Astro Blog

https://www.science.org/doi/10.1126/science.adg4155 By SAMANTHA K. TRUMBO  AND  MICHAEL E. BROWN , Science.  Excerpt: [Editor's summary:] Europa, an icy moon of Jupiter, has a subsurface ocean beneath a crust of water ice. Solid carbon dioxide (CO 2 ) has previously been observed on its surface, but the source was unknown. Two teams analyzed infrared spectroscopy of Europa from the James Webb Space Telescope to investigate the CO 2  source. Trumbo and Brown found that the CO 2  is concentrated in a region with geology that indicates transport of material to the surface from within the moon, and they discuss the implications for the composition of Europa’s internal ocean. Villanueva  et al . also identified an internal origin of the CO 2  and measured its  12 C/ 13 C isotope ratio. They searched for plumes of volatile material breaching the surface but found a lower activity than earlier observations. Together, these studies demonstrate t...

https://www.science.org/content/article/carbon-dioxide-detected-around-alien-world-first-time By Daniel Clery, Science Magazine.  Excerpt: Astronomers have found carbon dioxide (CO 2 ) in the atmosphere of a Saturn-size planet 700 light-years away—the first unambiguous detection of the gas in a planet beyond the Solar System. The discovery, made by the  James Webb Space Telescope , provides clues to how the planet formed. The result also shows just how quickly Webb may identify a spate of other gases, such as methane and ammonia, which could hint at a planet’s potential habitability for life. ...The Webb telescope is sensitive to infrared wavelengths of light that are mostly blocked by Earth’s atmosphere. ...the infrared sensitivity is also critical for researchers.... When an exoplanet’s orbit takes it in front of its star, some of the starlight passes through the planet’s atmosphere and carries fingerprints of its composition. The atmospheric gases absorb specific wavelength...

https://eos.org/research-spotlights/curiosity-rover-reveals-oxygen-mystery-in-martian-atmosphere Source:   By Sarah Stanley, Eos/AGU. Excerpt: The Martian atmosphere is thin and cold and consists mostly of carbon dioxide. Although certainly unsuitable for humans, Martian air could hold clues to whether other life-forms live—or once lived—on the Red Planet. Now Trainer et al. report the first measurements of the five major components of the Martian atmosphere captured over several seasonal cycles. ...On average, the data revealed, the equatorial Martian atmosphere consists of 95% carbon dioxide, 2.59% nitrogen, 1.94% argon, 0.161% oxygen, and 0.058% carbon monoxide. However, throughout the year, some of these concentrations vary widely because of seasonal freezing of carbon dioxide at the planet’s poles, which periodically removes much of this gas from the atmosphere. Seasonal polar freezing—and subsequent thawing—of carbon dioxide also causes atmospheric pressure to rise and fa...

Source:  By Shannon Hall, Earth & Space News (EOS; AGU) Excerpt: ...A new hypothesis might reconcile two opposing theories that have tried to explain Mars's mysterious history... suggests that lush periods just long enough to form water-created surface features, such as canyons, punctuated much longer, planet-wide frozen spells. ...In the 1970s, images of Mars taken by the Mariner and Viking spacecraft revealed enormous channels and valley networks—both of which are reminiscent of catastrophic floods and river drainage systems on Earth. The fluvial features were the first sign that 3.8 billion years ago, the planet was once a lush oasis, awash with oceans, lakes, and rivers. ...a 40-year-long debate that has divided planetary astronomers into two camps: those that think Mars must have once contained a thicker and warmer atmosphere—which made the Red Planet hospitable to liquid water and potentially the evolution of life—and those that think Mars was mostly cold save for sho...

Source:   Johanna L. Miller, Physics Today Excerpt: Radar data reveal a solid reservoir that contains almost as much carbon dioxide as the planet’s entire atmosphere. …because Mars doesn’t have a large moon, it… wobbles by up to tens of degrees on time scales of hundreds of thousands of years…. a profound effect on the planet’s polar icecaps. Substantial amounts of material sublimate and are redeposited, creating a complex structure of overlapping layered deposits. Most of those deposits are primarily water ice. …but now, data from the Mars Reconnaissance Orbiter reveal at least one large deposit of CO2 ice…if ...vaporized, as it certainly was at some point in the past and will be again in the future, it could nearly double the average pressure of Mars’s thin, CO2-based atmosphere. See also: www.nasa.gov/mission_pages/MRO/news/mro20100526.html physicstoday.org/resource/1/phtoad/v64/i6/p12_s1

Source:   NASA Excerpt:  ...NASA's Mars Reconnaissance Orbiter (MRO) has discovered the total amount of atmosphere on Mars changes dramatically as the tilt of the planet's axis varies. This process can affect the stability of liquid water if it exists on the Martian surface and increase the frequency and severity of Martian dust storms. Researchers using MRO's ground-penetrating radar identified a large, buried deposit of frozen carbon dioxide, or dry ice, at the Red Planet's south pole. The scientists suspect that much of this carbon dioxide enters the planet's atmosphere and swells the atmosphere's mass when Mars' tilt increases. ...The deposit holds up to 80 percent as much carbon dioxide as today's Martian atmosphere.... www.nasa.gov/home/hqnews/2011/apr/HQ_11-118_Mars_Atmosphere.html

Source:   Peter C. Thomas, Science Magazine   Earth's climate is buffered by massive oceans of liquid water and by gases, such as carbon dioxide (CO2).... Mars has no oceans to buffer its temperatures, and the thin atmosphere (95% CO2) provides little thermal buffering.  ...early space probes explored whether large CO2-ice deposits might buffer the atmospheric pressure of Mars (1).  ...Phillips et al. (2) report the discovery of thick deposits in the south polar region that are most likely composed of solid CO2 and comparable in mass to the present Mars atmosphere. www.sciencemag.org/content/332/6031/797.summary