These holes give additional clues to understanding Venus’s atmosphere – how the planet interacts with the constant onslaught of solar wind from the sun and perhaps even what is deep in its core.
They also point to a more complicated magnetic environment in Venus than previously thought, that may help us in understanding better this rocky planet.
“The ionosphere can conduct electricity, which makes it basically transparent to the magnetic field lines. The lines go right through down to the planet’s surface and some ways into the planet,” said Glyn Collinson, a space scientist at the Goddard Space Flight Centre in Greenbelt, Maryland.
Collinson is looking for signatures of these holes in data from the European Space Agency’s Venus Express which was launched in 2006 and is currently in a 24-hour orbit around the poles of Venus.
The observations also suggest the holes are more common than realised.
The Pioneer Venus Orbiter only saw the holes at a time of great solar activity, known as solar maximum.
The Venus Express data, however, finds that the holes may form during solar minimum as well.
“Interpreting what is happening in Venus’s ionosphere requires understanding how Venus interacts with its environment in space,” concluded Collinson.
The environment in Venus is dominated by a stream of electrons and protons – a charged, heated gas called plasma – which zooms out from the sun.
The study appeared in the Journal of Geophysical Research.