The United States Space Agency, NASA, reports that its car on Mars recently recorded a high level of methane on the planet. The discovery is fascinating, because the presence of methane can sustain the cause for life on Mars.
A recent NASA Curiosity car recorded the highest methane levels ever measured during the Seven Years of Mars missions.
Methane has no color or odor. A special tool at the Mars Science Laboratory in Curiosity was the increase in gas levels. The device, called the laser spectrometer, measures the levels of chemical elements and gases in the Martian atmosphere. In addition to methane, the device can record the levels of water and carbon dioxide.
Almost all of methane gas, which is in the Earth's atmosphere, is produced by biological activity. It usually comes from animals and plants. But it can also be formed geological processes such as interactions between rocks and water.
NASA said the increased methane was estimated to be about 21 parts per billion amount (ppbv). One ppbv means that if you take the air on Mars, then one billionth of the volume of air is methane.
It was not the first time Curiosity found methane in the atmosphere of Mars. About a year ago NASA announced that Curiosity had detected a sharp seasonal increase in gas.
At this time, NASA said that the measured methane gas level was clearly higher than any other that was observed in the past. NASA officials have even temporarily stopped other Curiosity activities for further investigation.
– It's interesting because microbial life is an important source of methane on Earth, "NASA said in a statement.
However, the Curiosity team conducted the next methane experiment, which showed a sharp drop in gas levels. In the second study, the level was less than one part per billion in volume. This number was "close to the background levels, which is a curiosity all the time," NASA said.
The rise and fall of the methane gas level left NASA scientists more questions than answers. Scientists continue to study the possible causes of sudden growth.
"The mystery of methane continues," said Aswin Wassawada, a research fellow at the NASA Passion Radiation Laboratory's Curiosity project in Pasadena, California. – We are more motivated than ever to continue to measure and put our brains together to see how methane behaves in a Martian atmosphere. "
No curiosity has instruments that could accurately determine whether a methane source is biological or geological. One of the leading theories is that methane is thrown out of underground territories created by possible forms of life that have long disappeared.
Despite the fact that Mars does not have active volcanoes, scientists consider it possible that methane is produced by reactions involving carbonaceous materials and water.
A clearer understanding of methane levels over time can help scientists to determine where they are are located on Mars, "NASA said. Scientists hope that such an understanding will come when curiosity continues to collect methane data in search of possible life.
I'm Brian Lynn.
Brian Lynn wrote this story for VOA Learning English based on NASA and Agence-France Presse reports. Caty Weaver was an editor.
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Words in this story
missions – n an important task, usually associated with travel
geological – near relating to the study of rocks, soil and physical structure of the Earth
amount – n quantity amount is something
microbial – near concerning microbes (very small living creatures)
motivate – v. to force someone to behave in a certain way
to determine – v. directly controlling or influencing
find it – v. find or pinpoint the exact position of something