Terrific Web Site

For all sciences, but particularly physics:

Click on the logo to go to the web site.

Therein is a wonderful article on outstanding questions remaining in the physics realm.

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Things I Learned Recently…

while reading Paul Davies’ “The Cosmic Jackpot”:

1) The ratio of the strength of the electromagnetic force to the force of gravity is 10 to the 40th power.   This ratio is needed for planets to form and for stars above the Chandrashekhar Limit to go supernova.

2) In string theory, the number of extended dimensions is not fixed at three out of the nine.  Instead you can have four extended dimensions and 5 compactified, or 2 extended dimensions and 7 compactified.  The latter seems to rule out life in any meaningful way (flatland here we come).

3) When the Universe was less than a trillionth of a second old, the Higgs field had an average value of zero, so all particles had zero mass.

4) The ratio of protons to neutron is 6.  This ratio came about because of the value of the strength of the weak force.

5) The cosmic background radiation (CMBR) comes from the primordial annihilation of matter and antimatter.

6) The amount of matter in the observable universe is ten to the 50th power, in metric tons.

7) In an infinitely sized universe,  the average distance to an identical you is 10 to the 10 to the 29th power.

8) In an infinitely sized universe, the average distance to an identical observable universe is 10 to the 10 to the 120th power.

Red Rover, Come Over!

The new pictures from the Mars rover Curiosity are surely fantastic.  When you look at them, you feel like you want to go for a walk on a nice sunny day on dear old Mars.

Unfortunately, the atmospheric pressure on Mars is 0.1% that of Earth’s, and there is almost no magnetic field on Mars.  So not a very safe place for a biological unit to hang out on.

Click on the image to enlarge it.