Evidence of Water on Mars
Context:
Water covers about 70% of Earth’s surface and has been stable on the planet for 4.3 billion years. On Mars, however, the story of water’s presence is less certain.
More on News
- Understanding when water first appeared, its location, and its longevity are key questions driving Mars exploration, particularly in the quest to determine if the planet was once habitable.
- Recent research published in Science Advances sheds new light on this mystery.
- By analysing a zircon mineral from a Martian meteorite, researchers found evidence that water existed on Mars as far back as 4.45 billion years ago, providing the oldest known record of water on the red planet.
Mars and Its Geological Timeline
- Mars, like Earth, formed about 4.5 billion years ago and has four geological periods:
- Amazonian (present to 3 billion years ago)
- Hesperian (3 billion to 3.7 billion years ago)
- Noachian (3.7 billion to 4.1 billion years ago)
- Pre-Noachian (4.1 billion to 4.5 billion years ago)
- Water’s role on Mars has been well-documented in later periods.
- The first evidence came from NASA’s Mariner 9 spacecraft in the 1970s, which captured images of river valleys.
- Subsequent missions like Mars Global Surveyor and Mars Express detected hydrated clay minerals on the surface, indicating the presence of water during the Noachian period.
- However, the presence of water during the earlier Pre-Noachian period has remained elusive.
| About Mars
Mars, the fourth planet from the Sun, is often referred to as the “Red Planet” due to its iron oxide-rich surface, which gives it a reddish appearance. Basic Characteristics Position: Mars is located between Earth and Jupiter in our solar system. Size: It is about half the size of Earth, with a diameter of approximately 6,791 kilometers, making it the second smallest planet after Mercury. Orbit: A year on Mars lasts about 687 Earth days, and a day (or sol) is approximately 24.6 hours long. Geological Features: Mars hosts the largest volcano in the solar system, Olympus Mons, which stands about 25 kilometers high. It also has Valles Marineris, one of the largest canyon systems, stretching over 4,000 kilometers long and up to 7 kilometers deep. Atmosphere: Mars has a thin atmosphere composed mostly of carbon dioxide (about 95%), with very little oxygen. This makes it inhospitable for human life without proper equipment. Temperature: The surface temperature on Mars can vary widely, ranging from around -140°C at the poles to about 20°C at the equator. |
Investigating Pre-Noachian Water
- There are three primary ways to search for water on Mars:
- Observing the surface with orbiting spacecraft.
- Ground-based observations from rovers.
- Studying Martian meteorites that have landed on Earth.
- The latter approach is crucial for understanding the Pre-Noachian period, as the only material from that era available for study comes from Martian meteorites.
- Among these, the meteorite NWA7034, or “Black Beauty,” stands out.
Insights from the Martian Meteorite Black Beauty
- Black Beauty is a unique meteorite composed of ancient Martian regolith, including zircons that formed 4.48–4.43 billion years ago.
- These zircons are the oldest known material from Mars.
- Researchers studying trace elements in a 4.45-billion-year-old zircon from Black Beauty identified patterns indicative of hydrothermal processes—interactions with hot water—during its formation.
The Role of Hot Water in Early Mars
- The zircon exhibited oscillatory zoning, a layered pattern where elements like iron, aluminium, and sodium were incorporated.
- This is unusual, as these elements are not typically found in igneous zircon.
- Their presence strongly suggests they were introduced by hydrothermal systems—hot water moving through rocks during volcanic activity.
- On Earth, such patterns are rare and are often associated with ore deposits, such as those at Olympic Dam in South Australia, where hot water concentrates valuable metals.
This raises the intriguing possibility that early Mars might have hosted similar ore-forming systems.
Implications for Early Mars
- Previous studies have proposed that Mars was wet during the Pre-Noachian era.
- Oxygen isotope ratios in a 4.43-billion-year-old zircon hinted at the existence of an early hydrosphere, and some researchers have even suggested the presence of a global ocean around 4.45 billion years ago.
- The new findings reinforce the idea that magmatic hydrothermal systems were active on Mars during its earliest geological period.
- While it remains unclear if stable surface water existed at that time, the evidence confirms that water was present in Mars’ crust shortly after the planet’s formation—an essential ingredient for habitability.
