When you develop projects you need to stick with it: NASA Gravity Probe B, 52 years in the making!

Wow!  52 years to get this experiment to confirm the Theory of Relativity completed.  Wow!

The Gravity Probe functioned using four ultra-precise gyroscopes using spheres machined to within 40 atoms of being perfect spheres.  It then pointed at a star named IM Pegasi, and then when the star had sunspots the probe got thrown off.  The odyssey of this probe is something every software designer, architect or others should read, this can happen to any project that you initially thought was a no brainer.

Oh sure on my http://blogs.msdn.com/reaserch blog I have been critical of the Mars Climate Probe, but the NASA Gravity Probe B is something to admire.

Starting at Stanford in the early 60s, it took 52 years to get this spacecraft into space.  The material science from this experiment was awesome!  They used spheres shaped to with 40 ATOMS of perfect roundness.  How did they measure that? 

The bad news: Space isn’t bent much by Earth, so if you plan on creating a “realistic” gravity slide game, forget about it, but if you don’t worry about the reality (as you shouldn’t) in the game, then go for it.

The experiment confirms, again, that large bodies like the Earth bend space, but not very much from a human point of view. From the NASA report:

The frame-dragging effect should cause the spin axis orientation of an orbiting gyroscope to change in the plane of Earth’s rotation (orthogonal to the orbit plane) by a minuscule angle of 0.014 arcseconds (0.000011 degrees) in a year. This effect has never before been measured directly.

Now that is precision.  On the other hand, bending space isn’t the big deal that Star Trek makes out of the idea.  Unfortunate.

What is the difference between precision and accuracy?


In software there is the concept of binary accuracy, but I won’t go over it in this blog post.


  • How do you make use of the data in your physics classes?  Do you need to make corrections in your homework now?  No.
  • What do you use to reach this type of precision in programming? 
    • In software, you use the data that you get elsewhere, so if the sensor teams gives you data that is bad, you can’t make it better.

But if you want to utilize an idea that can work in a game, but not in real life, here is a picture of the bending of space, keep in mind that the diameter of this circle is quite large to get the bending shown by the Probe B spacecraft.

NASA Collects Gravity Data to Test Einstein













Here is how a wormhole works, for the Stargate fans.  This would be one heck of big wormhole though.