, coffee, and fuel for their car. 

Luckily they have their other jobs to sustain them: Nacho travels the world as an agricultural consultant for aid projects, while Richardson regularly comes back to Britain for his journalistic career. 

When they first moved to their hidden valley, Richardson was fearful that their new neighbours would be hostile to a gay couple. 

The book ends with his marriage to Nacho in the local town hall. Guests come from all over the world, ‘but a greater number of the well-wishers are villagers, who crowd the square to hurl rice, confetti and compliments’. 

It’s a happy ending to a beguiling book about a lifestyle that many of us dream about, but few achieve

Book of the week 

Finding Hildasay by Christian Lewis (Macmillan £16.99, 352pp) 

In the spring of 2017, Christian Lewis stood on top of Swansea’s Rhossili cliffs looking down on the fiercest waves he’d ever seen. ‘I can definitely surf,’ he says. ‘But I’m no professional.

‘On any other day my normal sense of fear would have made me walk away,’ he said. But on that day, the former paratrooper ‘just didn’t seem to care’.

After ten years struggling to raise his daughter Caitlin (then 16) alone, she had decided to move out. The debt collectors were circling and Lewis was on the brink of eviction.

‘I felt an immense sense of calm, or was it abandon?’ he writes, as he attached the leash of his surfboard to his ankle and headed out to face ‘the monster’.

Although he says he ‘wasn’t suicidal’, he was aware of ‘not wanting to exist any more’ as he headed out towards the break. 

‘Then, behind me, thundering out of nowhere, came the killer wave. I turned myself and my board to face the oncoming slaughter, to give myself half a chance to dive underneath it.’ But as the muscular wall of water hurtled towards him, Lewis realised he was outmatched.

‘The white water hit me so hard my board was immediately ripped from my body. My arms and legs were being dragged every which way and felt as if they were being pulled out of their sockets. One second it was light and the next it was dark. I had no idea if I was upside down or facing upright.’

Somehow Lewis scrambled back onto his board. It took every fibre of his being to ride the next wave — ‘the longest and most beautiful of my life’ — back to the shore where he kissed the Welsh sand. ‘It was the first battle in a long time where I had triumphed,’ he recalls.

He’d struggled with the practicalities of civilian life ever since leaving the Army, and for the first time in too long he was ‘happy and grateful to be alive’. Having felt the pure joy of survival, Lewis decided to continue pitting himself against the British coast. As he’d been supported by forces charity SSAFA in the past, he resolved to walk the entire perimeter of the UK to raise funds for the organisation.

His journey began chaotically. He acquired a tent (with a hole in the top) from another ex-para and some (oversized) boots from his brother. Other friends donated a sleeping bag, camping stove and a Crocodile Dundee-sized knife (of the sort you wouldn’t want to be caught with). Then he got drunk and torched all traces of his old life: birth certificate, passport, driving licence. All went on to a fire in his garden.

The next day, his mum and stepdad drove him to Llangennith beach in the Gower, near his Swansea home, and waved him off. After they left, Lewis realised he hadn’t even decided whether to head north or south. ‘The only plan I had was to keep moving forward,’ he realised, and headed north with £10 in his pocket.

He quickly realised what he was up against. Hunger kicked in, reducing him to ‘a skeleton covered in skin’, as he rummaged through bins for food. He found it hard to find safe places to camp near towns. As wild camping is illegal in England and Wales, he had to pitch his tent secretively — once in the middle of a roundabout.

His clothes began to stink. ‘When I had a few quid to spare I’d walk into a laundrette to freshen up my clothes,’ he says. He’d don his army poncho and strip off beneath it, sitting silently ‘while the old ladies chatted away, itching to ask what I was doing!’

In towns, Lewis found himself befriending members of the homeless community, many of whom were also former veterans. Their plight hit him hard. Heading to the Lake District, his mood was lifted by the scenery.

But by the time he reached Scotland, the days were drawing in and a frozen shoreline stretched ahead. At night, temperatures plummeted and he couldn’t find enough dry driftwood to make fires. The cold made the pain in his hands and feet ‘unbearable’.

Then, crossing over to the Northern Irish coast, Lewis found a companion to warm both his body and soul. Jet is a beautiful white lurcher whose owners were struggling to keep her. ‘I looked into her wise eyes,’ recalls Lewis, ‘and wrapped my arms around her while she stood still. I had acquired the best friend I would ever have.’ From then on, Jet walked beside Lewis by day and slept at his feet by night.

