Archive for rotation

The Secret of the Universe

Posted in The Universe and Stuff with tags , , on September 14, 2018 by telescoper


SPIN, I spin, around, around,
  And close my eyes,
  And let the bile arise
From the sacred region of the soul’s Profound;
Then gaze upon the world; how strange! how new!         
  The earth and heaven are one,
  The horizon-line is gone,
The sky how green! the land how fair and blue!
Perplexing items fade from my large view,
And thought which vexed me with its false and true        
Is swallowed up in Intuition; this,
  This is the sole true mode
  Of reaching God,
And gaining the universal synthesis
Which makes All—One; while fools with peering eyes        
Dissect, divide, and vainly analyse.
So round, and round, and round again!
How the whole globe swells within my brain,
The stars inside my lids appear,
The murmur of the spheres I hear        
Throbbing and beating in each ear;
Right in my navel I can feel
The centre of the world’s great wheel.
Ah peace divine, bliss dear and deep,
  No stay, no stop,        
  Like any top
Whirling with swiftest speed, I sleep.
O ye devout ones round me coming,
Listen! I think that I am humming;
  No utterance of the servile mind        
With poor chop-logic rules agreeing
  Here shall ye find,
But inarticulate burr of man’s unsundered being.
Ah, could we but devise some plan,
Some patent jack by which a man        
Might hold himself ever in harmony
With the great whole, and spin perpetually,
  As all things spin
  Without, within,
As Time spins off into Eternity,        
And Space into the inane Immensity,
And the Finite into God’s Infinity,
  Spin, spin, spin, spin.

by Edward Dowden (1843-1913)

P.S. There are strict observational limits on the rotation of the Universe; see, e.g., here.

The Problem of the Spinning Tube

Posted in Cute Problems with tags , , on November 22, 2017 by telescoper

It’s been a while since I posted a problem in the folder for cute physics problems so here’s a nice little one for you to have a go at:

A vertical cylindrical tube of height 12cm and radius 6cm, sealed at the bottom and open at the top,  is two-thirds filled with a liquid and set rotating with a constant angular velocity ω about a vertical axis.  Neglecting the surface tension of the liquid, estimate the greatest angular velocity for which the liquid does not spill over the edge of the tube.

Answers through the comments box please!


The Problem of the Eiffel Tower

Posted in Cute Problems with tags , , , , on November 27, 2012 by telescoper

Too busy today (again) for anything else so I’m going to resort (again) to the Cavendish Problems in Classical Physics. I think I’ll eschew the multiple-choice format for this one, but will say that there is a small hint in the fact that the question is split into two parts:

The Eiffel Tower is 300m high and is situated at a latitude 49° N. What are the magnitude and direction of the deflection caused by the Earth’s rotation to:

  1. the bob of a plumb-line hung from the top of the Tower;
  2. the point of impact of a body dropped from the top?

Please give your answers, with reasons, through the comments box below. For legal reasons I should make it clear that you are not expected to perform either experiment.