Hidden world discovered underground
New research, originally published in Physics of the Earth and
Planetary Interiors, suggests that the state of our planet's inner
core ranges from solid to semi-soft and even liquid. Writes
about this Live Science (
https://bit.ly/3e5z2TZ). For Rhett
Butler, a geophysicist at the Hawaiian Institute of Geophysics
and Planetology, the new study began with a question of data
mismatch. Butler watched as seismic waves created by strong
earthquakes in five different locations on the planet travel
through the Earth's core and appear on the opposite side of
the globe. But something was wrong. Shear waves, which
were supposed to travel through a solid metal ball, were
instead deflected in specific areas.
The result surprised the scientist. He knew that the mathematics
of seismic waves was correct, which could only mean one thing:
the error was related to the obstacle that the waves collided with,
that is, something was wrong with the structure of the core. Then
Butler and his colleagues decided to revise the basic assumption
that the Earth's inner core is completely solid, and suggested that
the core has "pockets of liquid and soft semi-solid iron" near the
surface. This time, the results were correct. The new research has
the potential to revolutionize our understanding of the Earth's
magnetic field. According to data published in 2019 in the journal
Science Advances, the liquid outer core controls the magnetic field
of our planet, and the inner core helps to change it. At the same
time, NASA data on other planets such as Mars shows that they
have a liquid center, but both an inner core and a magnetic field
are missing. Butler and Irving believe that a deeper understanding
of the structure of the inner core of the Earth will help to
understand the relationship between the inner space of the planet
and its magnetic activity.
