Article Extract: The problem with motion is that “true motion” doesn’t exist. The best we can do is talk about “relative motion” and that requires something else to reference against. What you consider to be stationary (what you chose to define your movement with respect to) is a matter of personal choice. The universe isn’t bothered one way or the other.
Relative to the Earth: The Earth turns on its axis (you may have heard), and that amounts to about 1,000 mph at the equator. The farther you are from the equator the slower you’re moving. This motion can’t be “ignored using relativity”, since relativity only applies to constant motion in a straight line, and movement in a circle is exactly not that.On a planetary scale it’s responsible for shaping global air currents.
Relative to the Sun: The Earth orbits the Sun at slightly different speeds during the year; fastest around new years and slowest in early July (because it’s farther from or closer to the Sun respectively). But on average it’s around 66,500 mph. By the way, the fact that this lines up with our calendar year (which could be argued to be based on the tilt of the Earth, which dictates the length of the day) to within days is a genuine, complete coincidence. This changes slowly over time, and in several thousand years from now it will no longer be the case.
Relative to the Milky Way: The Sun moves through the galaxy at somewhere around 52,000 mph. This is surprisingly tricky to determine. There’s a lot of noise in the the speed of neighboring stars (It’s not unusual to see stars with a relative speed of 200,000 mph) and those are the stars we can see the clearest. Ideally we would measure our speed relative to the average speed of the stars in the galactic core (like we measure the speed at the equator with respect to the center of the Earth), however that movement is “sideways” and in astronomy it’s much much easier to measure “toward/away” speed using the Doppler effect. Of the relative speeds mentioned in this post, the speed of our solar system around the galaxy is the only one that isn’t known very accurately.
Relative to the CMB: The Milky Way itself, along with the rest of our local group of galaxies, is whipping along at 550 km/s (1.2 million mph) with respect to the Cosmic Microwave Background.
Article Link and source: http://www.askamathematician.com/2014/02/q-how-fast-are-we-moving-through-space-has-anyone-calculated-it/
Spaceship Earth concept: http://www.nhk.or.jp/co-pro/e/past/detail_20131129.html
Spaceship earth from Discovery: http://news.discovery.com/space/astronomy/spaceship-earth-we-are-interstellar-travelers-131014.htm
From Urban Astronomer : http://www.urban-astronomer.com/articles/questions-and-answers/how-fast-is-the-earth-travelling-through-space
Rotational motion (NASA) : http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970401c.html
Earlier post on spaceship earth: https://plus.google.com/110884604033336753419/posts/V6ojUHcSBfR
Our solar system's tail : https://plus.google.com/103586346709495625226/posts/W2JFbfhiccc
Does the sun rotate? : https://plus.google.com/103586346709495625226/posts/LqjusEkzaR6
Pics courtesy: Main pic on left - http://goo.gl/xasB25. Pic right top - from NASA via http://goo.gl/kYEktG. Pic right center: The solar system is not a vortex (artist's impression) - from rhysy.net http://goo.gl/ZqFQIh. Right bottom - from Chandra http://goo.gl/2EobKB.
#space #science #earth #spaceship #speed #relativemotion