The obvious line is, "Did the Earth move for you"?
The correct answer is, "Yes. A lot."
My old friend and evil twin Richard Wiseman came up with a funny idea: if you were to add up all the motions of the Earth over a given period of time, how far would it have moved?
Lessee: it spins at 1000 mph at the Equator (don’t forget to compensate for latitude), it orbits the Sun at 18 miles per second, the Sun orbits the Galactic center at about 200 mps, and the Galaxy is moving toward th Andromeda Galaxy while simultaneously falling into a massive cluster of galaxies called The Great Attractor. Oh — the Universe is expanding, with the visible edge receding from us (or equally, we are receding from it) at the speed of light.
So if you take some given amount of time, you can calculate how far you moved during that time.
Still, that’s a bit dry. How to make this exciting to the average person?
Why, create a website that calculates how far you traveled during sex, of course!
So he did: Behold EarthMove.info, where you can enter your city and the length of time it took you to, ah, well, trip the sheets fantastic. It will spit back at you the distance traveled during that time.
This is a pretty funny idea. Richard actually approached me about it months ago, but somewhere down the line I think I dropped the ball (a bit of calculus interruptus, I’m afraid), so he went to Scotland’s Astronomer Royal John Brown, who I suppose knows a thing or two about galactic motions.
There are some caveats: the velocities are not treated as vectors, so this is an upper limit to how far you moved; if, for example, the Earth is spinning in the opposite direction of the motion of its travel around the Sun (that is, you were getting some afternoon delight) then the distance traveled is slightly less.
Also, if you think about it, the biggest source or motion here is the expansion of the Universe. That’s the speed of light, and all the other velocities are small compared to that, so it dominates. Your latitude hardly matters at all.
Some people will probably be offended buy this, but it’s really just a fun way to get people to think about astronomy and science, so of course I stand behind it.
Tip o’ the… well, something… to Teek.
June 9th, 2007 at 10:17 am
165,270,000 miles. I’ll have to tell the wife.
June 9th, 2007 at 10:28 am
Ah! But this assumes there is a universal reference frame against which to measure proper motion. The whole point of GR is that no such frame exists.
June 9th, 2007 at 10:32 am
“Best bang for the buck” immediately springs to mind, with all it’s implied meanings.
For those who ‘believe” in TANSTAAFL, ever wonder how much it cost god to create the universe? I mean, how did he pay his contractors? Oh, right, I keep forgetting, IT WAS A MIRACLE,,,ie, read as ,,,something for nothing, which is why, I guess, so many folk believe in that,,,stuff,,,they’re looking for a free ride.
Too bad the universe doesn’t allow real magic(something for nothing) and miracles. We could then just pray away the high cost of oil,,,
GAry 7
June 9th, 2007 at 10:37 am
1,983,200,000 miles at tmax, assuming said universal reference frame.
WooHOOOOO!!!
June 9th, 2007 at 11:07 am
The best bang since the big one? Eccentrica Gallumbits, obviously.
June 9th, 2007 at 11:08 am
From now on, whenever I’m feeling snarky and want to say, “I want my (x amount) of minutes back that I spent (watching/reading/sitting through) that,” I’m going to say, “I want my (x-hundred million) miles back,” instead.
Sweet.
June 9th, 2007 at 11:09 am
Rats, I just checked. It was Zaphod.
June 9th, 2007 at 11:26 am
Kevin F,
165,270,000 miles.
Only 15 minutes?
I’ll have to tell the wife.
Why, was she not with you at the time?
SCNR
June 9th, 2007 at 11:36 am
Now THAT is putting Maths to good use!
June 9th, 2007 at 11:39 am
This is absolutely grand. I love it!
Not on topic, but you might enjouy this hilarious news story about pareidolia, where townsfolk are seeing the face of their late mayor in the bark of a tree.
http://www.cnn.com/2007/US/06/07/face.tree.ap/index.html
The last line of the news story is pure unintentional comedy gold:
“I see Jesus,” said Cathy Sansone, the membership director at the health club who says any resemblance to the late mayor is simply the “power of suggestion.”
June 9th, 2007 at 11:51 am
John Armstrong makes a good point, but it turns out there is a sort of universal reference frame coming from the cosmic microwave background radiation (CMB). We’re being constantly bombarded on all sides with radiation at a temperature of around 2.6K. This is basically residual energy from back when the universe was very hot. The expansion of the universe since then has caused wavelengths to stretch, and thus frequencies to drop, and the temperature of the radiation to cool.
