How big is the asteroid belt?
816136
The asteroid belt is between Mars and Jupiter and is a huge belt composed mainly from rocks and ice, it's about 6 AU (Astronomical Units) in size, 1 AU is the distance from the Sun to the Earth or 87,000,000 Kilometers..☺
533962
The link below has great overview info and statistics (including density) for all the planets, asteroids, comets, etc. \n\nCheck it out!
1124844
If something was to hit us it would only be visible with the naked eye as it tears through the atmosphere, minutes before impact. The likelyhood is that an asteroid of very great size would be spotted  through telescopes years before it hits us. Scientist are studying near earth objects that might have the potentian of hitting us:\nhttp://www.spaceweather.com/ (scroll down)\nHowever, only 793 are know so far, while the total number is estimated at 2000.
771981
Meteor craters are usually circular.\n\nThe Barringer Crater has a diameter of 4000 ft, so it has a radius of 2000ft.\n\nRadius = 2pi*r, so it'd be 12560 ft in circumference, give or take.
112912
Gravity pulls everything to the center. The larger the object the greater the gravity the more perfect a sphere. Jupiter has a smoother surface than the earth. The earth is smoother than the moon. Asteroids are even smaller and don't always have enough gravity to overcome the structural properties of the mineral it is made of, so smaller asteroids have more unusual shapes and are not always very spherical.
669815
According to computations by A. F. Zavsaev published in Solar System Research vol. 26, no. 4, page 375, this asteroid will come within 0.0485 Astronomical Units of the Earth on September 20, 2129. One Astronomical Unit is equal to 93 million miles so the passage will be within 4 million miles of the Earth. For a comparison, the asteroid 1620 Geographos came within 0.033 AU of the Earth on August 25, 1994. \n\nAccording to the May, 2000 revised list of Near-Earth Asteroids at the Minor Planets Center, the revised orbit indicates a close encounter on March 21, 2018 of 0.0896 AU. This is about twice the distance estimated from previous orbits made in 1997.
141215
i dont think anyone really knows for sure. probably like thousands of millions of years. unless it gets hit by a ginormus asteroid and explodes into teeny tiny peices!! lol
108382
As of right now we don't know sizes of other planets outside our solar system.\n\n But, Jupiter is the largest planet in the Solar System. With an equatorial diameter of 143,884 km, (89,405 miles), it is as wide as more than 11 Earths stacked side by side. The planet also has the shortest period of rotation - Jupiter days last just under ten hours.
884425
well the path of the planets is different for each due to the size but the are similar to a oval type shape, gravity hold the planets in orbit and as far as the asteroids they are freely moving until caught by a gravitational pull of a larger object
438648
The Moon has a surface area of 152 million square kilometers.\nThe Earth is 13.5 times larger.
146881
The Kuiper belt is the region of space beyond Neptune. In this region billions of pieces of primordial debris from the formation of the solarsystem resides. They slowly circle around the sun in highly eliptical orbits. Sometimes one of these objects loose some kinetic energy from a collision to put it in an orbit so elliptical it moves into the inner solar system. They then become Comets. More and more planet sized objects are found in this region and makes us ask wheter or not Pluto may actually be a medium sized Kuiper belt object instead of a planet. Otherwise the solarsystem may be getting a whole bunch of new planets.\nThe Kuiper belt streches from Neptunes orbit out to about 0.5 lightyears from the sun. Beyond the Kuiper belt lies another region with billions of "Comets-to-be" called the Oort cloud.
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.
487505
It's actually just a large asteroid, and they haven't decided whether to call it a planet yet. Problem is, they also discovered that Pluto is just a large asteroid, and if they disacknowledge the new planet, they would have to also disacknowledge Pluto.
824414
The asteroid belt is a region of the solar system falling roughly between the planets Mars and Jupiter where the greatest concentration of asteroid orbits can be found.
749360
There are no earth size asteroids. The earth is the 6th largest object in the solar system after the Sun and the 4 gas giants and bigger than Mars Venus and Mercury. So if there were an object as big as the Earth and therefore bigger than Mars Venus and Mercury, it would have long ago been classified as a planet, not an asteroid!\n\nYou appear to be unaware that there is international co-operation between NASA, the European Space Agency and others on a project called Spaceguard. which keeps an eye open for asteroids, comets and other objects that may perhaps be on a collision course with the Earth.\n\nThe term Spaceguard loosely refers to a number of efforts to discover and study near-Earth objects (NEO). Arthur C. Clarke coined the term in his novel Rendezvous with Rama where SPACEGUARD was the name of an early warning system created following a catastrophic asteroid impact on Italy. This name was later adopted by a number of real life efforts to discover and study Near-Earth Objects.\n\nA 1992 U.S. Congressional study produced a "Spaceguard Survey Report" which led to a mandate that NASA locate 90% of large near-Earth asteroids within 10 years\n\nWe know as of September 2006 of some 342,536 asteroids, But of these. only a relatively small number come inside Mars' orbit and less than 5,000 are classed as Near-Earth Objects.\n\nAs of August 31, 2006, 4,187 NEO's have been discovered: 57 near-Earth comets and 4,130 near-Earth asteroids. There are 792 NEO's which are classified as potentially hazardous asteroids.  \n\nEstimating the risks\n\nThere are two schemes for classification of impact hazards: the simple Torino Scale and the more complex Palermo Technical Impact Hazard Scale \n\nOn 25 December 2004, minor planet 99942 Apophis was assigned a 4 on the Torino scale, the highest rating so far. At 27 December 2004 there was a 2.7% chance of Earth impact on the 13 April 2029. However, on 28 December 2004, the risk of impact dropped to zero for 2029, but, due to a resonant return possibility the Torino rating for an April 2036 impact rose to 4 in early 2005 and, as of August 2006, has dropped gradually to a Torino rating of 0 (zero). The Palermo rating (August 2006) is −2.25.\n\nOnce the Spaceguard community is alerted to a potential impactor its orbit is immediately studied in great detail to get a more accurate projection of whether there will be an impact scenario or not. \n\nAs you can see the immediate threat anticipated on 25th Dec 2004 of an impact 25 years later was able to confidently be rejected, 3 days later. Word went round immediately there was an alert and the work needed was done, even though it was Christmas.\n\nSo the astronomers are on the case. and the paranoid should not let their uninformed imaginations run riot.\n\nCurrently, the only known NEO with a Palermo scale value greater than zero is (29075) 1950 DA, which is predicted to pass very close to or collide with the Earth (p≤0.003) in the year 2880. If this collision were to happen, the energy released by a collision with (29075) 1950 DA would cause an extinction event which would destroy most life on the planet. However, humanity has over 800 years to refine its estimates of the orbit of (29075) 1950 DA, and to deflect it if necessary.\n\nNASA maintains a continuously updated web page of the most significant NEO threats in the next 100 years - all or nearly all of which are highly likely to drop off the list eventually as more data comes in enabling more accurate predictions; however, that page does not, of course, include 1950 DA, because that will not strike for at least 800 years.\n\nSo it is down to vigilance so as to anticipate danger, precision so as to quantify it, and technical knowhow, so as to avert it.
1185813
yes\nA huge asteroid will have a close encounter with Earth this weekend, but astronomers say there is no danger of an impact. The asteroid, known as 2004 XP14, will whiz by about 269,000 miles from the Earth, slightly farther away than the moon.
940660
Much larger.  It is a gas planet, where Mars is a rock planet.