Asteroid Definition and 285 Threads

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. MajesticPenguin

    An Asteroid is moving along a straight line

    Homework Statement An asteroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 4.5*10^4 kg, and the force causes its speed to change from 7100m/s to 5500m/s. (a) What is the work done by the force? (b) If the...
  2. H

    Asteroid colliding with a planet

    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. What would have to be the mass of this asteroid, in terms of the Earth's mass M , for the day to become 26.0%...
  3. at94official

    Asteroid 99942 Apophis impacting the Earth in 2029

    Good Day everyone! :wink: I don't know if this thread is repeated already. Because I can't find one. I just want to ask you guys what are your insights for the asteroid apophis' possible impact to Earth by 2029? Upon its discovery in 2004, Apophis was briefly estimated to have a 2.7% chance of...
  4. E

    Cross Section for Asteroid Impact

    Homework Statement In this problem, you will estimate the cross section for an earth-asteroid collision. In all that follows, assume that the Earth is fixed in space and that the radius of the asteroid is much less than the radius R of the earth. The mass of the Earth is M_e, and the mass of...
  5. Dotini

    Asteroid 2004 BL86 and its small moon

    http://www.nasa.gov/jpl/asteroid-that-flew-past-earth-today-has-moon/ Radar observations of small object apparently orbiting an asteroid near Earth. Edit: a sharpened video. http://www.space.com/28438-asteroid-2004-bl86-moon-sharp-video.html...
  6. Andy Resnick

    Can Radio Telescopes Capture Detailed Images of Asteroids and Their Moons?

    Asteroid 2004-B186 is passing by this evening (monday), with a maximum magnitude 9.5 (visible with bionculars/small telescopes). Here's a chart: http://neo.jpl.nasa.gov/images/2004bl86_starchart.jpg Hoping for a (reasonably) clear evening...
  7. W

    Asteroid Collision: Calculating Impact Speed

    1. An asteroid is 10r away from the earth, and traveling at a speed of 12 km/s. What is the impact speed of the asteroid when it hits the earth?2. Gravitation problem: U = -Gm[E]m / r ...I think3. I've been looking in my book and online and cannot figure it out, please help!
  8. B

    How Massive Must an Asteroid Be to Extend Earth's Day by 28%?

    Homework Statement [/B] Suppose that an asteroid traveling straight toward the centre of the Earth were to collide with our planet at the equator and bury itself just below the surface. What would have to be the mass of this asteroid, in terms of the earth’s mass, for the day to become 28.0%...
  9. S

    Asteroid Orbits: Finding r with Kepler's Laws

    Homework Statement An asteroid of mass m is in circular orbit of radius r around the sun with speed v.It has an impact with another asteroid of mass M and is kicked into a new circular orbit with a speed 1.5v.What is the radius of the new orbit in terms r?[/B]Homework Equations (v1)^2/(v2)^2 =...
  10. C

    Holy Close Call Batman, asteroid 2014 RC

    Newly discovered Asteroid 2014 RC, the size of a house, gives Earth a close shave in 2 days, coming in about 1000 miles closer than the orbits of our geosynchronous Sats ! ...Sept. 7th above New Zealand. Details...
  11. anorlunda

    Why Is Asteroid Composition Highly Varied?

    A thread on this forum Plans for Asteroid Mining has more than 9000 views. From that I conclude that belief that asteroid composition must be highly varied mu thast be wide spread. I'm having a hard time understanding why that should be. So unless the planitesimals formed at approximately...
  12. Greg Bernhardt

    What are Trojan Asteroids and How are They Named?

    Definition/Summary A term referring to any of the small bodies that tend to collect at the L4 and L5 Lagrange points. Equations Extended explanation There are two stable points located 60° ahead and behind of Jupiter in its orbit where small astronomical objects tend to collect...
  13. C

    Did Anyone See Asteroid "Beast" Fly By Earth?

