10 Things We Still Don’t Know About Space
10. The Origins Of The Moon
Isn’t it weird? We’re getting ready to
colonize Mars but scientists are still unsure
of how the Moon formed.
Well, it’s not like they have no clue, there
are a few hypotheses but, none of them can
be taken as 100% accurate. So, the debate
is open and new studies keep coming, presenting
different, contrasting scenarios. The most
accredited theory is that the Moon was formed
after a Mars-sized body collided with Earth
several billion years ago. But here's the
problem with the theory. If this was true,
the Moon should share its genetic structure
with the impactor rather than from Earth.
However, according to the lunar samples we've
been collecting for decades, the satellite's
composition is very much similar to the Earth's.
Which is why, in 2017, Israeli researchers
Raluca Rufu, Oded Aharonson, and Hagai Perets
proposed instead that the Moon came from a
dozen of Earth's lesser impacts with objects
ranging from 1% to 10% of its mass. This would
basically make the Moon an orbiting disk of
debris. Still, no matter how interesting it
is, this remains a THEORY. And so the mystery
goes on.
9. Why The Universe Exists
Have you ever wondered why do you, or the
humankind in general, or - why not - the entire
universe exist? If so you’re not alone.
First of all because, according to psychology,
questioning your existence happens to everyone,
sooner or later. And second, there are scientists
who are actually working on the MATTER - you’ll
get the joke in a sec - trying to give a definitive
answer.
All we know so far is that the whole universe
started with an explosion. - Basic, right?
We learn that at school. - However, it’s
not so basic after all. According to the standard
model, the explosion happens with a clash
of equal amounts of matter and antimatter.
What the antimatter is it’s still a mystery
itself but, to simplify, let’s say that
it refers to subatomic particles that have
properties opposite normal subatomic particles
- the matter. Theoretically, an equal amount
of matter and antimatter would annihilate
each other, ending into nothingness. Which
makes no sense because we exist, the UNIVERSE
exists. So, how’s it possible?
That’s exactly what researchers have been
trying to find. The answer is still unknown,
but they’re working on that.
8. Does The Multiverse Exist?
If you can cope with the fact that our whole
existence literally makes no sense, now ask
yourself another - less existential - question:
we’ve established that our Universe exists,
does the Multiverse exist too?
The multiverse is a cosmos in which there
are multiple - well infinite - universes and
according to recent studies, it is a plausible
option. In 2017, the UK’s Royal Astronomical
Society published a paper on the so-called
Cold Spot, a cool patch of space seen in the
radiation produced by the formation of the
Universe more than 13 billion years ago. The
spot has been puzzling astronomers and cosmologists
for years. The hypothesis of the research
is that the Cold Spot is an optical illusion
produced by a lack of intervening galaxies
and, perhaps it was caused by a collision
between our universe and another parallel
one.
Put it like that, the Cold Spot should be
taken as proof of the existence of the Multiverse.
However, nothing is certain and one single
hypothesis isn’t enough, according to the
scientific method. Which is why many among
the scientific community, including Paul Steinhardt
- one of the original architects of the multiverse
theory - are still sceptical about it.
7. Where Is Planet 9?
Pluto has not been a part of the 9 planets
of the solar system since 2006. However, researchers
worldwide are in pursuit of a missing Planet
9. Why are they so sure there’s a ninth
planet?
Good question. The truth is that they’re
not a hundred percent sure BUT the presence
of a ninth planet would actually explain the
orbital trajectories of out-there celestial
bodies. Let’s take, for example, Sedna,
a planetoid discovered in 2003. Sedna has
roughly half the diameter of Pluto and is
located about 85 astronomical units from the
Sun - about THREE times as far as Neptune.
In 11,000 years the dwarf planet has swung
from 76 astronomical units to over 900 and
then back again. Which adds a further question:
How can such a massive object reach such an
extended orbit without getting completely
ejected from the solar system altogether?
The most likely answer is that there's a massive
gravitational body out there - let’s say
Planet 9 - pulling things out of whack. But
if so, how come we can’t find such a massive
planet? One reason could be we won’t have
the telescopic technology to detect it yet.
6. The Fermi Paradox
The problem here is that it’s not like we
don’t know what the Fermi Paradox is, but
rather how we can’t seem to overcome it.
What’s the Fermi Paradox? Well, let me put
it this way...it’s highly probable that
across the whole universe - or multiverse
- we’re not alone. If that’s the case,
then, why haven’t we heard from any other
life?
This is the Fermi Paradox, which takes the
name after physicist Enrico Fermi, who first
posed the question in 1950. Since then, scientists
have been working on the answer. Some believe
that the silence is the product of the Great
Filter, an evolutionary wall impermeable to
most life. This means that we're not receiving
communication because we’re either the most
or least advanced civilization. Others, such
as SETI - Search for Extraterrestrial Intelligence
- suggest that most of the universe is colonized
and communicating, but WE are stuck in a desolate
area - like when you visit your grandma in
the countryside and there’s no reception.
