Earth has a squishy interior. Earth’s interior is not solid but rather has a semi-solid or ‘squishy’ consistency owing to high temperatures and pressures. This squishy consistency allows the mantle to flow and move over geological timescales, which is responsible for phenomena such as plate tectonics, volcanic activity and Earthquakes. One consequence of this squishy interior is a process known as post-glacial rebound. During the last ice age, large portions of Earth’s surface were covered by glaciers, causing the underlying mantle to deform and sink. As the glaciers melted and receded, the mantle slowly rebounded back to its original position over thousands of years, causing the land above it to rise. This process is still occurring today in places such as Canada, Scandinavia, and Greenland, where the land is still rebounding from the weight of the glaciers that once covered the region. Recent research has found that West Antarctica is rising faster than anywhere else in the world, thanks to data from ESA’s GOCE gravity mission. The study of post-glacial rebound provides important insights into the structure and behaviour of Earth’s interior, and how it responds to changes in the surface environment over long timescales.
100 Mind-Blowing Mantle Facts
The Moon is drifting away from Earth. You read that correctly! The Moon is gradually drifting away from Earth at a rate of approximately 4 cm per year. This phenomenon is caused by the Moon pulling on Earth’s oceans creating tidal forces that produce a bulge of water on the side of Earth facing the Moon. This bulge in turn creates a gravitational pull on the Moon, causing it to accelerate slightly and move further away from Earth. Over time, this process has caused the Moon to move farther away from Earth each year. This gradual drift is not noticeable on a day-to-day basis, but over millions of years, it can have significant effects on Earth’s rotation. Today, most scientists believe the Moon is ‘Earth’s child’ – a large body collided with Earth, destroying our planet’s mantle and sending material into orbit from which the Moon formed. This ‘big splash’ theory would explain why the Moon’s rocks are similar to those on Earth. Bonus fun fact: Australia is wider than the Moon. The Moon sits at 3400 km in diameter, while Australia’s diameter from east to west is almost 4000 km. The Moon, as a sphere, has more surface area, but it’s still pretty impressive.