What is Asteroid: Definition and 279 Discussions

An asteroid is a minor planet of the inner Solar System. Historically, these terms have been applied to any astronomical object orbiting the Sun that did not resolve into a disc in a telescope and was not observed to have characteristics of an active comet such as a tail. As minor planets in the outer Solar System were discovered that were found to have volatile-rich surfaces similar to comets, these came to be distinguished from the objects found in the main asteroid belt. The term "asteroid" refers to the minor planets of the inner Solar System, including those co-orbital with Jupiter. Larger asteroids are often called planetoids.

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  1. Z

    Proof of planetesimals for asteroid belt?

    If asteroid belt objects are in part iron, is this then consistent with such differentiated pieces being solidified remains of a liquid core(s) of previous colliding planetesimals? p.s. total mass of asteroid belt may be just 4% of moon. http://en.wikipedia.org/wiki/Asteroid_belt"
  2. K

    What Happens to Light When a Flashlight Hits an Asteroid?

    if a flashlight is moving at half the speed of light and sending out light at a relative speed of c and then the flashlight runs into an asteroid and wham, it stops moving relative to the asteroid, does the light that has already been sent out put on its retro rockets so that is can resume its...
  3. C

    Changing the course of an asteroid

    Homework Statement Hello all, I am really having trouble with following. I want to find the answer myself, but i do not know what equation/s i should apply to solve the problem. My Question. How long will it take to deflect an asteroid on a collision course with Earth by...
  4. C

    Changing the course of an asteroid

    Hello all, I am really having trouble with following. I want to find the answer myself, but i do not know what equation/s i should apply to solve the problem. My Question. How long will it take to deflect an asteroid on a collision course with Earth by attaching a 2000N thruster. I...
  5. Philosophaie

    Location of the Asteroid Belt between Mars and Jupiter

    There is an Asteroid Belt between Mars and Jupiter. I have a few questions about it. Where does it start and end (Radius from the Sun)? Also, the Right Ascensions and Declinations of the extents of the belt or if it is continuous around the sun? I know that some of the larger asteroids...
  6. R

    What makes an asteroid an asteroid and not a comet

    Hi all Have been thinking about this for sometime, what is the fundamental difference that makes an asteroid an object orbitting around the star at a lesser speed and not a comet? Hope my question is clear, framing it otherwise why do asteroids not turn into raging comets or comets into...
  7. C

    Moving an asteroid into Earth orbit

    Suppose we want to use an asteroid to build a large space station. We could alter the course of a asteroid so that it will come very close to Earth, but the velocity relative to Earth will then be more than the escape velocity of 11.2 km/s. Presumably we must use aerobraking to let it lose...
  8. J

    What is the Largest Radius of an Asteroid from Which You Can Escape by Jumping?

    Homework Statement Asteroids have average densities of about 2,660 kg/m3 and radii from 470 km down to less than a kilometer. Assuming that the asteroid has a spherically symmetric mass distribution, estimate the radius of the largest asteroid from which you could escape simply by jumping off...
  9. S

    Solving the Asteroid Problem: Position, Energy, Deflection & Intercept

    1. The problem statement, Suppose that a compact asteroid with mass Ma=2.5x10^15kg is on a collision course with Earth (Me=5.974x10^24kg, Re=6.278x10^6m). At t=0 it's velocity is 5kms-1 directly towards the Earth and it is at a distance of 25000km from the surface. i) Derive an...
  10. K

    Asteroid Collision: Calculate Impact Speed & Change in Day Length

    Homework Statement Suppose an asteroid of mass 1 1019 kg is nearly at rest outside the solar system, far beyond Pluto. It falls toward the Sun and crashes into the Earth at the equator, coming in at an angle of 30 degrees to the vertical as shown, against the direction of rotation of the...
  11. W

    Close Call: Asteroid 2009 DD45 Passes Earth

    Wow! millions of people could have died yesterday, if perhaps some random intergalactic tug pushed the sucker on a trajectory towards earth. http://news.bbc.co.uk/2/hi/science/nature/7921279.stm
  12. W

    Asteroid 2009 DD45: Close Approach to Earth March 2nd

    On the night of March 1st, actually March 2nd UTC a small asteroid (2009 DD45) will pass very close to earth. Something within 0.00030 lunar distances. It will unfortunately (and then perhaps very fortunately) in all probability not be visible to the unaided eye. If it was very bright in the...
  13. W

