The Half-Astrophysicist Blog

A Couple of Good Reads

It’s well known that I am a big fan of Science Friday.  Last week’s show had interviews with two authors that intrigued me.

The first interview was with Jeff Potter, author of the soon to be released Cooking for Geeks: Real Science, Great Hacks and Good Food. There is a Cooking for Geeks website where you can learn things like how to make ice cream in 30 seconds.

Be sure to check out the blog for all the latest geek cooking tips.

The second interview is with Danica McKellar and covers the next book in her series of math books for girls, Hot X: Algebra Exposed.  McKellar first gained fame as Winnie on the Wonder Years before earning a degree in math and appearing on the West Wing.  She keeps chugging along and I am already trying to avoid coming up with semi-crude names for the inevitable Calculus Books (can anyone say Calculus Coed?  That’s one of the milder things that crossed my mind!)

They are both entertaining interviews.  If you’ll excuse me, I am hungry!


August 8, 2010 Posted by | Education, general science, Math | Leave a comment

Kitchen Science…Try This at Home

One of my favorite podcasts is the Naked Scientists (and its sister podcast, Naked Astronomy).  In spite of its name, this is a perfectly safe podcast for almost all audiences (save for an occasional mild double entendre).  Both podcasts originate from Cambridge University.  A rotating cast of faculty members tackle the science news on a weekly basis (monthly for Naked Astronomy) in a humorous fashion aimed at a general audience.

One of their weekly segments is called Kitchen Science.  Kitchen Science focuses on experiments that you can do at home.  And since its does not originate in the U.S., they do more fun experiments that a U.S. based broadcaster would dare air for fear of being sued.  Recently, they showed how to build a homemade cloud chamber to watch cosmic rays and radioactive particles decay, the science of Pop Rocks, and how to make a fire tornado.

Many of the activities have videos showing how to do them as well as the segments from the radio show.  They are great activities to play with at home or for teachers to check out for classroom use. The podcast and all materials on the website are free, so the price is right for the cash strapped (and many of the activities have low cost, using readily available materials).

So it’s a fun site to explore, whether you are a teacher looking for ideas or a bored tinkerer looking for something to put together and play with in your spare time.

July 28, 2010 Posted by | Education, Fun Stuff, general science | Leave a comment

The Trinity Site

This last weekend I visited the Trinity site in New Mexico, famed for being where the first atomic bomb was detonated on July 16th, 1945.  It is open to the public twice a year, the first Saturday of April and October.

I stayed in Socorro Friday night.  New Mexico Tech was on my short list of colleges so it was interesting to see it 20 some years later.  I came to the conclusion that I made a good choice and probably wouldn’t have liked Socorro as much as Grinnell.

I got to the site pretty early Saturday morning, a little after 8am.  Took about 15 minutes to get through the line at the entrance.  The site is on the White Sands Missile Range so you have to show ID to get in and they tell you that you are not allowed to stop and take photos until you get to the ground zero site (they didn’t say anything about snapping pictures out of your window while driving there, however, so I have a few interesting photos!)  You drive along and see all  kinds of intersting things with weird names, probably acronyms and you can play the “Guess That Acroynym” game.

There was no line for the bus when I got there, so I boarded and went to the Schmid/McDougal House.  This unassuming ranch house is where the plutonium core of the bomb underwent final assembly.
Here is the room where it happened.

They made it a “clean room” by putting plastic over the windows and telling people to wipe their feet when they came in…hard to believe it made much difference in the desert.

They restored the house and tried to make it as close as they could to its appearance in 1945.  The house is surrounded by ruins of the barn and a couple of windmills outside.

One thing that impressed me is the solemness of the occasion.  People spoke softly and showed a lot of respect for the house and the site.  There are some displays in the house with old pictures from the summer of ’45 and information on the family who built the house and its history.

Then back on the bus to go to ground zero.  In the parking lot are a couple of small booths, one stocking primarily books on the atomic bomb and another with the Trinity t-shirts and baseball caps.  A food vendor is also set up there (along with the obligatory porta potties).

Ground Zero is about a quarter mile walk from the parking lot and a fence now surrounds the site.  Right before you enter, there is an exhibit on radioactivity staffed by an enthusiastic bunch with Geiger counters showing off the radioactivity emitted by everyday items such as cat litter.  A historic marker has been erected at Ground Zero.

The bomb was at the top of a 100 foot tall tower.  One of the four bases still is visible.

And they had a replica of the Fat Man Casing.  Fat Man as dropped on Nagasaki.

There is no visible Trinitite and very little visible evidence of what happened there.  There was a bus tour there and the tour guide gave a great talk about the morning of the blast. People were again very somber and respectful.  There was no sign of anyone engaging in politics one way or the other.  It was presented as history, with all the good and bad that goes with it.

