Sunday, November 6, 2011

Physics Challenge Award Show II

Not a DeLorean.  You're doing it wrong.
[Update:  Prize Update / Added link to full solutions]

Welcome to the second Physics Challenge Award show!


Our judges have deliberated for several units of time and I now have in my hands the envelope holding our list of winners.  I could easily just tell you who won right now and save everyone some time, but award shows need some suspense to work effectively, so let's first give some tedious background information!


You may recall that the winner of the first Physics Challenge contest won a CRC Handbook.  We will not be giving out CRCs this time around.  We felt that such a prize was far too expensive impersonal, so we have opted this year for something much cheaper from the heart.  The following prizes will be awarded to our top three solutions:

First Prize:  Our first prize winner will receive an actual back-of-an-envelope used in one of our posts (gasp!) signed by all the of the members of the Virtuosi that I can find at colloquium tomorrow.  But that's not all!  Alemi will also salute in your general direction.  

Second Prize:  For our second prize winner, we appear to have run out of envelopes... but Alemi will still salute in your general direction.  You will not see him do this, but you will feel a major disturbance in the Awesome Force (mediated, of course, through the midi-chlorian boson).

Third Prize:  You will receive no material prize, but on your deathbed you will receive total consciousness.  So you've got that going for you, which is nice.  

Let's first remind everyone what the Challenge problem was.  The full text of the problem can be found here, but the gist is basically this:  You've created a time machine and you're biggest fear is that you'll be stuck back in the past without any way to communicate to the future that your design worked and you deserve all kinds of Nobel prizes.  The solution should be able to last long periods of time (who knows how far back in time you'll go?), should maximize the chances of modern people finding it, and be able to convince people that you have in fact gone back in time.  

Alright, let's get to some solutions already!  

First Place:  The first place solution comes from Christian, who uses some biological wrangling to solve the time traveller conundrum.  With some information from the announcement of "synthetic life" and some bio how-to from an entity known only as "steve," Christian plans to implant a message into the DNA of bacteria.  The message will contain his name, identifying information, and the url of a website which will (presumably) contain a video of him with one hand outstretched saying "Nobel prize please."  

Let's see how this solution satisfies our criteria for a successful solution.  Does it work for an arbitrary amount of time?  It appears to, so long as the bacteria manage to survive and the message doesn't become too garbled over time (perhaps some error-correction might be useful).  Additionally, if one is worried about introducing non-native bacteria to the wild you could bring back a bunch of bacteria that were known to exist over wide periods of time and just release those alive at the time.  Will modern humans find it?  It seems that geneticists are decoding just about any genome they can get their hands on, so this is a strong possibility.  Would it convince people that someone travelled in time?  If the bacteria has dispersed enough, shows enough variation over geographic regions, and contains specific identifying information about a missing person who has allegedly created a time machine, I think that's pretty strong evidence.  Neato, gang!

Second Place:  The second place solution comes from Kyle, who offers a space-based answer.  Kyle suggests etching detailed plans of the time travel mechanism (flux capacitor) onto a durable metal and putting that bad boy into space.  He suggests that anyone capable of building a fully functional time machine should have no problem launching a small satellite.  Fair enough.  Additionally, the satellite would use some kind of solar power or the like to produce a low-power radio signal.  In fact, this signal would only need to spit something out once every year or ten years or something.  Since radio communication precedes space exploration, the detection of an artificial satellite sending a message would attract a fair deal of attention.  The plans and successful reproduction of the time machine would then seal the deal.

Does this solution satisfy the necessary conditions?  I think so.  Assuming all goes according to plan, this would easily be detected by modern people and, assuming the time machine plans are accurate, would provide indisputable proof.  My main concern would be that the satellite could be launched and survive to the present.  Modern satellites need constant boosts to stay in orbit, without which they fall back onto Earth and burn up.  One potential solution would be to put it on the Moon.  This is technically much more difficult, but hey, you just created a time machine!  Also, putting it on the moon then allows for a totally rad recreation of the Monolith scene in 2001: A Space Odyssey.     

Third Place:  The third place solution comes from Yariv.  Though Yariv did not submit a solution through the proper channels (he follows no one's rules, not even his own), he was overheard to give a solution.  While the Physics Challenge planning committee was discussing the problem over lunch, Yariv flippantly dismissed the entire premise as "trivial" and suggested a two-word solution:  "radioactive paint."  Personally, I like the idea of bewildered archaeologists finding a cave painting of Yariv riding a dinosaur done using a variety of radioactive paints which all date back 200 million years.  For this amusement, I award Yariv the third place prize for this contest.  As a member of the Virtuosi, however, Yariv is ineligible to receive a prize and instead receives 5 demerits on his record for his willful disregard of our institution's rules and excessive flippancy.  One more slip-up and you'll lose your badge!

Full solutions are up on the Challenge website.  Thanks for joining us for this episode of Physics Challenge Award Show, and thanks to everyone who submitted a response!   

First and Second Prize Winners:  We present the following in partial fulfillment of our prize offer.

