## Archive for the ‘Science’ Category

## Numbers

Here’s another quiz:

Consider a list of naturally occurring numbers. And by naturally occurring is meant numbers like for example stock prices, number of inhabitants of cities, your electricity bills of the past few years, prices on your Saturday grocery receipt, lengths of rivers, number of books in the bookcases of all your friends, you name it.

The question then is about how often a particular digit appears as the first digit of the numbers in such a list.

Let’s take for example the digit ‘1’. The question then becomes: how often (in %) will ‘1’ be the first digit of these numbers in a given list? Or to put the same question differently: How many numbers in that list (in % of the total number of numbers) start with a ‘1’?

Hint: keep in mind the first category this post is published in!

## Subwoofer

Someone, somewhere, turned on a subwoofer.

My wife and I looked at each other and we both said “WOW”.

All windows in our house were rattling. Not just a little in the direction of the noise, but ALL windows around the house were vibrating at a low frequency.

It was 4:38 AM!

And the subwoofer was located some 40+ miles away from us.

That is, when it was turned on.

By the time our windows started to tremble, the subwoofer was already some 10 miles up in the air: one of the last Delta 2 rockets, blasted into orbit with the help of NINE solid rocket boosters, 6 of which were ignited on the ground, the other 3 during the ascent.

We were watching its launch form our backyard, and it was a true spectacle. We could clearly see the ignition of the 3 remaining boosters and the jettison of the burned-out ones.

Anyway, we now have a brand new GPS satellite in orbit. And it will also test the new L5 signaling for future, more accurate and more powerful GPS with extra provisions for aviation.

The Delta 2’s are being phased out and replaced by Delta 4 and Atlas 5 rockets.

Interested in one of the oldies? The Air Force has 5 of them for sale!

See: Delta 2’s for sale

(The picture is of an actual subwoofer: a 60 inch one! See Link)

## … Another spousal conversation

… just not one of mine …

… but it certainly and easily could have been one!

The following is a quote from a book I just finished (and recommended earlier: this is how chapter 21 starts in “The Black Hole War” by the renowned theoretical (theoradical!) physicist Leonard Susskind).

I post it here, because this is a **perfect** example of the type of conversations my wife and I sometimes have.

One morning, when I went down to breakfast, my wife Anne, remarked that my T-shirt was on backwards; the V shape woven into the fabric was in the back. Later in the day, when I came home from a jog, she laughed and said: “Now it’s inside out.” That set me to thinking: how many ways are there to wear a T-shirt? Anne mockingly said, “That’s the sort of stupid thing you physicists are always thinking about.” Just to prove my superior cleverness, I quickly declared that there are 24 ways to wear a T-shirt. You can stick your head through any of 4 holes. That leaves 3 holes for your torso. Having picked a neck hole and a torso hole, that leaves 2 possibilities for your left arm. Once you decide where your left arm goes, there is only one choice for your right arm. So that means 4 x 3 x 2 = 12 ways to choose from. But then you can turn the shirt inside out, giving another 12, so I proudly announced that I had solved the problem: 24 ways to wear a T-shirt. Anne was not impressed. She replied, “No, there are 25 ways. You forgot one.” Puzzled I asked, “What did I miss?” With a look that would freeze hell, she said, “You can roll it in a ball and shove it …” You get the idea

^{1}.

^{1}. Since writing this, Anne has discovered at least 10 more ways to wear a T-shirt.

Sometimes … you just can’t win.

## Elementary, Dear Data

In episode 29 of the Star Trek series “The Next Generation”, the holodeck computer generates a character from the Sherlock Holmes novels by Arthur Conan Doyle: the villainous Professor Moriarty.

The interesting twist is that this holographically created image, at some point, starts to realize that he, in fact, IS a computer generated entity, and not the actual human being he is supposed to represent.

A remarkable feat! Only outdone by his success in actually leaving the holodeck.

I found that a very interesting episode, mostly because I have often thought along those lines myself (and who hasn’t?) .. what IF? What IF we were just part of a computer simulation? Could it be we’re just somebody’s (cruel) science project? Could it be that the universe as we perceive it, is just a hologram?

As I recently found out, scientifically, this is maybe not such a crazy nutjob idea after all.

The idea more or less started when the Dutch physicist (and Nobel laureate) Gerard van ‘t Hooft proposed his holographic principle, which, simply put, states that all information in a three dimensional space can be mapped onto a two dimensional boundary surface of that space. Or, to turn that around, the information described on a two dimensional surface can be projected in a three dimensional ‘holograph’.

The American scientist (who started his career at age thirteen as a plumber) Leonard Susskind developed that idea further. If you find the idea of a holographic universe intriguing, you may consider getting yourself his book “*An Introduction To Black Holes, Information And The String Theory Revolution: The Holographic Universe*“ [Update: Disclaimer: This book is NOT exactly a ‘popular science’ book: it’s chockful of ‘higher’ mathematics! WAY over my head.].

Or, for a quick introduction, read the August, 2003 article in Scientific American by Professor Jacob Bekenstein.

Fascinating stuff, and I wish I would understand ten percent of it. [Update: Now that I have thumbed through the above mentioned book – that I no longer recommend for lay persons like myself – I have to humbly adjust that percentage from 10 to 1]

*“Computer … resume program!”*

[Update: Instead of the book mentioned above I WOULD recommend two of Leonard Susskind’s books that ARE written for the lay person. See below.]

The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics

The Cosmic Landscape: String Theory and the Illusion of Intelligent Design

## Seven Minutes of Terror

Last year, on August 4th, I wrote, although not immediately apparent, about the launch of a Delta rocket that would put the Phoenix space craft on its way to Mars.

After having traveled some nine months at around 74,000 miles an hour, Phoenix is almost at the end of its 423 million mile journey:

Tomorrow afternoon it will make its landing attempt: when is starts its harrowing descent to the Martian surface it will be flying over 12,000 miles per hour (relative to Mars).

Seven minutes later it should be touching down on the cold rocky planet.

Unlike the previous rovers, this is not a big airbag that is dropped and bounces around for a while: this is a real lander that is supposed to make a controlled soft landing using a parachute, retro-rockets, radar, lots of computer power and … quite a bit of luck: so far, only 55% of all Mars landings have been successful.

Is the Phoenix team confident they will pull this off?

Not quite:

I do not feel confident. But in my heart I’m an optimist, and I think this is going to be a very successful mission,” said principal investigator Peter Smith, an optical scientist with the University of Arizona. “The thrill of victory is so much more exciting than the agony of defeat.

The number of things that can go wrong in the seven minutes it takes the lander from going from almost 13,000 mph to gently stepping on Mars’ surface is mind boggling. One single small failure will make the difference between success and Mars having yet another impact crater. This is why the Phoenix team refers to this landing event as “The Seven Minutes of Terror”.

I will be watching the landing coverage tomorrow on TV and it will be a nail biting experience.

And if we’re lucky and Phoenix survives this mission critical maneuver, we’re in for yet another nail biting experience.

After all, Phoenix’ mission is to hopefully find a conclusive answer to that centuries old question:

Is there life “out there”?