If someone had asked a Roman citizen what the future looked like, they might have pointed towards a larger empire.
If someone had asked a sailor in the fifteenth century, they might have imagined discovering another continent.
Ask the same question today and you’ll hear answers about artificial intelligence, quantum computers, robots, fusion energy and machines clever enough to make us feel slightly underqualified in our own kitchens.
All of those possibilities matter.
Some may change the world more profoundly than we can currently imagine.
But I suspect history may remember something else.
Not the day we built a smarter machine.
Not the day we finally produced limitless clean energy.
Not even the day artificial intelligence began writing emails that sounded suspiciously more polite than we do.
Future generations may look back at the moment our species stopped living on one world.
Because once that happens, the story changes.
In 1964, Soviet astronomer Nikolai Kardashev proposed a simple way of measuring technological progress.
Not by counting armies.
Not by measuring wealth.
Not by asking which nation had the tallest building, the loudest politicians or the most confusing tax system.
He suggested measuring energy.
A Type I civilisation can use almost all the energy available on its home planet.
A Type II can harness the power of its star.
A Type III can operate across an entire galaxy.
It is a beautifully simple idea.
It also sounds completely ridiculous at first.
Then again, so did powered flight.
So did landing on the Moon.
So did carrying a device in your pocket that can access almost all human knowledge, only to use it for checking the weather and watching someone fall off a chair.
Progress has always had a strange sense of humour.
We are not Type I yet.
Not even close.
We have incredible technology, but we still waste energy on a heroic scale.
We can split atoms, edit genes, build rockets and train artificial intelligence, yet somehow we still struggle to agree that poisoning the only planet we currently live on is probably a poor long-term strategy.
That is not a criticism of one nation or one generation.
It is simply where we are.
Brilliant.
Dangerous.
Creative.
Distracted.
A species capable of reaching for the stars while arguing in the comments section below a video about breakfast.
The journey towards Type I status is often discussed in terms of energy.
Fusion reactors.
Solar arrays.
Global power grids.
Better storage.
Cleaner transport.
All of that will matter.
But I think the first true step may not be taken on Earth at all.
It may begin with Mars.
Not because Mars is comfortable.
It is not.
It is cold, dry, dusty, radioactive and generally gives the impression that visitors should have read the small print before booking.
Not exactly a five-star destination.
There are no beaches.
The air is useless.
The soil is toxic.
And the view, while spectacular, does come with the slight inconvenience of immediate death without a pressure suit.
Still, Mars may become one of the most important places in human history.
People often describe Mars as a backup planet.
I understand the idea, but I have never liked the phrase.
It makes the Red Planet sound like a spare tyre.
Useful if Earth gets a puncture.
That feels too small.
Mars is not merely an emergency option.
It is the first serious test of whether we can expand beyond the world that made us.
The goal should not be to abandon Earth.
That would be both tragic and deeply ungrateful.
Earth is not an old phone we replace when the battery starts behaving strangely.
It is our home.
The only living world we know.
The place where every poem, city, forest, friendship and terrible haircut in recorded history has happened.
Going to Mars should not mean giving up on Earth.
It should mean learning how to protect our future from depending on one fragile location.
Every known species before us has shared the same weakness.
One planet.
One environment.
One roll of the cosmic dice.
If disaster came, there was nowhere else to go.
An asteroid does not care how promising your art scene is.
A supervolcano does not pause because your economy had a decent quarter.
Nature is magnificent, but it is not sentimental.
For the first time, one species may have the tools to reduce that ancient vulnerability.
That alone makes Mars worth serious attention.
Not as fantasy.
Not as escapism.
As redundancy.
And if there is one thing engineers love, it is redundancy.
That, and explaining why something very expensive failed because someone ignored the redundancy.
Of course, the first steps will not look much like the films.
There probably won’t be a heroic astronaut walking across the red desert while dramatic music rises in the background.
Real exploration is rarely that tidy.
It is delays.
Checklists.
Broken parts.
Unexpected dust.
Sleepless engineers.
People staring at numbers and quietly wondering whether they should have chosen a calmer profession, such as lion dentistry.
Before large groups of settlers arrive, machines will almost certainly go first.
Robots will scout.
Drones will map.
Autonomous construction systems will prepare landing areas.
Excavators will dig into the surface.
Artificial intelligence will coordinate equipment, monitor faults, manage power and make decisions faster than any human team could manage from Earth, especially with the communication delay.