For those who solve problems (he salutes you)


  1. Thanks! Salute received! I feel more accomplished than I did at my high school graduation. This took more brains!

  2. 3d bioprinting = Immortality = go to stars

  3. (orbital station bike wheel-1g)... geostationary orbit, a huge "bike-wheel" is gyrating around its own axis for have 1g-centrifugal. Wheel held in place with 4 CABLES (each cable with a track for Train, for both trains crossing ↓↑) FORMING THE STRUCTURE OF A RHOMBUS♦ (minor diagonal of rhombus is the gyration-axis of the Station-Wheel)...rhombus´s below, the carbon nanotube´s Track towards Earth...rhombus´s above, the Cable towards a higher counterweight... if...WHEEL´s RADIUS = 250 mts... Wheel gyration´s Axis length = rhombus´s minor diagonal = Wheel´s radius = 250 mts... Cable´s length of the rhombus´s side = Wheel diameter = 500 mts. Wheel´s ZONE-1g: habitable length = 1571 mts*50 mts wide*50 mts height, gyrating 360º each 31 seconds, angular-speed = 11.61º/sec, linear-speed (tangential) = 182 kms/h... Station-Wheel´s GYRATION: AXIS IN PERPENDICULAR (90º) ORIENTATION TO THE ORBITAL TRAJECTORY...and so, while Station-Wheel follows its geostationary orbit, the Wheel does Not changes the spatial-orientation of its axis, and thus there are Not Precession forces actuating (and thus there is Not torsion´s force against Track)... Wheel with maneuver´s tangential-rockets for gyration´s start, or...gyration emergency stop...and maneuver´s axial-rockets for reorientation of Wheel´s axis, if it is necessary: because the Earth´s axis slightly and very slowly goes oscillating cyclically due to nutation and precession...that oscillation evidently produces transversal traction pulling of the Track towards aside from its anchoring on equator, thus would have an also slight pendular movement side to side and it would produce precession´s movements of the Wheel´s axis and thus a not wished torsion of the Track...but the system must supporting lateral charges, in the same orbital plane and thus without precession´s problems on the Wheel´s axis, of acceleration against W→Track←E produced by the Coriolis effect when movement´s direction is perpendicular to the gyration´s axis, that lateral charge is maximum on equator (there, a vertical movement is perpendicular tø Earth´s axis) and zero on poles (there, a vertical movement is parallel tø Earth´s axis); upwards charge to West, downwards charge to East; the gyroscopic-rigidity contributes for maintaining the gyration-axis perpendicular to the orbital trajectory... When the Maglev Train slowly arrives, using now cogwheels on Zipper-Track (zippers installed on the same Maglev-Track), Train stops in Geo 0g-Station placed over one extreme of the gyration-axis... Passengers disembark and entering into gyratory circular corridor, they take now the interior-elevator of one of the Wheel´s hollow-radius, and tunnel "descending" till Hotel into the final Zone-1g...where while Station-Wheel goes turning, the immense O2 producer Hydroponics Garden receives a filtered Sun light...and there are Earth´s awesome views.

  4. ☼↓↓▓0.08g▬▬▬←▬▬▬▬▬↓Moon▬▬♦1g▬→▬▬1g...Space elevator (orbital station ramp)... Faraway high beyond Earth surface at 150,000 orbital speed 11.4 kms/sec...with only 0.08g centrifugal, 0.8 mts/sec² (a person who has 80 kgs ↓ gravitational force on Earth equator radius=6378.1 kms; over there with a radius=156378.1 kms only has 6.64 kgs ↑ centrifugal force...gravitational force downwards minus centrifugal force upwards)...could be, if someday is cheap the maglev-track, the counterweight Terminal Orbital Station-Ramp... Awaits passengers in Earth-Station a hyperspeed vertical electric Train of Magnetic Levitation... "Spatial Train coming from Orbital Station-Ramp and Orbital Station-Wheel at these moments arriving will depart again after one hour, passengers with Moon destination please embark on SHIP-COACH when will be hooked at Train´s end"... (((if...Train´s mass=10 Tm and its vertical max-speed=10000 kms/h... CORIOLIS´s EFFECT AGAINST TRACK ↓ to East, ↑ to West: acceleration=0.4 mts/sec², FORCE=0.41 Tm... How Track is attached on Earth´s equator, this Lateral Thrust occur in the same orbital plane, orbit forward or backward, and thus almost there are Not Precession´s problems in the System...except because due to slight cyclic oscillation (nutation and precession) of Earth´s axis, would that doing each a certain time a little correction, with their own axial maneuver´s-rockets, for reorientation of Wheel´s Axis)))...medium-speed = 5,000 kms/hour: Earth/Orbital Station-Wheel, distance = 35,786 travel time = 7 hours... Orbital Station-Wheel/Orbital Station-Ramp, distance = 114,214 travel time = 23 hours...Well seized from retractable cogwheels, with slow-speed at the beginning travel of strong gravitation from Earth, with conventional Zipper-Track: MAGLEV ON...COGWHEELS ON... THE TRAIN DEPARTS►...

