From Out of Space...

Hobotopia iGoogle theme by Ape Lad

2008-11-25T11:49:00.001-06:00

Hobotopia iGoogle theme by Ape Lad
Originally uploaded by Perry G

I likes it!

Here's the link to the iGoogle Themes page.

Wow

2008-11-06T12:35:00.000-06:00

Can I just say how awesome Nate Silver is?

A steep climb ahead, we as a people will get there.

2008-11-05T11:36:00.000-06:00

President-Elect Barack Hussein Obama:

Is there something wrong with some 7-year old Muslim-American kid believing that he or she can be president?

2008-10-20T10:05:00.000-05:00

Here's something we don't hear about enough in the media and from the candidates themselves: Why should it even matter if one of the candidates were Muslim? I think Gen. Powell said it best over the weekend:

"I'm also troubled by, not what Senator McCain says, but what members of the party say, and it is permitted to be said. Such things as 'Well you know that Mr. Obama is a Muslim.' Well the correct answer is 'He is not a Muslim, he's a Christian, he's always been a Christian.' But the really right answer is 'What if he is? Is there something wrong with being a Muslim in this country?' The answer is 'No. That's not America.' Is there something wrong with some 7-year old Muslim-American kid believing that he or she can be president? Yet I have heard senior members of my own party drop the suggestion he's a Muslim and he might be associated with terrorists. This is not the way we should be doing it in America.

"I feel strongly about this particular point because of a picture I saw in a magazine. It was a photo-essay about troops who were serving in Iraq and Afghanistan. And one picture at the tail end of this photo essay was of a mother in Arlington Cemetery and she had her head on the headstone of her son's grave. And as the picture focused in you can see the writing on the headstone. And it gave his awards, Purple Heart, Bronze Star, showed that he died in Iraq, gave his date of birth, date of death. He was 20 years old. And then at the very top of the headstone, it didn't have a Christian cross, it didn't have a Star of David. It had a crescent and a star of the Islamic faith. And his name was Karim Rashad Sultan Khan. And he was an American, he was born in New Jersey, he was 14 at the time of 9/11 and he waited until he can go serve his country and he gave his life."

I'm passing this story along from Newsweek's Faithbook blog by Abed Z. Bhuyan.

Hooray for level heads!

2008-10-16T08:30:00.000-05:00

"Nobody is pro-abortion. We should try to prevent unintended pregnancies by providing appropriate education to our youth, communicating that sexuality is sacred and they should not be engaged in cavalier activity." -- Sen. Barack Obama

Things overheard

2008-10-15T10:03:00.000-05:00

on my iPod during my commute:

It's physics, not sports, but it makes sense.^[1]

- Hmm. That "but" says it all, doesn't it?

When he walked along, it looked as though he were moving in three directions at once.^[2]
- I really liked this line.

^[1] NPR interviewee discussing the "fast" swimming pools used in the 2008 Beijing Olympics.
^[2] Have to credit Garrison Keillor for that one.

An observation

2008-10-08T13:15:00.001-05:00

or two.

I've not spoken up about the presidential race yet, but I have two things to point out.

1. Gov. Sarah Palin won't call people with their titles of respect ("Can I call you Joe?") while Sen. Joe Biden consistently uses the title "Governor Palin". She also feeds the mob mentality of her audiences by encouraging violent threats and remarks that have no place in a presidential race.

2. Sen. McCain doesn't have a respectful conversation during a debate, but points at his rival and calls him "That one" (and of course, he says worse things when Sen. Obama is not within earshot). Sen Obama talks to respectfully to his rival's face and respectfully disagrees with him in his public addresses, even if it is clear that the rival's gloves are coming off.

That's all I got for now.

How about- "How to respect other people's opinions"?

2008-09-23T11:51:00.001-05:00

Generally, I like the WikiHow articles. This one on converting your atheist friends into Christians kinda irks me a bit. I mean, hasn't Christianity gained enough experience over the past millennium converting heretics? Do we really need a WIKIHOW ARTICLE for it? How about "How to revive the Spanish Inquisition"? This would at least be a lead-in to a one-liner: "Nobody expects it!"

About: Robots

2008-08-25T13:45:00.000-05:00

This is awesome. I for one, welcome out new robot overlords.

Sci-Fi LOLCat

2008-08-23T12:35:00.000-05:00

more animals

And many more at icanhascheezburger.com.

This is why I love the Laugh-Out-Loud Cats

2008-08-07T00:48:00.001-05:00

Laugh-Out-Loud Cats #907
Originally uploaded by Ape Lad

Adam Koford, available to the public at hobotopia.com, draws this awesome comic. The astronomical ones are among my favorites.

This is why I love APOD

2008-08-01T13:56:00.001-05:00

Playing Games with the Moon:The Moon's measured diameter is around 3,476 kilometers (2,160 miles). But apparent angular size, or the angle covered by an object, can also be important to Moon enthusiasts. Angular size depends on distance, the farther away an object is, the smaller an angle it covers.

