It’s a calm, clear night, and you’re lounging
on the grass, staring up at the twinkling stars, wondering about the vastness of space
and the mysteries of the universe. As you stare in awe at the cosmos, your mind
is filled with questions about the universe and our place in it. How many stars are there? How much of space can we even observe? Are we really alone in the universe? It may seem like we’re well on our way to
understanding the cosmos, but in reality we’ve explored less than zero-point-one percent
of the entire known universe, and there are still countless mysterious space events that
astronomers can’t explain. Humans have been watching the skies for millenia,
observing cosmic events and trying to interpret and predict their effect on events on earth. After centuries of stargazing, we now know
more about space than our ancestors ever could have dreamed - we know that earth is a planet
in the solar system that orbits our sun; we know that our solar system exists in the Milky
Way galaxy; and we know that there are countless other galaxies, stars, and planets in the
universe. We know that stars can “die” in spectacular
ways, and we know that our universe is constantly expanding. Perhaps most importantly, though, we know
how little we actually know about the universe, and we know that we will never know everything
about the cosmos. As impressive as humanity’s knowledge of
the universe is, there are many more space mysteries than cosmic answers when it comes
to our universe. Take, for example, the recent discovery of
The Cow, a mysterious explosion in deep space first observed in 2018. Astronomers and hobbyists alike were mystified
when they looked into their telescopes on June sixteenth and saw an unusually bright
glow in the sky that definitely hadn't been there the day before. Even seasoned astronomers thought this was
“super weird”. At first, experts thought they were looking
at a fairly common event somewhere in our galaxy - perhaps a white dwarf, the burnt-out
remains of a star that was consuming material from a nearby star, causing it to flare up. But, once astronomers analyzed The Cow’s
light spectrum, they realized that the thing they were seeing was not in our galaxy at
all - it was actually much farther, up to two-hundred million light years away! A white dwarf would never be visible from
that distance, and the object wasn’t displaying the hallmark changes in brightness that we’d
expect from a supernova. Experts were transfixed - The Cow didn’t
behave like any space events they were used to - it just appeared one day, and continued
to burn hot for nearly three whole weeks. The unusually long and steady duration of
the light pointed to some sort of massive explosion deep in space - we just have no
idea what caused it. Some think it was an unusual kind of supernova
where the star’s core collapsed inward after it exploded. Others think it was a tidal disruption event
- a star being ripped apart by a black hole. But, black holes big enough to tear apart
a star are usually only found at the centre of a galaxy, and the bright lights of The
Cow were coming from the outer edge of the galaxy’s spiral arm, leading some to theorize
that a smaller black hole is responsible - but we’re not sure if those kind of black holes
even exist! Anna Ho, a researcher from the California
Institute of Technology, finally decided to try observing The Cow using a submillimeter
array, which sends short frequency radio waves into space. This wouldn’t normally work, because the
phenomenon we’re trying to observe usually disappears before the radio waves can reach
it. But The Cow’s unusually long and bright
existence gave the waves enough time to reach it, allowing researchers to monitor the event
for several days before the signal dramatically dropped off. Based on this data, Anna theorized that the
light we could see was the result of the shockwave from some unknown giant explosion travelling
through a cloud of dust and gas, emitting light as the gasses heated. If you’re surprised by the fact that scientists
can’t agree on an explanation for an event that we can clearly see with our own eyes,
you may be wondering what else we don’t know about space. It turns out, there’s plenty we don’t
know. Take, for example, black holes. Common in both sci-fi and real scientific
theories, you might think we have them all figured out, but it’s actually shocking
how little we know about black holes. Black holes are giant masses of cosmic quicksand
that are formed when a giant star collapses and all of its mass implodes into a tiny area
of such intense gravity that even light gets sucked in. Because no light can escape from a black hole,
we can’t see them with our own eyes. We only know that they exist because we can
observe how the stars and gasses closest to them behave. The black hole’s super strong gravitational
force pulls any nearby objects towards it - when a star is close to a black hole, it
also creates a type of high-energy light that can’t be seen with the naked eye, but can
be detected using special satellites and telescopes. The types of black holes caused by an imploding
star are called stellar black holes, and they can be up to twenty times more massive than
our sun. Some black holes are as small as a single
atom, but have the mass of a large mountain. At the centre of each galaxy in the universe
is a supermassive black hole, which scientists believe were created at the same time as the
galaxy they are in. Sagittarius A is the name of the supermassive
black hole at the centre of our galaxy, the Milky Way, and it has a mass greater than
four million of our suns. Before you start panicking about how the Earth
is slowly being sucked into the black hole at the centre of our galaxy, let’s move
on to some other, less stressful space mysteries. We talk a lot about all of the different stuff
that makes up the universe -the planets and stars and solar systems and galaxies - but
we don’t often think about the absence of stuff in space. During the Big Bang, all of the matter in
the visible universe that had been compressed into a single point began rapidly expanding
outwards. More than thirteen billion years later, what
started out as small variations in the density of matter have turned into huge, empty voids
in space. The largest one that we know of, the Great
Void, is one and a half billion light years away from us, and measures more than one point
