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NASA Discovers Why Saturn's Moon Enceladus May Be the Best Place to Look for Alien Life
NASA scientists discover what two places in the solar system might have favorable conditions for alien life.
16 April, 2017
An illustration of an image from the Cassini spacecraft of Enceladus' south pole, showcasing its icy plume. Credits: NASA/JPL-Caltech
<p class="p1">NASA scientists announced its <a href="https://youtu.be/-nzaFDkDU7c" target="_blank">Cassini</a> spacecraft found evidence that the ocean on <strong>Enceladus</strong>, one of Saturn’s 62 moons, may contain all the ingredients necessary for the emergence of life.</p> <p class="p1">Cassini flew through plumes of gas bursting out from under the ice covering the oceans and detected a clear presence of molecular <strong>hydrogen</strong>. This might indicate the existence of <strong>hydrothermal vents</strong> on the moon’s ocean floor. Such vents would be similar to Earth’s hydrothermal vents where <a href="http://bigthink.com/paul-ratner/is-this-where-all-life-on-earth-began" target="_blank">some scientists believe</a> life on our planet originated. </p> <p class="p1">In the new findings, <a href="http://science.sciencemag.org/content/356/6334/155" target="_blank">described the journal <em>Science</em></a>, scientists consider the possibility of a chemical reaction called <em>methanogenesis</em> taking place in the moon’s underwater vents. This reaction has been <a href="https://www.newscientist.com/article/dn8882-methane-making-microbes-appeared-early-on-earth/" target="_blank">shown to be crucial</a> to the development of microbial life by providing an energy source for the microbes.</p> <p class="p1">The researchers cannot at this point conclusively state if <em>methanogenesis </em>is indeed taking place under Enceladus’s ice. It is also possible that this moon may be too young to have undergone the life-creating process. </p> <blockquote>
<p class="p3"><span class="s1">“Although we can’t detect life, we’ve found that there’s a food source there for it. It would be like a candy store for microbes,” <a href="https://www.nasa.gov/press-release/nasa-missions-provide-new-insights-into-ocean-worlds-in-our-solar-system" target="_blank">said</a> the study’s lead author Hunter Waite</span><span class="s2"> of the Southwest Research Institute in San Antonio.</span></p>
</blockquote> <p class="p3"><span class="s2"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODQwOTgyOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzY3MzE2Nn0.bEPkDn41pK7vBy6vY5AQQ4EAEpKOqhH9gwTnd3YJAXg/img.jpg?width=980" id="f6c1b" class="rm-shortcode" data-rm-shortcode-id="1c1efb88ff19a17e6c54b0e115cd8841" data-rm-shortcode-name="rebelmouse-image"><br></span></p> <div class="caption"><em>This is how Cassini scientists think water interacts with rock at the bottom of the ocean of Saturn's icy moon Enceladus, producing hydrogen gas. </em><em>Credits: NASA/JPL-Caltech</em></div> <p class="p5"><span class="s1">Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate in Washington, was also optimistic about the scope of Cassini’s current achievement.</span></p> <blockquote>
<p class="p7"><span class="s1">"This is the closest we've come, so far, to identifying a place with some of the ingredients needed for a habitable environment," <a href="https://www.nasa.gov/press-release/nasa-missions-provide-new-insights-into-ocean-worlds-in-our-solar-system" target="_blank"><span class="s3">stated Zurbuchen</span></a>.</span></p>
</blockquote> <p class="p9">Since 2004, the Cassini spacecraft provided no shortage of discoveries. As its head of imaging science Carolyn Porco <a href="http://www.sen.com/feature/an-interview-with-cassini-scientist-carolyn-porco.html" target="_blank">explained</a>, Cassini conducted over a 100 more “close flyby maneuvers” than have been done so far in the entire planetary program. </p> <p class="p9">It has given us an unprecedented understanding of Saturn, with stunning new images, insights into its rings, atmosphere and moons. </p> <p class="p9">In 2005, the spacecraft landed the Huygens probe on <strong>Titan</strong>, Saturn’s largest moon, a historic first for landing human machines in the outer solar system. The probe discovered a wealth of information, including an underground super-salty ocean. <span class="s4">The Cassini-Huygens mission was carried out in cooperation between NASA, the European Space Agency and the Italian Space Agency.</span></p> <p class="p12"><span class="s1">Here’s a film made by compiling imaging data from Cassini and the probe’s instruments as it descended towards Titan:</span></p> <p><span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="54961a0a547808f6152d46cc9e438190"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/TMxL3ZhO8A8?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span></p> <p class="p9">Cassini also came amazingly close to Jupiter, providing us with the best photos we have of the gas giant.</p> <p class="p9"><img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODQwOTgzMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMTIxNDY4Mn0.p0QEpkpNkDAhHiwr0v1AZ79LrWauC4k1CB3J8R0-ilk/img.jpg?width=980" id="4e24c" class="rm-shortcode" data-rm-shortcode-id="1d197beca099203494b78e6082a81d97" data-rm-shortcode-name="rebelmouse-image"></p> <p class="p9"><em>Composite photo of Jupiter, comprised of images taken by Cassini on December 29, 2000. Credit: NASA.</em></p> <p class="p9">The spacecraft will be decommissioned on September 15, 2017 by being plunged to burn in Saturn’s atmosphere. The reason for just a drastic demise lies in the fear that Cassini will soon run out of fuel and crash into one of Saturn’s moons, the ones we now think may contain life. It’s safer for it to burn up on entry than possibly contaminate the moons.</p> <p class="p9">On its way down, the spacecraft will transmit more data and images. These will include new maps of Saturn’s magnetic and gravity fields, and details on the composition of the planet’s rings.</p> <blockquote>
