Everything 010 (billions and billions)

  • August 31, 2015

billions and billionsMilky Way

In these galaxies, stars and their solar systems whirl around at high speed, slowly coming together toward the galaxy’s central Black Hole.

The number of stars in your average galaxy is about 100 billion.

The galaxy where we live is called the Milky Way. It contains 200–400 billion stars and may contain at least as many planets, which whirl around those stars.

Scientists tell us that this vast galaxy is moving through space at a velocity of 343 to 391 km per second, depending on the relative frame of reference.

It is estimated to be about 13.7 billion years old, nearly as old as the Universe.


2 Comments on Everything 010 (billions and billions)

  • Chris Alexander says:
    December 4, 2016 at 12:00 am

    The galaxy is moving through space at 343 to 391 km/sec, but compared to what? What is the frame of reference? And is our star moving at the same speed as all the other stars around it, and the planets and moons and dust motes, or is our star moving faster or slower, and do the dust motes stay where they are?


    • davidcrossley says:
      December 5, 2016 at 1:09 pm

      I’ve seen this first question before and don’t recall the answer and can’t think of a quick place to look, other than go to Google. Nor do I know the answer to the other questions. Would love to know them and hope it’s possible to have this kind of conversation around this website. You’re the first commenter, so I’m also in the dark about how the comments get into the public realm, other than to appear on the page. And thanks for reading and commenting.


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