Scientists study the Earth’s interior by observing how seismic waves from earthquakes are bent, reflected, sped up, or delayed by various layers. They analyze rocks, minerals, seismic waves, gravity, and magnetism to deduce its composition. The crust makes up the remaining 1 percent of the Earth’s interior, and our knowledge of the layering and chemical composition is continually being improved by earth scientists conducting laboratory experiments on rocks at high altitudes.
The most common seismic waves are S waves and P waves, which have more energy but can only move through. The crust makes up the remaining 1 percent of the Earth’s interior. The history and methods of seismology are explored, including how Danish seismologist Inge Lehmann used seismic waves to reveal the structure of the Earth’s interior and propose the existence of a solid inner core in 1936.
Seismic waves are used to map the interior layers of the planet, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust, excluding its atmosphere and hydrosphere. A new technique inspired by astrophysics allows researchers to chart the interior layers of the Earth, using echoes and resonant waves from earthquakes.
Indirect evidence indicates that the density of Earth as a whole is about 5.5 g/cm3, suggesting that the interior must be denser than the crust. Geologists use a network of seismometers to chart seismic waves that originate in the Earth’s crust and ricochet around its interior. By understanding the structure and properties of the Earth’s interior and surface, scientists can better understand the Earth’s internal structure and its role in the Earth system and other planets.
📹 How Scientists Study Earth’s Interior StructureVideo & Lesson TranscriptStudy com
As body waves travel through the Earth’s internal layers their speed changes causing the wave to bend this bending is similar to …
How did scientists discover the layers of the earth?
The available evidence indicates that the Earth’s materials have formed distinct layers with varying densities. These layers are primarily sourced from seismic waves and vibrations generated by earthquakes or explosions.
How do scientists know whats in the middle of the earth?
Geoscientists cannot directly study the Earth’s core, but rather rely on sophisticated readings of seismic data, meteorite analysis, lab experiments, temperature and pressure experiments, and computer modeling. Most core research involves measuring seismic waves, which change with pressure, temperature, and rock composition. In the late 19th century, scientists observed a “shadow zone” deep in the planet where a type of body wave called an s-wave either stopped or was altered, indicating a liquid layer.
In the 20th century, an increase in the velocity of p-waves, another type of body wave, at about 5, 150 kilometers below the surface, confirmed the existence of a solid inner core, indicating a transition from a liquid or molten medium to a solid medium.
How did the scientist identify and classify the layers of the earth?
The Earth’s interior structure is a subject of scientific study based on seismic monitoring, which measures sound waves generated by earthquakes and examines how they slow down through different layers of the Earth. This results in refraction, which is calculated using Snell’s Law to determine differences in density. Other measurements include gravitational and magnetic fields, and experiments with crystalline solids at specific pressures and temperatures.
Differences in temperature and pressure are believed to be due to leftover heat from the planet’s initial formation, decay of radioactive elements, and freezing of the inner core due to intense pressure. The Earth’s formation and composition have been studied since ancient times, with the earliest known cases being unscientific.
How did scientists discover the inner core?
In 1936, Danish seismologist Inge Lehmann discovered Earth’s solid inner core separate from its molten outer core. She observed seismic waves reflecting off the inner core boundary and detected it through sensitive seismographs on Earth’s surface. Lehmann estimated the inner core’s radius to be 1, 400 km (870 mi), close to the current value of 1, 221 km (759 mi). In 1938, Gutenberg and Richter estimated the outer core’s thickness to be 1, 950 km (1, 210 mi) with a steep transition to the inner core.
In 1940, it was hypothesized that the inner core was made of solid iron, but Francis Birch in 1952 concluded that it was likely crystalline iron. The boundary between the inner and outer cores is sometimes called the “Lehmann discontinuity”, although the name usually refers to another discontinuity. The rigidity of the inner core was confirmed in 1971.
What are two ways do scientists study the inside of the earth?
Geologists employ a combination of indirect and direct evidence to gain insight into the internal structure of the Earth, utilizing seismic waves and rock samples as key sources of data.
How do geologists study Earth’s interior?
Geologists employ a combination of indirect and direct evidence to gain insight into the internal structure of the Earth, utilizing seismic waves and rock samples as key sources of information.
How do scientists and geologists know what the layers of Earth are?
Seismograms, which are produced by seismographs, are of great importance to scientists seeking to gain insight into the interior of the Earth. Seismograms reveal the Earth’s crust to be a solid material, while body waves provide information about the interior of the planet. The mantle is solid because both P- and S-waves are able to traverse it.
