Curiosity Shows That Red Planet Is Losing Its Atmosphere

The Mars rover Curiosity is doing extra than channeling its internal tourist and snapping photos each chance it gets. Two new documents appearing in this week's issue of Science are the primary to come out of the Mars Science Laboratory that speak about the planet's surface. Both papers state that Mars has been steadily losing its atmosphere more than the past 4 billion years.

This isn't the first occasion that NASA has calculated the concentration of gases in the Martian atmosphere. "There was really revolutionary work done back in the '70s with the Viking landers," Paul Mahaffy, the lead author behind one of the papers and a NASA scientist, told ABC News. "But those lenders were a more ancient report of the thing that's landed on Mars now."

Curiosity calculate the quantity gases directly from the atmosphere, and also the gases released from solids, using two special instruments that are the component of SAM (Sample Analysis on Mars). Particularly, they are calculating the ratios of different isotopes (elements that have the similar number of protons, but differ in weight.)

Heavier isotopes are typically rarer in nature than lighter ones, but Mars is showing a higher ratio than what would seen on Earth. The higher the ratio of isotopes, the more atmospheric loss that is occurring. "When we look into the physics of how atoms escape from an atmosphere, we see that the lighter atoms can escape a little easier than the heavier," said Mahaffy. "It's not a very big effect, except if the molecules are lost over billions of years, it start to build up more of the heavy isotope.”

This gathering of heavier isotopes, or isotopic enrichment, is high-flying when looking at the levels of hydrogen in the Martian atmosphere. Curiosity found much more quantity of deuterium, a heavier isotope of hydrogen, than that is found on the Earth. "The ratio five times higher according to Chris Webster, the lead investigator behind the Tunable Laser Spectrometer, one of SAM's instruments. The ratio of deuterium to hydrogen is one of the basic measurements of any object in the solar system. Scientists had produced a model that explained the ratios on many objects. 

One of the well known theories explains this abnormality that a Pluto-sized object which rammed into Mars about four and a half billion years ago. The impact disrupted the planet's magnetic field, which in turn led to an unexpected loss of the planet's atmosphere. Following that unexpected loss, Mars has been gradually, but surely, losing its atmosphere. "The data we have doesn't prove this," said Webster. "But this falls in line with the theory."

The measurements which are obtain with Curiosity's instruments match up with what's been assumed by both the Viking lenders and Martian meteorite studies. Adam Burrows, a professor of astrophysical sciences at Princeton University in New Jersey, says that its the SAM's accuracy that makes these new discoveries stand out. "The Viking measurements were very crude. Now, measuring with two different instruments, we get a pretty consistent picture saying that there's been isotopic enrichment," he said.

Still, these calculations are not enough to give a absolute picture. Burrows want to see what Curiosity measures throughout the planet and throughout the Martian year (double than an Earth year). "These ratios change a fair amount from place to place and time to time," he says. "But it is the best data we've gotten from another world."