I don’t do conventions very often, but I recently went to ConBust out in Northampton, MA, while visiting some friends. While I was there, I had a guy propose something fascinating to me. I can’t remember the guy’s name, so if he or one of his friends sees this, post your info in the comments. (Edit: it was a dude by name of Thom Howe.)
The guy Thom had an idea for a date. He wanted to rent a cherry picker, drive it to her door, and pick her up in it.
Then, he’d drive to the beach, and get there at just the right time to watch the sun set.
Once the sun had set, he’d activate the cherry picker, they’d be lifted up above the beach …
… and they’d watch the sun set again.
Clearly, this is an excellent idea, and any girl would be lucky to see this guy Thom at her door. But is it plausible? How fast and how high does the cherry picker have to go?
I tried to work out the answer for him there at the table, but there was a line of people and there wasn’t time. But when I got home, I remembered it again, and I’ve worked out the solution.
Here’s the situation:
By the time the earth has rotated through angle theta, the cherry picker will have to have climbed to height h.
After t seconds, theta in radians is:
The height of the lift above the center of the earth is:
So the height above the surface (sea level) is:
Substituting everything so far we get this expression for the height the lift needs to reach t seconds after sunset to stay even with the sun.
Now, an actual cherry picker has a maximum lift rate (I Googled some random cherry picker specs, and 0.3 m/s is a normal enough top lift rate.) We’ll call that rate v, so the actual height of the lift will be this:
Substituting that in and solving for v, we get this:
(That’s arcsecant, not arcsecond). This equation tells us how fast the lift has to go to get from the ground to height h in time for the sunset1.
But we can also get the answer by just trying a few different heights. We plug it in to Google Calculator2:
2*pi*6 meters/(day*arcsec(6 meters/(radius of earth)+1))
and find that h=6 meters gives about the right speed. So, given a standard cherry picker, he’ll get his second sunset when they’re about six meters up, 20 seconds later.
You might notice that I’m ignoring the fact that he’s not starting at sea level — he’s a couple meters above it. This is actually pretty significant, since the sunset line accelerates upward, and it brings down his second-sunset height quite a bit. If he got a faster lift, or used an elevator, the correction would become less necessary. Extra credit3 for anyone who wants to derive the expression for the height of the second sunset given the lift speed and height of first sunset. For now, I recommend he dig a hole in the sand and park the lift in it, so their eyes are about at sea level4.
1 Ideally, we’d solve for h, but it’s inside the arcsec and that looks like it’s probably hard. Do one of you wizards with Maple or Mathematica wanna find the result?
2 If you work in one of the physical sciences and don’t use Google Calculator for all your evaluatin’, you’re missing out. I wish there were a command-line version so I could more easily look/scroll through my history. I know Google Calculator is largely a frontend to the unix tool units, but it’s better than units and available everywhere.
3 Redeemable for regular credit, which is not redeemable for anything.
4 I suggest a day when there aren’t many waves.
xkcd 
Randall- Thanks so much for putting some time into my idea (I was the guy who spoke with you about it at ConBust). I’m glad you guys all seem to think highly (for the most part) of the idea, but a romantic date is just the beginning of the endless possibilities for unconventional cherry picker use. What better tool to use when fighting raptors? (well, a cherry picker and a shotgun) And I think, on the way down, its more of a “maybe if you kiss me I’ll remember how this thing works”…
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Wow, I must be really old or or a serf from days of old. The picture is not a cherry picker. Its a forklift. A cherry picker is a truck with a reticulating arm like the space shuttle. In fact, the exercise would be more workable with a boom lift. ( a self-propelled, 4-wheel drive vehicle with a reticulating arm. It moves up and down quicker.
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> I wish there were a command-line version so I could more easily look/scroll through my history
When I was first learning Python, I wrote this:
http://hpcf.averageurl.com/gcalc.py
It’s a command line interface with Google Calculator (so you have to be online to use it) that lets you define variables.
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I wrote this when I was first learning Python:
http://hpcf.averageurl.com/gcalc.py
Command line interface with google calc, lets you define variables.
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Just take Video Camera with a Tripod, record the sunset while you and your girlfriend fondle each other and replay the sun set at home as many time as you want. Keep it as a memento and replay as needed to remember the occasion. Skip the Math.
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OK. I’m no math whiz, so I can’t tell for sure, but I don’t think you took into account how long it takes the sun to set. It’s not really an instantaneous moment, but a duration of, like, three minutes or something. I think, using your calculations, you’d watch the last glimmer disappear, then rise up and see the glimmer again, for a second or two.
Still, I love the romanticism of it.
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Cute, but I bet it’ll be really cold so bring a blanket. And a flashlight. And maybe some hot cocoa in a thermos.
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Actually, it you want to be precise about it, it gets even more complicated!
As the light is passing through the atmosphere, the atmosphere is of increasing density, and thus index of refraction, which BENDS the path that the light takes. This is well understood in celestial navigation. (determining one’s position on the earth using a clock and the stars/sun/moon.) To account for this in one’s calculations, one uses the “dip correction” (my textbook claims that it is on the inside of the front cover of the “Nautical Almanac”) with corrections for temperature and pressure (on page A4) (rarely used). This takes into account the relative angle of the apparent horizon, and the additional bending of the sun’s light.