How have scientists mapped the inside the earth?
Scientists study the interior of the Earth by observing how seismic waves from earthquakes are bent, reflected, accelerated, or delayed by various layers of the Earth’s crust, mantle, and core. This method of investigation differs from the conventional approach of drilling holes for samples in the crust.
How do we determine the layers of the Earth?
Earth’s interior is a complex system of layers, with the inner core being the innermost part, which is about 1500 miles thick. The outer core, which is liquid, is about 1300 miles thick and is composed primarily of iron and nickel. The inner core is under intense pressure, keeping it solid despite high temperatures. The outer core, which is liquid, is about 1300 miles thick and is composed of dark, dense rock similar to oceanic basalt. The mantle, which is about 1800 miles thick, is the most of Earth’s volume and is composed of dark, dense rock.
The deeper you go inside the Earth, the hotter it gets. The outermost layer of Earth is divided into continental and oceanic crust. Continental crust is composed of silica-rich rocks and is an average of 44 miles thick, while ocean crust is made of dark, silica-poor rocks like basalt and is thinner and more flexible than the continents.
Earth’s surface is directly related to its interior, as it formed from a hot cloud of dust orbiting a blazing sun around 4. 6 billion years ago. The inner and outer cores are extremely hot, with temperatures ranging from 7200 to 5000℉.
How did seismologists learn about the different layers of Earth?
Seismic waves, generated by earthquakes and explosions, are used by seismologists to explore the Earth’s deep interior. This fact sheet uses data from the 1994 earthquake near Northridge, California, to illustrate this process and Earth’s interior structure. Seismic tomography is an imaging technique that uses seismic waves to create computer-generated, three-dimensional images of Earth’s interior.
A travel time curve graph shows the time it takes for seismic waves to travel from the epicenter of an earthquake to hundreds of seismograph stations worldwide. The arrival times of P, S, and surface waves are predictable.
How do we map the interior of the earth?
The internal structure of Earth is a complex process involving various observations, such as topography, bathymetry, rock outcrop observations, volcanic activity samples, seismic wave analysis, gravitational and magnetic field measurements, and experiments with crystalline solids at Earth’s deep interior pressures and temperatures. The chondrite model assumes the light element in the core to be Si, while the chondrite model relates the chemical composition of the mantle to the core model shown in the chondrite model.
📹 An Overview of Earth’s Layers
We only interact with the very surface of the Earth, called the crust. So what else is down there? What is the composition of the …
Man, I just love this series. Somewhere along the way in my college education, decades ago, I had to make a choice about what I wanted to study. I ultimately decided on civil engineering, but I had so much interest in geology that I used most of my elective courses on topics like this. Looking forward to the next installment which will, no doubt, cover P-waves and S-waves and how we used seismic events on one side of the planet to better understand the deepest reaches of our planet from the other side. Great work, Professor Dave!
Before I begin my actual comment… Before I begin my actual comment, I would like to apologize in advance for my inadequate level of English proficiency. I am not a native speaker of the world’s current lingua franca which unfortunately leads to me making numerous embarrassing mistakes being made whenever I attempt to communicate using this language. Whenever I am reminded of how I lack the ability to convey my thoughts in an eloquent manner, I feel as though I have committed a cardinal sin, as though every English teacher in the world is simultaneously shaking their head and sighing due to how utterly disappointed they are at me. Although I know that saying sorry to those of you who are reading my comment will not change the fact that I fail miserably to write and speak perfect English, I am writing this as a way to deter a certain type of people who cannot stand poor English from mocking me by posting unwanted and unnecessary comments detailing my every blunder although you may be angry or made at me. so please don’t. Here is the comment i wanted to make: first.
In these tutorials I especially love that you don’t shy away from dumping a lot of information at once, since everyone can watch the article multiple times and review. This is very informative and condensed, and at the same time accessible even if you only half-remember high school introduction to geology.
Very good explanation! i spent 33 years in the mining industry as a mining geo and a Senior Engineer. Most recently at a project/mine owned by Sibanye/Stillwater her in southern Montana. Our deposit is a VERY old Intrusive unit that was uplifted during the Beartooth mountain uplift. Our deposits are dated at 1.2 Billion years old (yes, 9 zeros). Never got subducted again. Uplifted over MUCH younger Limestone unit. We mine Platinum and Palladium. We mine a little “sliver” of the entire original magma settlement. Just 1 corner (0.001%). but still our mine life is 50+ years that we know of. If you ever want an underground tour, you’re more than welcome!
