How many times have you made a mistake and wished you could go back and change the past?
Or how often have you dreamed about what the future might be like?
The idea of time travel has been enchanting people for generations, even though it’s
usually assumed to belong only to the world of science-fiction.
But is it really as farfetched as it sounds?
This is Unveiled, and today we’re uncovering the extraordinary reality of time travel in
real life.
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One of the easiest ways you can accomplish time travel is by simply looking into the
night sky.
Because it takes so long for a beam of light to reach us from other parts of the universe,
nothing you see in the sky is a true reflection of reality.
In fact, some of those distant stars might not even exist anymore… in the time it has
taken for their light to reach us, they could have blossomed into spectacular supernovas
or faded away completely.
To look at it another way, it’s often said that were aliens to today observe the Earth
from sixty-five million lightyears away, then they’d be able to see precisely what killed
the dinosaurs - provided they had a powerful enough telescope.
While that fact doesn’t mean a great deal to us (since we have no way of getting sixty-five
million lightyears away to look back at our own planet), we may someday see the equivalent
of this mind-bending phenomenon play out somewhere else in the universe, as the ancient precursors
of a different planet roam its landscape with us as witness.
With regard to whether this truly counts as “time travel”, however, we wouldn’t
be physically going anywhere…
It depends on whether you rank being able to see into the past as a type of time travel
in its own right?
As far as actual movement goes, all you really need to get to the future is speed.
The faster an object is moving, the slower it perceives time relative to a stationary
object; this is time dilation.
This means that if someone goes to space with a rocket, by the time they come back to Earth
they would have effectively visited the future.
This phenomenon is especially well-documented… so well-documented, in fact, that GPS systems
have to account for it to stay accurate – since the satellites they use to navigate move so
quickly in orbit.
Every astronaut who’s ever been to space has been affected by the same thing, though
not so much that they would notice.
In 2015, the cosmonaut Gennady Padalka broke the “time in space” record - with 879
days over multiple missions… and it’s been said that, overall, his combined time
spent moving at a higher velocity means he moved 1/44th of a second further into the
future than if he’d just stayed on Earth.
This is a tiny amount, but not so tiny that Padalka isn’t a time traveller.
He has, after all, travelled 1/44th of a second further into the future than most other people
have!
For all astronauts on board the International Space Station, their tiny amount of time travel
happens because the ISS is moving through space at a speed of 17,100 miles per hour.
But the ISS could never be a convenient mode for time traveling distances of any notable
length.
For instance, it would take an estimated 100 years aboard it for an astronaut to go just
one second into the future.
The fastest manned spacecraft in history, the Charlie Brown command module from the
1969 Apollo 10 mission, traveled at a record-breaking 24,791 miles per hour… which is quicker
than the ISS, but it would still take decades to move more than an increment into the future.
Even the fastest man-made objects ever wouldn’t stand a chance.
NASA’s Parker Solar Probe exceeds speeds of 150,000 miles per hour during its mission
around the sun…
Of course, there aren’t any passengers on it, and we’re very far away from a time
when a manned ship could travel at those speeds… but, even if we could propel astronauts at
150,000 miles per hour, we’re still talking years on board for a few seconds worth of
time travel.
Moving through time is no easy feat!
Elsewhere, the fundamental force of gravity can also affect time.
The stronger a gravitational pull on an object is, the slower it moves through spacetime;
it’s actually another reason for the temporal discrepancy between everyone on Earth and
astronauts.
It’s been proven that an atomic clock closer to the Earth’s surface ticks slower than
one that’s further away.
Apply that on a larger scale and many sci-fi creators have speculated that by utilizing
the gravitational pull of a big enough object we could provide the necessary forward momentum
for a trip to the far future.
The idea is that you could travel to something exceptionally massive - a black hole, for
example - orbit it for a while, and its intense gravity would mean that by the time you left…
you’d have zapped yourself into the future.