three billion light years across. To be fair, these voids aren’t totally empty
- they are filled with dust, gas and even dark matter - but the density of matter in
a void is less than a tenth of the average for the rest of the universe, making them
quite unusual. So, what is this Dark Matter that’s floating
around in these space voids? With all the talk about dark matter and energy
in recent years, it may seem like we’re well on our way to understanding these dark
forces, but much like black holes, we can’t actually see dark matter or dark energy, and
what little we do know about them is purely guess work. We know that the universe has been expanding
since the Big Bang, and for decades astronomers theorized that the rate of expansion was slowing
over time due to the effects of gravity. However, all their theories went out the window
in nineteen ninety-eight when the Hubble Space Telescope made a shocking discovery. By observing a very distant supernova, the
Hubble proved that the universe had been expanding more slowly in the past than it was today,
meaning that the expansion of space was actually speeding up, not slowing down. This discovery stumped the experts. No one was sure exactly why the expansion
was accelerating - perhaps it was a problem with Einstein’s theory of gravity, or the
existence of some unknown energy fluid in space? Even though astronomers couldn’t explain
this phenomenon, they gave it a name - Dark Energy. We know that Dark Energy exists - and how
much of it there is - by how it affects the universe’s expansion. Scientists have estimated that up to sixty-eight
percent of the universe is made up of dark energy. Some experts also theorize that dark energy
is evenly distributed through both space and time - meaning that as the universe expands,
it creates more dark energy. Dark energy does not have its own local gravity,
but instead has a repulsive effect on the universe as a whole, causing the expansion
of the universe to accelerate. Scientists need much more and better data
to make any headway in understanding dark energy. If Dark Energy makes up sixty-eight percent
of our universe, dark matter makes up another twenty-seven percent. That means that all of the so-called “normal”
matter that we can see and observe, even with our most sensitive equipment, makes up only
a measly five percent of the entire universe! That’s a little bit unnerving to think about... Like dark energy, dark matter is invisible. It does not interact with electromagnetic
forces - it doesn’t absorb, reflect or emit light - so the only way we know it exists
is by observing the effects of its gravitational pull on other matter. If dark matter were created during a controlled
particle collision at CERN’s Large Hadron Collider, the dark matter would escape undetected
by their equipment. But, scientists could infer its existence
by measuring the amount of “missing” energy after the collision. One of the most interesting theories about
dark matter is the existence of a “Hidden Valley” - a parallel world made entirely
of dark matter. If imagining an entire parallel world made
of dark matter is making you uneasy, wait until you hear about the evil twins of outer
space. Subatomic particles like protons, electrons
and neutrons all have an evil twin - antimatter. Antimatter particles have the same mass as
normal particles, but the opposite electrical charge. As a result, antimatter destroys normal matter
on contact. That sounds terrifying, but don’t worry
- there’s very little antimatter in the universe, and it can actually be harnessed
for good. PET scanners work by creating anti-electrons
and using the energy that’s released when they are destroyed to create sophisticated
images. Even more wild than evil twins is the theory
of Quantum Entanglement. In quantum entanglement, two particles in
completely different parts of the universe can actually be linked to one another, and
will mirror the state and behaviour of their partner over great distances. At first, this seemed to break some pretty
fundamental laws of physics, since they thought that the signals sent between particles would
have had to travel faster than the speed of light. But eventually, as scientists began to unravel
the puzzle of quantum mechanics they started to understand how this “spooky action at
a distance”, as Einstein called it, actually works. It would take a whole other video to begin
to explain quantum mechanics, but the basic idea is that unobserved particles exist in
all states simultaneously, and takes on one state only when it’s observed and measured. It’s like that old riddle - if a tree falls
in the forest and no one’s around to hear it, does it make a sound? As you lay back on the grass and take in the
marvel above you, there’s still one space mystery tugging at your curiosity - are we
really alone in the universe? This is yet another mystery of space that
continues to stump scientists. According to the Fermi Paradox, the universe
is so massively huge and so unimaginably old that all probability points to a high likelihood
of extraterrestrial life. And yet, we have no evidence of life outside
our own planet. Enrico Fermi, the Italian physicist credited
with sparking this debate, theorized that any civilization with modest rocket technology
could colonize an entire galaxy within the span of ten million years - the blink of an
eye in the timeline of our universe. It’s entirely possible that life has existed
outside earth, and that the lack of evidence is more of a problem of “right place, wrong
time” than proof that we truly are alone. If you really want to have your mind blown
as you gaze in wonder at the stars, consider the Multiverse Theory - the possibility that
our universe is just one of many, possibly infinite universes. The fact that this is a valid theory currently
being studied by renowned scientists just goes to show you how little we really understand
about the nature of the universe. As fascinating as space mysteries are, the
lack of definitive answers can be frustrating. Your best bet is to just enjoy your time laying
in grass, staring at the cosmos. And, if you’re lucky enough to see a shooting
star, maybe you can wish for an answer to these space mysteries that astronomers can’t
explain! If you thought this video was crazy, you have
to check out “What If You Die In Space?”, or this other great video.
They have several videos about the UFOlogy just wondering if their videos ade credible sourced?
No.