Choose a flat surface like a table. Take a normal piece of printer or lined paper. Holding one end of the paper, pull it across the surface of the table. There is some friction, but it is very little. Here is your puzzle: Without changing the table in any way, nor changing the paper in any way, how can you increase the friction between the two when you pull the paper across the table?

Planck decided to assume that atoms could only vibrate at certain frequencies that were whole numbers eg 2f, 3f and so on. others used to think that atoms vibrate continuously

Stars are born within the clouds of dust and scattered throughout most galaxies. a familiar example of such as a dust cloud is the orion nebula. turbulence deep within these clouds gives rise to knots with sufficient mass that the gas and dust can begin to collapse under its own gravitational attraction. as the cloud collapses, the material at the center begins to heat up. known as a protostar, it is this hot core at the heart of the collapsing cloud that will one day become a star. three-dimensional computer models of star formation predict that the spinning clouds of collapsing gas and dust may break up into two or three blobs; this would explain why the majority the stars in the milky way are paired or in groups of multiple stars.therefor, i would say the answer is: dust and gases contract.i hope this ! < 3

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