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| Impact of Devastation, Impact of Life |
| July 2005 true masked wabbit eagle averro credits listed below |
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| actual footage of a comet skimming our atmosphere in the 1970's |
| the comet skimmed over our atmosphere and bounced back into space |
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| Kohoutec Comet |
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| Hale Bop Comet |
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| Asteroid 1999KW4 |
| 65 Million Years ago an asteroid devastated earth and the majority of its inhabitants changing the course of evolution. One hundred million years before that evolution had been altered because of an impact on earth and so scientists have concluded through fossil findings that our planet earth had undergone changes in evolutionary outcome at least 5 times due to major impacts through the course of the 4.5 billion years of earth. There are approximately one hundred million of asteroids and comets in space, leftovers from when our universe was formed. Some have been in collision course with earth while others quietly orbit in our asteroid belt or get caught up by our two gas giants Saturn and Jupiter. From the time many witnessed the impacts of the 9 comets Schumacher and Levy into Jupiter, scientists now are space oriented to watch what other hazardous comet or asteroid might be heading towards us. What surprised many scientists is that they had found more than they ever had expected to be considered hazardous and certainly to keep a vigilant eye on their journey’s path. Are we safe from another collision? We humans feeling we are safe and we have everything under control is a fool hearted ideal. Nature will always have the last word as well as what is out in space. As estimated that at least every one hundred million years and asteroid has hit earth and caused devastation at a major proportion we are due any time any day for another to come this way. For this many scientists world over have turned their telescope towards any sign of an asteroid or comet possibly coming this way with the pressing question what can we do about it? To send a nuclear device to explode an asteroid has been ruled out since it would only shatter the asteroid or comet but the debris would hurdle towards earth just the same. Joseph Spitale, a research associate in planetary science at the University of Arizona–Tucson has found another way to nudge an asteroid away from earth’s orbit. "The thermal emission from an asteroid acts like a rocket force in the opposite direction, although it is really, really weak," Spitale said. "If we can somehow change the thermal radiation being emitted by an asteroid, we can affect the object's orbit. A tiny thrust acting over a long time can be enough to nudge an asteroid from a path heading towards the Earth to one that narrowly misses the Earth." In the search to find asteroids or hazardous comets heading towards earth scientists have also found cosmic dust. Plenty of cosmic dust that rains down onto our earth. We breathe it, we eat it, it’s part of our lives. In the nucleus of the cosmic dust scientists have also found all the ingredients to life and now the question arises whether or not comets actually carry with them all that which is necessary to commence life on whatever planet they might impact on. Such as it is speculated here on earth. Here are some experts from National Geographic and NASA articles I have come across as well as the above information I took from two National Geographic Videos. How Big A Threat To Earth? Earth-bound asteroids grab newspaper headlines for good reason. Scientists say the fallout of an asteroid several city blocks wide smacking into the planet would be catastrophic. Mass extinctions, runaway infernos, erratic climate fluctuations, and devastating impacts on human civilization are just some of the scenarios imagined. Why, then, does the threat of a comet impact with Earth—potentially as dire if not worse than an asteroid—rarely leak onto the pages of the popular press? "Primarily because the rate of comet impacts on Earth is not as great as the rate of asteroid impacts," said Daniel Durda, a senior research scientist at the Southwest Research Institute in Boulder, Colorado. Most comets, and potentially some asteroids, have orbits that bring them close to Earth only once every 200 years or longer. Such bodies are known to astronomers as long-period objects. The rate of long-period comet impacts on Earth is on the order of one every 32 million years, whereas the rate of comparably-sized asteroid impacts is more like one per every 500,000 years. "When—note that I do not say if—we find a comet which has some potential to hit Earth, it might cause an even bigger sensation than potential asteroid impactors," said Robert Jedicke, an asteroid expert at the University of Arizona in Tucson. The Threat The consequences of comet and asteroid impacts on Earth are roughly comparable. Both would cause widespread destruction and loss of human life, said Jedicke. "Big chunks of rock with a little ice, an asteroid, or big chunks of ice with a little rock, a comet, create a lot of damage when they impact Earth," he said. "[It's] like getting hit on the head by a stone with an icy coating or an iceball with a lot of rock in it—it's going to hurt your head." A key difference is that long-period objects, like comets, will impact Earth with much greater speed than short-period objects, said Dan Mazanek, an engineer at NASA's Langley Research Center in Hampton, Virginia. "If we happen to come across a long-period object that is dense, it would not have to be large to produce the same kinetic energy of a one-kilometer [0.6-mile] near-Earth asteroid," he said. "To me, that seems like something