How many comets intersect the orbit of our earth?
352708
We cannot accurately answer that question because of HOW LONG IT TAKES to get here. We could observe the sky for centuries and find a new one that only comes here every few millenia. Intersecting our orbit though, That is a very limited space, and many get defelcted as shown by Shoemaker-Levy-9's impact with Jupiter.
978319
The orbit is called geosynchronous.  Check out the NASA website.  Your can see all the satellites we human have put into orbit.  It'll shock you!
750080
There are 192 member countries recognized by the United Nations, and 193 recognized by the state department of the U.S. There are currently 9 (the number is disputed) planets if you count Pluto and 8 if you don't, but that is just in our solar system. There are a lot more planets out there.
712687
If you imagine a solar system that includes the sun and the Earth,and no other bodies, the Earth would travel about the sun in an ellipse (strictly speaking, the Earth and the sun would travel around their common center of gravity in ellipses).  An ellipse has two foci, which are points that define the ellipse in the same way that a point defines the center location of a circle.  Because the sun is so large and the orbit is so nearly circular, both of the foci lie near the center of the sun  So it is not correct to say that one of the foci is the sun -- both foci are in the sun, but they're really just mathematical points that define the shape of the orbit.\n\nWhen you add more planets to the mix, things get much more complicated, but one can think of each approximately elliptical orbit separately, and then there is a different set of foci for each pair of bodies if one neglects the influence of the other bodies.
196821
The plane formed by the Earth's orbit is called the ecliptic. While most of the planets' orbits are close to this plane, Mercury and Pluto's orbits differ by several degrees.
861683
The Earth's orbit is slightly elliptical.  When it is closest to the Sun it is a distance of 91.4 million miles.  At it's furthest it is 94.5m miles.  The distance between the Earth and the Sun is also known as 1AU (astronomical unit).
361769
Sol (our solar system) consists of 9 planets, over 140 moons (to date) and several small cosmic objects (comets and asteroids).\n\nMercury (0 moons)\nVenus (0 moons)\nEarth (1 moon)\nMars (2 moons)\nJupiter (63 moons as of 2004)\nSaturn (34 moons)\nUranus (21 named moons, 6 unnamed moons)\nNeptune (8 named moons, 5 unnamed moons)\nPluto (1 moon)\n\nThere have been discoveries of more "planetary objects" beyond Pluto, but they have not been declared to be planets in the same sense as the others.
1028317
The Solar System is believed to be around 4.5 billion years old. Hence, ignoring any changes in the length of the year, the Earth has orbited the sun 4.5 billion times.
541450
The diameter of the Earth's orbit around the Sun is about 300,000,000 kilometers
316427
None specifically. \n\nAll celestial bodies rotate.  The earth is no different.
161091
well, scientists are redefining the word "planet", so pluto might get excluded as a planet, and we might have only 8, or if pluto is a planet, 8 other bodies will be planets. so there could be 17 planets
307741
Right now there are officially 9.  Depending on what we decide in the next year or so that number will change to 8, stay 9, go to 10, or even larger.  An object larger than Pluto has been found, but we have not granted it official status as a planet.  Don't expect this issue to be resolved any time soon, we've more or less "tabled" the issue until our general meeting in August.
838857
The Earth, moving 30kilometers per second relative to the sun, orbits the sun in one year moving 942 million kilometers in that  year. But Earth has greater space velocities than this depending on other inertial frames of motion you may wish to consider. Sol(our sun...& Earth has to tag along with Sol) orbits around the center of our Milky Way galaxy at 217kilometers per second or 6.84 billion kilometers in that same year. Adding earth's small orbital motion component may bring total space motion to roughly 7 billion kilometers per year. But our Milky Way also moves relative to its neighbor galaxies at estimates that average out to 600kilometers per second or19 billion kilometers per year. Roughly calculating the small Sol-Earth component trajectory, there may be a total space motion of less than 20 billion kilometers per year. However, another frame of reference is the Cosmic Microwave Background that seems most likely to be the cooling evidence of the Big Bang. The Milky Way has a space motion of 552kilometers per second or roughly 17.4 billion kilometers per year relative to the Cosmic Microwave Background. So there you have it. Possible universal space motion estimates of under 20 billion or 17.4 billion kilometers per year. Picking either estimate, rules out any great contribution from Earth motion around the sun, even though that motion alone is 30kilometers per second! Good question.
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
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.......
77240
Our own solar system has 10 planets that we know of:\nMercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and the newly discovered 2003 UB313.  That last one is still being contended, and why that debate gets so heated is beyond me.\n\nThere are actually 155 known extrasolar planets, and that number is only going to rapidly increase.  You can find a list on the California & Carnegie Planet Search site below:
46875
Approximately 93,000,000 miles.  The distance varies because our orbit is not perfectly circular.