Credit & Copyright: Laurent Laveder (PixHeaven.net / TWAN)

read more | digg story

Pondering Equivalence

2008-07-17T16:32:00.000-05:00

In my continuing search for blogjoy, I'm going to re-post an article I wrote for a now-offline science blog. It has to do with a subject I teach, and I think I've come up with a pretty good way to explaining it. It has to do with General Relativity, and specifically what is known as "the equivalence principle" (on which GR is based). In a nutshell, I explain how the effects of gravity are just like the effects of accelerating motion (like turning or speeding up/slowing down). Also, I point out that Galileo discovered this idea in in the 17th century but didn't know it because "mass" hadn't been invented yet. It is a little long-winded, but then again, so am I. I hope you likes it.

Pondering equivalence

I teach a freshman-level course in which we study the ideas of Einstein's theory of General Relativity. It seems that one of the most difficult concepts for my students to comprehend is what Einstein described as the most beautiful thought of his life. It amounts to this: A falling person does not feel his/her own weight. In fact, it was this simple idea that started Einstein down the road to his General theory.

The canonical thought experiment is to consider yourself inside a sealed box, with no windows or other means to measure anything outside the box. Now consider two different scenarios.

1. You are standing in the box feeling your normal weight.

Are you and the box (a) sitting safely on the surface of Earth, both being pulled downward by Earth's gravity, or (b) being towed through space by a rocketship at an acceleration of 9.8 m s^-2 toward a hostile alien planet? Is there any observation or measurement that you could make from inside the box to tell the difference?

2. You are floating weightless inside the box.

Are you (a) adrift in the depths of space, far from any source of gravity, or (b) in free-fall toward the surface of the Earth about to be smashed upon impact? Is there any way to tell the difference in this situation?^[1]

Einstein contended that in each scenario, there was no experiment you could perform that would differentiate between the two possibilities^[2]. The conclusion then is that the effects of the force of gravity are equivalent to the effects of an acceleration through space. Moreover, gravity can be treated mathematically as such an acceleration, and anything being affected by gravity can be considered to be undergoing an acceleration.

This might sound like a simple statement, because a falling object is accelerating as it falls, but consider a person standing on the surface of the Earth, feeling their usual weight. The person is not moving, and yet one may consider that this person feels a force of gravity because he/she is undergoing an acceleration (just as if inside an accelerating rocketship). But if this person is not moving through space, then how can they be accelerating?

This is where the notions of "bent spacetime" and "worldlines" come in. Spacetime is the 4-dimensional combination of your 3 space-like coordinates (up/down, left/right, back/front) and your 1 time-like coordinate (tomorrow/yesterday). An object's worldline is the path it traces out in both space and time. So even if you are not moving in space with respect to the Earth when you stand still, you are still moving through time. Tracing out your worldline is like graphing your distance from home versus time as you drive around your neighborhood. If you include 2 space coordinates (like latitude and longitude), you have a 3-dimensional spacetime. If you also added altitude to have 3 space coordinates, then with time included you have 4 coordinates in your path; hence, this is called your worldline in "4-dimensional spacetime".

Einstein realized that when a worldline passes through a "mathematically flat" part of spacetime, no effects of gravity are felt. When the worldline passes through a mathematically "bent" part of spacetime, gravitational effects are felt. (This is like traveling in a car or other vehicle at constant velocity. You don't feel your speed unless the velocity changes, such as when you are speed up or when you steer the car around a corner.) He realized that gravity could be expressed as the side-effect of moving through bent spacetime and that massive things like the Earth or the Sun bend spacetime enough to make these effects very strongly felt.

What I find really interesting is that Galileo was already on the path to discovering the Equivalence Principle. Consider mass; there are actually two forms of "mass", but we don't usually bother to call them by different names as it turns out that they are really the same. the first is called "inertial mass"; Newton described the inertial mass as being the ratio of the force applied to an object to the acceleration it gains as a result of that force. This comes from his famous 2nd law of motion^[3]. The second is called "gravitational mass": This is the mass that determines an object's reaction to the force of gravity^[4].

Another way of expressing the Equivalence Principle is to say that an object's inertial mass is equal to its gravitational mass. However, there is no known reason why these two quantities should be related to each other at all, never mind being equal. In spite of that, when Galileo showed that all objects fall at the same rate, he effectively showed this to be the case^[5]! Since Galileo's experiments predated Newton's theory by about 60-70 years, Galileo lacked the mathematical formalism of Newton, and therefore had a somewhat limited notion of mass in the first place^[6].

