V101 Science 📤 2 years ago 2015-07-20
Looking up at the night sky, it's hard not to wonder how many stars might be home to Earth like planets that host intelligent life, intelligent life that may even be starring right back at us. Thanks to NASA's space telescope Kepler, we do at least have rough estimates as to how many Earth like, rocky planets there are in The Milky Way Galaxy that orbit in the habitable zone of another star. Around one in five Sun like stars have an Earth sized planet in the habitable zone. Assuming around 200 billion stars are in The Milky Way Galaxy, that would be 40 billion potentially habitable planets in our galaxy alone. If billions of potentially water laden, Earth size planets exist in our galaxy, then surely the odds suggest life is out there? So we know Earth sized rocky planets, in the habitable zone, are common throughout the galaxy, and we also know how to locate them, but outer space is massive, so big in fact that even Alpha Centauri, the closest star system to our Solar System is 4.37 light-years away (more than 25.6 trillion miles) So far away that sending a manned mission or probe there would not be possible in our lifetimes, unless alternate propulsion methods are discovered. So with that in mind, why are many of the worlds leading scientists confidently making the prediction "We will discover alien life within the next 10 - 40 years" The possibility of finding alien life in our solar system is still very plausible and the sixth-largest of Saturn's moons may be the perfect place for that discovery. Enceladus has a subsurface ocean underneath it's icy crust and has gained a lot of attention in the search for life beyond earth, this due to its erupting water geysers which are believed to be an indication of hot springs under its frozen surface. Another candidate, Mars, is believed to have once been home to vast amounts of water, Some of which is still present in the form of ice and a small amount of vapor in it's atmosphere. Microbial life could yet be found on mars, however... Alien life found in our solar system would likely turn out to be a lot less alien than you might think. Microbial life from earth would have almost certainly been blasted around the solar system by asteroid and comet impacts, transporting microorganisms protected deep inside rocks on a harsh journey through space. Or life here on Earth could in fact turn out be Martian, as we know life existed here around the same time Mars is believed to have been a much warmer and wetter place. Answers to mans undying question "Are we alone in the universe" will come as we widen our gaze beyond our solar system. Nasa's James Webb Space Telescope (JWST) is due to be launched in 2018, one of it's main uses will be to study the atmospheres of exoplanets, with the potential to follow up on and provide a more in depth look at some of the TESS missions most promising discoveries. The JWST and future larger space telescopes will be able to detect a strong enough signal from close by exoplanets to detect greenhouse gases present in their atmospheres. These detections are made using spectroscopy. When starlight passes through an planets atmosphere, the chemical signature of the atmosphere is in printed on the light as dark lines in it's spectrum , these lines precisely indicate what gases are present in the atmosphere.By detecting large quantities of biosignature gases in the atmosphere of an exoplanet, life can be inferred to exist there, one example would be oxygen, our atmosphere has around 21% oxygen in it, without life in the form of plants and photosynthetic bacteria we would have practically none. In one of the many close by stars systems an alien civilization could be looking at earth right now. After analyzing our planets atmosphere, they may have reached the conclusion that the high oxygen levels and water vapor amongst other things, are a clear sign of life on our planet. Perhaps several alien civilizations in the universe have made the discovery of life on earth and the only thing stopping a visit is the lack of technology to get here?
Music.Kevin Macleod - Clean Soul - Thunder Dreams - Deep Haze - Controlled Chaos.
credits=Bacteria-EJ Hassenfratz, Asteroid RD-NMK, Stephen Hall-Solar System, 2010 DIGITAL ORRERY-John Shells, Earth Zoom Out From Madrid - Puerta del Sol, The Mountain-TSO Photography.
NASA-Kepler Discovers First Earth-size Planet-The Search For New Worlds is Here,Alien Atmospheres, Kepler Field of View, Seeing Beyond - The James Webb Space Telescope, Icy Curtain Eruptions on Enceladus Create an Illusion of Discrete Jets.
ESO Observatory-Artist’s impression of Mars four billion years ago-A fly-through of the Alpha Centauri system-Artist’s impression of bright exozodiacal light-Artist’s impression of exocomets around Beta Pictoris