Dear friends and colleagues from the academic community. I am very glad
that we met here mob-handed in this auditorium of the famous Faculty of Science, Charles University.
It is with pleasure to introduce the speaker of today's contribution Jan Mestan,
whose contributions on facebook page of Faculty of Science induced a huge stir
that we decided to organize a lecture where the discussion may continue
directly in a verbal form from the academic plenum. So, I thank you for coming and give the floor to the speaker.
Can we turn off the light?
Turn it all off!
Good morning, I would like to thank to the organizers of today's lecture and discussion.
I would like to thank for the invitation.
My name is Jan Mestan, I studied at the Faculty of Science, majoring in Geology
where I focused on seismic sources and tested a small-scale seismic source.
So I went rather in the direction of geophysical methods. Of course, I am
also interested in hard geology, geodynamics and in the way Earth works as a planetary body.
The today's lecture has two parts.
In the first part, this is the title, we will show some basic relations between
the continental crust or lithosphere and the oceanic crust or lithosphere.
And in the second part, we will show consequences that may result from these relations or result from them.
The first slide.
At the beginning, we should mention that the Earth, as a planetary body, contains two basic units.
From the geological point of view.
We distinguish the continental and oceanic crust. The continental crust is defined by an interface,
approximately at depth 35 km. Here in Czechia or for example Bavaria.
It is defined by the Mohorovičić discontinuity.
In relation to the continental crust, I brought a few samples.
Unfortunately, I have no samples of the oceanic one. I don't have any basalts here.
But I have here some rocks that I collected in the Kamenne Doly Quarry near Pisek.
These are the light granitic. There you find feldspar, quartz, tourmaline.
And then, here something darker, we say melanocratic, these are syenites to durbachites with some mafic
to ultramafic enclave. These are types of rocks, very hard rocks that can be found for example here,
in the Bohemian Massif. Just in order to make it a little bit interactive.
So, the continental crust, the oceanic crust, we would rather show some picture, there is no point in talking
about details. I think that everybody has already heard about the two terms,
and that it's a little bit clear what are the differences between them.
You all have probably already seen this map.
It is a physical world map. There you can notice some basic relations of the planet Earth.
This means, here we have the Americas, here we have Africa, Eurasia, Australia.
These are the continental blocks, this is the continental crust.
The continental crust is characterized by the fact that there are extremely old parts in it.
This means for example here in Canada or in Australia, there are rocks and parts of some massifs
that are older than 4 billion years or around 4 billion years or 500 million years old,
billion years old, ok, so the continental crust is very old.
Compared to the oceanic crust. In order to show the oceanic crust or lithosphere,
for us, it doesn't matter since the crust is max. 35 km here at our place,
the oceanic crust is a bit more thinner. If we took the lithosphere,
it would be a bit more thicker. There is a part of upper mantle.
For us, we will be self-sufficient with the term crust since we will have a look
at the continental blocks from above. So, we don't care about any stratification
and what is at the depth 100 or 200 km. What we see here,
on the physical map, are large areas of oceans, here large areas, oceans, and here, I have to say something.
The terms ocean and oceanic crust are completely incompatible.
There terms are completely incompatible.
The name ocean is used for the water mass. And the water mass,
it can be seen simply here, Atlantic, Pacific, Indic.
And so on. And the ocean, the water mass, lies usually on the oceanic crust,
but also on shelves and also on continents. So, there exists no sign
of equation between the ocean and oceanic crust. And this map, if you study the Earth as a planetary body,
is unsuitable.
It is unsuitable since you don't get any information about the exact relations between the oceanic crust
and the continental one. You don't have any relations there.
You don't see any relation to the relief. You don't have any geological age there,
which you could determine and that could guide you.
So, if we want to study Earth as a planetary body, we would use this map.
This is a map that was produced by National Geographic.
The map is underlaid by a map of oceanic crust ages. What we see there?
The differences are immediately evident.
You see that the maps are diametrically opposite.
For example, you see here the mass of water, but here you see that there are some continental blocks.
This is the Zealandia. You simply see there a lot of structures, ok,
there are a lot of structures on the oceanic floor. And you cannot actually study these structures here.
If I describe the map in more detail, here we see some numbers.
180 million years, 140 million years, today, also 180 million years and so on.
These dotted lines are ridges. There is generated basalt, there arises basalt,
and gradually, the basalt solidifies and the new one is being made and solidifies
and the new one and solidifies again.
And it is actually constantly spreading. This means that at the ridges,
if we had the chance to date the basalt, radiometrically, we would find out that it is actually
a recent basalt that arises today.