    Nudging an Asteroid. Conservation of Momentum

    Homework Statement Homework Equations 1.) m1*v1 + m2*v2 = m1'*v1' + m2'*v2' Where the ' denotes the velocity/mass after the event/whatever. 2.) 0.5m1(v1)^2 + 0.5m2(v2)^2 = 0.5m1'(v1')^2 + 0.5m1'(v1')^2 The Attempt at a Solution I know its a conservation of momentum style of problem...
  14. E

    Final speed of an asteroid using escape speed

    Homework Statement The escape speed from a very small asteroid is only 32 m/s. If you throw a rock away from the asteroid at a speed of 44 m/s, what will be its final speed? Homework Equations Ki + Ui = 1/2mv^2 + (-GMm/R) = 0 (for v<<c) The Attempt at a Solution I am unsure of how to do...
  15. S

    What is the final velocity of an asteroid on a collision course with Earth?

    Homework Statement A NASA satellite has just observed an asteroid that is on a collision course with the Earth. The asteroid has an estimated mass, based on its size, of 5 × 10^9 kg. It is approaching the Earth on a head-on course with a velocity of 611 m/s relative to the Earth and is now 5.0...
  16. S

    Strategy for destroying a 6 km wide asteroid

    What do you think is the best statergy for destroying a 6 km wide asteroid which is heading towards the earth. Do you think it is possible to develop "clean fusion Nucs" which can be deployed from spacesations to intercept such a large asteroid also if a fusion bomb were to fall appart in...
  17. A

    Asteroid Speed: Calculating with Kinetic Energy

    Homework Statement A 4.50 x 10^4 kg asteroid has 6.20 x 10^12 J of kinetic energy. What is the speed of that asteroid? Homework Equations W=Fd P=W/T P=Fv The Attempt at a Solution V=p/f V=(6.2 x 10^12)/((4.50 x 10^4 kg)(9.8) V=1.41 x 10^7 m/s I am wondering about the...
  18. C

    Why doesn't the asteroid belt block our view of the jovial planets?

    Why doesn't the asteroid belt block our view of the jovial planets? I'm assuming it's because the asteroids are just too few, far apart, and small to affect our view, but I'm not sure and I'd like to know. Thanks!
  19. C

    Calculating Force of Asteroid Slowing Down

    Homework Statement The asteroid has a mass of 4.10 x 10^4 kg, and the force causes its speed to change from 7100 m/s to 5700 m/s. If the asteroid slows down over a distance of 1.50 x 10^6 m, determine the magnitude F of the force. Homework Equations w = -3.6736e11 J (I figured...
  20. S

    Finding the velocity and covered distance of Astronaut pushing asteroid

    Homework Statement An astronaut of mass 60 kg and a small asteroid of mass 40 are initially at rest with respect to the space station. The astronaut pushes the asteroid with a constant force of magnitude 250N for 0.35s. Gravitational forces are negligible. A)How far apart are the astronaut and...
  21. U

    History Asteroid impact events in history/mythology

    Given the frequency of relatively minor asteroidal impacts, similar to the Tunguska event, it seems to me that ancient literature would be rife with stories of them, probably interpreted as acts of the gods or God. For example, in the Bible is the story (2Samuel 24 and 1Chronicles 21) of David...
  22. S

    Asteroid in a circular orbit about the Sun

    If the Earth's period is 365.25 days and its distance to the (center of the) Sun is one astronomical unit (AU), what is the period, to the nearest day, of an asteroid in a circular orbit about the Sun with a radius of 3.04 AU? please show steps so that I can learn. thanks a lot.
  23. L

    Giant Asteroid Flattened Half of Mars, Studies Suggest

    In looking at the Martian hemispheric dichotomy (significant differences in the Martian crust over a large radius) simulations suggest that Mars was hit by something like a 1000 to 1700 mile wide asteroid about 4 billion years ago. http://www.sciam.com/article.cfm?id=giant-asteroid-flattened...
  24. K

