Topics about comet - 57 Discussions, Page 1

  1. xpell

    B How hard is it to detect extinct comets?

    Hi! I have read that cometary nuclei have a very low albedo, even lower than coal or asphalt. Because of this, they absorb lots of light and heat rather than reflecting them. So I was wondering how hard is it to detect extinct comets. Could the solar system be full of dead nuclei buzzing around...
  2. C

    B First Interstellar Asteroid Found

    The first asteroid ever seen from another solar system is whizzing through our own, and astronomers are racing to observe the visitor before it slips away. Links: Nature Sky and Telescope
  3. O

    Effective cross-section of catching a comet with the Sun

    Hello. 1. Homework Statement I have to find formula for effective cross-section (σ) of catching a comet with the Sun. I know mass of the Sun (M), radious of the Sun (R) and initial velocity (v) of the comet (at a big distance from the Sun). Homework Equations σ=πb^2, where b is on the...
  4. O

    Effective cross-section of catching a comet with the Sun

    Hello. 1. Homework Statement I have to find formula for effective cross-section (σ) of catching a comet with the Sun. I know mass of the Sun (M), radious of the Sun (R) and initial velocity (v) of the comet (at a big distance from the Sun). Homework Equations σ=πb^2, where b is on the...
  5. J

    I The Largest Air Burst on Earth

    On June 30, 1908, the remote Siberian region of Tunguska made headline news when an explosion knocked down 80 million trees in an area of only 770 square miles. The mystery was that there was no crater, which led to the assumption that the space bomb responsible for the catastrophe detonated in...
  6. ccarit3007

    What is the work done on a comet orbiting a star?

    If a comet is orbiting a star is there any work done? I understand that work is force * displacement, but the force must be in the direction of motion. In the case of a comet and star the star exerts a gravitational force on the comet, but this force is not in the direction of the motion of the...
  7. MelkoRR

    Calculation of a comet orbiting Sun

    Homework Statement a comet is orbiting around the Sun in a parabolic orbit . center of the sun to perigee of the comet's orbit distance is 58 km . find the time required for the comet to transit into the earth orbit around the sun . Homework Equations The Attempt at a Solution no clue
  8. P

    Investigating Comet 67P's Elliptical Orbit

    Homework Statement Currently, I am trying to prove the "conservation of energy" concept within a comet's elliptical orbit by finding the mechanical energy of the aphelion and perihelion point to see if they're equal. However, they don't equal each other when I calculate both points. (aphelion...
  9. C

    Stopping or re-routing comet 67p

    Hello, I am new here and I would like to know if anyone on here can answer a question for me. How far could a saturn V rocket ( push comet 67p off course if it were 100 million miles away? Also, how long would it take this rocket to stop the comet if it...
  10. bitznbitez

    Comets and Magnetic Fields

    Comets have what is called an "induced magnetosphere". Has anyone been able to document polarity in any of the observed comets magnetic fields yet ? If they have I'm curious how it relates to the orbital plane of the comet. I haven't been able to locate that info if it exists so just...
  11. L

    Solar radiation force on comets.

    I see this comet being chased by ESA, they said it is presently about 500 million km from the sun. That puts the radiation received by that comet at about 10% (roughly) as what we receive on Earth, well at least on top of the atmosphere, at 1355 watts per meter ^2. Looking at the size of...
  12. davenn

    Vale Bill Bradfield - The loss of a comet hunter

    Bill was a fellow Australian and prolific comet hunter and discoverer Quoted from the Ice In Space site He will be truly missed in the astronomical community :( Regards Dave
  13. C

    Time Comet Remains Within Earths Orbit

    Homework Statement A comet is going in a parabolic orbit lying in the plane of the earth’s orbit. Assuming that the earth’s orbit is a circle of radius a. The points where the comets orbits intersects the earth’s orbit are given by: cos θ = −1 + 2p/a where p is the perihelion distance...
  14. C

    A comet revolves around the sun

    Homework Statement A comet revolves around the sun in a closed elliptical trajectory. Ignore any force acting upon it besides gravity. Prove that the angle between the position vector (sun in the origin) and the velocity vector of the comet at its perihelion and aphelion is 90º. The...
  15. Spinnor

    Time lapse image of Comet ISON, what looks like snow?

