RismadarVoice Reporters, September 1, 2026
Scientists could be closer to determining how the Moon was formed as the BepiColombo spacecraft begins its arrival phase at Mercury, a mission that could provide important evidence about a possible ancient planetary collision.
The spacecraft, launched in 2018 on a joint European and Japanese mission, is expected to enter orbit around Mercury in November.
Scientists hope observations from the mission will help test a theory that Mercury once collided with the young Earth about 4.5 billion years ago, producing debris that eventually formed the Moon.
BepiColombo carries two spacecraft equipped with instruments designed to study Mercury’s surface, composition and internal structure. Data from the mission could help researchers determine where Mercury formed and how it evolved.
Mercury is currently the closest planet to the Sun, but scientists believe it may have formed much farther away, possibly closer to the region occupied by Mars.
One of the major clues is Mercury’s unusually large iron core and relatively thin outer layer. The planet’s core accounts for about 65 per cent of its total mass, compared with roughly 32 per cent for Earth.
This has led scientists to propose that a massive collision stripped Mercury of much of its lighter outer material billions of years ago.
Prof Geraint Jones, the lead project scientist for BepiColombo at the European Space Agency, said studying Mercury’s interior could help determine how well the collision theory fits the evidence.
Scientists have also proposed that material removed from Mercury during such an impact could have contributed to the formation of other bodies in the Solar System, including the Moon.
Prof Dirk Schulze-Makuch of the Technical University of Berlin has suggested that some of the material missing from Mercury’s outer layers may have ended up forming part of the Moon.
Another theory, developed by scientists at the University of Arizona, suggests Mercury may have collided with objects that eventually became Earth and Venus before reaching its present position.
Evidence from NASA’s Messenger spacecraft has also raised questions about Mercury’s origins.
Messenger, which studied Mercury between 2011 and 2015, found levels of potassium and thorium on the planet that appeared more similar to those expected on Mars.
Johannes Benkhoff, a BepiColombo project scientist, explained that potassium evaporates more easily under extreme heat, while thorium can withstand much higher temperatures.
He said Mercury’s relatively high potassium levels could indicate that the planet formed farther from the Sun before moving closer to its present location.
According to Benkhoff, a major collision could have both altered Mercury’s position and stripped away much of its outer material, leaving behind its unusually dense core.
BepiColombo consists of two orbiters: the European Space Agency’s Mercury Planetary Orbiter and the Japanese space agency JAXA’s Mercury Magnetospheric Orbiter.
The Mercury Planetary Orbiter was built by Airbus in Stevenage, Hertfordshire.
The spacecraft will travel closer to Mercury than previous missions, allowing scientists to produce more detailed maps of its surface and investigate its geological history.
Researchers also hope to determine whether Mercury contains water and whether geological activity is still occurring beneath its surface.
Another major mystery is the planet’s unusually dark surface. Scientists suspect that graphite may cover much of Mercury’s exterior.
The mission will also investigate the origin of Mercury’s magnetic field.
NASA’s Messenger mission previously detected organic material on Mercury. While scientists do not expect to find life there, studying the material could provide clues about the chemical processes that contributed to the emergence of life on Earth.
BepiColombo is named after Giuseppe “Bepi” Colombo, the Italian scientist and engineer from the University of Padua who played an important role in NASA’s Mariner 10 mission to Mercury.
Santa Martinez, the BepiColombo mission manager, described Mercury as one of the most difficult destinations in space exploration because of its proximity to the Sun.
She said the mission would provide scientists with unprecedented observations of the planet and open a new chapter in understanding the Solar System.
