Aditya MadanapalleJul 05, 2017 22:07:25 IST
In June 2017, the hacking collective Anonymous claimed that NASA was on the verge of announcing the discovery of extraterrestrial life. A video was released as part of the announcement, and alleged that evidence of advanced spacefaring civilisations had been covered up, and the impeding announcement was not just about micro-organisms on a global subsurface ocean on another body in the Solar System. However, buried deep within the video, are some scientific half-truths.
One of the main pieces of evidence quoted by the video is a statement by Professor Thomas Zurbuchen, Associate Administrator for the Science Mission Directorate during a Congressional hearing in April titled ‘Advances in the Search for Life’. “NASA’s recent advances, such as the discovery of hydrogen in Saturn’s moon Enceladus and the Hubble team’s promising results from the oceans of Jupiter’s moon Europa, are promising signs that we’re closer than ever to discovering evidence of alien life,” Professor Zurbuchen had said.
Are we alone in the universe? While we do not know yet, we have missions moving forward that may help answer that fundamental question.
— Thomas Zurbuchen (@Dr_ThomasZ) June 26, 2017
NASA was quick to dismiss the video. However, in the past few months, there have seen a series of announcements related to finding the conditions that are favorable to life as we know it on Earth, on planets elsewhere in the universe. Science is a slow process, where evidence piles on top of more evidence, and there is an increasing understanding of the universe humans live in and our relation to it. Even though Europa was long suspected to have a global subsurface ocean, NASA confirmed it only after Hubble captured direct images of what are suspected to be plumes of water erupting from the Jovian moon.
Even during the announcement, NASA made it clear that the images only provided more evidence of plumes of water erupting from Europa, and that even the captured direct images were not absolute proof of water plumes on Europa. Although NASA has not yet confirmed that there is life on Europa, the space agency has taken steps acting on the assumption that there is. To avoid any potential contamination of the icy moon, the Juno spacecraft has an orbit around Jupiter that is specifically designed to avoid Europa.
The plumes of water on Europa, if they exist, are good news for the scientists searching for extraterrestrial life. This is because access to the subsurface ocean is made easier by the plumes, and it is possible to use new and more powerful telescopes to analyse the plumes of water for chemical signs of life. The alternative would be to send a submarine probe to Europa, which would have to drill beneath the ice cap to look for aliens. The current understanding of the Jovian system is based on evidence provided by a number of spacecraft, including Cassini, Galileo, Voyager and Juno. The James Webb Space Telescope, which is to be launched in 2018, can confirm the existence of plumes through infrared imaging.
NASA can also send a probe to directly sample the plumes for evidence of life. Another NASA spacecraft in orbit around a gas giant, Cassini has also been configured to avoid potential contamination of planetary bodies that could harbour life. The fuel is running out of the spacecraft in orbit around Saturn, and NASA intends to crash Cassini into the planet to avoid losing control of the spacecraft. After a loss of control, the spacecraft could drift into another moon with plumes of water - Enceladus.
In April 2017, NASA researchers published a paper that showed that Enceladus has all the ingredients necessary to support life as we know it on Earth. Evidence gathered by two long running missions, the Hubble Space Telescope and Cassini were used for the study. The Cassini spacecraft has detected oxygen, nitrogen and carbon on Enceladus. The only remaining ingredients necessary to support life are phosphorous and sulfur.
Unfortunately, Cassini is not equipped with the instruments needed to detect these elements, but has provided evidence of underwater geothermal activity. Hunter Waite, lead author of the Cassini study said, “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”. Professor Zurbuchen, also commented on the discovery, “This is the closest we’ve come, so far, to identifying a place with some of the ingredients needed for a habitable environment. These results demonstrate the interconnected nature of NASA’s science missions that are getting us closer to answering whether we are indeed alone or not.”
A recent study provided evidence that there was a large quantity of methanol around Enceladus. The finding has implications for the possibility of life on Enceladus, and demonstrates the carefulness with which scientists handle evidence that could be interpreted in one way or another. " Emily Drabek-Maunder of Cardiff University in Britain says, "Our findings suggest that methanol is being created by further chemical reactions once the plume is ejected into space, making it unlikely it is an indication for life on Enceladus." Dave Clements of Imperial College added, "To interpret our results, we needed the wealth of information Cassini gave us about Enceladus’s environment. This study suggests a degree of caution needs to be taken when reporting on the presence of molecules that could be interpreted as evidence for life."
NASA has developed a simple technique that can look for life, particularly on ocean worlds, by identifying amino acids. The technique could one day be used to investigate Mars, Europa and Enceladus for signs of life. Peter Willis of NASA's Jet Propulsion Laboratory says "One of NASA’s highest-level objectives is the search for life in the universe. Our best chance of finding life is by using powerful liquid-based analyses like this one on ocean worlds."
Even the most sophisticated of our astronomical instruments struggle to find the necessary evidence to either prove or disprove the existence of life on worlds in our own Solar System. The difficulty is much more pronounced for worlds in orbit around other stars. Even so, the scientists are hard at work, scouring the skies for possible candidate planets that can host life. In June, NASA’s Kepler space telescope released a survey catalog identifying over 200 candidate exoplanets. Ten of these are believed to be Earth sized worlds in the habitable zones of their host stars, where the temperatures are just warm enough for liquid water to exist on the surface.
In February, NASA’s Spitzer Space Telescope team made one of the most exciting announcements. Seven earth sized rocky exoplanets had been identified in orbit around an ultracool dwarf star only forty light years away. Out of these seven planets, three were in the habitable zone of the host star, TRAPPIST-1. With the right atmospheric conditions though, all of these planets could have liquid water on the surface. Sean Carey, manager of NASA’s Spitzer Science Center said, "This is the most exciting result I have seen in the 14 years of Spitzer operations. Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets." The finding is an important step in the search for alien lifeforms.
A study conducted by NASA in April showed that planets in orbit around binary star systems can potentially support life under the right conditions. All the known exoplanets in orbit around two stars are gas giants, but a rocky planet like the Earth, could, in theory have liquid water on the surface. The study had to factor in the complicated and erratic orbit of the hypothetical planet, as well as the habitable zone of a binary star system. Siegfried Eggl, a Caltech postdoctoral scholar at Nasa’s Jet Propulsion Laboratory said "Our research is motivated by the fact that searching for potentially habitable planets requires a lot of effort, so it is good to know in advance where to look." Such a planet would be similar to Tatooine from the Star Wars series.
With the launch of newer, powerful and more sophisticated astronomical instruments such as the James Webb Space Telescope, which can capture direct images of exoplanets, the chances of finding more evidence in support of life elsewhere in the universe can only improve. Exciting developments related to aliens by other researchers include speculation by Harvard scientists that fast radio bursts may be alien civilisations propelling interstellar probes equipped with solar sails, the Max Planck Institute for Astronomy in Germany confirming an atmosphere around a rocky exoplanet 39 light years away, and KIC 8462852, the star with the alleged alien mega-structure experiencing a mysterious dimming event.
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