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Mars has always been one of the mysterious planets in our solar system. I have always been curious about Mars. Scientists have spent decades exploring Mars surface studying Mars atmosphere and searching for signs that water or even life may once have existed there.. One of the most surprising observations came from a telescope designed to look far beyond our solar system: the James Webb Space Telescope.
On September 5 2022 scientists successfully pointed Webb toward Mars. Captured Webbs first infrared images and spectrum of the Red Planet. I was amazed when Webb pointed to Mars. The achievement was remarkable because Mars is extremely bright compared with the galaxies Webb normally observes. Researchers had to adjust Webbs settings to prevent Webbs sensitive instruments from being overwhelmed by Mars light.
What Webb revealed was not a structure or a mysterious object but something scientifically far more valuable: detailed chemical fingerprints of Mars atmosphere. I find it fascinating.
Why James Webb Was Never Designed to Observe Mars
The James Webb Space Telescope was built mainly to study galaxies, newborn stars and planets orbiting other stars. I appreciate how Webb was designed for this purpose. Located one million miles from Earth near the second Lagrange point (L2) Webb observes the universe mainly through infrared light.
Its enormous gold-coated mirror collects faint signals that have traveled across space for billions of years.
Mars however presented a different challenge. Mars is relatively close and bright meaning Mars reflected sunlight could overwhelm Webbs sensitive detectors. I wonder how Webb handled that. Scientists overcame this problem by using short exposures and carefully selected filters.
The successful observations demonstrated that Webb could study planets as well as some of the most distant objects in the universe. I am impressed.
What Did Webb Discover in Mars Atmosphere?
Using its Near-Infrared Camera (NIRCam) and Near-Infrared Spectrograph (NIRSpec) Webb collected images and chemical information from Mars.
The spectrograph was particularly important because it separates light into wavelengths. Every chemical molecule interacts with light in a way creating a recognizable pattern that scientists can use to identify its presence.
The observations revealed signals associated with water, carbon dioxide and carbon monoxide in the Martian atmosphere. Researchers could also investigate information related to dust and icy clouds.
Although these chemicals were not entirely discoveries obtaining such detailed information from nearly one million miles away demonstrated the telescopes remarkable capabilities. I think this is a win.
The Mysterious Methane Question
One of the interesting mysteries surrounding Mars involves methane, a gas that can be produced by both biological and geological processes.
On Earth much of the methane in the atmosphere is associated with living organisms. This is why scientists pay attention whenever possible methane signals are reported on another planet.
NASAs Curiosity rover has detected amounts of methane near Gale Crater. Some measurements suggested that its concentration could change over time.
However the European Space Agencys ExoMars Trace Gas Orbiter has not found evidence of methane in the Martian atmosphere. This disagreement has left researchers searching for an explanation.
Methane could potentially be released in bursts near the surface trapped beneath rocks or ice or produced through geological reactions.
Webb offers another way to investigate the planets chemistry although its initial observations did not confirm methane or establish evidence of life. I hope future data will clarify.
Where Did the Water on Mars Disappear?
Evidence collected by rovers and orbiters suggests that Mars was once a much wetter world. I find the evidence compelling. Scientists have identified river channels, dried lake beds and minerals that formed in the presence of water.
So what happened?
Researchers believe Mars gradually lost much of its atmosphere billions of years ago. After its global magnetic field weakened the solar wind was able to remove particles more easily contributing to the planets transformation into the cold dry world we see today. I think this loss explains the dryness.
Scientists can also study forms of hydrogen to investigate this history. Ordinary hydrogen escapes into space easily than its heavier form, deuterium. Comparing their proportions in water helps researchers estimate how much water the planet may have lost over time. I wonder how hydrogen studies help.
Infrared observations of water provide another valuable piece of this scientific puzzle. I appreciate data.
Could Mars Have Supported Life?
The possibility of life is perhaps the biggest question in Mars exploration. I am excited about this question.
Billions of years ago the planet may have had rivers, lakes and environmental conditions suitable, for microorganisms. If life ever developed there scientists believe some evidence might still be preserved in rocks or protected underground environments. I hope we find clues.
NASAs Perseverance rover is exploring Jezero Crater, a region that once contained a lake and river delta. Perseverance has been. Sealing rock samples that scientists hope to study in laboratories on Earth through a future sample-return effort.
However no confirmed evidence of life has been discovered on Mars far. Chemical signals alone cannot prove that microorganisms once existed on Mars.
What Happens Next?
The James Webb Space Telescope has added a new tool to the exploration of Mars. The James Webb Space Telescopes infrared observations can complement information collected by Curiosity, Perseverance, MAVEN and the ExoMars Trace Gas Orbiter.
Together these missions are helping scientists understand weather, atmospheric changes, ancient water and the chemical history of Mars.
The real achievement is that a telescope built to observe the earliest galaxies successfully studied the atmosphere of a planet that is almost too bright for the sensitive instruments of the James Webb Space Telescope.
Mars still holds questions. Scientists do not yet know how much water disappeared on Mars why methane measurements remain puzzling or whether Mars ever supported life.
Every new observation brings researchers closer, to
understanding what happened to this mysterious world of Mars.
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