Back in Scotland, as spring turned to summer, Lewis was bitten raw by midges and cleggs (horseflies). On Skye, Jet ripped the tent with her claws, giving the insects free access to them all night.

But, in the absence of shops along the wilder coastline, he learned to forage for shellfish. Supporters of his Facebook fundraising page donated better gear to help him survive the icy weather and brought regular meals.

Lewis had scary moments, like when he twisted an ankle (and had to drag himself miles to safety), and when a gale blew a metal pan into his face, shattering a tooth (which he extracted himself using a guitar string).

At the tip of Mull, the terrain of freshly logged pine was impossible for Jet to navigate and Lewis was forced to carry her until he vomited with exhaustion.

His lonely days were occasionally balanced by evenings in local homes and pubs, where kindly Scots bought him meals and drinks and even got him dancing to traditional music. By the time he reached Jura his journey was making the national news and he’d raised almost £50,000 for SSAFA.

Lewis had walked 12,000 miles to Shetland by the time Covid struck. He spent the first lockdown in a former shepherd’s hut (with no running water, heating or electricity) on the 104-hectare island of Hildasay, off the west coast of the Shetland mainland.

There he learned to catch lobster and helped a farmer out by caring for the sheep. He bathed in the sea and one day spotted a football floating towards the shore. Thinking of Tom Hanks’s obsession with a volleyball in the movie Castaway, Lewis waded out to collect it. He drew a face onto it, added a driftwood body and a scallop shell bra and called her Hilda.

Lewis’s book (and his journey) ends there for now. Because back on the mainland he met a fellow walker called Kate and the pair became engaged. They now have a young son named Magnus.

But Lewis (who has so far raised £270,000 for SSAFA) promises that, as soon as Magnus is old enough, they will all continue on together. His adventure has taught him ‘how little I needed in the way of material possessions and home comforts to wake up happy’.

And he credits the brutality and beauty of the Scottish landscape and the warmth of the people with helping transform his life. ‘I came to Scotland a little broken and I’m going to leave here not just unbroken, but with a dog and girlfriend.

‘What I’ve really learned from this journey is that home can be in many different places and exist in many different forms.’

BOOK OF THE WEEK 

THE MARRIAGE QUESTION: GEORGE ELIOT’S DOUBLE LIFE 

by Clare Carlisle (Allen Lane £25, 384pp)

It had all the drama of an illicit teenage elopement. At dawn on June 20, 1854, Marian Evans (known to us as George Eliot), madly in love and abandoning all propriety, slipped out of her house in Kensington with her carpet bag and boarded a steamer on the Thames bound for the Continent.

She’d told no one where she was going, apart from two close friends sworn to secrecy. As Clare Carlisle recounts in her gripping and insightful new book, Marian was suddenly anxious that her lover George Lewes would fail to turn up. Would he jilt her at the last moment?

At last he appeared, rushing up the gangplank just in time. Off they sailed in a whirl of reckless excitement, to live in Germany for a year while Lewes researched his biography of Goethe.

These were not teenaged, or beautiful, young lovers. Marian was a spinster at the seemingly ancient age of 34, prone to melancholy and hysterics, with a long face, protruding teeth, a large nose and a heavy chin.

Lewes was 37, a thin little man with a whiskery face pitted from smallpox, unhappily married to his wife, Agnes, who was mother of their three sons and now having an affair with his friend by whom she was pregnant.

It just goes to show that looks don’t always matter when it comes to sexual attraction, because those two were crazy about each other.

Meeting in the bustling world of literary London, they fell in love with each other’s brilliant minds; the nose, teeth, whiskers and pockmarks seem to have been no impediment to their bliss. They would live together for 24 years.

From the day of their elopement onwards, Marian referred to Lewes as ‘my husband’, even though he was still married to another woman.

One year later, she admitted to her brother Isaac: ‘Our marriage is not a legal one, though it is regarded by us both as a sacred bond.’ Isaac, on reading that, cut off all communication with her.

Most of genteel, prurient Victorian society did the same; when the couple returned to England in 1855, they were considered scandalous and not invited to dinner parties.

Did Marian care? ‘I have counted the cost of the step that I have taken,’ she wrote to her publisher friend John Chapman, ‘and am prepared to bear, without irritation or bitterness, renunciation by all my friends.’

