WHAT DOES THE INSIDE OF EARTH LOOK LIKE?
Earth's crust is made of rock. Then going deeper we've got this huge expanse that we call the mantle. That's solid, rock-like material, but it's under high pressure and high temperature, so it's different to the rocks that you would find if you wandered out into a park. Beneath the mantle, we get into Earth's deepest regions, near the core. There, we leave the rocks behind and enter a world made of metal, specifically iron.
That metal ended up there because iron is heavy compared to rock. So that density contrast has put most of Earth's iron into this big ball at the centre. We're talking about a huge ball that's about half of Earth's radius and made of metal. But we can also split that core into two more distinct chunks. We have the outer core, which is made of molten metal that's roughly as runny as water. Then, in the middle of Earth, we've got the solid inner core, which has a radius about a fifth that of Earth.
HOW DO WE STUDY CHANGES OCCURRING WITHIN EARTH'S CORE?
We have a variety of techniques to make what we call 'indirect observations'. No hole that has been dug is deep enough to help. The deepest-ever hole was slightly over 12km deep. For us to reach the inner core, we'd need to go down thousands and thousands of kilometres, and we certainly have no samples from there.
Seismologists look at a record of an earthquake wave that has passed right through the rocky mantle, the liquid outer core, into the inner core, and then has come all the way back out and onto the far side of the planet.
Then they try and look for another earthquake that happened as close as possible to that first one and was detected by exactly the same seismometer some years later.
هذه القصة مأخوذة من طبعة March 2023 من BBC Science Focus.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 8500 مجلة وصحيفة.
بالفعل مشترك ? تسجيل الدخول
هذه القصة مأخوذة من طبعة March 2023 من BBC Science Focus.
ابدأ النسخة التجريبية المجانية من Magzter GOLD لمدة 7 أيام للوصول إلى آلاف القصص المتميزة المنسقة وأكثر من 8500 مجلة وصحيفة.
بالفعل مشترك? تسجيل الدخول
5 SIMPLE WAYS TO RECLAIM YOUR ATTENTION
Primed for constant interruptions, your brain is now distracting itself, says science. It's time to break the cycle and retrain your focus
GOING ROGUE
Some planets are stuck following the same orbital paths their entire lives. Others break free to wander alone through the vast, empty darkness of interstellar space and there's a lot more of them than you might think
BED BUGS VS THE WORLD
When bloodthirsty bed bugs made headlines for infesting Paris Fashion Week in 2023, it shone a spotlight on a problem that's been making experts itch for decades: the arms race going on between bed bugs and humans. Now, with the 2024 Summer Olympics fast approaching, the stakes are higher than ever
THE EYES THAT WATCH THE SKY
When it launches in 2026, the Copernicus programme's Anthropogenic Carbon Dioxide Monitoring satellite will give us a new window on to Earth's atmosphere... And how we're altering it
TIME-RESTRICTED EATING LINKED TO HIGHER RISK OF CARDIOVASCULAR DEATH
Skipping breakfast might not be so good for your health, after all
INSIDE THE PROJECT TO SCAN THOUSANDS OF RARE SPECIMENS
A major collaborative project has created 3D reconstructions of previously locked away museum specimens
VIDEO IS FIRST EVIDENCE OF AN ORCA KILLING A GREAT WHITE
Tourists sailing off the South African coast film a never-before-seen event: a lone orca attacking a 2.5m shark
AI REVEALS PROSTATE CANCER IS NOT JUST ONE DISEASE
DNA analysis carried out by artificial intelligence has helped scientists make a discovery that could revolutionise future treatment
MYSTERIOUS WAVES DETECTED IN JUPITER'S CORE
Scientists hope unusual fluctuations in the gas giant's magnetic field might reveal what's inside
MINI ORGANS GROWN FROM UNBORN BABIES MARK A BREAKTHROUGH IN PRENATAL MEDICINE
A new technique could allow congenital conditions to be diagnosed and treated before birth