Curiosity about our Universe

  1. As you may know, our planet(Earth) , solar system, galaxy are moving in a very fast speed travelling around the universe
    but, whenever a satellite being launched out from earth, and it's stationary means no speed
    then will it be left behind ??
  2. jcsd
  3. mfb

    Staff: Mentor

    There is no absolute velocity in the universe. Only velocities relative to something else.
    Satellites start with zero velocity relative to the earth and gain a small velocity (~8km/s) relative to it - just enough to orbit it. Therefore, they stay in an orbit around earth. The speed of (earth+satellite) relative to anything else does not matter.
  4. this seems interesting !!
    so even we're in stationary, we're moving with 8km/s

    Okay my curiosity solved !
  5. mfb

    Staff: Mentor

    Much more, depending on the view. Earth is moving around the sun with 30km/s (relative to the sun). The solar system is moving around the galactic center with ~200km/s (relative to the galactic center). Relative to the cosmic microwave background, we are moving with ~400km/s.
    Relative to high-energetic cosmic rays, we are moving with more than 99% of the speed of light ;).
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