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Could someone give the rough estimates of speeds of our travel through space?

I can easily find the two nearby ones:

  • Earth's own rotation - depending on latitude, up to 40,075 km/24h = 463 m/s
  • Earth's orbital speed around the Sun - 940 000 000 km/year = 29,786 m/s

Now how do these fare?

  • Motion of Sun within the arm of the galaxy, around the center of the galaxy?
  • Motion of the galaxy within the local supercluster?
  • (if possible to measure at all) movement of the supercluster within the universe?
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    $\begingroup$ The last item is, I think, meaningless as the expansion of space is just that - an expansion, so the galaxy isn't "moving" in the traditional sense of the word. $\endgroup$
    – ChrisF
    Sep 27, 2013 at 11:25
  • $\begingroup$ @ChrisF: Are you sure on top of space expansion there is no plain, old-fashioned movement happening, completely independently? $\endgroup$
    – SF.
    Sep 27, 2013 at 11:28
  • $\begingroup$ No, I'm not 100% sure. Which is why I used the term "I think". $\endgroup$
    – ChrisF
    Sep 27, 2013 at 11:30
  • $\begingroup$ The last item is meaningless because "within the universe" is not a reference frame. We can only talk about velocity when we have something to measure velocity relative to. The "universe" doesn't fit the bill for this. $\endgroup$
    – Manishearth
    Sep 27, 2013 at 19:28
  • $\begingroup$ @Manishearth: We can create some virtual reference frame by averaging motions of all objects within universe relative to each other. Take three randomly moving objects: their reference frame will be one relative to which the sum of their vectors of speed is smallest. While it doesn't say anything about speed "relative to the universe" ("ether"), it's still a good clue "how fast given object is moving" (comparing to all the rest). $\endgroup$
    – SF.
    Sep 28, 2013 at 22:26

1 Answer 1

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According to the Astronomical Society of the Pacific's website "How Fast Are You Moving When You Are Sitting Still?", we are moving:

Rotation of the Earth: 1600 km/h

Orbital rotation of the Earth around the sun: 107,000 km/h

The sun around the centre of the galaxy: 792,000 km/h

Going further, according to the article "Milky Way Galaxy: Facts About Our Galactic Home" (Redd, 2013) quotes the sun's speed around the centre of the galaxy as 828,000 km/h

The Andromeda Galaxy and the Milky Way are headed for a collision at 112 km/sec

According to "Milky Way moving away from void" (2007), the Milky Way galaxy is moving from the local void at 600,000 mph (960,000km/h)

According to the article "The Universe is expanding at 74.2 km/sec/Mpc" (Plait, 2009), the Universe is expanding at a rate of 74.2km/sec per megaparsec (3.26 million light years).

There seems to be some divergence of values in the articles, but these give a good estimate.

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  • $\begingroup$ rotation means angular speed and 1600km/h means linear speed.Sorry but I didnt clearly understood this $\endgroup$
    – SpringLearner
    Nov 17, 2013 at 8:56
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    $\begingroup$ Rotational speed can be expressed in km/hr, by dividing the circumference by time, as NASA have done here image.gsfc.nasa.gov/poetry/ask/a10840.html $\endgroup$
    – user8
    Nov 17, 2013 at 9:02
  • $\begingroup$ So do you have any idea to get the angular speed of earth rotations? $\endgroup$
    – SpringLearner
    Nov 17, 2013 at 9:04
  • $\begingroup$ @javaBeginner angular velocity of Earth tutorial = livephysics.com/physical-constants/mechanics-pc/… $\endgroup$
    – user8
    Nov 17, 2013 at 9:07

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