Mercury, currently the smallest planet in our solar system, was once similar in size to Earth, a new study has revealed.
Mercury's Unique Characteristics
Mercury, located closest to the Sun, captivates astronomers with its extreme temperature fluctuations (-173 degrees Celsius at night to 427 degrees Celsius during the day) and crater-riddled surface.
Challenges in Studying Mercury
Exploring Mercury poses significant challenges. Its proximity to the Sun requires spacecraft to expend significant energy to resist its gravitational pull.
NASA's Mercury Missions
Despite these obstacles, NASA has successfully conducted two missions that closely approached Mercury to map its surface.
Similarities to Earth
The findings indicate that Mercury, despite its diminutive size, possesses a proportionally larger core, smaller mantle, and thin crust than Earth. It also exhibits an unusually high concentration of thorium, an element that would normally have evaporated due to Mercury's intense heat. Additionally, like Earth, Mercury possesses a magnetic field, suggesting a similar internal activity.
Comparison to Earth
By comparing Mercury's composition to Earth's, planetary scientist Nicola Mari of the University of Pavia, Italy, and colleagues found striking similarities, implying that the planets may have been similar in size in the past.
The Missing Crust
To explain Mercury's current small size, researchers theorize that a massive impact removed much of its crust, leaving it in the diminished state we observe today.
Future Explorations
The European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) launched the BepiColombo mission in 2021 to further explore Mercury. Scientists eagerly await the results from this mission.
Summary
Mercury, once Earth-sized, has been reduced in size by an ancient impact that stripped away its crust. Despite its current diminutive stature, Mercury shares striking similarities with Earth, hinting at a shared origin. Future missions, such as BepiColombo, will shed further light on this intriguing planet.