    Asteroid Cooling: Solving Internal Temp & Cooling Rate for Radius

    Homework Statement Consider an asteroid with an iron core \rho_m = 8000 kg\; m^{-3} covered by a thin silicate mantle \rho_m = 3500 kg\; m^{-3} with a thickness of 20% the raidus R of the asteroid. Assume that the internal temp is T_i = 600K and is constant throughout the core due to...
  25. B. Elliott

    Concussive effects of asteroid impact on marine life

    I was doing some reading on the effects of air blasts from asteroid impacts when I realized that I've never seen any data of the potential effect on marine life. Since sound travels farther and faster in a liquid, wouldn't an asteroid impact in a large ocean (liquid) have a more profound...
  26. A

    Conservation of Angular Momentum of an asteroid

    Homework Statement Suppose that an asteroid traveling straight toward the center of the Earth were to collide with our planet at the equator and bury itself just below the surface. Now The question asks: What would have to be the mass of this asteroid, in terms of the Earth's mass {\rm M}...
  27. G

    Cooling rate of an asteroid.

    Consider an asteroid with an iron core (pc = 8000kg/m^3) covered by a thin silicate mantle (pm = 3400kg/m^3) with a thickness of 20% of the radius R of the asteroid. Assume that the internal temperature Ti = 600K is constant throughout the core. The thermal energy of the core is 3*k*Ti per...
  28. S

    Density of an asteroid from revolution period

    Homework Statement The rotation period of a small asteroid is 10.21 revolutions per day. What is the minimum density for this object?Homework Equations The Attempt at a SolutionI should be able to use angular momentum right? I'm trying to do this by approximating the asteroid as a sphere and...
  29. Astronuc

    Planetary Society - Asteroid Tagging Competition

    Planetary Society Names Winners of $50,000 Asteroid Tagging Competition http://www.planetarysociety.org/about/press/releases/2008/0226_Planetary_Society_Names_Winners_of.html I'm sure this will make the news periodically over the next 21 years.
  30. X

    What is the minimum angle required to deflect an asteroid heading towards Earth?

    Homework Statement A 4.50E10 kg asteroid is heading directly toward the center of the Earth at a steady 16.0 km/s. To save the planet, astronauts strap a giant rocket to the asteroid perpendicular to its direction of travel. The rocket generates 5.0E9 N of thrust. The rocket is fired when the...
  31. W

    Deciphering Asteroid Stats to Divert an Impact on Earth

    I'm currently in grade 12 physics. For my summative project in the class (which is worth a large part of my final mark) I have to think of three separate ways to divert a large asteroid away from hitting earth. We were each given a real object and stats on the object. My first problem is that...
  32. tony873004

    Is NASA prepared for a potential Mars-impacting asteroid?

    The asteroid 2007 WD5 was reported as having a 1 in 75 chance of hitting Mars on January 30, 2008. This was based on observations through December 21, 2007. New observations are in. It's predicted path is getting closer to Mars. The media won't run another story until NASA makes another...
  33. P

    Asteroid Hits Moon / Breaks it up:

    I don't know much about Astronomy or physics. But I am researching to write a fantasy book set in a historical age where Earth has 2 moons and in a sub-plot one is hit by an asteroid and destroyed. We know what the effect of an asteroid hitting Earth is. What about it hitting the moon, a...
  34. B

    Asteroid hits moon → moon hits Earth possible?

    I had a vivid nightmare the other night where I went outside in broad daylight and saw that the moon was not only visible but also enormous. I saw people running around in a state of panic and asked one of them what was going on. He told me a large asteroid had struck the moon on the side...
  35. B

    Asteroid Database: Find Objects with RA, Dec & Julian Date

    Hi guys, Do any of you know where I can find an asteroid database. I have sky coordinates (RA and Dec) and Julian date and I want to search to see if there are any asteroids around the provided coordinates at the given date. I guess a better question would be if there is actually a...
  36. Ivan Seeking

    What is the significance of asteroid 7307 Takei being named after George Takei?

    http://www.cnn.com/2007/TECH/space/10/03/takei.asteroid.ap/index.html :approve:
  37. Saladsamurai

    Calculation for Asteroid Orbital Period

    Of an asteroid whose Mass is 2.0*10^-2 times that of Earth's and whose distance from the sun is twice the Earth's distance from the sun. Find the period in years. I am supposed to use the concept of gravitational F=centripital force=m\frac{v^2}{r} and the fact that v=\frac{2\pi r}{T} so this...
  38. C

    Calculating Minimum Asteroid Size for Astronaut Safety

    Sorry guys, one more question for now. It is the only other one I couldn't really get on this homework assignment. Homework Statement An astronaut is about to explore an asteroid of average density \rho=5000 kg/m^3. He is worried that he may accidentally jump from its surface and float off...
  39. A

    What is the acceleration due to gravity on this asteroid?