    Did anybody see the "beast" as it whizzed by Earth today at 31,000 mph ? Just checking to make sure we didn't get hit. :-p Oops; maybe I should have put this under "stargazing & Telescopes"
  14. S

    Calculating Asteroid Impact Speed

    Hi there, I have a question here: "An asteroid is measured to have a speed relative to the Earth of 15 km/s while it is still far away. What is the speed of impact of the asteroid with the Earth?" I'm stumped. I don't even know where to start with this one -- it doesn't talk about how...
  15. M

    Period of falling through asteroid vs orbit

    Homework Statement Homework Equations See below The Attempt at a Solution My book derives the period of oscillation through the tunnel: T = 2pi/w = 2pi*sqrt(m/k) = 2pi*sqrt(3/(4pi*G*p)) = sqrt(3pi/(G*p)) Where p is the density of the asteroid, and G is the Newton's gravitational...
  16. L

    An asteroid is approaching Earth

    Hi, I am writing a sci-fi comic and would need an info, which is very similar to this thread: https://www.physicsforums.com/showthread.php?p=4724396#post4724396 My question is, how much would it take for an asteroid to reach Earth after detection? A cca 'from to' range would be sufficient...
  17. J

    Asteroid on course with planet problem

    Homework Statement A asteroid of mass m=5*10^20 kg , speed u=10km/s is on a direct course to hit earth. If nuclear weapons are used to split it into two equal pieces at a distance away of the moon's orbit, d, what is the minimum energy required for each half to miss Earth by s=600km...
  18. Dotini

    Discovery of Asteroid With 2 Rings - Centaur Chariklo

    http://webcache.googleusercontent.com/search?q=cache%3Ahttp%3A%2F%2Fwww.wral.com%2Fdiscovery-an-asteroid-with-rings%2F13510966%2F "The European Southern Observatory announced this week the discovery of rings around an asteroid 1.4 billion miles from Earth. Chariklo is the largest of the class...
  19. S

    Kepler's Law to Determine Period of Asteroid

    Homework Statement A newly discovered asteroid orbits at twice the Earth-Sun distance. Find its period of orbit (in years). Homework Equations I know that I'm supposed to use Kepler's third law to determine this. T2 = Kr3 K = 4∏2/GM and the Earth-Sun distance is of course 1 Au...
  20. A

    How long would it take for an asteroid to travel to our sun-system ?

    How long would it take for an asteroid to travel to our "sun-system"? I have been informed about the rules of the forum, that the administrators strongly encourage members to make an effort on their own first to sought out answers, but that one mustn't do that. I'm very tired of Wikipedia, and...
  21. Q

    The energy of debris ejected from an asteroid impact

    I have been struggling with this problem. I'll greatly appreciate someone pointing me in the right direction. I think it's safe to assume the velocity of the impact is the Earth's escape velocity 11.1*10^3 m/s Here's the problem: Impacting objects will excavate a certain amount of debris...
  22. |Glitch|

    Evidence of an asteroid encountering a pulsar

    The paper goes on to describe asteroids "formed from supernova fallback material" falling into the pulsar. Why would the asteroids be formed after the supernova? More importantly, how could an asteroid form from supernova remnants? If a star with less than ~9 solar masses had planets and...
  23. N

    How Can We Calculate Displacement and Average Velocity for a Complex Trip?

    Homework Statement A car drives north at 40mi/h for 10mins then turns east and goes 5min at 60mi/hr. Finally it goes southwest at 30mi/h for 6min. a) determine the displacement b)average velocity for this trip The Attempt at a Solution x-component: 60mi/hr/60min x 5min = 5mi...
  24. P

    Asteroid Gravity: Keplers 3rd Law

    Homework Statement An asteroid is discovered to have a tiny moon that orbits it in a circular path at a distance of 113 km and with a period of 41.0 h. The asteroid is roughly spherical (unusual for such a small body) with a radius of 19.3 km. a) Find the acceleration of gravity at the...
  25. Dotini

    Odd Body in Asteroid Belt with 6 Tails

    http://www.nasa.gov/content/goddard/hubble-sees-asteroid-spouting-six-comet-like-tails/#.UnvGoHemYRc Hubble photos http://www.nasa.gov/press/2013/november/nasas-hubble-sees-asteroid-spouting-six-comet-like-tails/ NASA press release
  26. D