If we were to start moving in one direction, the radiation coming from that direction would become blue-shifted, and thus appear to be at a temperature higher than 2.6K. Similarly, the radiation coming from the direction opposite to our motion would become red-shifted, and appear to be at a lower temperature. But at each point in space, there is exactly one frame in which CMB radiation appears the same temperature in all directions. This is basically the frame that was at rest in the hot plasma of the early universe, and didn’t accelerate while the universe expanded to its present size.
I’m not sure, but I think most galaxies are approximately at rest with respect to this frame (larger structures basically froze into shape as the universe expanded, so this is true if galaxies are sufficiently “large” structures). In this case, adding up the solar system’s motion through the milky way, the earth’s motion around the sun, and the earth’s rotation should give a decent approximation to how fast you’re moving relative to the CMB frame. I don’t think there should be any factor near the speed of light that dominates the sum.
John Armstrong is correct that there is no preferred frame as long as the universe looks the same at all points, in all directions, and at all speeds. But systems at finite temperature pick out a special direction for time evolution, and different speeds cease to be equivalent.
June 9th, 2007 at 1:14 pm
This reminds me of a book that appeared about 20 years ago calculating how many calories were burned during sex, starting with passionate love on the beach with Rachmaninov on the (cassette) payer to very minimal items. I recall that calories burned during the organisms of the sexes were vastly different.
Some of the funnier lower level ones were:
Avoiding a wet spot: 2
Expressing thanks: .05
June 9th, 2007 at 2:28 pm
I was going to point out what David S-D did about the CMB. There really is a universal reference frame, but the point of GR is that there doesn’t have to be.
Also, I don’t believe it is right to include the recession of the horizon at c since it’s the same in every direction. At the very most, you should be including our velocity with respect to the CMB.
June 9th, 2007 at 2:50 pm
In fact, if I remember correctly, there is indeed an observed dipole moment in the temperature fluctuations associated with the Earth’s motion relative to the CMB.
June 9th, 2007 at 3:35 pm
Frank O.
Only 15 minutes?
Give us a break, we’ve got kids and it was late.
June 9th, 2007 at 4:47 pm
I’d get in trouble if I mentioned this to my students, but what a way to capture teenagers’ attention!
June 9th, 2007 at 4:48 pm
5,288,500,000 miles…
…my loins hurt.
June 9th, 2007 at 5:06 pm
Nic, you Rang …
Remiind me to Tell Giirlfriend …
Assuming, of Course, I Actually Fiind One, Again!
*D’Oh!*
June 9th, 2007 at 8:23 pm
Yeah, Eccentra Galumbits said it, but it was in reference to Zaphod.
Doncha love this place? We get to talk about sex, Hitchhiker’s Guide and astronomy/physics all at the same time… and it makes sense!
June 10th, 2007 at 12:58 am
“Also, if you think about it, the biggest source or motion here is the expansion of the Universe. That’s the speed of light, and all the other velocities are small compared to that, so it dominates. Your latitude hardly matters at all.”
It’s worse than that. Because the answer is rounded to five digits of precision, the component due to latitude has absolutely no effect on the answer given by the website. Pick any city or any latitude, and the results will not change for a particular amount of time entered.
I’m not sure that using such sloppy science to promote real science ultimately benefits anyone.
June 10th, 2007 at 1:54 am
Would it be rude to ask a woman about her “mileage” then?
June 10th, 2007 at 2:25 am
By claiming that the non-vector number is a maximum, isn’t that going to give the false impression that the Earth’s rotation, the Earth’s orbit, and the sun’s galactic orbit are all in the same plane?
June 10th, 2007 at 4:05 am
It’s important to have goals. Mine is to find a woman with low enough standards to help me lose my virginity. Then I’ll visit that site.
June 10th, 2007 at 5:58 am
Hysterical! Loved it.
June 10th, 2007 at 6:30 am
Actually I am more curious what an astronomer is doing using MILES!?. Next thing you know he’ll be using Parsecs as a measure of time.
Bad Bad Astronomer! Bad!
June 10th, 2007 at 6:46 am
I think that, relative to the CMB, our galaxy is moving toward the Great Attractor somewhere in Virgo, isn’t it? Don’t know the speed… I know we’re also heading for a collision with the Andromeda galaxy in billions of years.
I agree that relative-to-CMB is the only frame that really makes sense for doing these calculations. Asking “how fast are we moving right now due to the expansion of the universe?” doesn’t really make sense, since first you have to ask “relative to what?” and, second, according to general relativity, relative velocities are only unambiguously defined locally anyway (citing recession velocities for distant galaxies makes some sense in a back-of-the-envelope way, but really there are a lot of arbitrary assumptions involved in calculating those, since it’s all happening in a curved and dynamic space-time manifold with no fixed signposts).
