how earth is saved from several asteroids, which at times hit other planets, is it a miracle?
478432
First: we are constantly being bombarded by millions of asteroids. The only thing that saves us is the atmosphere, which vaporizes them.\n\nI'll do a little math. We'll consider the solar system to end after the Oort Cloud, 100,000 AU or 9,300,000,000,000 miles. Therefore, the solar system has a volume of 4/3*π*(9.3*10^12)^3, or ........ about 3.369*10^39 cubic miles. The Earth has a volume of about 2.08*10^12 cubic miles.\n\nIn short, the Earth takes up 0.00000000000000000000000006% of the solar system. Even with trillions of potential threats, the chances are next to nothing.
367790
Greetings,\n\nCruithne discovered in 1986.\n\nWe currently have a couple of asteriod size objects oribiting the earth, if that is what you are referring to (Reference the first website listed as sources.)\n\nWe also have any number of Near Earth Objects captured by Earth's gravity, the second link posted.\n\n-matt
152829
After the solar system was formed millions of years ago, there were lots of massive objects left over that didnt form into planets, they just wound up in orbits around the sun.\nThey continue to orbit the sun, going round and round, but their orbits are not necesarily as nice as Earths almost circular orbit, they can get quite wild sometimes.\n\nWith all these massive objects wizzing around the solar system, srossing in and out of the orbits of the major planets, it is just a matter of time before there is a collision.\n\nFor some of the smaller meteors, they can burn up harmlessly in the Earth's atmosphere, but if not and they strike Earth, they can become quite dangerous.  When a meteor actually hits Earth, it is called a meteorite.\n\nLuckily for us, meteorites hitting Earth isnt too common any more (we will ocassionally get a few big ones), usually they burn up harmlessly, or land far off away from anything.  There have been instances of meteorites actually crashing through people's houses or hitting cars, but this is extreamly rare.  Even more rare indeed are large meteorite impacts, like the one that is theorized to have killed of the dinosaurs or the "meteor crater" impact site, these only happen once in a few million years.
970160
Yes, I do because Earth is not a closed system. If it were, meteorites would never hit.  I have an interesting comparison (to me at least)  about comets "seeding" the earth....... have you ever noticed that earth resembles an "egg" and comets resemble sperm?  they have heads & tails like sperm...... and the term panspermia......... just a thought.......
1117424
Here's what probably happened:  Planets normally move in an orbit around a star (sun).  There is the occasion that a rather large astroid may hit a planet knocking it out of sync with its orbit.  Based on that theory, the wobble produced could force the planet out of its orbit all together.  Then, yes, it would be possible for planets to collide.  Could you imagine what that might look like?  With that said, I'd say that there is an off chance of the same happening to earth.
669912
An asteroid is a small, solid object in our Solar System, orbiting the Sun. An asteroid is an example of a minor planet (or planetoid). These minor planets are much less massive than even small planets such as Mercury or Mars. It is believed that most asteroids are remnants of the protoplanetary disc. The incorporation of these remnants into the planets during the formation of the Solar System was prevented by large gravitational perturbations induced by Jupiter. Some asteroids have moons. The vast majority of the asteroids are within the main asteroid belt, with elliptical orbits between those of Mars and Jupiter.
567360
The Global Asteroid Monitoring System\n\nis a sometimes-loose collaboration of private institutions and government agencies, along with the amateur astronomers and several dozen professional asteroid researchers around the globe. \n\nhttp://en.wikipedia.org/wiki/International_Astronomical_Union\n\n\n\nMinor Planet Center\n\nis the official organization in charge of collecting observational data for minor planets (asteroids) and comets and calculating their orbits, and publishing this information.\n\nhttp://en.wikipedia.org/wiki/Minor_Planet_Center
776233
Well, considering an asteroid could wipe out life on this planet, and if detected early enough, we might have a chance of preventing that from happening - I'd say yes, it's worth it.