worthwhile to investigate." Consider this example. An asteroid 0.6 mile (1 kilometer) wide with a density of 187 pounds per cubic foot (3,000 kilograms per cubic meter) traveling at 12 miles per second (20 kilometers per second) would impact Earth with a force approximately 15 times greater than the world's total nuclear arsenal. A comet of just over half the size and one-third the mass traveling at 37 miles (60 kilometers) per second could achieve an impact of similar force if it were to strike Earth. "Size matters," said Mazanek. "But so does density and speed." Protection Some astronomers are working to safeguard the Earth from potential impact by comets or other near-Earth objects in orbit around the Sun. The Near-Earth Object Program at NASA's Jet Propulsion Laboratory in Pasadena, California, coordinates the study of these objects. As near-Earth objects are detected, scientists perform calculations on their orbits to determine if or when they pose a threat to impact Earth. The hope is that astronomers can detect all near-Earth objects decades before they would potentially impact Earth. Meanwhile, other scientists are busy trying to figure out how to throw such threatening objects off course, thus mitigating the pending doom. Long-period objects like comets, however, are not easily detected until they enter the solar system. "A long-period object by definition may not have any records of sightings in written history," said Mazanek. "If it came back into the solar system and it was on [an Earth-bound trajectory], we would not have much warning." Mazanek leads NASA's Comet/Asteroid Protect System, a program that would expand on the Near-Earth Object Program to include the detection of long-period comets, as well as small asteroids and short-period comets that pose an Earth impact threat. The space-based system, not to be in place for at least 25 years, would provide constant monitoring and a system to divert and modify the orbits of threatening objects. Confirmation of a long-period object on an impact trajectory would be possible at least a year before impact, allowing more time to take defensive action than current detection systems allow. The problem is that not much could be done if a long-period object on an Earth-bound trajectory were detected today, said Durda. "The worst scenario I can think of is a multi-kilometer-diameter, long-period comet discovered several months out on an impact trajectory as it is entering the inner solar system," he said. "There is absolutely nothing we could do about it at this point in time. Nothing." Is a Large Asteroid Headed for Impact With Earth in 2880? Scientists have identified a thousand-yard-wide (one-kilometer-wide) asteroid that may be heading for a collision with Earth—878 years from now. Using radar and optical measurements made over the past 51 years, researchers have calculated that there is up to a one-in-300 possibility that Asteroid 1950 DA will slam into Earth on March 16, 2880. Their work is published in the April 5 issue of Science. |
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| the interior of a sponge like comet several thousand times enlarged |
| the interior of a solid like comet several thousand times enlarged |
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| Asteroid 1950 DA, as seen by radar, has a one in 300 probability of colliding with Earth on March 16, 2880. The graphic shows the asteroid's position relative to Earth on April 5, 2002 |
| "We calculated the probability of collision based on what we know about the physical aspects of the asteroid and many other factors," said Jon Giorgini of NASA's Jet Propulsion Laboratory at the California Institute of Technology in Pasadena. "As we get more information we will be able to adjust the level of probability up or down." Odds of one in 300 may seem almost insignificant, but it is the highest Earth-impact potential ever assigned by scientists to an object in space, according to Giorgini. The consequences of a collision from an asteroid a thousand yards in diameter are speculative. Could a direct hit destroy an entire city? Would an ocean impact create a massive tsunami capable of deluging adjacent coast lines? "Nothing good can come from such an impact," said Giorgini. "But a collision between 1950 DA and Earth is so unlikely it is not worth worrying about. And even if it does look like there could be a collision, we have plenty of time and many ways to deflect the asteroid from its path." Changing the Trajectory One of the easiest ways to deflect the asteroid past Earth would be to alter its surface, changing the amount of heat energy it radiates, said Joseph Spitale, a research associate in planetary science at the University of Arizona–Tucson. That would have the effect of subtly altering the way the asteroid moves, causing it to slowly change its trajectory. In a separate paper published in Science, Spitale describes how the so-called Yarkovsky Effect could be used to make an asteroid drift off its path. The Yarkovsky Effect is a term used to describe how an asteroid's trajectory can be influenced by its heat radiation. "The thermal emission from an asteroid acts like a rocket force in the opposite direction, although it is really, really weak," Spitale said. "If we can somehow change the thermal radiation being emitted by an asteroid, we can affect the object's orbit. A tiny thrust acting over a long time can be enough to nudge an asteroid from a path heading towards the Earth to one that narrowly misses the Earth." Because the Yarkovsky Effect is completely determined by temperatures on the surface of a body, Spitale explained, it can be manipulated if the surface can be altered in a way that changes that temperature distribution. |
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| Diagram of how the magnifying glass would work to energize and nudge the asteroid away from earth's orbit diagram by true masked wabbit |
