Planets Definition and 509 Threads

  1. C

    Does Planet Weight Depend on Speed and Gravity?

    [SOLVED] Weight of planets Does the weight of planets depend upon the speed of the planet and gravity ?
  2. marcus

    Microlensing might detect planets as well as MACHOs

    massive compact halo objects have been detected by microlensing an invisible compact object passing in front of a distant source causes a temporary spike in the light curve by gravitational lensing---the brightening might last a couple of days this was written about in the late 1990s when...
  3. Ivan Seeking

    Giant star caught swallowing three planets: Newscientist.com

    http://www.newscientist.com/news/news.jsp?id=ns99994172
  4. E

    Can a Vacuum Pump Simulate Planetary Orbits?

    I was just playing with this little doo-hickey http://www.phy.ntnu.edu.tw/java/circularMotion/circular3D_e.html and was wondering; How is it that Jupiter and Neptune remain in orbit even as large as they are? Is it their mass and that the Suns gravity has THAT much of an influence on them?
  5. marcus

    Are Wet, Rocky Planets Common in the Universe?

    http://arxiv.org/abs/astro-ph/0209383 "Much indirect evidence suggests that wet, rocky planets are common." fairly recent article by Lineweaver (September 2002)
  6. H

    Gravitational effect on planets when

    If the sun becomes a black hole, all the planets in the solar system will stil be orbiting the sun as usual, but would there be any alteration in their orbit trajectories? And would the gravitational influence be stronger on the planets? If so, what is the relationship between the density of...
  7. phi1978

    What Are the Latest and Upcoming Missions to the Outer Planets?

    Two questions: 1) When in 2004 is the Cassini probe due to reach Saturn/Titan ? 2) Are there any missions being planned or that have been proposed (cost permitting :wink:) to any of the three outer planets (Uranus, Neptune and Pluto) in the not too distant future?
  8. S

    Centripetal Force, the planets

    Browsing through my physics book... The book defines velocity as the limit(t->0) [Δx/Δt], which of course makes sense. An acceleration can occur in two ways: either the speed (speed= ||v||) changes or the direction of the velocity changes. Centripetal acceleration (||a|| is...
  9. M

    Fact or Fiction: 2 Planets Discovered in Perpendicular Orbits?

    I've just talked with someone who informed me of a T.V. special, that dealt with the discovery of two planets, that move in perpendicular orbits - relative to the other nine planets. Is this true, or was I right in assuming that it was ridiculous?
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