Mars will not begin as a city.
It will begin as a building site.
A lonely, expensive, extremely complicated building site.
The sort where forgetting one bolt might ruin several billion pounds’ worth of optimism.
Imagine the first wave of machines arriving years before the first permanent residents.
They unfold solar panels.
They test local materials.
They extract water ice from beneath the surface.
They manufacture bricks from Martian soil.
They build storage units, power stations, tunnels and landing pads.
Slowly, the empty landscape changes.
Not into paradise.
Not yet.
But into preparation.
A place that was once entirely indifferent begins to contain intention.
That may sound small.
It is not.
A footprint is symbolic.
A habitat is a commitment.
The journey itself will also change.
Today, a trip to Mars can take many months.
For early crews, that will mean isolation, risk and an uncomfortable amount of time spent inside a metal tube with the same people.
This is where the romance of space travel meets the reality of someone breathing too loudly for six months.
Future spacecraft may be faster, safer and larger.
Some travellers may even spend part of the journey in medically induced hibernation or a form of suspended metabolism.
Science fiction has imagined this for decades.
Medicine is now beginning to ask whether parts of that idea might one day become real.
Imagine falling asleep near Earth and waking up to see another world outside the window.
A red planet hanging there, silent and waiting.
It would be one of the most extraordinary moments a human being could experience.
Although knowing us, someone would still check their messages first.
The first homes on Mars may not rise proudly above the surface.
They may be buried beneath it.
That sounds less romantic until you remember that radiation has no interest in romance.
Mars lacks Earth’s thick atmosphere and global magnetic field, which means future settlers will need serious protection from cosmic rays and solar radiation.
Several metres of rock could help provide that shelter.
Lava tubes, vast tunnels formed by ancient volcanic activity, may offer ready-made protection.
So the first Martian neighbourhoods may be underground.
Not gleaming towers beneath a glass sky.
Not elegant streets under golden sunlight.
More like pressurised caves with excellent engineering and questionable interior design.
Still, there is something powerful about that image.
To reach the future, we may first have to dig.
Over time, those hidden outposts would grow.
A laboratory becomes a base.
A base becomes a settlement.
A settlement becomes a town.
The early years would be harsh, practical and probably full of rules nobody enjoys but everyone needs.
Check the seals.
Monitor the oxygen.
Recycle the water.
Do not open the wrong door.
Do not wander outside because the horizon looks pretty.
Mars would not forgive carelessness.
But humans are very good at turning danger into routine.
The first person to cross an ocean faced terror.
Later generations booked cruises and complained about the buffet.
That is what we do.
We normalise miracles.
Then would come the domes.
Not immediately.
Perhaps not in the way old science fiction imagined them.
But eventually, enclosed spaces on the surface could allow people to walk among plants, meet in public squares, grow food, raise children and experience something closer to open life.
Imagine standing beneath a transparent shield while dust moves across the outside like a red storm.
Inside, there are trees.
Not many at first.
Perhaps just a few stubborn little things that everyone treats like celebrities.
The first tree on Mars would probably receive more attention than most actors.
And honestly, fair enough.
It would have earned it.
Those green spaces would matter far beyond food production or oxygen.
They would remind settlers what they were trying to preserve.
Not just survival.
Life.
Colour.
Growth.
The quiet dignity of something fragile choosing to continue.
Eventually, children may be born there.
That may be the real turning point.
The first generation for whom Earth is not home, but origin.
A place from stories.
A blue world in the sky.
They may learn about oceans the way children today learn about ancient forests or lost kingdoms.
They may find it strange that rain once fell freely from the sky.
They may ask why anyone would build cities beside so much uncontrolled water.
And somewhere, a teacher will have to explain umbrellas.
Every age has its burdens.
Those children would not think of themselves as visitors.
They would be Martian.
Not alien.
Not separate from us.
But shaped by another horizon.
Their bones, bodies, habits, humour and imagination may all adapt to a place their grandparents once saw only through telescopes and mission images.
That is when expansion stops being an event.
It becomes inheritance.
The relationship between Earth and Mars would not be simple.
Nothing involving humans ever is.
There would be arguments over law, trade, authority, ownership, research, ethics and who forgot to label the emergency valve.
Some people imagine space settlement as a clean escape from politics.
I admire the optimism.
But if two humans can argue over where to put a sofa, thousands living under pressure on another planet will definitely find subjects to debate.