    Calculating Mass Lost of Iron Asteroid Hitting Earth

    I am trying to figure out an equation that will allow me to calculate the mass lost of an asteroid that is coming towards earth. I know what I need to know the melting point of the asteroid, in this case we are using a completely spherical iron asteroid. Also kinetic energy would most likely be...
  27. A

    Collision of the Halley asteroid with a comet

    1. The problem statement a comet gets in the way of the Halley asteroid, so the question is: what's the new trajectory of the asteroid (its excentricity, its orbital rotation and it perihelion, aphelion) both objects have same mass and we suppose that the comet have an negilgeable...
  28. A

    Collisions Of Two Asteroids in the Main Asteroid Belt.

    Homework Statement If there are two asteroids A and B of equal mass (and density of 3000kg/m^3), with the same semi major axis of a=2.2 AU with asteroid A having a circular orbit and no inclination, and asteroid B has an elliptical orbit with an eccentricity of e=0.05 and an inclination of...
  29. W

    Asteroid Impacting Venus: Will it Strike or Explode?

    Lets say you have a 20 km wide stony/iron asteroid hurtling towards Venus at 18 km per second at a 45 degree angle. Would an asteroid of this size hit the surface of Venus or just blow up in the atmosphere? I know that an asteroid of this size would hit the surface of Earth but I am...
  30. T

    Leap Off an Asteroid: Escape Earthly Gravity?

    Suppose that on Earth you can jump straight up a distance of 50 cm. Can you escape from a 4.0-km-diameter asteroid with a mass of 1.0 times 10^14 kg?
  31. B

    Can Conservation of Angular Momentum Help Estimate the Mass of Binary Asteroids?

    Homework Statement Two asteroids (approximately the same size and mass) are orbiting each other at a given radius a. The center of mass is orbiting the sun at a distance (semimajor axis) b with an orbital period of P. I would like to estimate the mass/size of each of the asteroids. By...
  32. chasrob

    Slowing a Rogue Iron Asteroid: Can it Survive 900 Gees of De-Acceleration?

    Story line I'm working on: an iron asteroid--huge, 20 km in diameter--is zipping along in its orbit in the asteroid belt. It's solid Ni-Fe, same composition as an iron meteorite, only gigantic. I need to have its velocity slowed down. 900 gees of de-acceleration for 10 seconds. Can this...
  33. S

    Momentum Question: Asteroid Collision

    Homework Statement Asteroid A is traveling at 40.0m/s and collides with asteroid B which is at rest. Both asteroids have the same mass, but asteroid A deflects off of its path by 30.0° above the horizontal, and asteroid B begins to travel 45.0° below the horizontal. What is the speed of...
  34. L

    Does the Asteroid Pose a Threat to Earth?

    An asteroid is at a distance of 2 x106 km from Earth and is moving with a speed of 10 km/s. Without gravitational pull, the asteroid would miss Earth by a perpendicular distance of 25,000 km from the center of Earth. What is the closest distance between the asteroid and Earth? Does it hit...
  35. J

    An asteroid flying past the moon

    I am not that great in physics, but I put a lot of effort in trying to learn it. I would really appreciate any help on this problem, since I am not even sure where to start. An asteroid is about to fly past the moon (about 384,000km away) and is on a collision course with the earth...
  36. R

    Coincidence of asteroid and Russian meteor at same time.

    Astronomers have calculated that the Russian meteor and asteroid 2012 DA14 have very different orbits: Astronomers Calculate Orbit of Chelyabinsk Meteorite. Still because of the very unlikely probability of their occurring together purely by chance, I would like to see some simulations of...
  37. M

    Is Russian meteor related to a asteroid known as 2012 DA14?

