The 2019 revelation that methane was found on Mars sent shockwaves throughout the scientific community, as almost all of the gas on Earth is produced by life.
Now, scientists believe they have located the source — and it’s almost exactly where NASA’s Curiosity rover is.
Researchers at the California Institute of Technology used modeling techniques to determine that of the six methane spikes discovered since May 2017, the most recent is roughly a ‘few dozen miles’ from Curiosity, Space.com notes.
Scientists believe they have located the source of methane on Mars, roughly a ‘few dozen miles’ from where NASA’s Curiosity rover is
They took the methane gas particles, split them into different groups, took wind speed, direction and traced them back to approximately where the six points of emission came from.
‘..[O]ur back-trajectory modeling for atmospheric transport strongly supports surface emission sites in the vicinity of the Curiosity rover in northwestern Gale crater,’ researchers wrote in the study.
‘This may invoke a coincidence that we selected a landing site for Curiosity that is located next to an active methane emission site.’
Curiosity landed inside the Gale Crater on August 6, 2012, at a point now known as Bradbury Landing, named after famed science fiction writer Ray Bradbury. The rover made its first successful test drive on August 22, sixteen days later.
So far, it has traveled over 16 miles and spent 3,179 sols (Martian days) on its mission, snapping over 800,000 pictures.
Curiosity landed inside Mars’ Gale Crater on August 6, 2012 at a spot now known as Bradbury Landing
This view shows the first successful test drive of Curiosity on August 22, 2012 at Bradbury Landing
NASA’s Curiosity rover first measured a ‘strong signal’ of the molecule on June 15, 2013. But, some experts questioned the reliability of the discovery.
The six methane spikes were discovered by Curiosity’s Tunable Laser Spectrometer (TLS), which is able to find small amounts of methane at less than one-half part per billion (ppb).
One definite detection of about 15 ppb was discovered, while the others registered around 10 ppb.
In 2019, both the Curiosity rover and the ESA’s Mars Express spacecraft confirmed the presence of the unexpected discovery.
The measurement from Curiosity found 21 parts per billion of methane in the air, three times what was found during a 2013 measurement.
NASA has made sure that the methane is not from the rover itself, with the team operating it checking extensively.
According to Scientific American, between 90 and 95 percent of the methane in Earth’s atmosphere is ‘biological in origin,’ with much of it stemming from cows, goats and yak burps.
Other sources include termites, rice paddies, swamps and natural gas leakage and photosynthetic plants.
It’s unclear if an organism burping is causing the methane detections from Curiosity, but it provides researchers with a better place to look for the gas.
‘This would make this site interesting to visit, or other similar sites that could have the same properties,’ Håkan Svedhem, the project scientist for the European Space Agency’s Trace Gas Orbiter (TGO) said in an interview with New Scientist.
On Earth, methane has a detectable life span of 330 years and then it is completely destroyed by sunlight exposure. Its presence, however, is not a definitive sign of life.
As such, whatever is producing the methane may still be around, whether it’s biological or geological in nature.
The TGO has had trouble confirming the presence of the colorless, odorless gas in Mars’ atmosphere, but that may be due to the fact it is looking during the day, whereas the Curiosity rover has detected it at night.
The study was published June 3 on the preprint server Research Square and has not yet been peer-reviewed.
In May, NASA said the Curiosity rover may have discovered organic, or carbon-containing, salts on Mars, which the agency said could be chemical remnants of organic compounds.
WHAT EVIDENCE DO SCIENTISTS HAVE FOR LIFE ON MARS?
The search for life on other planets has captivated mankind for decades.
But the reality could be a little less like the Hollywood blockbusters, scientists have revealed.
They say if there was life on the red planet, it probably will present itself as fossilized bacteria – and have proposed a new way to look for it.
Here are the most promising signs of life so far –
When looking for life on Mars, experts agree that water is key.
Although the planet is now rocky and barren with water locked up in polar ice caps there could have been water in the past.
In 2000, scientists first spotted evidence for the existence of water on Mars.
The Nasa Mars Global Surveyor found gullies that could have been created by flowing water.
The debate is ongoing as to whether these recurring slope lineae (RSL) could have been formed from water flow.
Earth has been hit by 34 meteorites from Mars, three of which are believed to have the potential to carry evidence of past life on the planet, writes Space.com.
In 1996, experts found a meteorite in Antarctica known as ALH 84001 that contained fossilised bacteria-like formations.
However, in 2012, experts concluded that this organic material had been formed by volcanic activity without the involvement of life.
Signs of Life
The first close-ups of the planet were taken by the 1964 Mariner 4 mission.
These initial images showed that Mars has landforms that could have been formed when the climate was much wetter and therefore home to life.
In 1975, the first Viking orbiter was launched and although inconclusive it paved the way for other landers.
Many rovers, orbiters and landers have now revealed evidence of water beneath the crust and even occasional precipitation.
Earlier this year, Nasa’s Curiosity rover found potential building blocks of life in an ancient Martian lakebed.
The organic molecules preserved in 3.5 billion-year-old bedrock in Gale Crater — believed to have once contained a shallow lake the size of Florida’s Lake Okeechobee — suggest conditions back then may have been conducive to life.
Future missions to Mars plan on bringing samples back to Earth to test them more thoroughly.
In 2018, Curiosity also confirmed sharp seasonal increases of methane in the Martian atmosphere.
Experts said the methane observations provide ‘one of the most compelling’ cases for present-day life.
Curiosity’s methane measurements occurred over four-and-a-half Earth years, covering parts of three Martian years.
Seasonal peaks were detected in late summer in the northern hemisphere and late winter in the southern hemisphere.
The magnitude of these seasonal peaks – by a factor of three – was far more than scientists expected.