The NASA, NASA, says its vehicle for research at Mars recently recorded a high level of methane gas on the planet. The discovery is exciting because the presence of methane can support life on Mars.
NASA's Curiosity vehicle has recently recorded the highest level of methane ever measured over seven years of Mars mission.
Methane has no color or smell. A special instrument at the Curiosity Mars Science Laboratory has recorded an increased gas level. The device, called a laser spectrometer, measures the levels of chemical elements and gases in the Mars atmosphere. Except for methane, the instrument can record levels of water and carbon dioxide.
Almost all the gas in the Earth's atmosphere is generated by biological activity. Usually comes from animal and plant world. But it can also be formed geological processes, such as interactions between rocks and water.
NASA said the increased methane was measured at about 21 parts per billion volume (Ppbv). One ppbv means that if you take the amount of air on Mars, one billion of the volume of air is methane.
This is not the first time Curiosity found methane in the atmosphere of Mars. About a year ago, NASA announced that Curiosity discovered a sharp seasonal increase in gas.
This time, NASA said the measured methane gas level was obviously greater than any other in the past. NASA officials even temporarily stopped other Curiosity activities to further investigate.
"It's exciting because microbial life is an important source of methane on Earth, "NASA says in a statement announcing the discovery.
However, the Curiosity team carried out a subsequent methane experiment that showed a sharp drop in gas. The second review found that the level was less than one part per billion volumes. That number was "close to the background levels that Curiosity sees," NASA said.
The rise and fall of methane gas levels left NASA scientists more questions than answers. Scientists continue to study the possible causes of a sudden increase.
"The secret of methane continues," said Ashwin Vasavada, a Curiosity project scientist from NASA's jet fuel laboratory in Pasadena, Calif. "We are more motivated than ever to continue measuring and putting the brain together to understand how methane behaves in the atmosphere of Mars. "
Curiosities have no instruments that can determine exactly whether the source of methane is biologically or geologically. One of the leading theories is that methane is released from underground areas created by possible life forms that have long since disappeared.
Although Mars does not have active volcanoes, scientists believe it is possible that methane is produced by reactions involving carbon materials and water.
A clear understanding of methane levels over time "could help scientists determine where are they findings on Mars, "NASA said. Scientists hope this understanding will come as Curiosity continues to collect meta data in search of a possible life.
I'm Bryan Lynn.
Bryan Lynn wrote this story for VOA learning English, based on NASA and Agence-France Press reports. Caty Weaver was the editor.
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Words in this story
mission – no. an important task, which usually involves traveling somewhere
geological – adj. related to the study of rock, soil and physical structure of the Earth
volume – no. the amount of something
microbial – adj. related to microbes (very small living creatures)
motivate – in. that someone behaves in a certain way
determine – in. directly control or influence
find – in. find or discover the exact position of something