[1] Common responses from students are that "you can tell when you're falling", or "the air in the box would be moving around in the falling box", etc.
[2] Before you go looking to pick this apart, please keep in mind that this is a "thought experiment", and Einstein didn't mean it was a perfect analogy.
[3] The formula F = m×a leads to m = F/a.
[4] For example, this is the mass that determines your weight W in Earth's gravitational acceleration g, where W = m×g.
[5] m_inertial = F/a, and m_{gravitational} = F/g. Galileo measured that all objects (no matter the weight) have the same acceleration, a, of 9.8 m s^-2, so m_{gravitational} and m_inertial must be equal!
[6] Galileo did invent the idea of "inertia" upon which Newton's work was based, so I think he did know something amount this concept, but it was Newton who developed the idea into something mathematical.

The Joy of Blogging

2008-07-14T15:36:00.000-05:00

Somehow it hasn't hit me yet. What do I want to get out of blogging? Is my blog less attractive to me now that I've been in a committed relationship with it for a while? I'd like to blog about my life experiences, and occasionally to express myself in new and different ways. Unfortunately, I haven't found a comfortable way to do that yet. I'm not an artist or a particularly funny person, so a web comic is out. I'm not famous, so blogging about my everyday life is not going to hold anyone's interest particularly well. Witty social commentary probably wouldn't work either. What I do know a good deal about is science, especially astronomy and physics, so I think I need to find a niche there somewhere. The role of bad science debunker is already taken, and although I seriously don't agree with them, I'm also not on a mission to take down anti-science movements like intelligent design. So what's my story? Why should anyone give a frak about what I think? Like I said... still waiting for it.

Two Animaniacs classics

2008-07-05T11:43:00.001-05:00

Wordle Astronomy

2008-06-16T21:51:00.000-05:00

Did I say I was done?

Wordle Who

2008-06-16T13:45:00.000-05:00

This is the last one, (crosses fingers) I swear!

Walden Wordle

2008-06-16T09:54:00.000-05:00

Ok- I had to do another. This could get addictive.

Whitman Wordle

2008-06-15T22:06:00.001-05:00

I found a cool website that lets you make word clouds out of anything you can cut-and-paste or type. Here's one I made using Walt Whitman's "Song of Myself". Neat.

Savage Chickens: Blogging Cartoon

2008-06-08T19:58:00.000-05:00

Follow this link
Savage Chickens: Blogging Cartoon

The more of these I see, the more I like!

I guess the USA can't have all the superheroes...

2008-05-28T23:48:00.000-05:00

"Captain Britain and MI:13" is a new Marvel comic by sometimes Doctor Who writer Paul Cornell. Check it out!

Welcome to your new home

2008-05-25T22:50:00.001-05:00

Phoenix lander successfully reaches the northern region of Mars!

Phoenix descends

2008-05-16T11:51:00.000-05:00

I have to pass along a link to a NASA video passed along to me at badastronomy.com. It's a video describing the hair-raising sequence of events that must occur in the 7 minutes that the Mars Phoenix Lander goes from interplanetary orbital velocity (over 12,000 mph relative to Mars) to landing (0 mph relative to Mars). Here's the link to the NASA page, which includes a high-res version. The embedded video is below. Enjoy.

Intergalactic Truthiness

2008-05-13T13:37:00.000-05:00

Information Overload

2008-04-25T17:40:00.001-05:00

Flickr and Yahoo! and Facebook...
Email and Updates and Blogging...
Chatting and Podcasts and Playlists...

Oh my!

Aha!

2008-04-25T11:11:00.000-05:00

From today's New York Times:

Study Suggests Math Teachers Scrap Balls and Slices
By KENNETH CHANG
Published: April 25, 2008
The real-world examples incorporated more and more by educators in recent years can impede math learning, an experiment found.

Some Things I Notice, part i (krauq.ne.knard)

2008-04-23T12:07:00.000-05:00

My brain interprets the mirror image of the word "quark" as the mirror image of the word "drank".

Estoy aprendiendo español

2008-04-18T11:02:00.000-05:00

I've really been enjoying the Coffee Break Spanish podcast. I'm only up to lesson 11 (about 1 year behind), but it has definitely filled an empty space in my brain that has been waiting for another language!

Muchas gracias y hasta pronto!

Cosmology, Animaniacs-style

2008-04-14T16:48:00.000-05:00

No science education would be complete without Yakko's Universe!

John Archibald Wheeler, 1911-2008

2008-04-14T07:38:00.000-05:00

Today's New York Times reports that John Wheeler has died at 96. The career of this extraordinary man touched upon a great many physicists of the 20th century. If you don't know anything about him, you are almost certain to recognize some of the names and fields of physics mentioned in the New Yorks Times article.

Of particular interest to me was the mention of Dr. David Finkelstein, whom I had the good fortune to meet and talk with last month.

The Day the Earth Stood Still

2008-04-11T12:52:00.000-05:00

I would like to draw your attention, if I may, to the upcoming re-make of this classic film. What do you think? Teh suck, or not teh suck?