"Hello,
friends!" "In March 2003, the FBI arrested 44-year-old
Andrew Carlssin." Newspapers
reported that this man was extraordinarily lucky. "In the history of Stock Markets, he had
earned like no other." "He
invested $800 and within 2 weeks," it turned into $350 million. The FBI suspected that he was running a
scam. That he was an insider
trader. "When Andrew was
questioned," he answered that he
was a time traveller. He claimed that he
was a traveller from 250 years in the future.
And that he knew how the stocks would perform so he invested in
them. And got the extraordinary
result. The FBI was surprised at
this. The FBI was convinced that he was
lying. And they took it upon themselves
to prove that he was lying. "When
they investigated some more, they found that" "Before December 2002, there was no
record of Carlssin." Even more
surprising was that "on 3rd April,
Carlssin had to appear in court for his bail hearing," "but he had disappeared, never to be
found again."
Was he really a time traveller? Is it really possible to travel through
time? Or is it only fiction for novels
and films? "In today's Blog,"
let's understand the concept of time travelling scientifically. """Great, are you talking
about a time machine?"""
"""You know the rules of time jumps,
right?"""
"""Time travel: a concept that has been explored since
the early 1900s."""
"""I have no idea, but when we're talking about time
travel here."
"Either it's all a joke or none of it
is.""" "In 1895,
writer H.G. Wells wrote his groundbreaking novel" The Time Machine. It was after this that the phrase 'time
machine' became popular. A machine that
can take you into the future as well as the past. "With it, you can travel through
time." "Although this novel
was fiction," "a science
fiction novel," but several
philosophers and physicists were inspired by it. "Not only were serious research papers
written on time travel," but many
films were also made. "If we think
about it, the exact way time travel takes place" can be used to classify it into different
types. "First, let's use sci-fi
films," to understand this concept
better. Time travel can be of many
different kinds. The first is the
one-way travel to the future. You travel
to the future and you can't return. It
is one-sided time travel. Interstellar
is an example of this. "In it, a
time traveller travelled to the future,"
"but his family members and other people keep on ageing," when he meets them again. Some had even died. The second way is Instantaneous Time
Jumping. A person can jump from one
point in time to another instantly using
a time machine. It was shown in the film
Back to the Future. And in The Girl Who
Leapt Through Time. "The third way
can be when the time traveller stands still," and it is time that is moving around the
traveller. This was shown in the film
Harry Potter: Prisoners of Azkaban. When
Hermione uses the time turner. The
fourth is Slow Time Travel. As shown in
the 2004 film Primer.
"The time traveller gets inside a box," "with every minute he spends in the
box," he goes back into the time by
a minute. "So if he wanted to go
back a day," he had to remain in
the box for a day. The fifth is
travelling at the speed of light to
travel through time. This was shown in
Superman (1979). "In it, Superman
flew faster than the speed of light,"
and travels back in time.
"The question is, among all these concepts of time
travel," which way is actually
possible today? In real life. Which way may be possible in the future? And which way is completely unscientific and will never be possible. "Don't be surprised," "you might think that all of these are
rubbish," "science
fiction," and can't be
possible. That's not true. "Some of these are actually possible to
do," even today. "Broadly speaking, there can be two
types of time travel." "One is
to travel into the future," and the
other is to go back into the past. Let's
talk about travelling to the future first.
"The scientific explanations and theories of travelling to the
future," are derived from Albert
Einstein's Theory of Special Relativity.
"The concept of time dilation," was introduced by Einstein. "Before Einstein, it was believed that
time is constant." "Whether
you're on Earth," or on Mars or
near a black hole.
Time was believed to be something that was constant. "One of the most famous mathematicians
and physicists in the world," Isaac
Newton was the one to say this. "In
his opinion, regardless of the speed with which you're travelling through space," "regardless of the position," the flow of time would be constant. Albert Einstein was the first person to
refute this. He said that Newton was
wrong. Time isn't constant. He claimed that time was like a river. "Like water flows in a river," "sometimes it slows down," "sometimes the flow of the river speeds
up," "similarly, the flow of
time," sometimes it slows down and
sometimes it picks up the pace.
Depending upon speed and gravity.