If you went farther away from the ridge, along the ridge lines or transform faults,
if you went farther away, you would find out that the basalt is older
and older and older.
You would get up to 180 million years. The term 180 million years, it is here,
as you may notice, it is the highest, it is actually the highest one.
It is here, it is here, here is also around 140, 180, here 180, 180, here 140. 180,
around Antarctica 180. Of course, the observant person notices
that there some small violet spots. There the age, yes, is around 300 million years.
This is actually the oldest oceanic lithosphere that may be studied on Earth today.
You all probably know that, it is known from the end of 16th century, then it was repeated,
then there was the 20th century, geologist Bullard, and others,
Wegener, Wegener's Pangea, that these continental blocks fit together. This means,
you all probably know, everybody notices it when looking at the map,
that South America with North America fit together with Africa.
This is a certain fact. The question is, when you may connect the Atlantic
together in 180 million years, is it also possible to connect the Pacific in 180 million years?
Is that possible or not? Of course, people have been asking it almost the last hundred years.
Ott Hilgenberg published his work in 1933 and said that Earth could expand.
That we could put the continental blocks together and make the Earth smaller.
This was Hilgenberg 1933, then it was Carey, geologist Carey, Australian geologist, this was for example 1975,
80s, he already died, I guess in 2000. And then there were other people,
for example an Australian geologist again, Maxlow. And others. There were comic makers,
which tried to put it together in some way. We will show it. And. So.
This is a picture from the animation from comic maker Neal Adams.
Neal Adams made in the year 2007 a work, a reconstruction. He tried to take the continental blocks
and put them together when Earth is made smaller. Unfortunately,
he did it so that he took Australia and put it actually to Alaska.
So he took Australia and in this way he put it here. But it is not logical since the floor,
the oceanic crust, was generated in this direction. So, how could he put Australia there?
This was 2007, then there is for example a work from Sudiro, 2014.
This is a work that tells us that Earth's expansion is a pseudoscientific belief.
He definitely says that Earth is not expanding, that it is nonsense, the article is somehow
Transition of Expanding Earth Hypothesis to Pseudoscientific Belief.
So, this is a picture from Sudiro's work. Unfortunately, Sudiro did it wrong as well.
Because he took the Australia, he didn't respect these lines again,
he didn't respect them at all, he didn't care about it. He simply took Australia, and even,
he didn't respect the fact that there exists Zealandia, ok, he simply,
it evaporated for him.
So, he took Australia and he directly put it to South America,
of course, it didn't fit as well. It didn't fit again. So... Eureca! It fits!
In fact, a fundamental element that we can notice on the oceanic crust are ridges and ridge lines
or sometimes also called transform faults, lines-transform faults,
and so, these ridges are often symmetrical. Ok, this means,
the continental blocks were connected together, they were together, and then, gradually, they separated
from each other. This is simply a symmetrical ridge.
I will also show it here in this picture. This is simply symmetrical, this is a symmetrical ridge, this is
symmetrical ridge. And such a symmetrical ridge does exist between the eastern continental edge of Zealandia
and Antarctica. Ok, so this is simply this ridge. These are the wrinkles
that arise around the ridge, they are the same, it is wrinkled similarly to the area between
the Americas and Africa. And here, there are areas of smoother basalt. This is probably related
to some heat management. Simply, when the Earth has more heat, so, you know it with plaster,
so if there is more heat, it was liquid, it became smoother,
when there was less heat the structures could be created, they solidified there.
And I will show it here on this map. So, what we did.
We took the eastern continental edge of Zealandia and followed these lines and connected it here with
Antarctica, ok. What will happen? If we connect it together in this way,
then this edge fits here, to the tip of South America. This means that this
block could, could actually correlate here with the coast of South America,
with its continental edge. It turned out as a good requirement, because,
I will show another image here. Here you see, this is the fit, this is Zealandia and this is the block
of South America. You can see the original separation from Antarctica, it is here,
and here is even seen the bevel, ok, it fits perfectly, bevel, here the arc, arc, then it goes back,
back, and an arc again. So, it fits really very precisely. These maps are the best maps that you can
use for this type of study. The maps are based on VGG, Vertical Gravity Gradient,
this means, the continental crust and the oceanic crust have different densities. And since they
have different densities, you can distinguish between them with a certain method.
The optimal one is related to some gravity field. This is simply a fact. Another fact is that the connection
of the two continental blocks took place 180 million years ago. If we have a look at the age of basalts, ok,
here at the edge, then it is around 180 and 140 million years. 140, 180. So, here we see that probably
the most logical, the most logical explanation, for me, would be that if we put it all together,
we must make the Earth smaller. To this, if someone was interested into it,
I will present this thing, if, someone, I hope so, if I get the chance, I already submitted it,
so if someone wanted to look at it, here is the abstract, but it is basically the thing I was talking about.
