Asteroids Definition and 65 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. Nik_2213

    Writing: Input Wanted Metal-rich moonlets / asteroids of lone Brown Dwarf sub-stars?

    My limited research suggests Metal-rich moonlets / asteroids will be uncommon around lone Brown Dwarf sub-stars. By their nature, either they've been 'starved' on the ingredients front, or have been ejected from an unstable association, latter probably stripping outer satellites... Either way...
  2. Hak

    How Does Angular Momentum Conservation Affect Asteroid Collision Dynamics?

    Before the collision, the total linear momentum of the system is ##p = mv##, where ##m## is the mass of the minor asteroid and ##v## is its velocity. The total angular momentum of the system is ##L = mRv##, where ##R## is the radius of the major asteroid. Since there are no external forces or...
  3. ananonanunes

    Average distance between asteroids in the asteroid belt

    What I did was find the total area of the space between the Kirkwood gaps and the area occupied by the asteroids (assuming they all had a 100m radius). I subtracted the two to get the area that is empty in that region. To find the average empty area between asteroids I divided this by the...
  4. Rendering

    Impact events: when were they first seen as potentially catastrophic?

    (This is a history of science question, so please let me know if it's not appropriate to this forum.) When did someone first realize that major Earth impact events (asteroids, etc.) could potentially be catastrophic? To be clear, I don't mean in the purely theoretical sense (the likely given...
  5. mfb

    I Number of known asteroids reaches 1 million

    1,002,726 or 993,960 known asteroids depending on the database. We find asteroids faster than ever before. By 1921 astronomers knew 1000, then it took almost 70 years to extend that to 10,000 (1989). Just 16 years later we reached 100,000 (in 2005), and 15 more years later we reached 1 million...
  6. S

    Stargazing Possibility of detection of Earth approaching objects by gravity?

    Hey everyone, lately I read a german newspaper article about an Asteroid which passed Earth in a very small distance (asteroid 2020 QG, distance of closest approach was about 2950 km). Here is another link about this event written in English: Article about 2020 QG (Businessinsider.com). As far...
  7. A

    I Can you See Neighboring Asteroids from an asteroid?

    It is well known that the asteroid belt is relatively sparse, with the asteroids spread out pretty far away from each other. From what I have read, asteroids are generally separated from other asteroids by about 500,000 to 1,000,000 km on average from their nearest neighbors. If I stood on an...
  8. E

    B Mining asteroids for minerals and resources?

    In the distant future, will it be possible to mine asteroids for valuable raw materials and resources? What kind of materials could be extracted? What about moons and other planets in our solar system?
  9. alva3

    I How is asteroid 101955 Bennu possible?

    Summary: Five questions about the structure of asteroids; specifically 101955 Bennu. Please forgive my ignorance, but I need help reconciling a few things... I'm curious about the images I've seen of asteroid Bennu: 1. If gravity is proportional to combined masses divided by their distance...
  10. R

    Stargazing Who Tracks and Warns Us About Asteroids?

    1. Which organization or group of organizations is it the responsibility of to detect and track worrisome asteroids? I believe NASA and the USAF track such bodies if I'm not mistaken, but how many others are there? Who is "best" at it, or most relied-upon for spotting and cataloging them? 2...
  11. S

    I So astronomers really don't have an idea about density of asteroids?

    This article about an "Armageddon" scenario says that astronomers don't have a very good idea about the density of asteroids. https://slate.com/technology/2019/05/international-planetary-defense-conference-asteroid-impact.html I had thought that they had a much better idea about it. Can't the...
  12. Mlesnita Daniel

    B Previous thoughts on destroying asteroids were wrong: Nuking them is a bad idea

    This study from Johns Hopkins University shows that even if we manage to nuke an asteroid and "destroy" it, it will have a core back, in almost 2 hours. Nuking them was a bad idea before, but now seems worse. More details here...
  13. jim mcnamara

    B Destroying asteroids shown to be very difficult

    Charles El Mir et al, A new hybrid framework for simulating hypervelocity asteroid impacts and gravitational reaccumulation, Icarus (2018). DOI: 10.1016/j.icarus.2018.12.032 https://phys.org/news/2019-03-asteroids-stronger-harder-previously-thought.html Modeling the destruction of asteroids in...
  14. T

    I Where in our solar system are asteroids that contain ammonia

    Hi! I'm doing a research project titled "Is it possible to colonise Mars?" I'm currently researching how to raise the temperature and pressure - and I've discovered to do this that re-directing asteroids towards Mars containing Ammonia would be vital. However, where do these asteroids that...
  15. ATY

    Physics I need your help for an job interview in astrophysics

    Hey guys, I'll have an interview for a PhD position on monday (they told me today) and need your advice. They want me to outline a sheme on how I'd create an experiment about sublimation on asteroids. The problem is, that I don't know anything about this topic. Do you have any ideas for me or...
  16. J

    I Forming Asteroids: Dust, Gas & Vacuum Mysteries

    So stoney and metalic asteroids formed from dust and gas condensed from plasma. You would think they would be fluffy, dust piles, unless they had been part of a body large enough for its own gravity to melt it--large enough to form a sphere? Yet we're told that Sol's asteroid belt was never part...
  17. A

    B Are asteroids found by the light they reflect?