"Yup, you heard it right, Einstein had said that" time can actually be sped up and slowed
down if the speed and gravitational
force could be changed. This is known as
time dilation.
"The way that your pupils dilate," "similarly, time dilates too when the
speed of the object increases" or
if an object is subjected to an increased gravitational force. How had Einstein actually discovered
this? "We can talk about this in
some other Blog," it's a long explanation. It took me days to understand that. So I won't go into that explanation. "Basically, time dilation can be done
in two ways." The first is with
speed. If you are sitting in an object
that is going very fast. Like an aeroplane
or a spacecraft. "The faster
something goes," the more would
time slow down for it. Relative to a
person who isn't going as fast. "If
I have to explain it with a practical example," "suppose you have two clocks," I keep one clock with me and put it on the
ground. And I send the other clock with
you on an aeroplane. The aeroplane goes
around the earth once and lands back.
"If we then compare the two clocks," "though the clocks showed the same time
initially," "but now the clock
that you took with you on the aeroplane,"
the time it shows would be some nanoseconds behind the other. The two clocks wouldn't show the same
time. Because one clock was travelling
at a higher speed. It's subjected to
Kinematic Time Dilation. I'm not making
this up. There was an experiment in
1971. Atomic clocks were used. Because time was to be measured
precisely. And it was seen that "the clock that was in the
aeroplane," the time it showed was
behind that of the other clock. This was
known as the Hafele Keating Experiment.
This had proved Einstein's theory of time dilation. "It doesn't mean that time is actually
slowing down for the clock," the
one on the aeroplane. "Rather, it
means that time is relative."
"If we observe the clock on the aeroplane from the
ground," time slows down in our
relation. "Because we're seeing it,
time is slowing down." "For a
person on the aeroplane," "and
the clock on the aeroplane,"
"for it, time would continue to move as it did."
"Theoretically speaking," "if we could build a rocket," "that travels at the speed of
light," and you get in that
rocket. You remain in that rocket for 10
years travelling at that speed.
"And then you return to Earth," "the time that you see on
earth," "would be 9,000 years
later." "Simply
speaking," "If you want to
travel into the future," "you
can already do it now," It is
scientifically possible to do so today.
The only problem is that there
isn't an aircraft that travels at this speed.
You can get to the speed of light.
"But with improvements in technology," we can build more such aircraft and
spaceships that can fly faster. It would
slowly become possible. "For now,
Gennady Padalka, a Russian astronaut, "
is credited with the most time travel into the future. It's because he remained in space the
longest. 879 days. "And he was travelling at the speed of
28,000km/hr in space." "Accordingly,
he has travelled 0.02 seconds into the future. " "In comparison to the people on
Earth," he is 0.02 seconds
younger. He is so much younger. "If someone gets the opportunity to
travel to the past,"
one thing that
everyone would want to do that everyone
would wish would be to invest in
Bitcoin. "Because had you invested
$10 in Bitcoin in 2010,"
"today, that $10 would have turned into $20,000." "But do you know what,
friends?" You might have done this
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description. Download this app and start
your crypto journey. If you're upset
because you think we can't get the technology
with which we can travel so fast that
"we can travel through time significantly in the future," don't be upset. Because there's another way of Time Dilation
as laid down by Einstein.
By using gravitational force. "Similar to time dilation with
speed," gravitational force leads
to time dilation too. "More the
gravity, more would be the time dilation."
"The time dilation that takes place because of gravity," "to visualise it, Einstein asked us to
imagine" a fabric of
space-time. "Imagine a mesh, like
shown in this photo," And put balls
on it. You can think of these balls as
planetary objects. "The heavier a
ball would be," the more this mesh
would get wrapped. "The more mass
in the ball," "in the
planetary object," the more would
be its gravitational force. Earth's
gravitational force is less than Jupiter's.
Sun's gravitational force is more than Jupiter's. "Similarly, in the fabric of
space-time," "you get to see a
curve," with the gravitational
force of an object. "The closer you
get to an object with a high gravitational force," the more would you feel time slow down. Time would slow down for you. "In this mess, you can see," "the steeper the drop is," the more time slows down for you. You can have an approximate estimate with this
visualisation. This basically means
that "if you want to travel through
time in the future," "spends
some time near Jupiter," "or
around the Sun," or near an object
that has even more gravitational force.