| Asteroid 1950 DA "looks like a good candidate to test the Yarkovsky Effect," he added. "We have a really long base line in time and we are able to predict its orbit over that time." To use the Yarkovsky Effect to nudge 1950 DA off its course would require doing something on Earth to change the asteroid's surface temperatures. "I think people will come up with all sorts of creative ideas about that," Spitale said. "For example, if we could cover the surface of the asteroid with one centimeter (half an inch) of dirt, that would plausibly be enough to change the Yarkovsky Effect quite a bit. Of course, that's a lot of dirt and it would probably require a couple of hundred rockets to get it all up there. It would be really expensive." Another possible solution, Spitale said, would be to "paint" the asteroid's surface white. "That would make a big change to the way the object reflects sunlight. That might require a thickness of only one millimeter or so (less than a 20th of an inch) over the entire surface," he said. A third solution might be the use of conventional explosives. One rocket might be enough to complete the job, and getting it there would certainly be possible using current space technology. The last approach would be the cheapest solution, Spitale said. "Unfortunately, you would probably lose most of the debris to space," he said. "However, this approach might alter the character of the surface in some other useful way." How to push 1950 DA away from the Earth—and whether it will ever be necessary to do so— depends entirely on the exact physical nature of the asteroid, said Giorgini. "We won't know for sure whether this asteroid is on a collision course until we can determine which way its north pole is pointing." Current calculations are based on all the possibilities, and the outcome of these scenarios, he noted, ranges from a zero to 0.33 percent probability that there will be a convergence in the orbits of Earth and the asteroid. Host of Factors This is the first time such a wide array of factors has been taken into account in predicting an asteroid's orbit, Giorgini said. He and the other researchers looked at not only the asteroid but also factors such as the gravitational influence of other asteroids, the shape of the sun, and the effect of solar wind (the forces created by light and heat from the sun). Until now, 1950 DA had been seen only twice—once in 1950 and again on December 31, 2000. Although the asteroid orbits the sun once every 2.2 years, its orbit is close to that of Earth only about once in every 51 years. The asteroid can be seen visually through telescopes as a moving point of light. Only through radar, however, can scientists determine the nature of its surface and how it spins. Because the asteroid needs to be fairly close to Earth for radar to be effective, opportunities to study it with this technology are rare. Astronomers can use telescopes to observe the asteroid at greater distances before it fades from view. The next time scientists will be able to use radar to study the asteroid will be in 2032. But Giorgini said astronomers will get an optical view of the asteroid in about five or six years, when there may be an opportunity to learn more about its physical aspects. "We need to know how it spins, its mass, its exact shape, and the patterns of darkness and lightness on its surface," Giorgini said. "If we can't get this information from our telescopes, then the only way to do it will be to send a spacecraft to go and take a look at it." |
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| Did Comets Make Life on Earth Possible? An ambitious new NASA research project aims to answer perhaps the most vexing and profound of scientific mysteries: How did life on Earth begin? The multimillion-dollar undertaking, led by the NASA Goddard Space Flight Center in Greenbelt, Maryland, brings together an interdisciplinary team of scientists from around the world to study how organic molecules are created in interstellar clouds and delivered to planets as they form. The research will focus on the role of comets. Many scientists believe there is increasing evidence that comets supplied at least part of the raw material for the origin of life on Earth. The theory is changing the way scientists think about life in the universe and raises the possibility of alien worlds. "Our mission is to gain a greater understanding of the origin and evolution of organic material on Earth," said Michael Mumma, a comet expert and director of the Goddard Center for Astrobiology, NASA Astrobiology Institute, who is leading the research. "The key question is: Were water and organic molecules delivered to Earth by cometary impact and does [that process] extend to planets elsewhere?" |
| Dirty Snowballs Astronomers believe that stars, planets, and comets form in a massive chain reaction that begins when a cloud of interstellar material collapses under its own gravity. Some of the material forms the star—like our sun—and some of it gets spread out in a disk around the nascent star. Some material in this disk later aggregates and forms planets. Close to the sun, where it's warm, leftover debris (rocky material) turns into asteroids. In the outer regions, where it's cold, icy chunks of rock and dust turn into comets. It is generally believed that organic molecules, which contain carbon atoms and are present in all life forms known to science, are trapped in large amounts in both interstellar clouds and comets. "We have extremely definite evidence from our radio observations that there's quite an array of organic molecules in interstellar space," said Bill Irvine, a professor of astronomy at the University of Massachusetts in Amherst, who is measuring radio waves from celestial objects as part of the research effort. There's other evidence that comets contain organic material. When European spacecraft analyzed dust particles from the Halley comet in 1986, it turned out to be some of the most organic-rich material measured in the solar system. Meteorites that have hit Earth contain a whole suite of molecules, including amino acids, which play an important role in terrestrial biology. |
