# What would happen if I stopped? **URL:** \ **Category:** Factual Questions\ **Created:** [February 6, 2004, 2:32pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843 "2004-02-06T14:32:03Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Zebra](https://avatars.discourse-cdn.com/v4/letter/z/c0e974/32.png) [@Zebra](https://boards.straightdope.com/u/Zebra)\ **Post date:** [February 6, 2004, 2:32pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/1 "2004-02-06T14:32:03Z")
I mean a complete stop. Suppose I’m sitting in some sort of craft that would survive this, let’s say the craft is in NYC’s Central Park and that I either pass through objects or just plain miss them. How long will I: Still be in the earth’s atmosphere? Still be in the solar system? Still be in the Galaxy? How much of a speed change would be involved in coming to a complete dead stop relative to the universe? ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [February 6, 2004, 2:43pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/2 "2004-02-06T14:43:26Z")
There’s no such thing as an absolute dead stop. All motion is relative. ---
**Author:** ![Small\_Clanger](https://avatars.discourse-cdn.com/v4/letter/s/9fc348/32.png) [@Small\_Clanger](https://boards.straightdope.com/u/Small_Clanger)\ **Post date:** [February 6, 2004, 2:52pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/3 "2004-02-06T14:52:50Z")
Your man Einstein says your question doesn’t make sense. There is nothing ‘fixed’ about the universe. You need to pick something to have a speed relative to, your best bet for this example would be what’s usually referred to as _the fixed starts_. This would give you a lot of component velocities (sorry I’m not an astronomer I don’t know what the speeds are) Earth’s rotation Earths orbit round the sun Sun’s motion through the galaxy The galaxy’s motion relative the the local group (or whatever it’s called) and so on… I guess that the first two would be swamped by the later ones. C’mon guys someone out there knows. Lets give **Zebra** the dope. ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [February 6, 2004, 3:00pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/4 "2004-02-06T15:00:58Z")
Well, as in all deep and meaningful questions we must ponder, I turn to Monty Python. The Galaxy song. > [@](#): > > Just remember that you’re standing on a planet that’s evolving > And revolving at nine hundred miles an hour, > That’s orbiting at nineteen miles a second, so it’s reckoned, > A sun that is the source of all our power. > The sun and you and me and all the stars that we can see > Are moving at a million miles a day > In an outer spiral arm, at forty thousand miles an hour, > Of the galaxy we call the ‘Milky Way’ I’ll let you do the math. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 6, 2004, 3:30pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/5 "2004-02-06T15:30:26Z")
> [@AndrewL](#): > > There’s no such thing as an absolute dead stop. All motion is relative. As **Small Clanger** said, “You need to pick something to have a speed relative to.” The best choice for this would be the cosmic microwave background. As these [COBE and WMAP](http://www.astr.ua.edu/keel/galaxies/cmbr.html) pictures show, the earth’s velocity shows up as red or blue-shifting of the 2.7°K radiation. Too bad I can’t find a number to stick on that speed this morning ☹ . ---
**Author:** ![Zebra](https://avatars.discourse-cdn.com/v4/letter/z/c0e974/32.png) [@Zebra](https://boards.straightdope.com/u/Zebra)\ **Post date:** [February 6, 2004, 3:35pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/6 "2004-02-06T15:35:37Z")
If relative to the Milkyway, I came to a complete stop etc… ---
**Author:** ![NurseCarmen](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@NurseCarmen](https://boards.straightdope.com/u/NurseCarmen)\ **Post date:** [February 6, 2004, 3:42pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/7 "2004-02-06T15:42:19Z")
Okay, I had some time, so some math was done. Just remember that you’re standing on a planet that’s evolving And revolving at nine hundred miles an hour, 900 mph That’s orbiting at nineteen miles a second, so it’s reckoned,19 mps = 68,400. So we get 900 + 68,400 = 69,300 mph A sun that is the source of all our power. The sun and you and me and all the stars that we can see Are moving at a million miles a day. A million miles a day i approx 41,667 mph. So 69,300 + 41,667 = 110,967 mph. In an outer spiral arm, at forty thousand miles an hour, 110,967 + 40,000 = 150,967 Of the galaxy we call the ‘Milky Way’ I’ve asked physisists that I’ve met how accurate The Galaxy song was, and they’ve tended to be of the opinion that Idle did a pretty good job. Sorely lacking is expansion speed, but that really gets to be an Appelatian dating pool (it’s all relative). ---
**Author:** ![QuickSilver](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quicksilver/32/7832_2.png) [@QuickSilver](https://boards.straightdope.com/u/QuickSilver)\ **Post date:** [February 6, 2004, 6:14pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/8 "2004-02-06T18:14:06Z")
> [@NurseCarmen](#): > > Okay, I had some time, so some math was done. > \ > In an outer spiral arm, at forty thousand miles an hour, 110,967 + 40,000 = 150,967 > Of the galaxy we call the ‘Milky Way’ But these are angular velocities with not only speed but (changing) direction, in 3 dimensions. So we can’t stack them on top of one another in a direct line. In short, there is a strong likelyhood that one might head through the center of the earth into space as likely as head off at some tangent or some other ridiculous angle. Either way, I recommend seatbelts and a good lid on your coffee cup. ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [February 6, 2004, 7:41pm UTC](https://boards.straightdope.com/t/what-would-happen-if-i-stopped/227843/9 "2004-02-06T19:41:59Z")
> [@Squink](#): > > The best choice for this would be the cosmic microwave background. As these COBE and WMAP pictures show, the earth’s velocity shows up as red or blue-shifting of the 2.7°K radiation. Too bad I can’t find a number to stick on that speed this morning. [Here you go.](http://www.astro.ucla.edu/~wright/CMB-DT.html) We’re moving at 389 km/sec with respect to the cosmic microwave background, which is (as **Squink** said) the best choice for a “fixed background.” I would guess that these values are corrected to cancel out the satellite’s motion around the earth and the earth’s motion around the sun, though (since these measurements were taken over a period of years.) So you’d have to add back in the Earth’s rotation and revolution. I’ll leave those as an exercise for the reader.