    My guess is that asteroids are discovered by the sun light they reflect, is this correct? What if, hypothetically, an asteroid absorbed all the sunlight that impacted it, could it still easily be found from other methods?
  18. DiracPool

    Asteroids Nostalgia: Reliving My 1980 Arcade Trophy Win

    So I'm doing some spring cleaning in late June, and low and behold, I find an old relic out of a storage area I was cleaning out that I had to share with y'all. It was 1980, Ventura, California. I was 13 years old and the hormones were raging and my passion for all things technology was raging...
  19. pioneerboy

    Stargazing Is a Telescope for Asteroids the Key to Discovering New Main Belt Objects?

    Would such a telescope be useful for discovering new main belt asteroids: http://www.officinastellare.com/products_scheda.php?idProd=29
  20. Lamonte Johnson

    Are Asteroids Formed by Collisions or Accretion?

    I ask this because most asteroids seem to small for gravity to compress them into stony material. Does this mean they are pieces dislodged in larger body collisions?
  21. phion

    Sentinel’s Mission to Find 500,000 Near-Earth Asteroids

    http://spectrum.ieee.org/aerospace/satellites/sentinels-mission-to-find-500000-nearearth-asteroids
  22. V

    Schools [Q] University Physics & Researching Asteroids

    Hello all, It's been a long time since I posted in this forum. I'm glad to be back to ask for advice from very talented individuals. Pardon me if my thread is not under the correct category. The following set of questions are related to my career, academic life, and satisfaction of...
  23. A

    A question about bacterias traveling in\on asteroids.

    How long can a bacteria dwell? Can it dwell in space, or would the air be sucked out of it and the cell would be destroyed? Would it have to be incased in an airtight chamber inside an asteroid for it to travel in space? Thanks :bugeye:
  24. E

    About a spacecraft trip to the asteroids

    This was something I was kicking around and wanted some advice on. Let's assume you had a big spaceship -- the kind you'd use t set off on a trip to the Asteroids, and were willing to take some time about it, on the order of a couple of years. Maybe you want to do asteroid mining or mine...
  25. B

    Can Light Alter the Velocity of Asteroids in Space?

    Hey what's up! So I'm trying to wrap my head around this concept that light is able to push asteroids in space. I understand the Yarkovsky Effect and how it acts as a propulsion system, but I want to know if light is able to push objects in space strictly based on a collision basis. Can it...
  26. G

    How can we improve asteroid detection to prevent future impacts?

    After a rock hit a Russian town unexpected, i think we still can develop in that field. I would like to have two questions. First, certain sources tell, that even with the help of passively detecting infrared radiation, objects can be detected from very far away in space, and a complete...
  27. J

    Avoid Killer Asteroids: Simple Solution Discovered

    As far as avoiding a killer asteroid in the future, I have what I consider to be a simple solution. Japan has already demonstrated the technology of landing a spacecraft on an asteroid, so what could be more simple than to land on an asteroid, rotate the landing engine 180 degrees, fire it up...
  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. T

    Satellite surrounded by four asteroids question

    Homework Statement A 100 kg satellite is surrounded by four asteroids. Asteroid A has a mass of 8.5x10^5 kg and is 800 km North of the satellite. Asteroid D has a mass of 9.0x10^4 kg and is 500 km West of the satellite. Asteroid B is 1200 km south of the satellite and asteroid C is 1500 km...
  30. B

    Asteroids and their total energy

    http://s9.postimg.org/vejo37agv/physics.jpg for picture Asteroids X, Y, Z have equal mass (6kg each). They orbit around a planet with M=6×1024kg. The orbits are in the plane of the paper and are drawn to scale. TE, KE and PE represent Total, Kinetic and Potential energies. Select G-Greater...
  31. P

    Near earth Asteroids and a space elevator

    Ok so this is silly and purely hypothetical... I am under the impression that should we ever decide to construct a space elevator we would need a pretty large mass on the space side of things. and that is one of the hurtles to making one. I am wondering if we have the capability to...
  32. E

    How do Trojan Asteroids effect a planets' orbits

    Question: What would happen if a planet's trojans were removed or added to? And I don't mean "very little" please. What exactly would happen, for example, if a planet's huge trojan asteroids were pushed out of orbit into the Sun? What would happen if L4 and L5 had asteroids as big as the planet?
  33. P

    Could You Have Spotted the TanDEM-X Satellites Near Saturn?

    After waiting about 10 days for clear weather last night and this morning I spent several hours testing a new observational rig: a very heavy high power set of binoculars mounted on a heavy tripod with a geared turret. Conditions were good: clear, still and cold (-4 degrees C) but with some...
  34. D

    How Should We Mine Asteroids: Robots or Humans?