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| "If such material exists in meteorites, which come from a class of asteroids, there's every reason to think it must also exist in comets," Irvine said. Most scientists have long believed that life on Earth began as a "primordial soup" in a lake or pond some four billion years ago. According to this theory, chemicals from the atmosphere combined with some form of energy necessary to make amino acids—the building blocks of proteins—to create the first primitive organisms, kicking off the evolution of Earth's species. But the primordial soup theory is being increasingly disputed. Many geophysicists now say the Earth did not have enough gases, like ammonia and methane, from which organic material like amino acids could be produced. Instead, a growing cadre of scientists believes the organic material needed to create life may not have been produced on Earth, but was instead brought here by comets. The newly formed Earth was likely subjected to a fierce bombardment of comets four billion years ago. These comets may have brought with them the organic compounds that later evolved into living matter. According to the most radical theory, known as "panspermia," life in a ready-made form is ubiquitous in the galaxy and is brought by comets to new planets. Few scientists subscribe to this hypothesis, however. Perhaps the main question is whether organic molecules can survive space travel or if they break up and contribute the atoms that are necessary to ultimately make biological material and water? "Our museums contain examples of primitive meteorites that likely are very similar to the material delivered by comets," said Mumma. "The key point is that small bodies deliver their organics intact to Earth's surface. This must have been a common event on the early Earth." Many scientists are now leaning toward a combination of the comet impact theory and the primordial soup thesis. Some chemical building blocks may have come from comets, but the assembly into life took place on Earth. "The comet impact theory fits in with the primordial soup theory," Mumma said. "They can be complimentary." Drilling Into Comets Scientists will measure the molecular make-up of comets to better understand what chemical reactions formed them. This may provide clues to the evolution of carbon-based chemistry on Earth in its early history. The new research will combine laboratory experiments, observations with telescopes and spacecraft, and missions to sample comet and asteroid material. A European mission not associated with NASA is even going to land on a comet and drill into it as the comet journeys toward the sun. An important part of the project will focus on water, which is seen as an essential ingredient of life. Scientists want to know if the Earth's water was incorporated into the Earth as the planet formed or if the water arrived on Earth as a result of cometary impacts after the Earth was already formed. "Earth's new oceans were filthy, and should have been full of organic molecules and dust particles carried to our planet by comets and primitive meteorites," said Mumma. "We want to learn how significant their contribution was to the genesis of life on Earth." The comet research could have a tremendous impact on the quest to find life on other planets. After all, comets have slammed into many other planets. If they supplied the raw material to form life on Earth, what is to say the same thing hasn't happened on other planets? One thing is for sure, however. Finding out exactly how life on Earth began, and if it extends elsewhere, will take some time. The first stage of the NASA project will last five years, but Mumma thinks it could take as much as 25 years before scientists have a definite answer about the origin of life on Earth. What are the risks? |
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| Animation #1 (238K) Distant view from north pole of solar system, looking down. Shows 1950 DA's uncertainty region approaching Earth and being disrupted by the close encounter. The larger red dot is the highest probability position, surrounded by "virtual" 1950 DA positions of decreasing probability. Animation runs from 1 February through 18 Jun 2880. Animation from J. Giorgini (JPL). Animation #2 (288K) View zooms in from north pole of solar system. It shows 1950 DA's uncertainty region approaching Earth and being disrupted by the close encounter. The larger red dot is the highest probability position, surrounded by "virtual" 1950 DA positions of decreasing probability. The circle around the Earth depicts the orbit of the Moon. Animation runs from 3 March 2880 to 9 May 2880. Animation from J. Giorgini (JPL). Animation #3 (570K) View rotates to an oblique perspective of the solar system as 1950 DA's uncertainty region approaches Earth and is disrupted by the close encounter. The larger red dot is the highest probability position, surrounded by "virtual" 1950 DA positions of decreasing probability. Animation runs from 1 March 2880 to 3 May 2880. Animation from J. Giorgini (JPL). |
| credit acknowledgement NASA National Geographic other links given by byoch of BPE http://www.meteoritecentral.com/index.shtml Prehistoric Asteroid "Killed Everything" |
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| The Experiment by true masked wabbit Can an asteroid be nudged into a designated orbit? Yes it can. |
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