However, the most supported theory is that,
if others out there are transmitting signals,
we’re probably just listening wrong, like
we don’t have the right technology or understanding
of the universe yet.
5. The Big Crunch
You may have guessed by the name the Big Crunch
theory has something to do with the Big Bang.
We can say the Big Crunch is based on a specular
process. As everything started, so it should
end: with a massive explosion.
According to the theory, all the mass in the
universe will eventually give way to gravity
and be drawn together into a smaller space,
then merge into a dense and hot point and,
ultimately, get wiped out. - how fun.
Still, not all experts are on board with the
theory. In fact, some argue that such a hypothesis
doesn’t quite make sense with what we currently
know about history. Especially, in regards
to ongoing studies and discoveries on Dark
Energy. According to some in the scientific
community, over the past few billion years,
the dark energy has kept pushing the universe
outwards. Therefore, if the universe keeps
expanding, how exactly will it collapse on
itself?
Fair point. Still, we can’t rule the theory
out because, just like we don’t know how
the Big Bang started yet, we might find the
answer, after all.
4. Mysterious Radio Signals
Remember one of the answers to the Fermi Paradox
could be we’re unable to understand the
signals we receive? Well, that’s exactly
what could be happening right now.
Last February, the scientific community revealed
that an object 500 million light-years away
appeared to be transmitting signals every
16 days. The discovery has been made while
in the process of the collaboration of two
types of research: the Canadian Hydrogen Intensity
Mapping Experiment and the Fast Radio Burst
Project. Over the course of four days, the
signal would release a burst or two each hour.
Then, it would go silent only to come back
after 12 days.
The signal is in FRB - Fast Radio Burst - bursts
of radio waves in space that last just a millisecond.
The problem? Astronomers can’t figure out
what causes them and why they occur in an
interval of 16 days. They have been able to
trace back the signal to its home galaxy,
but can't go further than that, for now. Researches
continue hoping that by tracing the exact
origin of the bursts, the mystery will be
solved.
3. How Many Exoplanets Are There?
Some of you may not know or remember what
exoplanets are, so, before deepening further,
let’s recap briefly.
According to both NASA and ESA, an exoplanet
is, by definition, a planet outside our own
Solar System. To date, we were able to map
and confirm more than 4000 exoplanets. Even
if part of different systems, they may have
analogies with our planets. Some are massive
like Jupiter for example, others are rocky
or icy just like ours. Others may differ slightly,
so massive planets can orbit much closer to
their host star than ours do to the Sun. Then,
many simply do not have analogues in our Solar
System. The possibilities are endless, which
is why the pursuit of exoplanets is an ongoing
process. Therefore there’s no way to tell
exactly how many exoplanets are out there.
As far as we know, the Milky Way could contain
around 100 THOUSAND MILLION exoplanets.
They are extremely important because, among
them, there may be planets with the right
conditions to host life as we know it. That’s
why it is so important to keep going. To date,
more than 4,000 exoplanets have been discovered
and are considered "confirmed." However, there
are thousands of other "candidate" exoplanet
detections that require further observations
in order to say for sure whether or not the
exoplanet is real.
2. Space’s Chicken And Egg Dilemma
Yes, it looks like scientists have their own
causality dilemma. Which came first: the galaxy
or the black hole?
First of all, we - mere mortals - have to
understand why the two are connected. So,
the general consensus is that things start
off with the galaxy. The reason you can find
a black hole is that the gas and dust in it
will go into the black hole and feed it to
grow its mass. However, research from astronomers
examining radio-frequency pictures that provide
data about early galaxies suggests the black
holes may have gotten an early start. Back
in 2012, an international team of astrophysicists
discovered a galaxy with a black hole with
a mass that is t 100 times larger than expected
based on the typical galaxies. And this, according
to the research team, leads to believe that
black holes formed first and then, somehow,
they formed a stellar galaxy around them.
Still, according to other scientists - and
NASA too - such assumptions can’t be taken
for certain. Therefore, the question remains
one of the great puzzles of our universe.
1. We Don’t Know Our Own Biology
You made it till the end of the video to find
out that the most important thing to advance
in space discovery is take a step back and
look at yourself. Why? What does human biology
have to do with space research?
Actually, a lot! From roles in the health
and nutrition of humans during spaceflight,
through to the question of life on other worlds,
microbiology is fundamental to the exploration
of the cosmos. Therefore, a LARGE focus of
space research has been focusing on studying
our microbial world. The same teams are also
studying what makes us differ from “alien
life”. I mean, space exploration has been
focusing on looking for forms of life as WE
know it. Maybe, the reason we still haven’t
found what we’re looking for is that we
haven’t looked outside of the box.
Now, microbiology studies are paying off.
There’s recent evidence that conditions
different from the one we know to support
microbial life exist elsewhere. Not only on
Mars but on Saturn's icy moon and Enceladus,
whose hydrothermal activity and the production
of molecular hydrogen and carbon dioxide may
sustain methanogenic microbial life.