    Visiting New Scientist web site the following time lapse movie caught my eye, see, from, I get the emissions from the sun, the stars, and the comet, but what is in the movie that kind of looks like...
  16. C

    Flickering Comet

    Hi folks, Had an idea for a science fiction story I'm writing, wondered if it would actually work in reality. Basically, if a comet's nucleus were comprised of concentric layers of ice and dust, would it produce a coma/tail in an on-and-off manner? Would it outgas and stop, outgas and stop...
  17. 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...
  18. Philosophaie

    Hyperbolic Comet C-2012 S1 (ISON)

    What is happening with Hyperbolic Comet C-2012 S1 (ISON)? It is going to crash into the Sun at the end of Nov. Was it downgraded from a Comet? Here is a site that used to track it: I should be big in the...
  19. E

    Comet Velocity?

    The popular press has been alive lately with stories of asteroid interception and even asteroid recovery. Has there been any thoughts of a spacecraft closely approaching a comet? How big are they? How fast do they travel? Is it remotely possible using existing technology? Could we land on one?
  20. J

    How does Jupiter protect Earth from comets and such?

    How does Jupiter "protect" Earth from comets and such? I've commonly heard that Jupiter protects Earth by flinging comets out of an orbit that would otherwise leave them heading for Earth. I understand that Jupiter can throw comets and other objects out of their current orbit when they pass by...
  21. S

    Do a comet's tails ever point in the same direction when in an orbit?

    Homework Statement The problem and its solution are attached as TheProblemAndSolution.jpg. Homework Equations *The (“instantaneous”) dust tail is opposite the direction of motion. *The plasma tail is oppositely directed to the star in question (at all times). The Attempt at a Solution...
  22. Y

    Question Regarding the Orbit of Comets

    Recently, I attended a lecture at my university entitled "The Life and Death of a Star-Grazing Comet" presented by John Raymond, an astrophysicist at Harvard Smithsonian. In this lecture, he talked about Comet Lovejoy and how it allowed us to help study the corona of the sun. As the comet was so...
  23. C

    Comet Elliptical Orbits Question

    Homework Statement Comets move around the sun in very elliptical orbits. At its closet approach, in 1986, Comet Halley was 8.79 x 10^7 km from the sun and moving with a speed of 54.6 km/s. What was the comet's speed when it crossed Neptune's orbit in 2006? Homework Equations Mv1r1=Mv2r2...
  24. E

    Journey of a Comet & Relativity

    I am wondering about the journey of a comet: 1. Lets say this comet is located in the Kuiper Belt. From my understanding it is inert. Trying to tie in my limited Relativity understanding, could I say that it is in free float? From my understanding, it is getting its movement orders from...
  25. Vorde

    Comets in the Northern Hemisphere vs the Southern?

    Hey all, I haven't been alive for that long, so I guess my data probably isn't as good as it should be, but in my experience there have been far more noteworthy comets appearing only to the southern hemisphere, and not to the northern one. In fact, I haven't ever seen a comet (since I was a...
  26. O

    Comet C/2013 A1

    First post...Hi everyone. Now that the Chelyabinsk meteor has been determined to be 700,000 tons and 56 feet in diameter, is there anyway of "guesstimating" how much inbound comet C/2013 A1 would weigh at approximately 50 kilometers in diameter? Also when would/could the final trajectory be...
  27. F

    Ison Comet

    In November 2013 the comet Ison will be visible , spectacular, brighter than the moon:
  28. J

    Using Kepler's Law to find speed of a comet in orbit

    Comets travel around the sun in elliptical orbits with large eccentricities. If a comet has speed 2.5×104 when at a distance of 2.3×1011 from the center of the sun, what is its speed when at a distance of 5.9×1010 . Using Kepler's Law T2 is proportional to R3 T2/R3 is a constant (C)...
  29. O

    Apparent size of comets in images from the SOHO satellite

    I've gotten into an amusing discussion with another individual on the topic of the apparent size of comets as seen in SOHO satellite images of Sungrazing or Sun-impacting comets. I won't go into the crackpot conspiracy theories I've heard, but will instead ask: why do these tiny comets appear so...
  30. K

    Comet Crashes in Earth Conservation of Energy

    Homework Statement A comet is traveling towards the earth. The comet has a mass of 4.80E+12 kg and a radius of 385 m. The comet is traveling with a speed of 19 km/s and spinning with a period of 0.12 seconds when its center is a distance 1.88E+7 m away from the center of the earth. The comet...