    I know that mining asteroids will be a real possibility in the future, but I want to know what the most efficient and safe way of doing that is. Would it be easier to bring the asteroid to earth? or mine it in the belt? etc.
  35. D

    Do sound vibrations from plate tectonics (earthquakes) attract asteroids?

    I'm not sure whether to put this in Earth or Astrophysics. How far would these sound vibrations/waves travel? Do they just stay within the Earth, or is it possible for them to travel through space; and if so, how or why or is it possible for these vibrations to attract asteroids?
  36. Y

    Asteroids and the formation of planets

    I was watching How the Universe Works, and they mentioned that planets were formed by dust particles that came together to form rocks, and that those rocks collided with one another and became larger and larger eventually forming planets. My question is why did the asteroids in the asteroid belt...
  37. E

    The Mystery of Jupiter's Gravity: How Can it Eject Asteroids?

    Hi, I read sometimes that the gravity of Jupiter is enough to eject an asteroid or comet out of their orbit and fling them outside of the solar system. But gravity is an attractive force, how can it eject something? Thanks for any clarification.
  38. A

    Can Earth's Electromagnetic field block asteroids?

    If it can block portions of anti-matter I am assuming. Could it possibly be true, that it can deflect asteroids?
  39. J

    Two Asteroids Colliding- Find the Initial Velocities

    1. Homework Statement Two asteroids of 1.0x107kg and 6.0x107kg respectively, are initially at rest in interstellar space separated by a large distance. Thier mutual gravitational attraction then causes then to fall toward each other on a straight line. Assume the asteroids are spheres of...
  40. F

    Solving Extrasolar Planet Orbital Radius & Angular Displacement Problems

    An extrasolar planet can be detected by observing the wobble it produces on the star around which it revolves. Suppose an extrasolar planet of mass mb revolves around its star of mass ma . If no external force acts on this simple two-object system, then its CM is stationary. Assume ma and mb are...
  41. rrw4rusty

    Bringing iron asteroids down to Earth?

    Hi, I'm writing a science fiction story and in the future we are having to bring iron asteroids down to Earth. These asteroids are 1 to 3 miles in diameter and shaped charges brake up the asteroid and push it down into the atmosphere in such a way that the house size chunks land in an...
  42. B

    What shape would the arcade classic Asteroids' universe be?

    I heard this puzzle on the MathFactor podcast (which I highly recommend). If you don't know what Asteroids is (somehow), here's a youtube video: If you fly off the right side, you reappear on the left side, and vice versa. If you fly past through the bottom, you reappear at the top, and...
  43. nismaratwork

    How close did the asteroids come to Earth in 2010?

    http://www.cnn.com/2010/US/09/08/earth.two.asteroids/index.html?iref=NS1 OK, on the face of it this looks a bit frightening, but it's CNN soooo... can anyone here tell me if this was indeed a recent find? On a related note... holy crap, size of the rock aside, that is just too damned close.
  44. S

    Mining Asteroids: The Future of Plutonium Based Metals

    First off, I would just like to say that I am still in the early stages (3rd year) of obtaining my B.Eng in Aerospace Engineering and that I realize many things can and will change in the next couple of years. However, early preperation is neccesary for this type of thing. That being said...
  45. F

    Asteroids, Meteorites and Meteors: The Differences Explained

    What is the main difference between an astroid, mereorite and a meteor?
  46. K

    Harvesting Asteroids: Soft Landing Nickel/Iron Megaton on Earth?

    using the proper orbital mechanics, could a megaton nickel/iron asteroid be soft landed on Earth without the use of heat shields?
  47. M

    Accuracy of the exploding asteroids in The Empire Strikes Back movie

    http://img718.imageshack.us/img718/2489/asteroidtiming.jpg Here is a scene of a star destroyer firing on an asteroid. The entire explosion takes about 10 frames of video -- less than a third of a second. It's widely believed that the asteroid in question is about 40 meters in diameter and...
  48. I

    Speed of a rocket between 2 asteroids

    As part of a daring rescue attempt, the Millennium Eagle passes between a pair of twin asteroids, as shown . If the mass of the spaceship is 2.50 *10^7 kg and the mass of each asteroid is 4.49×10^11 kg A picture is shown here...
  49. M

    What Size Must Asteroids Be to Exceed Melting Temperatures of Ice and Rocks?

    Consider main-belt chondritic asteroids. How large should be an asteroid so that the maximal internal temperature exceeds the melting temperature of ice? Of rocks? For your calculations, use the present-day chondritic heat production w = 4×10-12 W kg-1, typical thermal conductivity of...
  50. D

    Gravity in space problem just asteroids instead help

    Homework Statement Between the orbits of Mars and Jupiter, several thousand small objects called asteroids move in nearly circular orbits around the Sun. Consider an asteroid that is spherically shaped with radius r and density 2400 kg/m^3. Part A: You find yourself on the surface...
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