Maybe now, it would be good to... Here, if some of you wanted to open this application
in your computer at any time, you have the chance to look at the VGG data here on the 3D globe,
you can calmly try it alone to connect the continental blocks, it is here on the website
of The Guardian or you can find it simply also on the official pages.
It was made by the people from Californian university San Diego. And you can this globe,
gorgeously, gorgeously actually study, ok, here you for example see, as we were talking
about the Zealandia, this is the eastern edge and this is Antarctica. So, actually this block,
you may trace it gorgeously ok, how the blocks fit together, ok. So, you may simply trace,
similarly, you have another situation here, ok, here you also have, you may perfectly trace the way
the continental blocks wander to each other. This means, here smoother, smoother, here it is
a bit more wrinkled, ok, and the situation is the same here. So, if we wanted to visualize the ridge more in
detail here, in a high resolution, you can precisely trace the ridge, these ridge, ridge lines.
We will probably get back to this application during the discussion.
Beautiful here, beautiful are these... There is a large belt with a structure of turbulent flow. As you may notice it.
Up to the Himalayas, the Himalayas, here a part of this belt are for example the Alps, the Carpathians,
the Himalayas, the Pyrenees. Ok, it is a large and long belt. We will get back to this map.
I won't waste time with it. Would be ideal, for you, if you wanted to try it, ok,
in some way to play with the map and for example try to connect something alone.
You have vector editors today, it is no problem, you can take the map in 2D. And so on.
Here we finished, we already showed this, So, now there is the second part of the lecture and
these are the consequences resulting from the continent fitting. A good question would be, ok,
if Earth has been expanding, expands, we should be able to measure it somehow. So this is one of the maps
from the year 2014 where you see the vertical motions of geodetic stations.
You see that Greenland grows significantly, I read that Iceland even exponentially, then you have Norway,
here the north, the north of the United States, Canada and so on. The conventional interpretation
would be that it has something to do with postglacial rebound. Ok, so some isostatic uplifts,
there was simply ice and now it is lifting up. Ok, this would be some conventional interpretation.
To these measurements, I have a few notes. What are the troubles you deal with when performing
the measurements. Ok, so simply this is a map. In 2011, two basic... Two interesting works were published.
One from NASA and one from a group of authors from the Wuhan University, the Shen's group.
I have here the paper from the group from the Wuhan University. If someone wanted to look at it, just at the
results. These works were different. NASA told us that Earth is not expanding and didn't expand. It simply
convinced us, it was in media. But the author from the Wuhan University told us, no,
it is expanding and has been expanding over the last several decades, but only a little.
Only in tenths of a millimetre ok, it is really a little. I tried to, based on these 2 works, to notice the problems,
the basic problems the authors deal with. This means, for example anomalous values cutting.
In the papers, there are mentioned values when for example, you have a certain station, vertical one, and
you measure a motion by 5 meters. They take it as irrelevant to the expansion,
but what if the expansion goes just in the way that it compensates suddenly always on a certain place?
We will show that probably yes. It is not like that it goes 'according to regulations'. Ok,
nothing in the nature works 'according to regulations'. This was the anomalous values
cutting. The lack of data from oceanic floor. Have a look at the map. How much data
do you have from the oceanic floor? These data, they are, I think, some islands. Here some islands. You have
no data. So, we have no information about what is going on with the oceanic floor. So, this is, this is certainly
a problem. I could paint here, or not, this will be to the next picture. So, here, I already said that,
postglacial rebound, ok, it is certainly a possibility. That we have a climatic period
that the glaciers retreat. It is loaded, then the glaciers melt, then it compensates,
then glaciers again, and it goes again. This is a possibility, and... But these,
then you have for example the Himalayas. The Himalayas grow, it is a large block
that grows more than 6 cm per year. Ok, so. The authors should take it into account as well.
A lack of data and reliable data in general. So, reliable data. You would also probably
conclude that you cannot measure vertical motions on the desert, on water areas.
Soils. In the case of soils, you have easily a subsidence by one meter. So, the Earth's surface is roughly
so alive and you want to measure something like this.
This is a big problem. Glaciers. You cannot measure, you simply know nothing. So, here, you are also not allowed
to measure. You may measure only somewhere and you must hope that what you measure somehow correlates
with your hypothesis. It is, it is a big challenge. A big challenge for future cartographers, geographers,
geodesists, to deal with it somehow. Here, I just wanted to show a few photos, this is an island in Pacific that
arised in only 3 years. As I said, we have no data from the oceanic floor, so we don't know
what is for example here, in this area, whether it goes up by 10 centimeters per year.