I’m tackling a bachelor’s degree in biology and geology in early September, and this man is a hero! All hail Professor Dave Farina, Holy Slayer of Ignorance! EDIT: Well, it turns out I couldn’t solve my illiteracy in mathematics and thus had to abort the whole project. Oh well. At least I can still enjoy science thanks to YouTube websites such as this one!
I cannot thank you enough for this article. My young son was asking me about what caused volcanos and I was not able to articulate it well. We watched this together and paused whenever he needed to study the image. He even correct his uncle when they talked about lava vs magma which made me so proud as we had talked about it after your article. Thank you as always Professor Dave.
One thing I didn’t understand though. I think you mentioned that the inner core is rotating faster than the crust/mantel and then explained that it was due to the magnetic field, similar to an induction motor. But induction motors always spin SLOWER than the magnetic field. This is a necessary part of how they work. If the rotor was spinning faster, the induced currents and field interactions would apply torques in the opposite direction, slowing the rotor down. (for example a magnetic field in an induction motor stator might rotate 1800 RPM, but the rotor will spin at 1780 RPM) So, how does the magnetic field make the inner core spin FASTER???
I’m sorry but your pronunciation of “peridotite” is driving me crazy. It’s actually pronounced “peri-dough-tight.” Additionally, the rock shown consisting mainly of olivine is likely dunite named for Dun Mountain in New Zealand. The only addition I’d make to the presentation is that there are melts of intermediate chemistry between high silica felsic and low silica (ultra)mafic rocks. The Andes Mountains are a prime example of an intermediate composition. The amount of silica affects the viscosity of a melt that directly determines the kind of volcanic eruption might occur. High silica results in trapped gasses and water vapor resulting in an explosive eruption like Mt St Helens vs a runny lava like in Hawaii. Then you could get into that sexy Bowen’s Reaction Series. But I’m just a nerd that taught that so it’s my bias. But as always, great presentation and completely on point. It’s always a good day when you know that folks are being presented with accurate information and getting educated. As we’d say in the Navy, “Bravo Zulu!’
As usual, the energy source of the Earth’s heat got glossed over with a generalized radiogenic heat. There seems to be a great variability in geological activity within the Earth. Flood basalts and super volcanos come to mind. My thought is that there is probably nuclear fission naturally occurring deep in the Earth creating significant heat. Natural fission is variable in output as the parameters of the critical mass change. This is all probably true but geologic science does not say so or explore the concept. I think its moving at geologic speed.
Always loved your articles and presentations Professor Dave. And I especially love your debates, I’ve used some of your points to argue against Flat Earthers a few times. Would you mind me asking if you’ll ever do any kind of Live debate again, or would you prefer to move onto something a little more calm?
Basically the oceanic crust, as it pushes underneath the continental crust, turns back into molten rock. And If I’m not mistaken, it’s a continuous cycle as the mantle and circulates with the outer core and creates convection just like a lava lamp, as Professor Dave explained. Man, I really enjoy brain food.
Hey Dave have you ever considered making a article about the moon landing? I’ve been seeing that topic pop up a lot lately, amongst (most predictably) flat-Earthers. Oh, and I’m also seeing denial that nuclear bombs exist as well… that Hiroshima and Nagasaki were just standard incendiaries—like Dresden—and Chernobyl was apparently just a hoax 😂
Dave, sir, I have a question regarding homeopathy. It stems from a article you put out 4/3/19 titled “astrology: fact or fiction”. I’m a bachelor-degree-level nurse, and I believe in science. However pseudoscience can be helpful in some cases. For instance, aloe vera does seem to heal burns and wounds as quickly as medicinal ointments. Certain homeopathic remedies do help to control blood pressure and regulate cholesterol and blood sugar. Although these are homeopathic, they are also widely used. Do these remedies ever get accepted by true science?
btw: its debated if the collision and absorbtion of theia played a huge part in injecting additional heat and core material into earth, and thus we can enjoy a magnetic field still, while all other rocky planets in the solar system are magnetically dead, as they did not have this injection of heat and core material. their cores are already too solid and cant produce such a life saving field anymore….
Interestingly, I have read about oil drilling, & in the Alaskan oil fields between 1,100ft & 1,700ft down there is perfectly preserved ancient tropical forests. They are frozen, not petrified. Oil drillers have pulled up many palm trees, ferns, pine cones, & other frozen tropical forms of life in the Alaskan oil fields. Scientists have studied this, but its not information given to the general public, except in a few books. They also say that oil is the 2nd most abundant liquid on Earth, & not from dinos. ‘Oil shortages’ are complete BS created by TPTB.