These images of the Earth show how magma circulates inside it, what its gravitational field is like, the shape of its ghostly magnetic field, faults, clouds and hurricanes.
Apples don’t fall at the same speed everywhere, something Newton could hardly notice. The mass that the Earth is made of is not homogeneous. The differences are marked by layers of ice of greater or lesser thickness, underground water flows, slow magma currents in the depths and a myriad of geographical variables.
Since mass is not uniform, neither is its gravitational field. The differences are very slight, less than 1% between the most extreme points. The comprehensive measurement was carried out by a NASA mission with a woman’s name, GRACE. GRACE’s first work was an exaggerated map of the uneven Earth’s gravitational field: a deeply dented multi-colored sphere in India.
GRACE’s globe is contained within the confines of a supercomputer, and it is not the only one created by man. Some of the virtual planets that you can see in the image gallery show the Earth without water, others the invisible magnetosphere; some allow us to see the past of the planet, others the future.
The loss of 109 cubic kilometers of water in India decreased its gravitational field
NASA’s GRACE program warned of the loss of 109 cubic kilometers of groundwater in northwestern India. This loss of mass causes its gravitational field to decrease. Colors range from blue (minimum severity) to red (maximum)
All are representations of millions of real data from sensors and satellites. For its measurements of Earth’s gravity, GRACE uses two identical satellites, in the same orbit, 220 km apart. As they both rotate, the regions with stronger gravity affect the first satellite: they move it slightly away from the second. They can detect a change in the distance that separates them from a micrometer, half the thickness of a hair.
NASA takes the cake in Earth studies. Among them, the one known as CLASS Project, which is part of an environmental macro program. Its experts claim to have received a whopping 8.3 million files of climate observations since 1980.
IN THE DEEPEST
Shuo Wang, from the University of Minnesota (USA), uses one of the techniques that allow observing the interior of a human body, thermography, to reconstruct the center of the Earth. The application is called AMIRA, and it works mainly with temperature data.
Using them, Wang has created a 3D model of the Earth’s mantle, showing plumes of magma rising to the surface and fanning out there before turning into cooler rocks and sinking. “This simulation allows us to understand the complex dynamics of plate tectonics,” says Wang.
The world of Karin Sigloch, from the Department of Geosciences at Princeton University, has been created thanks to the same technology that allows to recreate a human brain in 3D: in this case CT scans. The system consists of bombarding with X-rays from multiple angles what you want to see.
The combined information redraws the brain in 3D, and in Sigloch’s lab, the entrails of the planet. The sensors it works with register seismic waves caused by large earthquakes. The waves they generate are so powerful that they cross the planet from end to end, and travel at different speeds depending on the temperature of the material they pass through. Sigloch has collected information from at least 600 super earthquakes and reconstructed a tectonic plate, known as the Farallon. He now plans a global 3D model of the interior of the Earth.
MAGMA COLUMNS HEATING THE EARTH’S CORE
This transparent ball shows how the columns of magma (purple) heated by the core (orange) rise in the Earth’s mantle and how they reach the outer layer of the mantle and then fall, cooler, in a fan shape.
3D model of the convection of the Earth’s mantle. Created by Shuo Wang of the University of Minnesota. It shows, in green, how magma circulates in the Earth’s mantle. This process is originated by the nucleus, in yellow. Convective currents in the mantle are what move tectonic plates and form volcanoes in the planet’s crust.
FOLLOW THE CLIMATE TRACKS
But the big virtual monsters are the balloons responsible for the predictions about climate change. To use these representations you need the most powerful computers that exist. Experts divide the planet into an extensive grid of millions of cells, similar to pixels in an image, but in 3D, stretching from the Earth’s surface to the stratosphere. Each of these cells carries data on air temperature, atmospheric pressure, wind speed … The computer can take days, years, even decades to solve the macro equations that this information generates.
Today, the most accurate simulations recreate objects as small and fast as typhoons, and predict their movement to the millimeter. But before long, the world’s models will rotate into even more powerful computers. They will cross data from the oceans, air and living organisms. They will be more beautiful and even more reliable planets, with information – perhaps not so beautiful – for the next generations.