Scientifically and mathematically speaking, this almost definitely checks out, but it’s
still an imperfect method for real-life time travel.
For a start, even something as massive as a supermassive black hole might only slow
you down by about fifty percent- so ten years near a black hole might equate to twenty years
for people back on Earth.
Sure, a decade-long trip to move another decade into the future shouldn’t be sniffed at…
but it wouldn’t be all that practical.
And the other big problem we have are the distances at play.
Say, as a means of time travel, you used the supermassive black hole believed to be at
the Milky Way’s galactic centre.
It’s about 26,000 lightyears away from us… so, if you were somehow traveling at the speed
of light, it would take you 26,000 years to get there.
Upon arrival you perform your “turning ten years into twenty” trick, and jet off back
home… by the time you finally got back to Earth, well, you’d find it more than 50,000
years into the future rather than the measly twenty you were hoping for - thanks to sheer
journey time.
So, while black hole time travel is a theoretical possibility, don’t expect to be harnessing
its power any time soon.
For it to work, the black hole would have to be right next to us from the outset…
but if a black hole really was that close, it would probably have destroyed us and the
solar system long before we could manipulate it for temporal displacement.
Of course, when we imagine a time machine, we don’t just want a device that can take
us to the future only - we also want the possibility of visiting the past (or at least of returning
home from the future!).
Generally speaking, most theories on backward time travel concede that it’d only be possible
if we were ever able to break the speed of light… which would break the laws of physics
and is generally held to be impossible.
But, are there any other ways to take a trip to the past?
The astrophysicist Ron Mallett thinks that there are, and he’s dedicated most of his
career pursuing a lifelong interest in proving that time travel is possible.
Mallett specializes in the famous theories of Albert Einstein and has suggested a means
for backward time travel which involves “twisting” spacetime rather than needing to reach the
speed of light.
Mallett says that by creating a gravitational field with a ring of lasers you could twist
spacetime into a ring shape, allowing you to travel the loop you’d made… and ultimately
go to the past.
If this sounds too good to be true, it’s because there is a big catch: using Mallett’s
method, you could only travel to the past as far back as to the moment the machine itself
was switched on.
That means that we wouldn’t be able to zap back in time to the dinosaurs, or miraculously
prevent past events already committed to history from happening.
But such a machine would still be incredibly useful.
Any future event worth a redo could be given one, and Mallett’s ring of lasers would
make forward time travel much less risky, as well; it would allow a traveler to the
future a way to get back home, to their original time, rather than effectively “disappearing”
from the present.
It should be said, though, that Mallett’s ideas have been criticized by his colleagues,
and he himself stresses that the technology is extremely far away from becoming a reality.
Finally, real-life time travel would mean real-life time travellers, too.
But, might they already be among us?
While nobody attended Stephen Hawking’s famous “party for time travellers”, plenty
of people have claimed over the years that they are from the future.
One notable case was that of John Titor, who allegedly came to the 2000s in search of an
IBM 5100 computer.
Titor had a compelling story but his predictions never came true, and he’s since been written
off as a complete hoax.
Others have come forward to tell their story to the press or to make cryptic blog posts
and viral videos, though none have been able to truly convince the wider public that their
time traveling tales are the real deal.
Nevertheless, there have been various images of supposed time travelers that appear throughout
history, as well… and some of the more unusual likenesses have peaked public interest.
For many, the fact that there are no confirmed time travellers is enough to prove that time
travel will never exist.
For others, though, our tendency to be suspicious of time travel claims means that, even if
we did one day invent backward time travel, we probably wouldn’t believe the people
lucky enough to use it.
For now, we can take some solace in the fact that, ultimately, we are all traveling through
time, every day… into the future at a constant rate of one second per second.
It’s not quite as glamorous as it is in the movies, but at least there’s no real
risk of us getting stuck in a far-flung future or a land that time forgot.
What do you think?
Is there anything we missed?
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