    Homework Statement An astronaut's pack weighs 15.3 N when she is on Earth but only 3.05 N when she is at the surface of an asteroid. a. What is the acceleration due to gravity on this asteroid? B. what is the mass of the pack on the asteroid? Homework Equations ok, I know I have to...
  40. R

    Force question involving an asteroid and spacecraft

    Homework Statement This is a 5-part problem. In June 1997 the NEAR spacecraft ("Near Earth Asteroid Rendezvous"; see http://near.jhuapl.edu/), on its way to photograph the asteroid Eros, passed within D=1200 km of asteroid Mathilde at a speed of 10 km/s relative to the asteroid...
  41. G

    Can Mars Effect the Asteroid Belt?

    I was looking at this picture of the asteroid belt on wikipedia http://en.wikipedia.org/wiki/Image:InnerSolarSystem-en.png And assuming that the picture is somewhat accurate in the placing of distance between objects in the solar system, I couldn’t help but wonder if it’s possible that the...
  42. S

    Solving for Earth's Velocity After Collision with Asteroid

    I am trying to solve a physics problem involving the velocity of Earth and primitive earth. I have solved it using m1v1+m2v2=(m1+m2)v2 for inelastic equation and get a velocity of 29.65 km/s. Which I think is incorrect since the Earth's rotational velocity today is 30 km/s. But I can't figure...
  43. matthyaouw

    Asteroid Impacts: What Happens In the Deep Ocean?

    I've been wondering- what would happen to an asteroid striking the deep ocean? On land they leave fairly massive craters, but at sea, would there be an impact crater on the floor, or would the resistance of the water reduce the asteroid to a fine sediment before it could impact with the bottom?
  44. V

    Complicated Asteroid problem

    Hi everyone, this problem is truly pain in the a**. I understand that Newton's third law applies here, but whatever I have tried nothing worked out. I know that the force applied is the same in magnitude, but opposite in the direction and accelerations of these two masses are different...but no...
  45. J

    That asteroid where's it going?

    Here's an assessment of the feasibility of diverting asteroid 1981 Midas into a collision with Earth in the year 2018. I'm posting this to show the potential military-political advantage to controlling access to space. Note the relatively small size of the divert delta-vee. Only about 301.5...
  46. L

    Asteroid Collision Course and Sagging Backpack

    We recently had a study group to look over some problems we were given in preparation for our upcoming exam. There were two problems that gave us a little bit of difficulty. There's a lot of stuff here, but I tried to trim it up as much as possible so as not to scare off any help. If I need...
  47. S

    Compression of a Spring on an Asteroid?

    Homework Statement A package with mass m sits on an airless asteroid of mass M and radius R. We want to launch a package straight up in such a way that its speed drops to zero when it is a distance 4R away from the center of the asteroid, where it's picked up by a waiting ship before it can...
  48. F

    Asteroid Trajectory Equations?

    Homework Statement I need to know how to apply the coefficent of friction and gravity to a 3-coordinate (3D) velocity vector. For my Intro to C Programming class, our final project is to write a program that simulates the trajectory of an asteroid passing a gas giant. The problem is, I...
  49. P

    Fragmentation of a asteroid.

    Hi I got this question, it looks like its simple. But I don't know if I've done it right or not? Please help me check it. A 2kg rock is heading straight for a space station at a speed of 100 m/s. The crew plan to break the rock up into small fragments by hitting it with a rocket of 3kg...
  50. C

    Momentum of an asteroid / Earth

    Please help me to understand this question: I'm paraphrasing it. A speed (relative to earth) and mass for an asteroid are given, and the asteroid strikes the Earth tangentially in the direction of the Earth's rotation at the equator. The question tells us to use angular momentum to find the...
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