According to published in 2016 in the journal "Geophysical Research Letters", ESA's spacecraft Venus Express has detected a surprisingly strong electric field at Venus – the first time this has been measured at any planet. With a potential of around 10 V (Earth is thought to have an electric field of less than 2 V).

Just as every planet has a gravity field, it is believed that every planet with an atmosphere is also surrounded by a weak electric field. While the force of gravity is trying to hold the atmosphere on the planet, the electric force can help to push the upper layers of the atmosphere off into space.

At Venus, the much faster hydrogen escapes easily, but this electric field is so strong that it can accelerate even the heavier electrically charged component of water — oxygen ions — to speeds fast enough to escape the planet’s gravity. When water molecules rise into the upper atmosphere, sunlight breaks the water into hydrogen and oxygen ions, which are then carried away by the electric field.

The researchers were monitoring electrons flowing out of the upper atmosphere when it was noticed that these electrons were not escaping at their expected speeds. The team realized that these electrons had been tugged on by Venus’ potent electric field. By measuring the change in speed, the team was able to measure the strength of the field, finding it to be much stronger than anyone had expected.

The spacecraft orbited Venus between 2006 and 2014.

More Info: www.nasa.gov