Mars rocks embark on an extraordinary journey to arrive on Earth, primarily as meteorites.
Getting a rock off Mars is significantly easier than from Earth. This is because Mars has weaker gravity (about one-third of Earth's) and a much thinner atmosphere (about 125 times thinner).
The Journey to Earth
- Ejection from Mars: Large impacts from asteroids or comets can strike the Martian surface with enough force to blast pieces of rock and soil into space. The weaker gravity and thin atmosphere make this ejection process more likely to succeed compared to Earth.
- Interplanetary Travel: Once ejected into space, these Martian rocks become meteoroids. They then begin a long journey, orbiting the Sun.
- Arrival on Earth: According to the provided reference, "After orbiting the Sun for more than a million years, some of the ejected pieces eventually struck Earth as meteorites." When these meteoroids encounter Earth's atmosphere and survive the fiery passage to land on the surface, they are then called Martian meteorites.
These rare pieces of Mars provide scientists with invaluable samples for study, offering direct insights into the composition and history of the Red Planet without needing to send a return mission.
