Episoder
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In a recent paper published in the International Journal of Astrobiology, a philosopher Dr. Vojin Rakić (voyin rack itch) reviews some 50 or so proposed solutions to Fermi’s paradox, including, that human life is so exceptional that it happened only once in the universe, that perhaps other civilizations destroy themselves like we are trying to do, civilizations broadcast radio and TV signals only for a relatively brief period of time, alien intelligent life maybe incomprehensible to our species, and that maybe the energy requirements and distances in the Milky way are too great allow us to discover others of our kind and many more ideas. After sorting through all of these concepts, Dr. Rakić (rack itch) suggests that alien life might be unobservable to the senses evolution has given humans and/or perhaps alien beings live in part of the wider universe we don't know of or cannot yet detect and observe.
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The National Oceanic and Atmospheric Administration has published an extensive data based review, analysis, and summary of the Earth's Climate. 2016 was hotter than 2015 which was hotter than 2014. 2016 is the warmest year the Earth has been in the more than 180 years of record keeping. Overall in 2016 the whole Earth was 1.8 F above the 1951-1980 average. The Arctic in 2016 was 7.2F higher than it was the pre-industrial age.
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Mangler du episoder?
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Scientific results are consistent with the hypothesis that the dinosaur killing, K-T layer forming Chicxulub impactor came from well beyond Jupiter while the other 5 impactors in the past 541 million years as well as most meteorites found on Earth came from asteroids formed between Mars and Jupiter. All of this prompts us to marvel that we are here at all and puzzle over how to prepare for what the future might hold. In particular asteroid hunters should take seriously the possibility of an impactor from deep space with our number on it.
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An example that a relatively large space rock can approach the Earth suddenly started with what appeared as a bright star moving across the images that I had just obtained with the Catalina Sky Survey's 60 inch telescope on Mt. Lemmon, Arizona. It was about 100 times brighter than most of Earth approaching objects asteroid hunters discover. Over the next 64 hours it was tracked by 45 different observatories around the globe. This previously unknown space rock, now named 2017 AG5, is approximately 370 feet in diameter and can come closer than the Moon's distance to us.
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4015 Wilson-Harrington (1979 VA) was discovered as a comet by Wilson and Harrington in 1949, lost to astronomers for 30 years, and rediscovered in 1979 as an asteroid named 1979 VA. In 1992 with more data it was determined that comet Wilson-Harrington and asteroid 1979 VA are the same object.
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2016 was another record year for asteroid hunters during which we discovered 1,894 new Earth approaching objects. My team, the NASA funded, Catalina Sky Survey, led the pack with 931 Near Earth Asteroid discoveries.
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Binary asteroids are important since they enable astronomers to study how objects interact in space and in some cases the data can even yield their sizes and shapes.
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A location 9,000 feet above sea level in the Atlas Mountains of Morocco is ideal for an asteroid hunter since the weather is often clear and the skies are dark. It was thus intriguing for me to see that a new asteroid discovery was posted from J43 which is the Morocco Oukaïmeden [pronounced Oukaï-meden] Sky Survey or (MOSS) located near Marrakech , a name I had not encountered except in the Crosby, Stills, and Nash song "Marrakech Express". The MOSS observatory has team members in Morocco, France, and Switzerland, call themselves amateurs, and produces professional quality results.
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Approximately once every 45 million years a long period comet strikes the Earth with catastrophic results. Astronomers have identified and calculated orbits for more than 25 comets which have passed less than 40 times the Moon’s distance from us prior to the year 1900. There is the possibility of a Leonid meteor storm in mid November from 2021 to 2031 as the Earth passes through the debris left behind from Comet 55P/Tempel-Tuttle. Find a natural night sky location like the Cosmic Campground in New Mexico and check it out for yourself.