We don't know it, but as soon as the island hatches out, in this way, in 3 years, we learn about it.
We learned about it and it was a sensation in media a few days ago. So I deliberately
gave it here, maybe, some of you read about it, so this is one of the examples.
Another example, here it jumped up a little bit, this is another example. In 2016, a strong earthquake hit the
area near New Zealand. The result was an uplift, an uplift of the floor again,
oceanic, by 2 meters. This was in approximately 1 second, it compensated by 2 meters, a big area,
you can find it on the internet. There are scenes from the helicopter, it is a wide area,
and the assumption is that it is a permanent, a permanent physical feature of the relief.
So, this is an example from the last two years. What we measured directly
in relation to the oceanic floor. This is a map that you all maybe know or have seen
it in some variants. The map shows us horizontal motions measured on the Earth's surface.
You take some GPS station, put it somewhere, and the GPS station is able to measure its position.
You simply have some WGS84 ellipsoid, this is some reference ellipsoid that is defined
by some coordinates, geographic latitude, longitude, and the satellite, no, station actually measures the
coordinates, where it is on the ellipsoid. And, so, you may then equivalently evaluate
some absolute motion, this means for example centimeters, it doesn't move too much somewhere,
like for example here in Antarctica, here Australia moves a lot. What you may notice on the map is
the fact that the arrows in some way correlate with the ridges. Here you have the Mid-Atlantic Ridge.
The arrows tend to go from the ridge. Here, you also have a large ridge system.
The Australia as well. It goes from here, then there, the ridge system rotates, we already seen it, rotates around
the South America, here, and here another one. For example South America,
South America a motion towards the north, this could be maybe interesting for someone.
And to this, I wanted to paint a picture, because, these are the frequent questions.
A frequent question is, but we can measure that the plates move! Ok, I will paint here a picture,
let's have a, let's have a system of coordinates, this is the z-coordinate, this is the x-coordinate.
We have Earth, we cut it from pole to pole, we cut it in polar direction.
I will paint the Earth, now try to imagine that for example, that for example here and here is some margin
of the continent, and this is the oceanic crust. Here is the ridge, here is the ridge, you take some station,
and you put it for example here, so you have some distance A. And you put here
the station. If I made the sphere bigger, I will make it bigger this way,
then I make it bigger this way. You put the station inside a hard basalt, but it's simply hard.
So, this distance A is the same all the time, the distance A is the same, so, the distance A, distance A,
here you have the ridge all the time, it grows this way, the age grows in this way, here is for example
180 million years. The age of the oceanic lithosphere. It grows, ok, but what is changing is yet the angle,
since, first, you have some angle alpha, here you have angle beta,
and here the angle gamma. And since you measure with the stations the coordinates, then these coordinates
change, ok, so, the coordinates change. And there is a question whether they change by the mechanism
that I have painted here or they change because of some plates. And because these plates
move against to each other in some way.
Now, I am jumping further. Since a majority of you read the discussion on facebook,
I think, you already have a little background why was the discussion created. It was created since I had an idea.
The idea was that Earth could be a chthonian type planet. A chthonian planet.
A chthonian planet is a planet that was a gas giant in the past.
And because of its close proximity to the mother star or other various reasons, its outer
shells were cut away, the core became naked. And the core, the core was previously pressurized
to quite high densities. And so there is a question whether Earth could be such a core of a gas giant.
But, Earth is far away, approximately 150 million kilometers from the Sun, it is simply too distant.
So that Earth, in some way, that Earth orbited the Sun, and that the solar wind removed, removed the shells,
it is out of the question. Another thing, we know that the continental crust is old, the first derivatives of the
continental crust are 4 billion years old. At this time, there were no pressures like for example
1000 GPa. Today, in the core should be hydrostatically 360 GPa. If it was a gas giant,
then here at the surface was a pressure like for example, 5x, 5x higher than in the core today.
So, we must make it so that the shells of the gas giant were stripped away suddenly at the beginning.
There exists something like Herbig-Haro objects, they are well studied. These are objects that last,
phenomena that last a few centuries. They occur in the vicinity of borning stars. They are like,
if I had to compare their speed with something we know, then their speed is approximately 2500x
higher that the speed of a hurricane on the highest degree number 6. You can simply realize that this could
have a decent force. In order to remove some helium, hydrogen and other shells.
The objects, usually, when the star spew them out, it has a mass of for example 20 Earth masses.