But as Carlisle shows us in her incisive book, Marian did actually care a great deal about what the world thought of her. She would need to build up her reputation and her legacy in another way. Rather than having babies, the couple had novels. Marian wrote them — under the male pen-name George Eliot — and Lewes promoted them, negotiating lucrative deals with publishers and encouraging, enabling and goading Marian to write the next one.

He kept her hard at it: one acquaintance commented: ‘She was worked harder than any carthorse’. And gradually, through the astonishing success of her psychologically astute page-turners, she built up a reputation so great that it trumped the public’s disdain for her non-marital status.

She received fan letters from Charles Dickens; Queen Victoria became addicted to her novels and gave them to her children; and she was visited by such eminent figures as Henry James, Wagner, Longfellow and Turgenev — all paying homage to her in her grand house in St John’s Wood, acquired with the proceeds of her best-sellers.

It’s at this point in the book that Carlisle starts referring to Marian as ‘Eliot’, so I’ll do the same here. All seemed rosy; but there were a few dark corners of the situation, some darker than others.

First, there was no question of Eliot herself receiving the proceeds of her success; the money from her novels and the money due to her from her own inheritance was all paid into Lewes’s bank account. That was the way things were in the late 19th century; but from our perspective it seems odd that this strong woman was financially dependent on her ‘husband’, who was perpetually greedy for more money.

Lewes used her earnings to support his wife who was heavily in debt. He relished Eliot’s wealth and became addicted to it; she was far more successful as a writer than he was.

Then, there were Lewes’s three sons — Charles, Thornton and Bertie. When Lewes and Eliot first fell in love, those boys were still at boarding school in Switzerland.

But after leaving school, they came to live with Lewes and Eliot in their St John’s Wood villa, and it rather upset the peace and quiet of their perfect ‘solitude a deux’. Eliot did her best to be a good stepmother, but it didn’t suit her. What to do?

While the eldest son, Charles, did all right, getting a decent job at the General Post Office, the two younger, less academic boys were shipped off to Natal — a convenient way of getting rid of under-achieving sons in those days of Empire. Thornton hated it there and became ill.

Horrifyingly, both of the brothers would die young, of obscure South African diseases.

And there seems to have been a remarkable lack of grief for them felt by Lewes and Eliot, who could now resume their selfish life. As Carlisle remarks: ‘Eliot’s marriage, and the creative life that was inseparable from it, could not sustain the presence of Thornton and Bertie … the success of this marriage was bound up with failure, losses and some brutal choices.’

A brilliant aspect of this book is that Carlisle takes us deep into the world of each of Eliot’s novels, reminding us what masterpieces they are.

Her depiction of Gwendolen in Daniel Deronda, skewered inside a miserable marriage, and of Dorothea repenting at leisure her rashly idealistic decision to marry the desiccated old stick Casaubon in Middlemarch, suggest Eliot’s strange glee in imagining others immeasurably less happy than she was.

When Lewes died in 1878, Eliot went into Queen Victoria-style mourning, not leaving the house for three months. She buried herself in finishing his unfinished book and obsessively reading poems about death and loss.

But she was wooed again; first by a younger woman, Edith Simcox, who was passionately in love with her. They definitely kissed, but it went no further. Then she was wooed by John Cross, her devoted fan who was 20 years younger — he proposed, and she accepted, just two years after Lewes’s death.

Was she really in love with Cross, or was this just a way of restoring her reputation, by marrying a proper Anglican, rather than living in sin with an atheist, as Lewes was? We can’t know; but the honeymoon in Venice sounds like a disaster.

Eliot dragged her young bridegroom round all the museums. Then, one evening, Cross jumped from their hotel balcony into the Grand Canal. The police were called and recorded the incident as a suicide attempt.

But they stuck together after this horror and moved into a house on Cheyne Walk in Chelsea. Just three weeks later, Eliot died suddenly, aged 61. Cross pleaded with Westminster Abbey to allow her to be buried there.

The Abbey said no, citing ‘her notorious antagonism to Christian practice in regard to marriage’. It would take another hundred years for the Abbey to lay a stone for her, in the centenary of her death.

She was buried in the unconsecrated section of Highgate Cemetery, next to Lewes, and their love letters to each other were buried with him.

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Published: 18:00 EDT, 4 May 2023 | Updated: 18:54 EDT, 4 May 2023