335043
Yes. Here's the proof: There has been talk that the asteroid 1997XF11 will crash into the Earth in the year 2028. The bottom line is that this asteroid poses no threat to the planet Earth in the next century. But, it will pass by the Earth over and over again in the next centuries, so it is worth knowing what our countermeasures are if it ever gets too close!\n\nRight now, they have the technology to divert a comet or asteroid coming towards the Earth. Our rockets and explosives would be sufficient to break apart even a large object of about 1 kilometer in diameter. We would of course need some lead time (10 years would be a nice minimum notice). Blowing up an asteroid or a comet too near to the Earth, would just create a chaotic mess of smaller pieces flying towards the Earth. If we were to discover an object coming towards the Earth with only 1-2 years notice before impact, our technologies might not be adequate. The best we could hope to do would be to evacuate the impact site. So the best plan right now is to continue surveying for Near Earth Objects, so that we will know where these asteroids and comets are in time to prepare any countermeasures that might be necessary.
701683
My opinion is that we would have to change course of an asteroid headed for Earth.  That means that we would have to detect it years in advance.  With enough notice, we could build a Nuclear Electric Propulsion (NEP) system.  Actually we would have to build several and attach them to the asteroid and start pushing.   They would need to be refueled, so we have to make several visits.   If successful, a project like this would be a real boon to the space program, the economy, and scientific knowlege.
496342
At the time Earth formed 4.5 billion years ago, other smaller planetary bodies were also growing. One of these hit earth late in Earth's growth process, blowing out rocky debris. A fraction of that debris went into orbit around the Earth and aggregated into the moon.
746904
1.  At this stage of the life of the Solar System, there are not many large meteorites left to intersect the Earth's orbit.  The gravitational fields of the large outer planets, especially Jupiter, have had the effect of either hoovering them up, or shepherding them into stable orbits in the asteroid belt.\n\n2.  The Earth is small compared to the separation between large meteorites.  If it was twice the diameter, it would get four times as many impacts, just like an archery target.\n\n3.  Large meteorites reach the surface with so much energy that they usually disintegrate, instead of staying in one piece.  The fragments can disappear by erosion much quicker than the crater does.
718750
A meteorite is an extraterrestrial body that survives its impact with the Earth's surface without being destroyed. While in space it is called a meteoroid. When it enters the atmosphere, air resistance causes the body to heat up and emit light, thus forming a fireball, also known as a meteor or shooting star.
712619
Yes, alas, all things must eventually come to an end, especially the good things. Earth will indeed be destroyed eventually by some asteroid with our name on it. One such asteroid has been found: 99942 Apophis, which we still dont know if it will indeed strike the Earth in 2036. But, it isnt the proverbial dinosaur killer, its only 820 feet across, a peanut compared to others that have hit. But, yes, we could terraform Mars and turn it into another Earth, the way it was so many thousands of years ago. I mean, we can grow food hydroponically, create our own little magnetosphere, and create the feeling or effect of gravity. The problem with terraformation is that we have no idea how long it would take, estimates have ranged from half a decade to an amount that is not realistic. Yes, we would go there by spaceship unless the Gov. reveals its Stargate program or some other means of transport. I would assume that a large majority of people would go, but there are always gonna be the fanatics and those who would rather die where they were born. And, you cant realistically transport EVERY human off the planet unless we had many, many, many decades of warning, which we may not have. Sorry to be pessmistic about it, but the numbers just dont really work out in our favor unless we have the benefit of time. But, I would imagine that a majority of the people would make it off, because I would assume that in that realisation, costs would be waived. And imagine the chaos that would grip the globe! But its all very possible to do, we could go right now if we wanted to. And for those who didnt go... It would not look pretty. We're talking about water being flashboiled, tons and tons of rock and ash being thrown into the atmo. if the initial blast doesnt kill you the ensuing volcanic nuclear winter would. Crops would be destroyed and we've learned that nothing with a body weight of over 60 lbs made it through the last ice age. Those who stay behind... Their future would be very grim.
