Cruise to the Innermost Planet

The rays of Mena crater. Credit: NASA/JPL.

December 1, 2020

BepiColombo continues its long journey.

The BepiColombo mission was launched October 20, 2018 on a joint mission to Mercury. The mission will consist of two satellites: the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). MPO is designed to study Mercury’s composition, while MMO will study Mercury’s magnetosphere.

BepiColombo was sent into an Earth-trailing orbit. After a year and a half, it caught-up to Earth, where a gravity-boost deflected it toward Venus. Since BepiColombo must decelerate as it approaches the Sun, two Venus flybys and six Mercury flybys will lower its relative velocity until Mercury captures it on December 5, 2025. Currently, the spacecraft is finalizing the cruise phase of its mission: the six year journey to Mercury, and is already over 50 million kilometers from Earth.

The MESSENGER spacecraft was the last manmade object to circle Mercury, until it was deliberately crashed into the planet’s surface after it ran out of maneuvering fuel. MESSENGER discovered that Mercury possesses a weak magnetic field, but astrophysicists do not know how it is generated. Modern theories use ideas about Earth and transfer them onto Mercury. So, a rotating “dynamo” of molten metal is thought to exist inside Mercury, although the molten interior should have cooled off long ages ago.

Mercury is a small planet, only 4878 kilometers in diameter, meaning that the moons Ganymede and Titan are both larger. Mercury revolves at a mean distance of 57,910,000 kilometers from the Sun, so a year on Mercury lasts 88 days. Since it rotates once every 58.6 days, the planet completes three rotations for every two orbits.

Consensus theories cannot explain Mercury’s mixture of 5% iron, with a thin, silicon-rich crust, since the ratio of iron to silicon is opposite that of the other rocky planets. BepiColombo will also investigate Mercury’s atmosphere. Temperatures there are greater than 400 Celsius at noon, and the planet receives nine times more radiation than Earth, so how does it have a detectable atmosphere?

A planet whose gravity is only 38% that of Earth, with such intense solar irradiation, should not exhibit even the thinnest atmosphere. Therefore, in the Electric Universe view, it is possible that Mercury is a young planet, like Titan (a possibly young moon of Saturn). So, it retains some of its primordial envelope, despite low gravity.

A previous Picture of the Day proposed that celestial bodies like Mercury should not be thought of as geriatric denizens of a wizened Solar System. Rather, given the anomalies, it is more appropriate to think of them as youthful members of a dynamic ensemble. If true, then there was a period in Mercury’s history when the surface was the scene of gigantic electric discharges pulling out craters, cutting vast chasms, and rearranging the atomic structure of the planet’s crust over large areas. Given those circumstances, no theories about Mercury will stand unless electricity is given its due.

Stephen Smith

The Thunderbolts Picture of the Day is generously supported by the Mainwaring Archive Foundation.

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