It goes to few parsecs in the polar direction. The distances are unimaginable. In the equatorial direction,
it goes to shorter distances. If Earth, or if planets were in the polar direction,
which is nonsense, I can't imagine, if the planets stayed there, after the process.
So, if you wanted to find it, there is a lot of literature about it on the internet, they deal with it a lot at
the European Southern Observatory. Someone even did a PhD about it there, there you have thousands,
or tens or hundreds of links to works that deal with the observation of Herbig-Haro objects.
The idea was that Earth had an icy sarcophagus, so that it was packed in ice. This means,
the sarcophagus had surely a thickness of say tens kilometers. And since we know that the expansion is
calm, this is measured, yet the basalts, the basalts go gradually, very slowly,
very slowly, so maybe only a little would suffice in order to keep the Earth, to keep it,
and this could be the sarcophagus. And since we know that the luminosity from the Sun
increases, it has an increasing trend, then it suggests itself that Earth has been simply
+/- in this form, for about 4 billion years, and as this value increased, increased, increased,
this started to melt, and it gradually melted, and as it melted, melted, melted,
it weakened and the Earth came into bloom. So, this is an idea, otherwise,
we know these bodies with the sarcophagus in the Solar System. I named it sarcophagus,
but it is simply an icy shell that has a thickness for example 50 km.
This is the moon Europa at Jupiter. There is also an assumption that after some time it will melt
completely. But I don't know, in, say, billion years. Here you see a meteorite hit, a hit into the sarcophagus.
Of course, there were meteorite hits, the sarcophagus had to catch a lot of material. Briefly to the basic
problem, from the view of physics.
The basic problem when solving the relaxation of these cores are, are these two forces.
This means, these are the repulsive forces of the ultracondensed state vs hydrostatic loads
and resistance forces. This means, when you go in the Earth to the depth, the hydrostatic pressure increases,
this means loads. And you have some resistance as well. The rocks that are circulating
among you, as you may notice, are extremely hard. And the resistance is a really significant element,
and in the case of the sarcophagus, the resistance would play one of the key roles as well.
So, the core could be stable, the forces are balanced. You know it from high school
physics. A zero resultant force means that the body is at rest, nothing happens,
but if the interior wanted to get out in some way, then the core could relax.
I already said that, the ultracondensed state, it is a state of matter, when you, when
you have the granite in your hand, then the fundamental interaction that determines the constitution
of the granite, so that you could have it in your hand, is electromagnetic.
One of the four fundamental force interactions in nature. And these electromagnetic forces, you go against
the barriers of the electromagnetic forces. This means, when you pressurize hydrogen,
experimentally, then the electron shells go through each other, ok, for example, this means,
you can realize that if you take electron and electron, and you will press them together,
it will be harder and harder and harder. If you had sufficiently high pressures,
say 10000, 5000 GPa, like in the cores of gas giants, then you will make it.
Then you have brown dwarfs, stars and even something you maybe haven't ever heard about,
the so called degenerate matter, which is a matter with a density say 1000x higher than
that of the granite. This also exists in space, you have a wide range there.
There is an assumption that such an ultracondensed state of matter could
be a part of the lower mantle and the core. A few textbooks were published.
Ultracondensed Matter by Dynamic Compression. Experimentally, you cannot take some diamond
cells and press the matter to say 5000 GPa, this is impossible. But you may use shock waves,
shock waves, lasers and similar devices that may locally press the matter in some way.
This book, there you can read about very interesting things like for example, some alloy or some magnesium
for example, was pressed to a density of 40, normally, magnesium, I don't know what is
its density, it is in first grams to centimeters squared, they press it to say 30 or 40,
ok. So, this book is very complicated since when you go into the microworld, there are some
strangenesses, compared to the usual conventions of classical physics.
So, from this point of view, the description of the behavior of these materials is very complicated.
Here a picture of a telescope that is being built in Chile. It should be completed
in the year 2024, E-ELT, Extremely Large Telescope.
And such a telescope, it's been said, according to some calculations, could allow us even
to directly observe the exoplanets. So, it is possible, that as we find some Earth
and we visualize it, hard to say, whether we visualize directly its image,
but if it was a success, we would for example see that it has similar relations
between the continental and oceanic lithosphere like our Earth. And this would be really interesting.
Ok, so here I finish, and now, I would give a space for a discussion. And I will ask you
because we are at the department of biology. The debate on facebook was
also about biological issues and because it sounds a little bit crazy from the view
of evolution, the age or length of evolution, so I am interested also in the opinion of biologists.
And that we could discuss about it. Thank you for your attention!
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