You know that I am going to speak about Astronomy. But Astronomy is a huge science, it encompasses the study of all extraterrestrial objects and phenomena: From artificial satellites to black holes and the Big Bang. The title of my presentation is an answer. IS SOMEONE OUT THERE?
Poner fotos de películas cutres (Mars Attack, Alien, Alf, Predator, Avatar, X-Files, UFOs, Contact…) I am not going to speak about that, what I want to speak about is the serious attempt to find life that may exist or may have existed in the universe outside of Earth . The search for extraterrestrial life encompasses many fundamental scientific questions. Three of these questions are studied by Astrobiology, and the other one is just a problem of technical development. Nowadays any telescope achives the high sensibility that is needed.
No one knows which aspects of living systems are necessary, in the sense that living systems everywhere must have them, and which are contingent, in the sense that they are the result of evolutionary accidents such that elsewhere a different sequence of events might have led to different properties of life. In this respect the discovery of even a single example of extraterrestrial life, no matter how elementary in form or substance, would represent a fundamental revolution in science. Do a vast array of biological themes and counterpoints exist in the universe, or are there places with living fugues, compared with which Earth's one tune is a bit thin and reedy? Or is Earth's the only tune around?
Life on Earth, structurally based on C, H, N, and other elements, uses water as its interaction medium. Phosphorus , as phosphate bound to an organic residue, is required for energy storage and transport; sulfur is involved in the three-dimensional configuration of protein molecules; and other elements are present in smaller concentrations. Must these particular atoms be the atoms of life everywhere, or might there be a wide range of atomic possibilities in extraterrestrial organisms? A biology based in Si instead of C is posible and has been tested artifictialy.
the very atoms needed are exactly those that are around. It remains a remarkable fact that the atoms most useful for life have very high cosmic abundances. So, with all these conditions, let’s start the search.
What about the moon? It has more or less the same chemical distribution than Earth. One point. But the temperature in moon surface ranges from 100 K (-170ºC) to 400 K (120ºC) making improbable the existence of any kind of life. Also, because of the absence of either an atmosphere or a magnetic field , ultraviolet light and charged particles from the Sun penetrate unimpeded to the lunar surface.
Venus is the most earth-like planet. It has a similar size than Earth, its ecuator is a 95% of earth’s ecuator. Venus is like a catastrophical future vision of Earth. Venus has an extreme green-house effect, the CO2 concentration on atmosphere is much bigger than in Earth The average surface temperature of Venus is approximately 750 K (477 °C, or 891 °F). Even at the poles or on the tops of the highest Venusian mountains, surface temperatures do not fall below 400 K (127 °C, or 261 °F). The temperatures on Venus are too hot for Earth -style life. However, carbon dioxide , sunlight, and water (according to the results of the Venera space vehicles) are found in the clouds of Venus. These three are the prerequisites for photosynthesis. Molecular nitrogen also is expected at the cloud level, and some minerals are likely convectively raised to the cloud level from surface dust. The cloud pressures are about the same as those on the surface of Earth, and the temperatures in the lower clouds also are quite Earth-like. Although highly acidic by virtue of their sulfur , the lower clouds of Venus are the most Earth-like extraterrestrial environment known. No organisms on Earth lead a completely airborne existence, so most scientists dispute the possibility that organisms exist buoyed in the clouds of Venus.
Mars is inclinated 24.9ºC to its orbital plane, so Mars have seasons like Earth. That was discovered not so long time ago, in 1884, ¿and how? Because a seasonable change in color is observed. The same happens with Earth. At first it was thorugh that it could be produced because of the seasonal changes in the color of plants.
Europa , the fourth largest satellite of Jupiter, may be the best candidate for extraterrestrial life in the solar system. The Galileo orbiter revealed a crust of water ice and a complex surface on this moon. Optical imaging, thermographic temperature probes, and magnetic field measurements support the strong inference that a liquid saltwater ocean surges beneath the frozen crust. A wisp of an oxygen atmosphere has also been detected by spectrographic techniques. Furthermore, since organic molecules including methane and nitrogen-rich gases such as ammonia abound on Jupiter and some of its other moons, such “prebiotic chemicals” are highly likely to be present on Europa. The Galileo flyby also detected abundant sulfuric acid , a potential chemical power source, on the surface of Europa. (Such discoveries in the Jovian planets inspire further investigation of the limits to diversity of life on Earth. Lakes such as Vostok in Antarctica reside under more than 3 km [2 miles] of ice. Studies of bacteria in these lakes and of water seeps within cavities in granitic and carbonate rocks provide models for the viability of possible Earth-like life-forms on Europa and other Jovian moons.)
Titan is far colder than Earth , and its surface seems to lack liquid water . On the other hand, Titan appears to have lakes of liquid ethane and or liquid methane on its surface, as well as rivers and seas, which some scientific models suggest could support non-water based life, although not all scientists agree with these theories, as they are still subject of much discussion and debate in the scientific community, including at NASA. Titan's atmosphere is also thick, chemically active, and is known to be rich in organic compounds , which has spurred additional speculation about life, or precursors for life, especially suspended in the higher atmosphere. The atmosphere also contains hydrogen gas, which is cycling through the atmosphere and the surface environment, and which living things comparable to Earth methanogens could combine with some of the organic compounds (such as acetylene ) to obtain energy
Picture by Hubble. 2008. 115 AU!!! Mass ranges between 0.5 and 3 MJup
¡¡¡Poner al día!!! 540 planets (13/april/2011)
Gliese c was discovered in April 2007. Gliese g was discovered in September 2010 may content water 89th closest star to sun
How a record player works
¿Is someone out there
IS SOMEONE OUT THERE?
<ul><li>What are the basics requirements for life? </li></ul><ul><li>Could life have arisen elsewhere in solar system? </li></ul><ul><li>Are there other planets like Earth? </li></ul><ul><li>How likely is the evolution of intelligent life? </li></ul>
Basics requirements for life Hellicobacter pylori
<ul><li>Major atoms in abundance </li></ul><ul><li>Constant temperature </li></ul><ul><li>Medium for molecular interaction </li></ul><ul><li>No nocive cosmic radiation </li></ul><ul><li>Source of energy </li></ul>