Arthur’s Agony: How Inception’s Arthur Could Have Resolved His Momentous Dilemma | Science Not Fiction

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inceptionarthur2This post necessarily has spoilers, so most of the text is below the jump. But those who have seen Inception will recall the character Arthur, played by Joseph Gordon-Levitt, had to solve a moderately interesting physics problem to resolve a part of the plot. His solution struck me as…exotic. Some alternative proposals after the jump.

To recap, in order to get Cobb, Ariadne, et. al. out of dream-within-a-dream level 3 and up to dream-within-a-dream level 2, Arthur had to give them their “kick”: The sudden sensation of falling. Yusuf’s special soporific concoction didn’t effect the inner ear, so sleepers would wake up from a feeling of sudden acceleration like falling. We later learn that the “kick” can be the sense of falling itself, or the sudden stop at the end of falling, generally known as “crashing”.

The original plan in the film was to blow up the floor of the hotel in room in which the characters slept, causing them to fall and thus wake up. But when the van in dream level 1 went off the bridge, by the rules of the film, the dreamers became weightless. How to make them fall?

Arthur’s solution was to tie together all the bodies with a cord, push them into the elevator, attach the explosives to the side of the shaft above the elevator (or possibly on the elevator roof, I forget exactly), and set off the explosion, propelling the sleepers downward and waking them up. That worked, but seemed like a lot of labor.

How about:

* Pushing the tied together bodies out the door into the hallway. Tie one end of a length of line (or wire) to the people and tie the other end to the door handle or something else solid. Push the bodies away as hard as possible. They should accelerate until they wake up, or when they reach the end of the line, they’ll stop with a sudden jerk.

* Taking the tied together sleepers, spinning them around fast. If that didn’t work, Arthur could grab a door jamb with one hand and the spinning block of bodies with the other hand, bringing the spinning to a sudden stop. (Credit for this idea to my wife and ad hoc inner ear expert Miriam Goldstein)

* Using a fire extinguisher, or multiple extinguishers. Most hotels have fire extinguishers in the hallways. Water extinguishers use a CO2 canister at 2000 PSI to propel the water, so the initial burst might provide some momentum, and CO2 fire extinguishers are often stored under far higher pressure. One may not be enough to get those bodies moving, but several in succession might do the job.

* Using the explosives, but skipping the elevator part. Push the bodies into the hallway and tie them together as described above, and then set off the explosive maybe from one end of the hall. The shock wave would propel everyone at high speed. Maybe Arthur wouldn’t even need to tie the group together.

Clearly, Arthur had options. Anyone else have ideas?


NASA Instrument Tracks Pollution from Russian Fires

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Side-by-side comparison of carbon monoxide pollution from the series of devastating wildfires burning across central and western Russia, as seen by the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft on July 21, 2010 (left) and Aug. 1, 2010 (right). The AIRS data show the abundance of carbon monoxide present in the atmosphere at an altitude of 5.5 kilometers (18,000 feet). Image credit: NASA/JPL/Leonid Yurganov, University of Maryland, Baltimore County - Larger view

Drought and the worst heat wave Russia has seen in 130 years have sparked a devastating outbreak of wildfires across the nation this summer, primarily in the country's western and central regions. According to wire service reports and Russia's Emergency Situations Ministry, as of Aug. 6, 2010, some 558 fires were burning. The fires have killed at least 52 people, destroyed some 2,000 homes and charred more than 1,796 square kilometers (693 square miles). Russia's capital city of Moscow is currently blanketed in a thick smog, which has curtailed activities and disrupted air traffic. According to the Associated Press, levels of carbon monoxide pollution in Moscow are at an all-time high, four times higher than normal.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua spacecraft is tracking the concentration and transport of carbon monoxide from the Russian fires. The figures presented here show the abundance of carbon monoxide present in the atmosphere at an altitude of 5.5 kilometers (18,000 feet). AIRS is sensitive to carbon monoxide in the mid-troposphere at heights between 2 and 10 kilometers (1.2 and 6.2 miles), with a peak sensitivity at an altitude of approximately 5 kilometers (3.1 miles). This region of Earth's atmosphere is also conducive to the long-range transport of the pollution that is lofted to this altitude.

As shown in Figure 1, acquired July 21, 2010, the concentration of carbon monoxide from the fires on that date was largely limited to the European part of Russia (western and central Russia). This contrasts dramatically with the data in Figure 2, acquired on August 1, when the carbon monoxide concentration was much higher and the area of the fires had increased significantly. The concentration of carbon monoxide is continuing to grow. According to Aug. 4 NASA estimates, the smoke plume from the fires spans about 3,000 kilometers (1,860 miles) from east to west, approximately the distance from San Francisco to Chicago.

Figure 3 shows changes in the total amount of carbon monoxide above western Russia in megatons through August 1, 2010 (shown by the red curve). The changes are plotted again the base year of 2009, which saw normal levels of seasonal carbon monoxide. This is contrasted against the year 2002, when peat fires predominated in Russia. The 2002 data are from the Measurements of Pollution in the Troposphere (MOPITT) instrument on NASA's Terra spacecraft. On August 1, 2010, the excess carbon monoxide content almost reached the maximum values seen in 2002. The rate of growth (approximately 0.7 megatons, or 700,000 metric tons, per day) characterizes the rate of emission; the current rate is approximately three times higher than in 2002.

AIRS is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2010-261

Hard Ball vs a Reamer

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When can I use a hard ball to size a hole instead of using a reamer? I know balls are forced through holes to size them. Is it the hardness of the materials that govern or the degree of precision? Obviously the piece containing the hole has to be softer than either the ball or the reamer.