6 feet has a dip of 2.4 minutes of arc
20 feet has a dip of 4.3 minutes of arc.
I’m really rusty on my Celestial . . .
So the horizon appears 2.1 minutes of arc lower (when measured from the horizontal) when one has gone from 6 feet to 20 feet. The sun travels 360 degrees in 24 hours, so it travels 15 minutes of arc in one minute of time, or one every four seconds. Therefore you have about eight seconds to get to the new height, or about two feet a second. I’m not sure if cherry pickers move that fast!
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As this is supposed to be a date, I’m still trying to work out whether “cherry picker” or “forklift” gives the better wordplay.
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I bet superman can do it.
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…You people seem to be confused as to what a forklift is. A forklift is for lifting pallets of heavy things, not people.
What we see in the visuals for this blag post is not technically a cherry picker either, it seems. From what I’m seeing on wikipedia, to be called a “cherry picker” the arm has to articulate beyond just vertical movement. I don’t think there’s really a better name to use in this case, though.
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Looking at the final equation – should not it read as follows:
V=2Pi r(2
__________
DAY+ARSEC (h+Re – 22/7 ????
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Excellent idea 🙂
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@ Uhhh… – You are right; the drawing does not show a forklift (which has forks, not a bucket), but they do make work platforms that are designed to be lifted by forklifts. Of course, if you used one of those you would need someone to operate the forklift for you:
A “scissor lift” would be the more common aerial work platform of this size, but lifts like the one pictured do exist:
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I have been waiting for goosh to feautre the full power of Google Calculator. Alas, I am just too busy (& lazy) to help the project. It shows a great deal of promise and I encourage all to check it out:
http://goosh.org
http://code.google.com/p/goosh/
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A couple of thoughts: one, you have not accounted for the portion of sky in degrees (or radians) that the sun actually occupies. As anyone who has stared at the sun will tell you, the sun is not only bright, it is big. Also, if you wanted to be impressive, you could instead of using a cherry picker at sunset use a boring mechanism at sunrise and repeat this process I would guess 3, maybe even 4 times before noon.
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The cherry picker would fall over for sure on the beach. Sand is too unstable. “Oh honey, look at the sta AAAAAHH!” Not a very good date…
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Not only is this plausible, but it is actually possible. I have heard of people watching a second sunset on top of the World Trade Center, before they were destroyed of course.
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@djm3532: There is no calculus in this. This is ordinary algebra and some basic knowledge of trigonometry. Twelve year olds should be able to do this. (I should know, as that was only five years ago for me).
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If you’re looking for command line google try http://goosh.org. Though using google calculator in it is somewhat clunky.
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Just one problem… you poor slobs live on the wrong coast; your feeble sun doesn’t set over the ocean 😛
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Sirs, I’m surprised you haven’t stumbled upon Frink:
“Frink is a practical calculating tool and programming language designed to make physical calculations simple, to help ensure that answers come out right, and to make a tool that’s really useful in the real world. It tracks units of measure (feet, meters, kilograms, watts, etc.) through all calculations, allowing you to mix units of measure transparently, and helps you easily verify that your answers make sense. It also contains a large data file of physical quantities, freeing you from having to look them up, and freeing you to make effortless calculations without getting bogged down in the mechanics. ”
http://futureboy.homeip.net/frinkdocs/
Let me know if this is what you were looking for! Love the site/webcomic/blog/community/memes(s)/what you’re putting out there/stuff you do etc.
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Any lighthouse fitted with an elevator? Might work if the elevator is fast enough and the lighthouse is high enough 🙂
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Any lighthouse fitted with an elevator? Might work if the elevator is fast enough and the lighthouse is high enough :))
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Another great idea: Guy takes girl on date up a fire lookout tower to watch sun set. Girl has massive vertigo and has to be talked down veerrry slowly.
I know this can work, as the aforementioned were my parents, and… well, here I am, right?
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The height = taller than any real cherry lift
The speed = faster than the speed of the sunset
The expression = wonderment
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They aren’t going to see any sunset they are on the wrong beach! Sun Sets in the West
N
W E
S
They are facing the wrong direction
unless they are in Australia then its
S
E W
N
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I’d certainly swoon, and swoon twice.
And I know this matter is of great concern and thought of you when reading it. I direct your attention to the Velociraptor section.
http://objectiveministries.org/creation/projectpterosaur.html
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Just today, I ran into a guy on a cherry picker, and asked him how long it took to reach it’s apex. He said a little over a minute. Unfortunately, if that is accurate, it would mean that you would miss your second sunset by 20 seconds
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chuck norris would just command the sun to rise again.
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OK, this is probably the first thing I would do if I had a time machine. There are a couple other stops I would make, like getting everyone to drive on the right side of the road, but visiting Ben would definitely be the first stop.
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I am teaching a beginning programming class using Python this quarter, and have used this blog post as the basis for the first lab assignment!