Like a black hole. "If you
spend some time near a black hole,"
time would pass you by slowly.
This is the same concept shown in the film Interstellar if you
remember. "The main character in
it," "lands on a planet near a
black hole," "and each hour he
spends there," it's 7 years for the
people not on the planet. That was the
amount of time dilation in that film because of the black hole.
It is a scientifically accurate depiction. It will actually happen like so. But whether someone can survive being that
close to a black hole is unknown. It's
said that black holes are the heaviest objects in the universe. It's also said that light starts bending
around black holes. "This was
considered to be purely theoretical,"
"but 3 years ago," a
telescope clicked the first picture of a black hole and proved it. "On 10th April 2019," the Event Horizon telescope clicked this
picture. This photo went viral on the
internet. Because this is the first
rendered visual image of a black hole.
"Anyway, if we get back to time travel," I told you two ways of travelling into the
future. "The first is to travel at
a high speed," and the second is to
get very close to a gravitational object
"with a high gravity, and a high mass." "Practically speaking," "I would like to give you another
example of this," "the GPS
satellites, that keep revolving around the earth, at a high speed," they are farther than earth's gravity than
compared to us. "That's why we get
to see time dilation, in both senses, in the GPS satellites." And the scientists need to keep rectifying
the time calculations on those
satellites because of this time dilation.
"If they don't rectify the clocks on the satellites," then the time on those clocks and those on
earth will differ. There would be
problems with GPS communication. "Interestingly,
friends,"
there is a third way of time travelling in the future. Cryosleep.
It has been shown in many films too.
"There was a recent film Passenger, you might remember." "People were travelling on a
spacecraft," they were frozen. "They were in cryosleep," "in it, for months and years, humans are
put into a condition where" they
don't age. They remain asleep. It's science fiction. "But in reality, NASA is trying to
develop a Stasis Chamber." "In
it, astronauts would be kept in a state of mild hypothermia," "in a cold environment," "in it, astronauts would be able to
sleep continuously for 2 weeks." A
hibernation of sorts. The concept behind
it is that "when a body is kept
cool,"
the chemical reactions in the body would slow down to quite
an extent. this would lead to energy
conservation in the body and would slow down ageing. "There was a case in Japan, related to
this," "an injured man
survived 24 hours without food or water,"
when his body went into a hibernation of sorts. The temperature of that man's body was only
22°C. "Normally, if a human body is
this cold for a long time," it may
lead to death. "But by chance, I
don't know with what miracle,"
"not only did this man survive," but he also made a full recovery from that
mode. After his body was discovered by
someone else. Medical reports claimed
that there was no permanent damage to
his body. His organs had slowed
down and his brain was unharmed
too. Cryosleep is something which may be developed in the future. By NASA or some other space agency. We'll have to wait and watch. But you would have noticed one thing. "All the ways I talked about till
now," were of time travel into the
future. What about the past? "Can we travel into the past,
realistically?" "I sort of
told you one of the ways to do it,"
in the Blog on the James Webb
telescope. "As of now, we can't
travel into the past," But we can
get a glimpse of the past. "Because
it takes a significant time for light to travel," "from one place to another," "even with how fast light
travels," "if we talk about
distance in light-years," it takes
years for light to travel to some places.
"So if we could get somewhere before the light reaches
there," "and then look back at
the approaching light," the light
would be from the past. That is how we
can see the past. "I explained it
in detail in that Blog," you can watch it to understand. This was getting a glimpse of the past. Can we actually travel through time into the
past? "On 28th June 2009," "world-famous physicist, Stephen
Hawking, hosted a party" at the
University of Cambridge. "There
were balloons and champagne at the party,"
but what was special about the party was that "though everyone was invited, no one
attended." Stephen Hawking had
hosted this party for time travellers.
