Gigantic Volcano Eruption Swiveled Mars' Entire Surface

We're just starting to understand the nature of Mars' surface, but as it turns out, the Red Planet once looked a whole lot different. 3.5 billion years ago, a titanic volcano eruption displaced the top two layers of the planet, and essentially tilted the entire surface 25 degrees.

According to a new study published in Nature, the volcano itself was gigantic, approximately half the size of France, and spewed molten lava for two hundred million years. This enormous amount of magma solidified into an outcropping called the Tharsis, a dome-shaped plateau that's more than 2,000 square miles wide and 7.5 miles tall. 

"The Tharsis dome is enormous, especially in relation to the size of Mars. It's an aberration," Bouley told Phys.org.

"If a similar shift happened on Earth, Paris would be in the Polar Circle," said Sylvain Bouley, a geomorphologist at Universite Paris-Sud. "We'd see Northern Lights in France, and wine grapes would be grown in Sudan."

Computer simulations show that if the Tharsis dome were removed today, Mars' surface would once again shift on its axis until it were restored to its original position. This new theory explains a slew of observational evidence from Mars' surface, including the position of the rivers, the placement of the frozen underground reservoir in relation to the poles, and the location of the Tharsis dome on the equator. However, the researchers state that there are still many "unanswered questions" that need to be explored in light of these new findings.

"Did the tilt cause the magnetic fields to shut down?" said Bouley. "Did it contribute to the disappearance of Mars' atmosphere, or cause the rivers to stop flowing? These are things we don't know yet."