    I doubt it. The trajectory of meteor was very close to be horizontal, so it could make revolution('s) around the Earth and fly opposite direction to asteroid known as 2012 DA14, being a remnants of 2012 DA14.
  38. C

    Finding angular velocity after asteroid collision

    Homework Statement In the figure a spherical non spinning asteroid of mass M = 4E16 kg and radius R = 1.5E4 m moving with speed v1 = 2.4E4 m/s to the right collides with a similar non spinning asteroid moving with speed v2 = 5.9E4 m/s to the left, and they stick together. The impact parameter...
  39. A

    Effects of perpendicularly-approaching asteroid on Earth

    Assume the following hypothetical situation: an enormous body, 20,000 ly in diameter (I recognise that 'asteroids' per se tend to be smaller), approaches the Milky Way, perpendicular to its equatorial plane, and headed straight for planet Earth, or at least on a trajectory where it will...
  40. chasrob

    How Bright Must an Asteroid Be to Catch an Amateur Astronomer's Eye?

    In a SF story I'm working up, an asteroid is launched(long story made short) from its orbit in the asteroid belt in a collision course with earth. It is 30km wide or so, one of 10,000 such planetoids in the belt, IIRC. From the viewpoint here on earth, it is in the milky way of Gemini and...
  41. B

    The baseball pitcher on an asteroid

    Homework Statement A baseball pitcher can throw a fastball at a speed of 150 km/hr. What is the largest size spherical asteroid of density rho=3 g/cm^3 from which he can throw the ball fast enough that it: (a) escapes from the asteroid into heliocentric orbit? (b) rises to a height of 50...
  42. J

    Can conservation principles solve the killer asteroid problem?

    The problem: Killer Asteroid Some data: Mass of Earth = 6.0 x 1024 kg Radius of Earth = 6.4 x 10³ km Gravitational constant G = 6.67 x 10−11N-m/kg² You receive an urgent phone call from NASA. Their scientists have just detected an asteroid headed for Earth. Its mass is 6 x 10 15 kg, which is...
  43. J

    Can an Asteroid Impact the Moon's Orbit?

    If an asteroid was moving in the opposite direction of the moon, could it slow it down enough when it hit it to cause it to crash into the earth. and vice versa, could it be going the same direction and acceleration it enough to excape the Earth's gravitational pull? If so, about how large would...
  44. S

    Fictional Earthbound Asteroid Collision

    Hello all, New to posting, but I've lurked the forums here for awhile. And I feel like there is some odd coincidence of me posting right after another fellow decided to ask about a fictional near Earth collision. I'm a filmmaker, writer, and artist. I'm currently working on a comic book...
  45. S

    Finding the Velocity of an Asteroid with a Given Mass and Kinetic Energy

    Homework Statement An asteroid of mass 2500 kg has a (relativistic) kinetic energy of 1e+20 J. What is the speed of the asteroid? Homework Equations KE=(mc^2/sqrt(1-v^2/c^2)-mc^2 The Attempt at a Solution I tried plugging in my values to this equation and got 216480727.3. the...
  46. J

    Calculating Historical Positions of the Asteroid Belt's Orbit

    Is it possible to calculate the historical whereabouts of the asteroid belt, as it seems to be moving ever outward due to the radiometer effect? Can it be calculated, for instance, where it was 1,000 years ago? 100,000 years ago? Etc. In particular, I'm curious as to whether the science is...
  47. S

    Asteroid orbit determination from observations

    It is said in the literature, I believe, one needs several nights of observations to calculate an orbit for, say,an asteroid. Using celestial mechanics mathematics and methodology, one produces the six orbital elements. It seems to me that most introductory texts on the subject, talk about...
  48. J

    Asteroid, Meteorite, Meteoroid, or Meteor?

    So I know a meteoroid is the small thing floating in space while an asteroid is the large one. I know a meteor is the streak of light a meteoroid creates as it falls through the atmosphere and a meteorite is what remains after the impact on the Earth. Also, that meteorites can sometimes be...
  49. T

    Can Asteroid Mining Technology Serve as a Global Defense System?

    Is it worth spending billions for some technology for deep mining in space. Isn't it easier to bring those asteroids to Earth and then mine it here on earth. http://www.bbc.co.uk/news/science-environment-17827347
  50. R

    April Fools' Asteroid just miss to hit

    An Asteroids named 2012 EG5 about 150 feet wide passed near the earth, its distance from Earth was only 230,000 kilometers which is nearly half of distance between Earth and moon.
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