Despite its extraordinary surface temperature that hovers around 900 degrees Fahrenheit (480 degrees Celsius), Earth’s twin planet Venus was suspected to have some indicators that pointed towards ‘habitability’. When NASA’s Magellan entered Venus’ orbit on Aug.10, 1990, it found key similarities between Venus and its planetary neighbour Earth in terms of size and density. Besides, the planet's rocky terrestrial features such as the volcanoes, long lava channels, pancake-shaped domes, and evidence of hot mantle plumes at depth like the one responsible for creating the Hawaiian Islands made scientists hopeful.
In September 2020, scientists made a groundbreaking discovery after they found a gas called ‘phosphine’ that is an indicator of life on Earth in the atmosphere of Venus.
Study co-author and astrophysicist and planetary scientist at Massachusetts Institute of Technology, Sara Seager, said “Something completely unexpected and highly intriguing is happening on Venus to produce the unexpected presence of tiny amounts of phosphine gas”. Approximately 20 parts-per-billion of the gas was found to be present in Venus' clouds.
On Monday, June 28, however, a new study published in the journal Nature Astronomy that analyzed the data from the several probes that flew to Venus found that the amount of water in the atmosphere of Venus is so low that the planet is incapable of supporting even the most drought-tolerant microbes of the Earth. Scientists accumulated data about the temperature, humidity, and pressure in the thick sulphuric acid clouds of Venus.
For instance, NASA’s Parker Solar Probe has made multiple flybys of Venus, coming within about 515 miles (830 kilometers) of the surface on July 11, 2020. Spacecraft had flown through the planet’s upper atmosphere. This was the first direct measurement of the Venusian atmosphere in nearly 30 years.
On June 2, 2021, NASA announced two new missions to Venus as part of the agency's Discovery Program. The selected missions are DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) and VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy). The European Space Agency (ESA) announced the selection of EnVision to make detailed observations of Venus with NASA’s Synthetic Aperture Radar, called VenSAR to document the planet’s surface features.
Putative Venusian life 'not possible'
However, the data from the probes already gathered by the scientists has revealed that the very cloudy planetary atmosphere that had regenerated interest in the idea of life in clouds due to the presence of phosphine, is not at all conducive for life. “There is no reason to suppose that putative Venusian life would have the same biochemical basis as that on Earth,” the study that determined habitability for Venus’s acid clouds, indicated. It added that microbial growth cannot occur anywhere near the Venusian clouds, given that permissive water activity is a prerequisite for the active metabolism of terrestrial life forms.
[This image is a composite of data from NASA's Magellan spacecraft and Pioneer Venus Orbiter. Credits: NASA/JPL-Caltech]
“At Venus, We observed a strong reduction of water activity even at modest sulfuric acid concentrations,” the scientists said after they derived results from the study of the two independent thermodynamic models of H2SO4–H2O mixtures. The level of the water was approximately 100 times less (than was previously thought of) to support any life form.
"The water in the clouds of Venus is just not up to the levels required to support life," said study co-author Christopher McKay, a NASA scientist. Meanwhile, the study’s lead author John E. Hallsworth of Queen's University, Belfast, said, the “new research shows that the sulfuric acid clouds in Venus have too little water for active life to exist, based on what we know of life on Earth.”
Although, scientists have been able to find that the water levels in Jupiter’s clouds have a higher concentration as compared to Venus as well as adequate temperature to support life. "We have also found that the conditions of water and temperature within Jupiter’s clouds could allow microbial-type life to subsist, assuming that other requirements such as nutrients are present," the lead author Hallsworth stated.
https://news.google.com/__i/rss/rd/articles/CBMiiwFodHRwczovL3d3dy5yZXB1YmxpY3dvcmxkLmNvbS90ZWNobm9sb2d5LW5ld3Mvc2NpZW5jZS9jbG91ZHMtdG9vLWRyeS1zdHVkeS1ydWxlcy1vdXQtcG9zc2liaWxpdHktb2YtbGlmZS1vbi12ZW51cy1kdWUtdG8tbGFjay1vZi13YXRlci5odG1s0gEA?oc=5
2021-06-29 07:32:00Z
52781699926562
Tidak ada komentar:
Posting Komentar