825274
There are some 432,536 asteroids at the latest count. Less than 5,000 of these are Near Earth Objects i.e. come inside the orbit of Mars.\n\nThe two you may have heard about are 99942 Apophis (320 metres in diameter) and 29075 1950 DA (1.1 - 1.4 kilometres in diameter).\n\n1950 DA\n\n29075 1950 DA is the Near Earth Object with the highest known possible probability of impacting Earth, according to the Palermo Technical Impact Hazard Scale. For a few days in December 2004 it was temporarily surpassed by 99942 Apophis (which at the time was named only by its provisional designation 2004 MN4).\n\nIf 1950 DA continues on its present orbit, it will approach near to the Earth on March 16, 2880. Over the intervening time, the rotation of the asteroid will cause its orbit to change (by the Yarkovsky effect). (See second link.)\n\nA preliminary analysis shows two possible pole directions (Giorgini, et al., 2002 "Asteroid 1950 DA's 2880 Encounter with Earth"). One trajectory misses the Earth by tens of millions of kilometers, while the other has an impact probability of 1⁄300. The radar observations are currently being reanalyzed, in combination with the optical lightcurves.\n\nThe energy released by a collision with an object the size of 1950 DA would cause major effects on the climate and biosphere which would be devastating to human civilization.\n\nThe discovery of the potential impact has heightened interest in asteroid deflection strategies. (See third link.) \n\nDespite the fatalism of one contributor above, there is plenty that could be done about avoiding an impact, especially with over 800 years notice of one!\n\nAPOPHIS\n\nIn July 2005, former Apollo astronaut Rusty Schweickart formally asked NASA to investigate the possibility that the asteroid's post-2029 orbit could be in orbital resonance with the Earth, which would increase the probability of future impacts. Schweickart asked for an investigation of the necessity of placing a transponder on the asteroid for more accurate tracking of how its orbit is affected by the Yarkovsky effect.\n\nIf this project were undertaken, we would have a spy in the sky to tell us of any impending problems. This is just one example of how mankind can intervene in its own destiny.\n\nDISCOVERY AND NAMING \n\nApophis was discovered on June 19, 2004, by Roy A. Tucker, David J. Tholen, and Fabrizio Bernardi of the NASA-funded University of Hawaii Asteroid Survey from Kitt Peak National Observatory in Arizona. This group observed for two nights. The new object received the provisional designation 2004 MN4.\n\nOn December 18, the object was rediscovered from Australia by Gordon Garradd of the Siding Spring Survey, another NASA-funded NEA survey. Further observations from around the globe over the next several days allowed the Minor Planet Center to confirm the connection to the June discovery.\n\nWhen first discovered, the object received the provisional designation 2004 MN4 and news and scientific articles about it referred to it by that name. When its orbit was sufficiently well calculated it received the permanent number 99942 (on June 24, 2005). Receiving a permanent number made it eligible for naming, and it promptly received the name "Apophis" as of July 19, 2005. Apophis is the Greek name of the Ancient Egyptian god Apep, "the Destroyer", who dwells in the eternal darkness of the Duat (underworld) and tries to destroy the Sun during its nightly passage.\n\nPOSSIBLE IMPACTS\n\nApophis has an orbital period of 323.6 earth days and crosses our orbit twice a year. Only a minority of its approaches will find us at a point of our orbit where an impact may occur.\n\nThe 2029 approach was thought at first to be potentially hazardous, but further observations ruled that out. Then an impact in 2035 was considered a possibility and further observations then ruled that out, too.\n\nOn August 5, 2006, Apophis was lowered to a Level 0 Torino impact hazard scale. As
1033042
The earth IS protected from solar flares.  Unlike most other planets we have analyzed, the earth has an EMF field around it.  Its like a magnet.  Magnets have a North (positive) pole and a South (Negative) Pole.  Electro-Motive Force (EMF) is a flow of electrons from the negative pole to the positive pole.  This flow of electrons acts like a shield and deflects solar flares from reaching the earth.  Now, its not absolute!  There are actually some solar flares that do indeed reach us, but I think this is a bit much for this forum.  I hope this helps!
783845
"Earth" is the name the inhabitants of the third Solar planet call their world. This word is an ancient one, and is in English. All the logical paths that lead to a planet's name require the conclusion that no other planet could have this exact name.\n\n;-D Of course miracles happen every day! If some aliens like the name "Earth" then I won't stop them from calling their planet 'Earth!"