On the other hand, relative-to-CMB is actually a local frame that you can use as a starting point, and the answer isn’t even that hard to measure directly. Ned Wright says that the Solar System is moving at 368 km/sec relative to the CMB, so you can add motions of the Earth to that, I guess.
June 10th, 2007 at 7:34 am
Why time travel gets me upset…
I finally saw a blog post that provides me with an opportunity to explain why I feel that most if not all time travel stories are unrealistic (hah!). The original post was made by the Bad Astronomer and he links to a cool website which let’s you …
June 10th, 2007 at 7:42 am
Er.. how can you put the “moving away from the edge of the Universe” bit into the calculation? All the other things listed are measurable vectors relative to some averaged universal rest frame. The edge of the Universe is however present in ALL directions. It should not be part of the calculation. I think this is an instance of Bad Cosmology!
June 10th, 2007 at 8:41 am
Left off nutation, http://www.answers.com/topic/nutation
Quick easy read about the the Local Void (dark energy repulsor)
http://groups.google.com/group/sci.astro/browse_thread/thread/3b999ee7132e8dcf/a486c9783b6eab38
Do things like the Local Void means there’s a ballooning bubble so that the Steady State theory can come back into vogue?
June 10th, 2007 at 9:16 am
So there’s a CMB. You’ve just gotten rid of special relativity’s Lorentz transforms. I can show you uncountably many different coordinate transforms that leave the CMB fixed, all of them are perfectly valid, and all of them give different “distances”
Where this whole thing fails is that science calls on us to use the tools and conventions apropriate to the situation, and to be explicit about them. You wouldn’t use a Bible to determine the age of the Earth, and if you did you’d include that in your answer.
The most natural coordinate system here is one in which the center of mass of the two-body system is at rest, and the result needs to be stated as, “relative to this frame of reference”.
Bad Cosmology indeed, VK.
June 10th, 2007 at 3:02 pm
If you’re timing yourself you’re not concentrating on what you’re doing
June 10th, 2007 at 5:55 pm
So, does this make you a geek or a nerd? My answer? I think it makes you a geek, as geeks are loveable, hip nerds. While geeks are calculating how far they’ve traveled while having sex, nerds are wondering how far they would travel IF they had sex… (Ba-dum-dum-ching!) Thank you, thank you.
June 10th, 2007 at 7:48 pm
HA!
Thanks. What a simple way to show the vast distances our minds can’t normally wrap themselves around!
And, it honors the Great Bonobos.
Seems like after 500,000,000 miles, friction begins to take its toll though…
June 11th, 2007 at 5:29 am
Guys, it’s just a bit of fun. It’s just to help your average Joe or Joanne tie the movement of the earth to something everyday and normal. Most people have no idea that the earth is moving great distances all the time. Some people barely realise that it’s moving at all. Some people still believe the earth is the centre of the universe.
There is only one way to get the media such as tabloid press to run anything about astronomy, and that’s to give it a context which captures imagination. If this gets people talking about the stars at the water cooler or when they get home from work, then that’s only a good thing.
If the attitude “nothing is better than this compromise” prevailed then we’d have little to inspire people with. I’d rather get a full page in the biggest-selling newspaper in the UK (which we got) and start people talking about astronomy than not bother at all.
But seriously, if anyone who is criticising the math cares to send me the javascript for what they consider a better method, then please do so. The site is still being worked on so there’s always room for improvement if you want to put your money where your mouth is.
June 11th, 2007 at 3:18 pm
“Everyday”?! Man, I need to get out more. . .
June 16th, 2007 at 10:01 pm
It sometimes boggles the imagination that all of this motion is taking place. To our senses we think of being in ‘one place’, such as sitting at a computer. But as each second goes by, that ‘place’ is 183,633.3 miles away (according to the calculator). Every single atom in your body, the chair, the computer, the digital bits have all shifted through the universe. It introduces a sense of non-reality to think that this goes on every instant of every day…being shifted through space-time in a coherent pattern. The science behind how we do that gets a little wonky as we look at the details of it. You have never occupied the same ‘place’ within the universe for more than an instant, no matter how many times you’ve sat in the same chair or walked to the fridge that holds the ice cold refreshment you put there yesterday. It’s a good thing we can’t perceive of all this motion going on, besides the wretching sense of vertigo it would create, we’d also have to take some responsibility to maintain the illusion. It’s better on auto-pilot…makes it easier to type.
June 19th, 2007 at 7:26 pm
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