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Asteroid Armageddon: “Unimaginably Catastrophic” Earth Cannot Always Dodge 500,000 Near Earth Objects
It sounds like the script for a Hollywood film: a giant meteorite from outer space heading straight for the Earth and threatening the destruction of mankind. And yet such a scenario does represent a real threat to our planet, as researchers reckon that we can expect an asteroid to collide with Earth every few hundred years.
Our planet orbits the Sun amid a swarm of hundreds of thousands of inner solar system objects capable of causing destruction on Earth. They range in size from 45-meter Tunguska-like objects to the extremely rare 10-kilometer objects which can cause a catastrophic mass extinction.
The Cretaceous-Tertiary (K-T) Extinction, 65 million years ago, was probably triggered by the impact of a 12-kilometer-diameter asteroid in what is now the Yucatan Peninsula of Mexico. The planet-wide effects of Chicxulub eliminated about 70% of all living species, including the dinosaurs.
Tons of cosmic material fall on the Earth every day, but nearly all disintegrates and burns during passage through the atmosphere. However, when objects larger than approximately 45 meters in diameter strike, the atmosphere cannot fully screen us. Even NEOs which do not make it all the way to the ground can cause destruction through the production of a damaging fireball and shock wave. The most famous example occurred in 1908, when 2,000 square kilometers of Siberian forest were destroyed by a multi-megaton impact called the Tunguska Event.
“One solution would be to launch a relatively solid space probe designed to hit the asteroid at high speed,« says Professor Alan Harris from the German Aerospace Center’s Institute of Planetary Research as he explains the basic concept. Professor Harris leads the EU-funded NEOShield project. Meanwhile, scientists from Fraunhofer EMI are helping to research the foundations of this technique. »Asteroids are typically made of porous materials, so the first step is to build up a basic understanding of what happens when materials like that are hit by a foreign object,« says Dr. Frank Schäfer, head of the spacecraft technology group at Fraunhofer EMI.
To do this, he and his team use a light gas gun – one of the fastest accelerator facilities in the world. Within the gun’s approximately one-and-a-half-meter barrel, millimeter-sized pellets are accelerated to speeds of almost 10km per second. That equates to a speed of around 36,000 kilometers per hour.
The Fraunhofer scientists use what is known as a target chamber to bombard stone blocks used to approximate asteroids with a high-velocity mini projectile. The aim is to analyze with as much precision as possible how the material reacts. High-speed cameras document the experiment by taking up to 30,000 pictures per second. As in the crash testing of vehicles, the Fraunhofer researchers are interested in quantifying the force of the collision. Data are adjusted to account for actual scale and are imported continuously into computer simulations.
In the long term, NEOShield project leader Professor Harris would like to see the defense techniques that arethe subject of this research tested in international space missions: »This kind of test mission is bound to throw up a few surprises, and will teach us a great deal.«
Incidentally, Harris reckons that averting an oncoming asteroid from its collision course by means of a huge explosion – just like in a Hollywood film – could in fact be an option in an emergency. Time would have to be pressing though, or the object concerned at least a kilometer in diameter.
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| Credit: NASA |
Deflection to save Earth
In general, the two conditions above require a combination of both substantial total impulse to avoid the direct impact, and precise orbit control to assure that the NEO passes between return keyholes. Primary deflection causes the NEO to miss the Earth whereas shepherding guides the NEO such that it passes between all keyholes as it passes nearby the Earth.
If a threatening NEO passes close by the Earth in the decades prior to a potential impact, it will have to pass through a keyhole during that close encounter in order to subsequently impact Earth. If this scenario is seen to be developing sufficiently in advance of the potential impact, a shepherding mission can be launched to guide the NEO around the keyhole thereby avoiding potential impact. If, however, there is no close encounter with Earth between the discovery of a potential impact and the date of impact, then the NEO is on a direct impact path and a full deflection campaign (e.g., primary deflection plus shepherding) must be mounted to avoid the impact.
Primary deflection and shepherding requirements cannot be met with any single existing deflection technique. Available instantaneous force (IF) concepts (kinetic impact and nuclear explosion) can provide considerable total impulse, thereby meeting the primary deflection needs, but will result in a large uncertainty in the velocity change imparted to the NEO (up to 500% uncertainty).
Continuous force (CF) deflection methods, such as a gravity tractor, can provide only limited total impulse, but that impulse can be provided with high precision resulting in a well-determined (even a pre-determined) final NEO orbit, thereby being ideal for shepherding operations.
