Did giant tsunamis rock the ancient oceans of Mars? Scientists say the evidence is there of not one but two massive tsunamis that swept through the oceans of Mars, leaving telltale signs that may hold the clues to life on the Red Planet.
The images that the world has seen of Mars as it is now consist largely of dry, red sand and a desert-like terrain, but researchers found the evidence of not one but two tsunamis that washed over Mars’ northern hemisphere.
Their conclusions are published in a study in Scientific Reports, and involves an analysis of data from various missions that allowed scientists to create a detailed map of the northern region of Mars. J. Alexis P. Rodriguez, a senior scientist at the Planetary Science Institute in Tucson, is lead author of the study. He is quoted in Scientific American.
“Imagine this enormous red wave coming towards you, up to 120 meters high. It would have been pretty spectacular.”
Scientists have long speculated about the possibility of an ancient Mars that was much different than it is today, including the presence of water in large enough quantities to create oceans. A variety of space missions have produced a range of images of the red planet; however, none show the kind of shoreline markings that are present on earth. Alexis Rodriguez explains.
“However, we didn’t find it and that kind of remained a paradox. Why do we have an ocean but we have no constant shoreline around the ocean?”
Tsunamis on Mars
Rodriguez began to search for explanation and came upon the idea of tsunamis after visiting the site of Japan’s 2011 tsunami. His team examined the images, particularly lobe-like deposits that has previously been identified in the northern region of Mars. On earth, such formations would typically indicate debris that had been pushed up by waves of water.
Since the debris flows with the water, it will generally flow downhill. The formations on Mars, however, flow uphill, which is an indication of how strong the flow was. The signs are consistent with the action of a tsunami. Virginia Gulick, a planetary scientist at NASA Ames Research Center, is co-author of the study.
“A tsunami deposit is like a flood deposit; it’s just in the reverse direction.”
The study’s authors concluded that not one but two giant tsunamis had washed through the area. They theorize that the two tsunamis occurred about 3.4 billion years ago and within a few million years of each other. The first tsunami roiled over an area about 800,000 square kilometers (300,000 square miles) with waves between 10 and 120 meters (400 feet) tall. The second was even larger, affecting an area of about 1 million square kilometers or 400,000 square miles. To put it into perspective, after the tsunami that hit Japan in 2011, the waves that hit the shore rose to about 39 meters or 127 feet in height.
Meteorites, tsunamis, and life on Mars
The cause of the pair of destructive tsunamis isn’t known, but scientists speculate that asteroids may be to blame. Incoming comets or meteorites that hit the oceans would have created impact craters and triggered the kind of massive waves that left the evidence on Mars. Researchers found supporting evidence in the form of about two dozen marine impact craters.
What happened to the oceans on Mars? Mars’ magnetic field is much weaker than the one we experience here on Earth. That means it has little protection against the solar wind, a blast of charged particles that flows out from the Sun throughout the solar system. The solar wind played havoc with the atmosphere and weather, resulting in the dry and barren Red Planet we know today. The lobe-like formations may also hold clues to the existence of life on ancient Mars. Virginia Gulick is quoted in the LA Times.
“If there was life that formed, say, in the large body of water, then tsunami deposits might have brought up some of that material that might show evidence for microbial activity in the past.”
Cold oceans on Mars
The evidence also suggests a changing climate – one that was getting colder. The shoreline shrank back between the first and second tsunamis and it appears that the waves from the second event that caused the lobe-like formations actually froze in place and did not recede. Alberto Fairén, is a Cornell visiting scientist in astronomy and principal investigator at the Center of Astrobiology, Madrid. He explains in a media release.
“These lobes froze on the land as they reached their maximum extent and the ice never went back to the ocean – which implies the ocean was at least partially frozen at that time.”
The oceans of Mars were salty but also cold. Despite the chill, they may still have been able to support life as the salt content would have kept at least some of the water unfrozen. Fairén compares the oceans on Mars more to the frigid waters of the Great Lakes in winter than the sunny beaches of California. Fairén and the NASA team plan on continuing their analysis of data on the tsunamis on Mars to find suitable areas for future missions to explore.
[Image via NASA/JPL/USGS]