Albert Einstein in his infinite wisdom once said the more i learn the more i realize how
much i don't know and this has never been more true despite great advancements in
mankind's knowledge in recent years some of our greatest questions remain unanswered here are 7
of science's greatest unanswered questions be sure to let us know what you think of the video
down in the comment section below and let's jump in up why is there stuff now this might sound like
we're about to get philosophical right off the bat but don't worry this is still a science channel
scientists have long puzzled over why there's anything in the universe
the stuff you're made of is matter which has a counterpart called antimatter differing only
in its electrical charge when they meet they annihilate each other in a flash of energy
and both disappear our best theory suggests that the big bang created equal amounts of the two
meaning all matter should have since encountered its antimatter counterpart deleting them both
and leaving the universe awash with only energy it seems that in the moments after the big bang
that for every 10 billion antimatter particles there were 10 billion and one matter particles
the matter and antimatter annihilated the 10 billion and left us with the one
clearly nature has a subtle bias for matter otherwise you wouldn't exist
researchers are sifting through data from experiments like the large hadron collider
trying to understand why that is number two why does time seem to flow only in one direction
since einstein physicists have thought of space and time as forming a four-dimensional structure
known as space-time but space differs from time in some very fundamental ways in space you're
free to move around as you wish in the x y and z directions but when it comes to time we're stuck
we grow older not younger and we remember the past but not the future time unlike space seems to have
a preferred direction that physicists call the arrow of time some physicists suspect that the
second law of thermodynamics provides us a clue it states that the entropy of a physical system
roughly the amount of disorder rises over time and physicists think this increase is what gives time
its direction for example a broken teacup has more entropy than an intact one and sure enough smashed
teacups always seem to exist after an intact one and never before entropy may be rising now
because it was lower earlier but why was it so low to begin with was the entropy of the
universe unusually low 14 billion years ago when the big bang brought it into existence
many physicists consider this the missing piece of the puzzle if we can explain why the
early universe had a low entropy then the rest would follow naturally but still others think
the deeper part of the question is why is time so different from space it's one of those things
that's weird to think about at first of course time is different from the way you can walk
around your room but it's much more confusing to explain from a physics perspective for now this
remains unanswered next up the question we've all asked ourselves looking up at the night sky
are we alone in the universe for decades astronomers have been scouring the universe for
places where watery worlds might have given rise to life from europa and mars in our solar system
to planets light years away radio telescopes have been eavesdropping on the heavens but have fallen
on deaf ears and even today astronomers are able to scan the atmospheres of distant worlds
looking for the telltale gas signatures they could hint at the presence of life of course the only
way to get a definitive answer to a question like this is to actually find alien life but with all
this searching we still haven't found any for decades the fermi paradox has mocked us with
its simplicity in the 1950s fermi realized that any civilization with a modest amount of rocky
technology in an in modest amount of imperial incentive could rapidly colonize the entire galaxy
within 10 million years every star system could be brought under the wing of the empire
now 10 million years may sound like a long time but it's really a split second compared to the
13.5 billion year age of the galaxy the crux of the fermi paradox is that with billions of
stars in the milky way galaxy they're bound to be millions of earth-like planets and many millions
if not billions of years older than ours and if some gave rise to advanced civilizations
that developed interstellar travel even at the slow pace humans currently envision interstellar
travel the milky way should have been completely colonized long ago but the paradox is that despite
statistics telling us there should be heaps of intergalactic civilizations roaming the galaxy
we don't see any there are a few straightforward possible answers to this paradox the first is that
intelligent life is incredibly rare and we're one of if not the only ones the second that
the lifetime of such civilizations is short and the rise of intelligent life naturally
leads to its own destruction in today's world it's easy to see how this could be the case
thousands of nuclear-powered rockets are pointed not outward towards the stars but inward towards
ourselves superbugs have risen in prominence and the connectedness of mankind has allowed diseases
to spread far and fast it's possible that the prerequisites of an intergalactic civilization
naturally lead to their own destruction as a side note if one of these two is the answer we should
hope it's the first one because if it's the second it means we're most likely doomed and the third
and final simple solution is that they exist but for some reason we don't see them 200 years ago
if a friendly alien sent us a radio message we would have no way of detecting it today we scour
the stars looking for electromagnetic waves like radio waves or gamma rays they could come from
far-off civilizations but perhaps alien technology uses principles that we don't understand yet and
therefore we haven't figured out how to detect or maybe there's some prime directive type rule
in the intergalactic government preventing aliens from making contact with us turning from the stars
to the spreadsheets what's so weird about prime numbers the fact that you can shop safely on the
internet is thanks to prime numbers those digits that can only be divided by themselves and one
public key encryption the heartbeat of internet commerce uses prime numbers to fashion keys
capable of locking away your sensitive information from prying eyes and yet despite their fundamental
importance to our everyday lives the primes remain an enigma an apparent pattern within them
the rayman hypothesis has tantalized some of the brightest minds in mathematics for centuries
however as of yet no one has been able to figure out how to officially discover new prime numbers
doing so may just break the internet and speaking of the internet can computers keep getting faster
our tablets and smartphones are mini computers they contain more computing power than what the
astronauts took to the moon in 1969. moore's law tells us that the number of transistors
on a microchip should double about every two years but if we want to keep on increasing the
amount of computing power we carry around with us how are we going to do that and in recent
years computer engineers have struggled to live up to moore's expectations as modern transistors
are getting to be so small that quantum physics has started coming into play if transistors are
made any smaller electrons could start quantum tunneling through the incredibly thin switches
meant to hold them back as engineers have struggled to put transistors any closer together
they're now looking into new materials software improvements and entirely new systems like quantum
computing to pick up the slack but the question remains how long can moore's law be maintained
number six what is consciousness we're still not really sure we know that it has to do with
different brain regions networked together rather than any single part of the brain
the thinking goes that if we can figure out which parts of the brain are involved
and how the neural circuitry works we'll be able to figure out how consciousness emerges the harder
more philosophical question is why anything should be conscious in the first place a good suggestion
is that by integrating and processing lots of information we can do more than focus
on what's currently in front of us and imagine future scenarios things like what would happen
if i hunted that lion with a spear instead of my bare hands and this ability to imagine the future
is a clear advantage to help us adapt and survive but even though we can understand the importance
of consciousness we still don't understand how it emerges last up lucky number seven can we
find a unified theory of physics we now have two overarching theories to explain just about every
physical phenomenon einstein's theory of general relativity and quantum mechanics the former is
good at explaining the motion of everything from golf balls to galaxies and quantum mechanics is
equally impressive in its own domain the realm of atoms and subatomic particles the trouble is
the two theories describe our world in very different terms in quantum mechanics events unfold
against a fixed backdrop of space-time while in general relativity space-time itself is flexible
and we don't understand how the two theories would come together but that hasn't stopped people from
trying string theory which pictures matter as made up of tiny vibrating strings or loops of energy
has been touted as the best bat for producing a unified theory of physics but some physicists
prefer other theories like m theory loop quantum gravity and a few others each approach has enjoyed
some success techniques developed by string theorists in particular are proving useful
for tackling certain difficult physics problems but none of these have been tested experimentally
for now the long sought theory of everything continues to elude us if you're tired of all the
things we don't know try learning about what we do know with this video on the biggest scientific
discoveries from the last year have a great day and remember there's always more to learn