It is therefore the application of an instantaneous deflection followed potentially by a continuous force deflection which is necessary to assure a successful deflection, i.e. a primary deflection followed by a shepherding operation. These two deflection concepts, however, require two quite different mission designs, the deflection requiring an intercept trajectory, and shepherding requiring a full rendezvous with the NEO.
However, the requirement for two distinct missions in a deflection campaign is not limited to obtaining the magnitude and precision of the NEO deflection per se. There is also a requirement for a precise NEO orbit determination both before and after the deflection maneuvers. Furthermore, there is a high value in being able to observe and confirm the primary deflection by the shepherding spacecraft from a stand-off/observing location
Dr. Frank Schäfer
Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut, EMI
If a 500m asteroid hit the earth it’s gonna hurt!!
The radical uptick in comets passages, asteroid flybys, meteor appearances, meteorite hits and unusual solar activity cannot be explained by the existing scientific paradigm.
Neither can the radical transformation of the Solar System (SS) be explained with the same tenuous and sophomoric assessments.
Only something extraordinary justifies the current phase of intensified cosmic activity manifesting throughout our SS!
http://cosmicconvergence.org/?p=4877
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Such is the future of a world without God; ie constant fear and uncertainty.
However, assuming that God created the universe in the first place, and would not allow such random events to upset His creation, then we need not fear about these matters.
In fact, these NEOs are almost certainly derived from the ejecta from earth itself which occurred in approx. 3290 BC, at the time of the Flood. Comets contain large amounts of tritiated water, which arises through neutron irradiation of ordinary water; this neutron flux was a part of the seismic processes which occurred at that time.
See Dr Walt Brown’s Hydroplate Theory for an exhaustive analysis of this event, and how it has affected earth right up to the present time.
Wrt “the extinction of the dinosaurs 65mya”, be aware that this is a fallacy. Mary Schweitzer will tell you that she has recovered intact skin and RBCs from T Rex and various hadrosaurs in this Year of our Lord 2013. These fossilized animals are generally found in great disorganized heaps; sometimes halfway up mountainsides; I will leave you to speculate as to what might have caused this phenomenon.
The Epic of Beowulf from the middle of the second millennium records eye witness accounts of Beowulf fighting with and killing a juvenile T Rex; ( by ripping one of its arms off, rather cruelly, I thought ) and this from a time when no fossils of these creatures had been recovered, and so descriptions of them matching what we know today about their configurations could not have been given. References are also made to a variety of sea-dwelling and aerial creatures of a highly-suspicious nature.
Job ch 40 v 15 onwards records a description of a creature, “behemoth”, which I defy anyone to tell me is not a large dinosaur. The creature is described as “the chief of the ways of God”, so this is no ordinary quadruped, and its tail moves “like a cedar”, which rules out any living creature I can think of. Crocodilians are clearly not described as the chief of anything.
Okay that is just stupid talk.
Maybe. Maybe not.
Every time someone starts with all the nonsensical ravings about “God”, I can’t help but get an image of millions of simpletons sitting in open fields being showered upon by fireballs while holding their precious bibles open above their heads.
Just because YOU have never had a prayer answered in such a way that proves unequivocally the existence of God…..doesn’t mean it hasn’t happened for others.
Lack of proof isn’t proof of non existence.
In return, your lack of belief makes you a “simpleton” in the eyes of believers. We are usually to kind to say so, but I’m in a “mood.”
CrowPie, the time for niceties is over. We, as christians, have to be direct with people like Litlinn33. There is not enough time for long conversions anymore. Time is very short, and they need to hear the Truth. Give your life to Jesus, or perish in a lake of eternal fire. Hard message, but it is the Truth.
Lack of proof isn’t proof of existence either.
@Fr.Duffy Fighting 69th
You may be a believer…….but I disagree with most of your bully tactics and over bearing responses.
I believe that Christians should behave as Jesus taught. You seem to stick to Old testament behaviors.
But I forgive you.
we are gone , run run for your lives, Wait a minute they said this last year and the year before probably NASA needs their grant renewed.
I quit reading this article when the author stated, “These considerations make it inevitable that the international community, through the United Nations and its appropriate organs, will be called upon to make decisions on whether or not to deflect a NEO, and how to direct a proposed deflection campaign.”
The United Nations is going to make decisions about whether or not to deflect, and how to do it? Why do I sense that this article is prelude towards the UN taking away all sovereignty for your “safety?” If the UN is the decision maker for such a serious decision, then it should also be for any other public danger – or nuisance. They’re starting with earth-killing reasons, but eventually, the same author will be arguing for why you must submit landscaping plans, file building permits, or register your pet with the UN. Governments only seek more power.
All governments are a racket, and every good, decent man will one day condemn his government. I am just taking a pre-emptive shot at world governance. Keep it.