Still, the existence of another living world would change the way we think about ourselves.
Earth would no longer be the whole stage.
It would be the beginning.
For most of history, the word “world” meant everything.
In the future, it may simply mean one address among several.
That shift in imagination could be enormous.
Mars would also transform Earth.
That is often forgotten.
The technologies required to survive there would be useful here.
Closed-loop water systems.
Ultra-efficient agriculture.
Recycling methods with almost no waste.
Compact energy generation.
Advanced robotics.
New construction materials.
Medical techniques for isolation, radiation exposure, bone loss and long-duration travel.
When you solve problems in an environment that is trying to kill you politely but constantly, the solutions tend to be useful in easier places too.
Apollo helped advance computing, materials and engineering.
A long-term Martian programme could do the same on a much larger scale.
The benefits might not always look dramatic.
They may arrive quietly.
Better filtration.
Smarter farms.
Cleaner energy.
More resilient homes.
Improved disaster response.
The future often enters through the back door wearing work boots.
And perhaps this is where Mars connects to the idea of Type I.
Not because settling another planet automatically gives us control over Earth’s energy.
It does not.
But because the attempt would force us to mature.
A species that can maintain life on another world must understand energy better.
It must recycle better.
It must cooperate across distance.
It must design systems that last.
It must think in decades, not election cycles.
Mars would demand competence.
Not slogans.
Not wishful thinking.
Competence.
The Red Planet has no patience for speeches.
It only cares whether the pressure holds.
In that sense, building there may teach us how to live better here.
To become Type I, we may first need to stop behaving like a species that assumes someone else will tidy up the mess.
There is also a spiritual element to all of this, though not necessarily in a religious sense.
For thousands of years, humans have looked upward and imagined the heavens as unreachable.
The sky was where gods lived.
Then it became where birds flew.
Then aircraft.
Then satellites.
Then astronauts.
Each step made the impossible slightly more ordinary.
Mars may do the same for the rest of the Solar System.
Once there is a permanent settlement there, the Moon feels closer.
Asteroids become resources.
The moons of Jupiter and Saturn become future questions rather than distant lights.
The map grows.
Not all at once.
Not cleanly.
Not without mistakes.
But it grows.
And with every new foothold, the idea of humanity becomes less local.
The ancient story of the Tower of Babel is often read as a warning against human ambition.
Build too high, reach too far, and everything falls apart.
There is wisdom in that.
Ambition without humility is dangerous.
Technology without responsibility is worse.
But perhaps the lesson is not that we should avoid building.
Perhaps the lesson is that we must learn to understand one another before we build something too large to control.
A future among worlds will require more than rockets.
It will require trust.
Patience.
Shared purpose.
The ability to disagree without destroying the structure beneath our feet.
Which, judging by the internet, may be the hardest engineering challenge of all.
Still, we have managed extraordinary cooperation before.
The International Space Station proved that nations with deep differences could build and maintain something remarkable above the Earth.
Mars would ask for the same idea on a far greater scale.
Not one laboratory in orbit.
A living branch of the human story on another world.
I do not think Mars will be easy.
I do not think it will become a paradise.
I do not think the first settlers will spend their evenings sipping tea under a dome while calmly discussing philosophy, although I sincerely hope someone tries.
It will be difficult.
Expensive.
Dangerous.
Frustrating.
There will be failures.
There will be moments when people ask whether the whole thing is worth it.
But almost every great step has looked unreasonable before it became obvious.
Crossing oceans was unreasonable.
Flying was unreasonable.
Landing on the Moon was unreasonable.
Building a home on another planet may be the next unreasonable thing that later generations treat as inevitable.
That is how progress often works.
First it is fantasy.
Then it is madness.
Then it is engineering.
Then your grandchildren complain that the journey takes too long.
Perhaps the first Martian city will not look impressive by future standards.
Perhaps it will be small, buried, practical and permanently covered in dust.
Perhaps its corridors will smell faintly of metal, recycled air and someone’s attempt at growing tomatoes.
Perhaps the first public square will be no larger than a school hall.
Perhaps the first park will contain three trees, one bench and a sign asking people not to touch the moss.
But if people live there, love there, argue there, create there, grieve there and dream there, then something profound will have happened.
A second world will have joined the human story.
Perhaps Mars is not our destination. Perhaps it is simply the first brick. A humble beginning to what may become humanity’s greatest adventure: evolving into a truly multi-planetary species.