The universe operates in dark and mysterious ways.
But in bright and fantastic ways, too!
And across all the stars, planets and asteroids in the ever-expanding cosmos, change is always
afoot!
So, what will happen if we look far enough into the future?
This is Unveiled, and today we’re uncovering what the universe will be like 500 million
years from now.
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All too often, we humans see the future through the lens of our own existence.
And the first question many ask when contemplating any future world is whether or not humanity
would still be alive?
But let’s be frank, 500 million years is an exceptionally long time.
All of recorded human history spans for only five thousand years by comparison, and modern
humans have only been here in any capacity for about 300,000 journeys around the sun.
So, 500 million is just… mind boggling for us to imagine.
In all likelihood then, by the timeframe of today’s question, humanity is either long
extinct or we’ll have spread our existence out across multiple planets.
But that second option, where we’ll have spread out and survived, might be seen as…
optimistic.
The typical species lifespan for mammals is only around a million years, so we’d have
to be extremely atypical to last five hundred times as long as that.
But let’s not feel too down about ourselves!
It’s also not impossible that we would still be here, and in the meantime we can at least
picture and try to predict what will have taken place.
Because, in the grand scheme of a 13.8-billion-year-old universe, 500 million years is a much more
manageable chunk of time.
And yet, it’s still time enough for plenty of different cosmic events to unfold… each
as monumental as the next!
The universe might seem as though it’s a pretty stable place, and in many ways, it
is… but it’s always on the move.
At any moment, stars are being born in fiery explosions, asteroids are careening into planets,
and black holes are distorting all before them.
Gravity is constantly changing the position of every astronomical body in existence, and
most models agree that our universe is growing even larger.
In 500 million years, then, the observable universe - that which we can see - will have
certainly, dramatically changed.
If humans are still alive to observe it, then it’s a sure bet that our technology would
allow us to see further out than ever before… but, because the universe is expanding (and
that expansion is accelerating), it doesn’t necessarily mean that we’d be seeing more
stuff.
Say you were alive 500 million years from now and you were looking through a telescope
500 million years more advanced than today’s are… what you could and couldn’t see would
still depend upon how far and fast the universe had grown.
For this reason, it really is impossible to predict exactly what a map of the universe
will look like so far into the future… but there are still some things we know for sure.
We know, for example, that many of the stars we use to navigate Earth will change or disappear
in the coming centuries and millennia.
Such as the North Star, which will rotate through a number of different stars, as the
Ursa Minor and other nearby constellations shift and evolve from our point of view.
Elsewhere, the red supergiant Antares in the Scorpius constellation, one of the brightest
stars in our sky, is likely to have gone supernova in around ten thousand years’ time.
By 500 million years, it almost certainly will have blown itself up.
Other stars scheduled to supernova between now and then include Betelgeuse in Orion,
Alpha Lupi (the brightest star in the Lupus constellation), and Spica (the brightest in
Virgo).
When these stars self-destruct and blow their mass across the universe, they’ll be visible
as unusually bright lights in the night sky here on Earth.
These spectacular events could even shoot Gamma Ray Bursts in our planet’s direction…
a potential disaster, if life were to still be here to witness it!
But, again, it’s not all bad news.
As well as all the stars that will die, new ones will also be born.
And frequently.
It’s estimated, for example, that between one and three stars are formed every year
in the Milky Way.
So, in 500 million years, that’s 1.5 billion new stars to populate the sky - from our galaxy
alone.
There are at least two trillion galaxies in the entire universe, and that universe is
constantly recycling star matter.
Which is another reason why it’s impossible to paint with detail just what it will look
like in the future.
There are so many unknowns, and so many things that haven’t even been created yet.
So, across the timeline of the universe, we know the stars are changeable.
They feel ever-present and reliable to humans on Earth, but really… they’re not.
Which means constellations are scheduled to change, too, regardless of how stable and
predictable they may have seemed to us over the last few thousand years.
And it isn’t only because stars are dying.
It’s also their movement through space.
As little as fifty thousand years in the future, the motion of the stars through the milky
way will cause our current constellations to totally change shape.
In 500 million years, some will be completely unrecognizable.
The sky would be so different that if we were to somehow witness it tonight, we might think
we had been transported to a different universe entirely.
It would be a similar case across smaller regions of space, too.
Even the orbits of our neighbouring planets might’ve dramatically changed.
To try and understand it, we can think about the mathematical concept of Lyapunov time.
This relates to predictability in a system, with Lyapunov time being how long before chaos
descends (and it’s no longer possible to reliably predict anything).
The Lyapunov time for the solar system is generally given as five million years at the
lower end (which is just one percent of our 500-million-year frame).
After that, uncertainty takes hold and even the course of our local planets becomes more
and more difficult to plot.
Add into the equation that it takes about 240 million years for our solar system to
make just one trip around the Milky Way galactic centre, and there are yet more reasons why
it’s hopeless to paint a clear picture of our future sky.
We’ll be in a different place, everything else will be in a different place, many things
will have died or changed significantly, and many other things will have emerged as new
out of the dust.
Good luck accurately foretelling all of that.
And that’s before we’ve even considered that most enigmatic cornerstone of astronomy
and science, black holes.
Black holes are notoriously difficult to learn about, not least because they’re so hard
to detect due to the lack of light they emit.
But we generally know how they form; through the implosion of massive stars.
And we can estimate how many stars there are that are likely candidates to form them, based
on size, mass and star-type.
The numbers vary, but some projections claim as many as 100 million black holes in just
the Milky Way.
Whilst others suggest that new black holes could be forming as rapidly as every few seconds
in the universe as a whole.
In 500 million years, that’s a lot of new black holes!
And these things take a long time to die, too.
Especially supermassive black holes, which some calculate could hang around in the universe
for hundreds of trillions of years.
And so, so far beyond the parameters of today’s question!
It’s no wonder then that multiple models for the end of the universe have black holes
as the last remaining objects.
As the final reminders that anything was here.
But even within the realms of today’s question only, it figures that in 500 million years’
time there should be many more of them across the cosmos.
Let’s hope that, if humans are still around, we have a better understanding of them by
then!
Ultimately, let’s hope we’d have a better understanding of everything!
Can you imagine what it would be like to live 500 million years from today, informed by
all that extra knowledge we’ll have gained between now and then?
Perhaps, at a point so far into the future, if we were to ask the same question again,
then there’d be far fewer mysteries surrounding the answer.
We’d be able to predict future maps of the universe with greater accuracy.
Or to schedule precisely when a certain star will go supernova, down to the exact year,
or day, or minute.
Or to calculate specifically when and where a new star will form.
Will there be any secrets left for us to uncover if we’re still around to witness this far-off
time?
Maybe not.
But, for the time being, we still have so much more left to learn!
Because that’s what the universe will be like 500 million years from now.
What do you think?
Is there anything we missed?
Let us know in the comments, check out these other clips from Unveiled, and make sure you
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