02 MAR 2019 by ideonexus

 Entropy in our Everyday Lives: Active Stability

Because things naturally move to disorder over time, we can position ourselves to create stability. There are two types of stability: active and passive. Consider a ship, which, if designed well, should be able to sail through a storm without intervention. This is passive stability. A fighter jet, in contrast, requires active stability. The plane can’t fly for more than a few seconds without having to adjust its wings. This adjustment happens so fast that it’s controlled by software. Ther...
  1  notes
10 MAR 2017 by ideonexus

 1937 Description of Lightspeed Travel

After a while I noticed that the sun and all the stars in his neighborhood were ruddy. Those at the opposite pole of the heaven were of an icy blue. The explanation of this strange phenomenon flashed upon me. I was still traveling, and traveling so fast that light itself was not wholly indifferent to my passage. The overtaking undulations took long to catch me. They therefore affected me as slower pulsations than they normally were, and I saw them therefore as red. Those that met me on my hea...
  1  notes
03 SEP 2011 by ideonexus

 Focusing Light Increases Heat Where Focused

The sun's rays proceed from the sun along straight lines and are reflected from every polished object at equal angles, i.e. the reflected ray subtends, together with the line tangential to the polished object which is in the plane of the reflected ray, two equal angles. Hence it follows that the ray reflected from the spherical surface, together with the circumference of the circle which is in the plane of the ray, subtends two equal angles. From this it also follows that the reflected ray, t...
  1  notes

Alhazan's famous observations on reflecting the sun's rays and bending light.