Science

In the last general assembly of the international astronomical union, astronomers voted to demote planet Pluto, to strip it of its planetary status. The reasons for the reduced status are clear. (And it was coming for a long while!) The surprising bit, however, was the definition the particular astronomers concocted, eh, came up with. They were looking for a precise definition, and indeed found one, one which is precisely wrong. According to it, Earth is not a planet either!

Recently added material in ScienceBits includes:

• Passing the Eddington limit without getting a ticket: A detailed summary of the theory of porous atmospheres and how they can explain the existance of super-Eddington objects.
• Standing on Ice? Ever wondered how cold should it be and for how long, if the ice is to be thick enough for you not to fall through it?

Here are some pictures and a physicists take of a fantastic hail storm which took place west of Jerusalem in October 2004. The largest stones were up to 5 cm in diameter and several car windshields were shattered!

A few days ago I stumbled upon an interesting article from Time magazine, entitled: "Another Ice Age?". No it is not a recent article. It is politically incorrect to talk about global cooling these days. The article appeared in 1974, after "three decades of cooling" prompted some to believe that an imminent ice-age may be coming. It is interesting to read it in perspective, and perhaps there is a lesson we could learn from it. Here are a few excerpts from it. Read and enjoy.

Recently added material in ScienceBits includes:

• Estimate the basic stellar parameters using the tendency for energy equipartition. In particular, the temperature at the center of the sun, the mass-radius relationship of white dwarfs and their Chandrasekhar limit are all estimated. These were taken from my order-of-magnitude course notes.
• Row Row Row your boat, but at which maximum speed? This is a classic example of an order of magnitude analysis giving a lot of physical insight (and impressive predictive power).
• Analysis of the classic homemade water rocket, taken straight out of my first year physics majors classical mechanics notes. There is even a rocket simulator with which the trajectory can be calculated and graphed.

It may sound strange, but you are probably as likely to die from a meteor as you are from a plane crash. Think it's bizarre? Here is the statistics.

A conversation I had with a friend made me realize something interesting. Modern medical technology is responsible for the constant degradation of the human gene pool. How? Simple, we allow bad genes to propagate.

Take me for example...

Did you know that there are huge earthquakes which aren't felt? Did you know that similar waves appear everyday when two objects with dry friction between them start to move?

Recently added material in ScienceBits includes:

• My angle on global warming, i.e., the fact that it is mostly solar and not anthropogenic. I am sure a lot of people will not like it. Let the fun begin ;-) .
• How can snow fall at a few degrees above freezing? Ever wondered? Well, I did, and now you can find out how. If you like, there is also a calculator with which you can estimate the probability that any precipitation will be in the form of snow.

When visiting the president, I learned about a strange event that was recorded by the Columbia space shuttle: A lightning flash without a thunderstorm! What could it be??