Observing "weather" (stratospheric temp.) with cosmic rays

An article in New Scientist reports on an analysis of cosmic ray muon data from the MINOS underground detector, which correlates with "sudden" (24-hour timescale) temperature changes in the stratosphere. The original article in Geophysical Research Letters gives you a good flavor for how this kind of analysis is actually done, and written up for publication. The figure below (Figure 3 of the article) shows the beautiful correlation between the temperature (5-day running average in blue) as measured by sounding balloons, and the muon rate in MINOS (also 5-day running average, red band with uncertainties). The alignment of the two curves is obviously not known a priori. The exact numerical calibration between muon counts (red, right scale) and temperature (blue, left scale) is a fitted output of the analysis, not an input.To me, it's just kind of neat that particle physics can relate so sharply to some "real world" large-scale properties.

Topic by kelseymh 10 years ago  |  last reply 10 years ago


Why are there few or no clouds in the stratosphere? Answered

        The stratosphere (STRAT  uh sfihr) lies above the troposphere. It extends from about 11km to 50km above the earth. In the lower part of the stratosphere, the temperature does not change with height. But, in the upper part , temperature increases with height.  At 50km, the temperature is about 7o/c.          Air in the stratosphere is dry and thin, and there are very few or no clouds.

Question by Waren-Neutron 8 years ago  |  last reply 8 years ago


If You Could Do Something Incredibly Stupid Without Consequences

If you could do something incredibly stupid without any consequences such as injury or death, what would you do? Here's what my friend said: He'd ride a lawn chair attached to balloons into the stratosphere, jump of (parachute not included) with a ton of home-made explosives, land in a large tub of Jello, and detonate the explosives. :D

Topic by Spl1nt3rC3ll 11 years ago  |  last reply 9 years ago


Suggestions for a cheap, simple robot unicorn build

My 5yo daughter has figured out that her mad-Scientist daddy can make crazy things come true.  For her birthday, she got a real unicorn and a princess crown (see picture attached).  Now for Christmas, she has her heart set on a ROBOT unicorn, and I think I'm going to try to tackle this, but I need to keep the scope tight so that when Christmas arrives, I'll have a deliverable for her. (My instinct always leap to grandiose ideas like actual quadrupedalism that would balloon the time/effort/money inputs into the stratosphere.   My biggest obstacle to make this work for Christmas is to stick with K.I.S.S. principles.  I can do basic welding, woodworking, fabricating, stitching, etc.  I'm reasonably good at electronics, and am a professional programmer with a degree in Aerospace Engineering.) Here is my rough  build plan:  (Completely open to improvement suggestions) 1)  Build frame out of 1/2" square steel tubing and weld together.  Leave large torso cavity for electronics and batteries.  Feet will have wheels concealed by a hoof shroud.  Feet will be upgradable (see tech features below) 2)  Use blue foam to rough out body shape.  3)  Cover with about 1/2" of soft foam covered with felt.  Use yarn for mane and tail.  Cover should be removable and washable. I'm trying to figure out tiers of work so that as long as I get the basic frame and covering down, I'll be able to increase/decrease the scope to ensure I'll have a deliverable for Christmas.  Here are the tiered robotic features I am envisioning: Tier 1: Make the saddle bounce at about .5Hz with an amplitude of roughly 1/2".  Possibly make head/neck bob up/down in sync. Tier 2:  Add horse sound effects Tier 3:  Build sensors for the reigns and stirrups.  Monitor if stirrups get pushed inward in a basic kick the horse motion.  Monitor if one reign or both are being pulled.  Make sounds effects based on inputs.  (E.G.  Clop, clop of hooves begins when stirrups are pushed in, and stop when reigns are pulled.)  NOTE:  Since they have access to real horses, keeping the controls reasonably close to riding a real horse will make this double as a trainer/simulator for her and her friends. Tier 4:  Upgrade wheels to powered.  Move based on reign and stirrup inputs.   Max speed will be very slow (40fps or so), so that it can be used inside safely.  Movement is mostly just to augment her imagination, not to move like a real horse. Tier 5:  (Not much chance I'll get this far prior to Christmas)  Upgrade software, sound effects, etc. Current back of napkin ideas: Frame will probably have 3 pieces: legs/torso, neck/head, Saddle/back  Saddle/back removable for electronics access. Neck/head will be joined to torso in 3 spots:  the top point will be anchored with a chain link between two eye-bolts, the other two points would be on the sides of the bottom, with compression springs pushing the neck and torso away from each other, limited by a mechanical linkage.  This should give reasonable motion ability, and allow the two base points to become the sensors for the reigns being pulled. I'm thinking a small 12V deep cycle battery, and 12v salvage DC motors powering the wheels.  Depending on the motor torque, I'll either power the back two feet and keep the front feet as swivel casters, or power all four and turn tank-style. The budget needs to stay reasonable, say $100ish.  This is a kids toy, and I've got lots of other mad-scientist projects to pump money towards. Outstanding questions: Motor selection, cheapest with high enough torque Good, cheap way to make seat and possibly head oscillate.  Mechanism needs to not break even if a 200lbs rider sits on it.  (Doesn't need to work when overloaded, just can't be permanently damaged when overloaded.) Locate inexpensive 12v charger that won't overcharge if left connected, but will charge a 3ah battery reasonably quickly.  (Or schematics to build one)  Essentially, looking for a best bang-for-buck charger. Least expensive way to play audio clips?  I've got plenty of horse-sound clips located, but I need a way to play them economically. Not sure how much force will be needed for movement.  I'm assuming a 70lbs rider/robot max and that it will primarily operate on flat surfaces, potentially on carpet.  Can't burn out if overloaded.  Suggestions on simplifying this?  Suggestions on simple improvements?  Ways to keep the costs down?  Sources for economical parts?

Topic by SvdSinner 6 years ago  |  last reply 6 years ago