    1. ..."Passengers please belts"...starting horizontal from Station, when train goes climbing (100 kms/hour) is VERTICAL , looking upwards...vertical-train with special zig-zag corridor with protections and seats also in the center for avoiding passenger´s fall down in straight line till coach´s bottom... Already enough far (100 kms height: that train still would weight...9692 kgs↓ - 35 kgs↑ = 9.65 Tm↓, thus its maglev strength would must be at least 10 Tm↑ thrust...), with some minor gravitational Earth attraction: Cogwheels off... Here we go...goooooo!...constant acceleration upwards...Maglev hyper-speed→... Already braking enough near from each Station...slow-speed, changes propulsion system again: COGWHEELS on... Entering in slow-track on rhombus structure... 7 hours: half length above half length below through Station´s floor, Train is on rhombus inclined track at zero-speed, near from Water-Recycling Plant with carbon nanotube´s filters...and the other Air-Filtering Plant with catalysts...the passengers disembark in weightlessness: Geo 0g-Station...passing from static-platform to gyratory circular corridor, go taking soon an interior-elevator in one of the hollow-radius (also could be an exterior-elevator running for a simple maglev-radius) and "descending...finally, the passengers have arrived at destination: Wheel centrifuge 1g-Station, with its gyration´s-axis perpendicular to the orbital trajectory... A Wheel with 500 mts in diameter, gyrating 360º each 31 seconds (((10 Floors with 25 mts in height each one...a person with 80 kgs mass, would have in each Floor a centrifugal force:... Floor 1: 1.04g=84 kgs... Floor 2: 0.94g=75 kgs... Floor 3: 0.84g=67 kgs... Floor 4: 0.73g=59 kgs... Floor 5: 0.63g=50 kgs... Floor 6: 0.52g=42 kgs... Floor 7: 0.42g=34 kgs... Floor 8: 0.31g=25 kgs... Floor 9: 0.21g=17 kgs... Floor 10: 0.1g=8.4 kgs)))...gyrating into 4 cables, each cable with a track for Train, a rhombus structure forming for Wheel´s supporting...

  5. (2) (orbital station ramp)... Tour continuing again... THE TRAIN DEPARTS►... once passed the slow zipper-track on rhombus structure, enters again on fast main maglev-track... km 50,630: braking...Moon-Launching-Point, Train is at zero-speed, rear SHIP-COACH is released staying alone, again... THE TRAIN DEPARTS►... (((SHIP-COACH, while Earth turns, awaits patient the hour for releasing from Track and going to Moon with exact and goes transferring orbits till Moon orbit where firing rocket again, brakes and lands on Moon☺Station... "Come to occult face with us and visiting the ancient Alien in ruins City"...and once recharged with fuel and passengers...equal than aircraft carrier, from a Launching-Catapult... SHIP-COACH TAKEOFF►... and returns conventionally to Earth)))... Already enough near from Terminal (magnetic shield anti-radiation and UV rays protection)...slowly by zipper-track maglev and train´s cogwheels are braking strongly "downhill"... 23 hours: Train is horizontal on Terminal at zero-speed, near from Ship´s Launching-Ramp towards Jupiter/interstellar Space, in spectacular and covered by transparent graphene´s domes with Earth views always in the ceiling, the passengers disembark at destination: counterweight centrifuge Ramp 0.08g-Station.

    1. from Moon... SHIP-COACH TAKEOFF►... and returns conventionally again to geostationary orbit next to Bike-Wheel´s Geo-0g-Station and tying up on its «Port for Spacecrafts»...when any Train returns, stops and SHIP-COACH is hooked again at Train´s end returning to Earth)))

  6. (3) (orbital station ramp)... On Track, besides, there are 3 (one at down in Earth-Station, one at middle in Rhombus-structure, and one at top in Ramp-Station) special powerful automatic maglev-vehicles which, in case of emergency, would go out to Train´s encounter and equaling speed between both: soft contact and braking and both stopping... On Train, besides, 2 gigantic and folded in little compartments resistant graphene´s parachutes with a rigid central-ring for Track passing through: one parachute at Train´s front only for emergency when Train goes climbing, and so it could return "softly" to ground... And other parachute at Train´s rear with a sophisticated system also maglev of rigid central-ring for Track passing parachute´s through without hitching... On come back, at 9,000 kms height (exosphere) maglev central-ring is launched and pulling extracts and, when according it descends goes sufficiently increasing for it the Atmosphere´s density, deploys its parachute probably below 100 kms height from Earth surface...when Train comes hyper-speedy and maglev-braking falling towards Earth, for avoid now already Gravity´s regulating with a major or minor Distance between Train and canopy´s rigid-central-ring of the parachute: max Distance, chute totally deployed max braking...less Distance, chute partially deployed less braking. System of rear parachute which normally before touch ground is automatically refolded (bringing again the canopy´s central-ring into its Train´s compartment and coiling the canopy and its fine cords around motorized gyratory cylinders)... Train enters on terminal horizontal-track and stops in Earth-Station.