Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

An Online Planetarium

  1. Nov 16, 2007 #1


    User Avatar

    Here's a link to a site which is great for beginners such as myself. You can set it for your own location and time. It identifies the stars and galaxies you can see at any moment looking in different directions. http://www.astronomy-page.com/open_planetarium.php

    btw out of curiosity and probably a daft question but if the methods used to calculate distances in the universe were wrong and distances are smaller than thought would this nullify the need for dark matter to explain galaxy formations?
    Last edited: Nov 16, 2007
  2. jcsd
  3. Nov 16, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    There is also this http://www.fourmilab.ch/skyscrsv/ planerarium screensaver which shows you the sky for the current time.

    No it's still necessary for Galaxies to have 10-100x as much gravitiational mass than we can see as visible stars. This is necessary for the galaxy to hold together as it rotates.
    Forming galaxies in the first palce is a whole different problem.
  4. Nov 16, 2007 #3


    User Avatar

    Looks interesting. Any idea what folder you need to copy the screensaver into in Vista in order to run it?

    Isn't gravity inversely proportional to the square of the distance? So if the distances were less than thought wouldn't gravity based on known masses suffice to hold galaxies together in their formations?
    Last edited: Nov 16, 2007
  5. Nov 16, 2007 #4
    Thank you Art :D, it's nice of you to say that, i really appreciate it. (FYI I'm the webmaster of astronomy-page.com, and it so happens that I found this page completely by chance!) I didn't actually develop the planetarium myself, but it's under GPL so I can reproduce and modify it if I like. All the rest is mine!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: An Online Planetarium