Take a look: http://140.160.140.37/csci139/lab1.pdf
If there is anything terrible wrong with my interpretation of it (other than that I’m assuming the cherry picker moves directly perpendicular to the Earth’s rotational axis), let me know…
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To clear all of this nomenclature up:
What Randall drew is NOT A FORK LIFT. It is in fact most similar to an Aerial Work Platform (made by Genie), which is kind of generic, or, when made by JLG are called Vertical Mast Aerial Work Platforms. The most common ones of these are pushed around, but both companies do make driveable ones (The Runabout from Genie, for example). The term cherry picker is pretty generic but typically describes the standalone telescoping/articulating boom type lifts or a boom on the back of a truck. But for anyone that thinks that looks like a forklift, I’d like to know where the “forks” are.
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You missed that he is not at the equater, so that radius of the earth parallel to the patch of the sun is different where he is. I believe this is the cosine of the latitude.
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Someone put Mythbusters on this!
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So, my French class is reading «Le Petit Prince»?
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That was supposed to be an ellipsis, not a question mark.
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Youre on Jalopnik.
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Am I the only capitalist here? I’m thinking I want to be the person who speeds up the cherry picker’s rise rate and rents it out to all the hopeless romantics and moves on to the next town when they’re all tapped out. Heck, it could even be a franchise!
Make the cherry picker go only vertically and the truck doesn’t have to be as heavy duty- maybe it could fit into a reasonably-sized pickup/van. For a premium, sell the “accidental” broken controls. Make it an enclosed, heated basket for winter use. Again, make the “broken” heater controls a premium, but supply a blanket- small, of course. Call me a romantic, but I think an anti-fog treatment on the windows would be spoiling things.
Certainly cheaper than trying to buy beachfront property and building an elevator to nowhere.
As mentioned before, it works better the thigher up you start, so it would be perfect for a lover’s lane lookout point. “Yeah, I know it’s our first date, but trust me, it works better here.”
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I did exactly that… Or quite.
Much easier to do in an airplane, we were on the runway when the sun went below the horizon, tookoff, and… 2nd sunset of the day!
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I just used this for a class assignment. Students report the assignment went well, no major problems. They did not indicate that they enjoyed it, but I know they did 🙂
Here’s the lab assignment:
Click to access lab1.pdf
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You have to make sure that the bucket on the cherry picker can go in 3 dimensions, instead of just up and down. If it just goes up and down, you won’t be able to pick her up at her door… from the bucket of the lift.
Also, if you live on the wrong coast (as I do), an alternate to the sunset is a simple stargazing expedition. “Hey baby, how about you and me get a little closer to the stars…”
also- if anyone has or knows where I can buy/rent a cheap cherry picker, shoot me an email (this also satisfies the “leave your contact info in the comments” section of the blog) at thomhowe[at]gmail[dot]com
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The speed of the cherry picker arm needed to keep up with the sunset and make it last forever is modeled by the function:
v(t) = r*k*sin(k*t)/(cos(k*t)^2)
where k is 2pi/day* and r is the radius of earth (*note that the units used for day will determine the units of the speed of the cherry picker)
As long as the cherry picker arm can rise that fast the sun will never go down. Too bad we’ve got a zero to divide by. You can watch the sunset until that function value is greater than the top speed of the cherry picker, then you’re done.
Using the value you gave for cherry picker speed and the values google gave me for the rest of the constants, the longest you could watch the sunset is 8.9 seconds. With this short of a time, the cherry picker arm would only have to be 2.67 meters long. Not really worth all the trouble you’d have to go through to get the cherry picker. An airplane is a much better idea. Or how about going somewhere where there are dunes; watch the sun go down at the bottom, then race to the top. Much more romantic don’t ya’ think?
You could definitely pick the girl up in an unmodified cherry picker, you’d have to make her get in from her window. If my girl doesn’t want to crawl out of a window to ride in a cherry picker with me, then the relationship is not worth the time.
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You’re really smart.
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Couldn’t you write a simple bash script which uses cURL to get a command line version of google calculator?
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Maybe I’m missing the point, but how much more of the sun will you actually be able to see? It’s not a point after all. Also, nobody’s figured out how long the sun is actually setting for. How high high how fast would you have to go to see the entire sun, not just a small part of it?
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It doesn’t gain *much* of an extra sunset. Still, the final part is what matters most in my opinion. If we actually go and calculate, it seems jumping from sea level to 6 meters gains about 0.08 degrees. Or 16% of the sun’s diameter. To double-check, the sun moves about its diameter in 2 minutes, and 1/6 of that is 20 seconds, our original result. Of course, you won’t normally jump from exact sea level to 6 meters instantly, and as you get higher the gain will quickly diminish. Say, to get the whole half degree of the sun, you need an instant jump from sea level to over 240 m. Or if you start even a little bit above sea level, you need some pretty significant extra height (the first meter is worth 8 seconds or 6.4% of the sun, height-wise). Still, it would be very satisfying.
Regarding latitude, *and season*, it typically gains you some pretty small linear factor. Nothing too significant. Can be helpful but doesn’t throw you out of the ballpark.
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THE BEST IS WATING THE NEXT DAY THEN YOU CAN DO LOVE LONGER BETWEEN TWO SUN SET (french hypothes)
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