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The ALMA radio telescope located in the Atacama desert of northern Chile is able to see the faint millimeter wave length glow emitted by gas molecules and dust particles in the disk of material surrounding the very young star named HD 163296. This solar system in formation is located about 400 light years away in the constellation of Sagittarius. HD 162396's age compared to our Sun is like that of a 3 day old human baby compared to a 65 year old adult.
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As astronomers learned to measure the distance to the stars and how the laws of Physics works with rockets, it seemed that travel between the stars would take so much energy and time to get there that interstellar travel is a remote possibility at best. On the other hand, objects have been discovered being ejected from our solar system by a close encounter with Jupiter.Recently a team of researchers identified a region of our solar system where interstellar comets, asteroids, and even rouge planets might permanently reside after being captured by the Sun’s gravity.
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To discover what would happen if an asteroid were to strike a large body of water, Dr. Galen Gisler led a team of scientists who used high performance computing facilities at Los Alamos National Laboratory to calculate and visualize a 3-D model of an asteroid entering the Earth's atmosphere over one of the world's oceans. These efforts won them the Best Visualization and Data Analytics Showcase award at Supercomputing 2016. Reality is that what happens depends upon the mass, size, speed, angle of approach, and composition of the impacting object. Galen's group of scientists documented the hunch that since an asteroid strikes the water at a single point, it only effects the immediate region around the impact point, whereas to create a tsunami, you need something like an under water landslide which disturbs an entire water column from the ocean floor to the surface.
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My Catalina Sky Survey Teammate David Rankin was asteroid hunting in the constellation of Pegasus with our 60 inch telescope on Mt. Lemmon, AZ when he spotted a faint fuzzy object moving through a set of his images.David’s discovery is classified to be one of the more than 30 Encke type comets. This family small solar system objects have orbital periods about the Sun similar to their namesake comet 2P/Encke’s orbital period of 3.3 years
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Collect your own beautiful micro-meteorite sample.
It is estimated that several hundred thousand pounds of left over particles from the formation of our solar system enters the Earth's atmosphere every day with perhaps 10% of the of the total reaching the surface of our home planet. The individual grains of cosmic dust or micro-meteorites as they are also called range in size from the diameter of a human hair to twice the thickness of a dime. -
RADAR is very powerful tool since it can precisely measure an asteroid’s position and velocity as well as in some cases yield information about its size, shape, and other characteristics.
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Protection against a comet strike is worth considering. Every year, if we are lucky, several comets can come close enough for the Sun to warm and us to see the beautiful changing dust and gas clouds around them with binoculars or our unaided eyes. So far asteroids have gotten most of the attention as dangerous celestial neighbors, however, Dr. Joseph Nuth, a researcher at NASA's Goddard Space Flight Center in Greenbelt, Maryland recently pointed out "Comets can also deliver a heaping helping of calamity to Earth, and scientists and policymakers alike should start taking measures to combat the threat".
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Solar storms on our home planet occur when bursts of visible, ultraviolet and other photons hit our atmosphere and/or streams of energetic particles in the solar wind interact with Earth’s magnetic field. Mild solar storms produce beautiful aurora while the most intense ones have the potential to do trillions of dollars in damage to power grids, pipelines, rail networks, aviation, mobile phones, banking, credit card users, GPS, satellite communications, spacecraft, and more.
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It's a good thing this one will miss Earth.
Riding the surface of the asteroid that my Catalina Sky Survey teammate Richard Kowalski recently discovered would be an incredible experience. -
Astronomers measure an asteroid’s position on the sky using a two dimensional system similar to the latitude and longitude coordinates we obtain with our GPS. For the vast majority of asteroids, we cannot measure the third dimension, the distance to the asteroid directly.
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When asteroid hunters follow an object in the night sky for a few hours or a couple of days they are only able to observe a snippet or tracklet of the object's hundreds to thousands of days long path around the Sun. If we only have a short sample of an orbit we loose precision to locate the object as the length of time since the last observation increases. It is thus possible to lose the knowledge of where to find a particular asteroid.
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