<p class="p13"><span class="s1">"It’s inspiring, adventurous and romantic — a fitting end to this thrilling story of discovery," <a href="https://saturn.jpl.nasa.gov/mission/grand-finale/overview/" target="_blank"><span class="s5">wrote NASA</span></a></span><span class="s6">.</span></p>
</blockquote> <p class="p15"><span class="s1">Watch this beautiful new film from NASA on Cassini’s final journey:</span></p> <p><span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="eee3741f9a67f7008ed25b5f1a1ae815"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/xrGAQCq9BMU?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span></p> <p class="p15"><span class="s1">Notably, another NASA team just <a href="http://iopscience.iop.org/article/10.3847/2041-8213/aa67f8" target="_blank"><span class="s5">published findings</span></a> on a different ocean world that might have some form of life. Their paper on observations from the Hubble Space Telescope program showed new evidence of water vapor plumes found on Jupiter’s moon <strong>Europa</strong>. In fact, they think they spotted a huge 62-mile-high plume over Europa’s equator, in the same place a plume candidate was spotted in 2014.</span> </p> <p class="p15"><span class="s1">These warm plumes are thought to be potential hosts for life. Considering that Europa is billions of years older than Enceladus, the chances for life to have emerged there could actually be greater.</span></p> <p class="p15"><span class="s1"><img alt="Europa" height="1147" src="http://assets3.bigthink.com/system/tinymce_assets/5314/original/europa.jpg?1492329704" title="Europa" width="1720"></span></p> <p class="p15"><em><span class="s1">Europa. Credit: NASA</span></em></p>
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Scientists Identify the Common Ancestor to All Life on Earth
Researchers possibly identify LUCA, the common ancestor to all life on Earth, and figure out where it lived.
27 July, 2016
Scientists may have identified the ancestor that started all life and where it lived. We are talking about LUCA, the Last Universal Common Ancestor, also known as the “microbial Eve”.
<p>This is the organism from which all modern cells descended which likely lived underwater in <strong>hydrothermal vents</strong>, an area where seawater and magma come together on the ocean floor. </p> <p>As the researchers say in their paper in “<em>Nature Microbiology</em>” -</p> <blockquote>
<p>“The concept of a last universal common ancestor of all cells (LUCA, or the progenote) is central to the study of early evolution and life's origin, yet information about how and where LUCA lived is lacking.”<span> </span></p>
</blockquote> <p><span>The search for this single-celled, bacteria-like ancestor from about <strong>4 billion years ago</strong> is what prompted </span>William Martin, an evolutionary biologist from Heinrich Heine University in Düsseldorf, Germany, and his colleagues to comb through DNA databanks.</p> <p>They analyzed a tremendous amount of data, grouping <strong>six million genes</strong> into related gene families to identify <strong>355</strong> gene families that were present in all modern organisms. These are the families that the scientists believe were also present in LUCA.</p> <p><span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="f0e103a4a292ade6fdda659f06eb0df2"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/K2IwSgbBymY?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span></p> <p><span>This identification led the researchers to a fuller picture of the ancestor they were hunting. </span>The organism likely lived underwater, during the period of Earth’s history called “<strong>the late heavy bombardment</strong>,” when it was constantly hit by comets and meteors. </p> <p>LUCA was a “thermophile,” living in an environment without oxygen, feeding on hydrogen gas from hydrothermal vents like those from undersea volcanoes. </p> <blockquote>
<p>“It was flabbergasting to us that we found as many as we did,“ said <a href="https://www.newscientist.com/article/2098564-universal-ancestor-of-all-life-on-earth-was-only-half-alive/" target="_blank"><span>Martin to the New Scientist</span></a>. “It’s spot on with regard to the hydrothermal vent theory.”</p>
</blockquote> <p>It’s important to note that the hydrothermal vent theory of where and how life began is just one of the ideas under consideration by scientists, albeit one that has been gaining more and more evidence and support. Another significant theory posits that life began on land, in pools of water that Darwin called <span>“<strong>warm little ponds</strong>.”</span></p> <p>If you want to learn more about hydrothermal vents and volcanoes, check out this video from NOAA (National Oceanic and Atmospheric Administration):</p> <p><iframe frameborder="0" height="360" src="http://oceantoday.noaa.gov/underwatervolcanoes/embed.html" width="640"><a href="http://www.nature.com/articles/nmicrobiol2016116" target="_blank">You can read the full study on “The physiology and habitat of the last universal common ancestor” here.</a></p> </iframe></p>
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