In 1968, scientists described a phenomenon that had not been observed until the Space Age. Spacecraft flying over the Earth’s poles had detected supersonic winds of particles “escaping from the Earth’s atmosphere.” The best explanation was an electric field.
“Any planet with an atmosphere should have a dipole field,” says astronomer Glenn Collinson of NASA’s Goddard Space Flight Center. “Now that we’ve finally measured it, we can start to learn how our planet has shaped over time.”
The research team explained that the process begins at an altitude of about 250 km, in a layer of the atmosphere called the ionosphere, where intense ultraviolet and solar radiation ionizes atmospheric atoms, leading to the separation of negatively charged electrons and the transformation of the atom into a positively charged ion.
In this case, the lighter electrons will try to fly into space, while the heavier ions will try to drift towards Earth, but the plasma environment will try to maintain charge neutrality, which creates an electric field between the electrons and ions to bind them together.
This field is called a dipole field because it works in both directions, with ions providing a downward pull and electrons providing an upward pull.
Because this dipole field is so weak, Collinson and his team designed instruments to detect it. The Endurance mission launched in May 2022, reaching an altitude of 768.03 km before returning to Earth with its precious data.
The mission succeeded in measuring a change in electrical voltage of only 0.55 volts.
“Half a volt is hardly anything,” Collinson says. “It’s only as strong as a watch battery. But that’s the right amount to explain the polar winds. This field is a fundamental part of how the Earth works. Now that we’ve measured it, we can start asking some of these bigger, more exciting questions.”
The study was published in the journal Nature.
Source: Science Alert
#time. #Discovery #invisible #electric #field #Earth
2024-09-01 03:48:09