"If a time traveller was visiting our timeline from the
future,"
they were welcome at this party. This comedic experiment was conducted to
prove that it isn't possible to travel
to the past. "Had this been
possible," we would see future time
travellers all around us. Where are the
travellers travelling to the past? Why
don't we meet them? "Theoretically
speaking, Einstein's theory of relativity," doesn't disprove time travel to the
past. "Einstein had said that in
the mesh of space-time," if a
gravitational force is put on it
"that is so heavy that the object falls through the mesh," it would create a wormhole. We can use that wormhole to travel into the
past. "It's said that to do this,
we'd need an extremely powerful gravitational field." Similar to the one of a black hole. "Perhaps a spinning black hole can
generate so much gravitational field,"
that it bends the curvature of the space-time back on itself. It would create a close time-like curve known as CTC.
You can try to understand it through this diagram. You can try to imagine it. "Nobel Prize-winning physicist, Kip
Thorne believes" that small
wormholes get created and then disappear in space all the time. But they are really small. Smaller than atoms. "And if we want to travel through
them," we would need to open them
up somehow. It would take a lot of
energy to expand them. "Not only
normal energy, but we would need negative energy also." Negative energy is a kind of anti-gravitational
energy that would repel the fabric of
space-time. Like the same poles of
magnets repel one another. Negative
energy would work in the same way to repel it.
"This would make it possible to keep the wormhole for a long
while,"
and to travel through it.
How would this negative energy be harvested? How would it be created? It's something to think about. This is purely theoretical for now. "But it is a theory by a Nobel
Prize-winning scientist, so it holds a lot of weight." "With this, you may think
that" it might be theoretically
possible to travel to the past.
"But when we talk about travelling to the past," there are a lot of hurdles. There are major obstacles for us. I'm talking about Paradoxes. Such as the Grandfather Paradox. The paradox goes like this. Suppose I go to the past while time
travelling. And I kill my
great-grandfather.
"If he dies, how would I be born?" "If my great-grandfather
died," I shouldn't be alive. "And if I was never born, I never
existed," how could I have gone to
the past and killed him? How do you
explain this? This is a paradox. Either I'm alive or I'm not. This goes against logic. There are some theories to explain this. Such as the Theory of Multiverse. The theory claims that what happened once was in one universe. "But when you travel back in time and
change something," "it would
create a new universe," creating a
multiverse. So there are multiple
universes with different things
happening. "Related to this,
there's another paradox," the
Predestination Paradox. "It claims
that when I'd go into the past,"
"and do whatever,"
everything I do shapes my present timeline. This paradox claims that things are destined
to turn out in a certain way. Things
will play out as written in destiny.
"No matter how much you try to change the past," "whatever you try to change," "and the result of that
change," would be your
present. "If you're confused, let
me give an example." "Suppose
your friend meets with an accident,"
and he dies. I hope it
doesn't "but imagine that it
happens," and you have a time
machine. "You go into the
past," and try to prevent that
accident from happening. But what
actually happens? "By going into
the past, you have done something,"
that actually caused the accident.
And then you find out that
"it was because you went into the past," "and you tried to prevent that accident," that was the reason for the accident. This was the concept in many films. "12 Monkeys," "Timecrimes (2007),"
"The Time Traveller's Wife (2009)," Predestination (2014). "Overall, there would be many logical
problems when travelling to the past."
"There would be paradoxes,"
"due to these, it may never be possible." "But travelling to the
future," "it is possible, even
today." And it will become more and
more probable in the future. "And
to get a glimpse of the past," is
currently possible too. "So in a
sense, time travel already exists."
"And as shown in films like interstellar," it was the scientific truth to an
extent. But what about Andrew Carlssin's
story? I didn't say much about it. "The story that I told you at the
beginning of the Blog,
friends," "was actually a
story published in a satirical newspaper,"
called The Weekly World News.
"Later it was printed by Yahoo News," "and several other media organisations
reported the story," as if it were
fact. "But the truth
remains," that story was a
satire. "It was fake news that was
circulated in newspapers," and
people believed that it was true. It was
a fabricated story basically. I hope you
found this episode informative. I have
made 2 other episodes in this series.
One on the Malaysian Airlines flight.
And the other on the mystery of the Bermuda Triangle. You can watch both episodes from this
playlist. On which other topics would
you like to watch more Blogs in the
future? Let me know in the comments
below. "Some unexplained,
mystery-related topics," that don't
have enough scientific explanation. Drop
your suggestions in the comments. Thank
you very much!