I will say that I am glad the U.S. developed this technology rather than Germany or Japan.  Nuclear technology has changed the world, and not just militarily.  It has countless applications from energy production to medicine.  As terrible as nuclear weapons are, two superpowers both armed with them may have prevented some major wars in the second half of the 20th century.

I know some people argue it was immoral to use the bomb.  I have some sympathy for that argument.  Nuclear weapons are the ultimate WMDs and we used them.  We didn’t fully understand everything they did and the effects of radiation poisoning at the time, but we knew one plane could kill tens of thousands of people (or more) instantly.

Others argue we were justified using a variety of arguments such as we didn’t start the war (which I think is irrelevant) or that fewer people died in the bombings than would have in an invasion (which is harder to refute, but does that make it right?)

I have thought about it and come to the conclusion that is was the best of bad choices.  I would say I give it qualified support.  If we did not use the bomb on Japan, we would not have known the horrors of nuclear war.  When new weapons are developed, there is a tendency to use them in conflict.  Look at chemical warfare in WWI.  They were used until the world community decided they were too horrific to use in war.  I don’t think we would have learned that lesson without someone using nuclear weapons…if that first use came in a US-USSR war, the casualties could have been in the millions or higher.

Let us never forget the lessons of Trinity, Hiroshima and Nagasaki.  The future of humanity depends on it.

April 6, 2010 Posted by | general science | 1 Comment

The Crystal Cave

I am going to look down today instead of up.  Just last week, there was an expedition to the Crystal Cave of Giants in Niaca, Mexico.  This cave was discovered in 2000 and contains some spectacular crystallized gypsum.

You can see that they aren’t kidding.  The suit is due to the fact that it is hot and humid in there…112 F (50C ) and 90% humidity.  You don’t want to hang out there long without a cooling suit.  The crystals are up to 11 meters long and weight up to 55 tons.

This is not exactly my field, so I will let you read the account of the journey and see the other pictures. National Geographic has a nice story summarizing how they formed as well.

September 10, 2009 Posted by | general, general science | Leave a comment

Rainbows…I Have Got to Get a Polarizing Filter!

I was outside as a storm was rolling in and saw a nice rainbow.

IMG_1638I was looking at it with my sunglasses on…I have polarized sunglasses.  Rainbows are polarized so you get a very different view of them if you rotate your sunglasses 90 degrees.  I should get a polarizing filter for my camera, but I don’t have one so I just held up my sunglasses in front of the camera.

IMG_1640So you can see the rainbow nicely.  I rotated the sunglasses 90 degrees and snapped the next photo mere seconds later (no visible changes took place in the rainbow if you looked at it with your eyes).

IMG_1641Note how the rainbow almost totally disappears!  What’s up here?

Okay, rainbows always appear opposite the Sun (this is looking east as the Sun was in the west).   Blue light slows down more than red light when it passes into the raindrop and bends more so the blue and red light (and all the other colors) get separated.  This process is called dispersion.  The light then reflects off the back of the raindrop and heads toward you (and undergoes a second round of dispersion when it leaves the raindrop).  The angle of reflection necessary to see a rainbow is about 42 degrees.

When light reflects off of a surface, it becomes polarized.  If the angle is right, it can become almost completely polarized.  For rainbows, the polarization is about 94% for the primary rainbow (and 90% for the secondary rainbow, when visible).  By turning my polarizing filter so it is exactly perpendicular to the angle of polarization of the rainbow, I can block almost all the light at least all that my camera can detect!)

Next time I am at a photo shop, I am buying a polarizing filter for my camera.

August 24, 2009 Posted by | Fun Stuff, general science, Optics | 1 Comment

The Feyman Lectures: Project Tuva

I saw an article on CNET today about Bill Gates and Project Tuva.  Project Tuva is putting classic science videos online and they have picked a doozy to start out: A series of physics lectures by Nobel Prize winner Richard Feynman.

Feynam is one of the true giants of 20th century physics as well as a legendary character who had a real zest for life.  If you have never read Surely Your’re Joking, Mr. Feynman, go get it now.  It’s not a hardcore physics book (although there is some science in it) but rather a collection of short stories about his life from playing with radios as a child to working on the Manhatten Project to his Nobel Prize.  It is the most laugh out loud science book you will ever read (my favorites are the mischief he caused at Los Alamos while learning to crack safes).

The name, Project Tuva, is a tribute to Feynman.  He had a quest to travel to Tuva which is related in the book Tuva or Bust.

Feyman is not just known for his brilliant science and quirky personality, but his ability to explain science in terms others could understand, a master teacher on top of it all.  These videos give us a glimpse at one of the most remarkable teachers and scientists of the last 100 years.  Watch and enjoy…thank you Bill Gates.

July 16, 2009 Posted by | general science, Science History | Leave a comment


I was catching up on podcasts at the gym this morning and listened to the most recent episisode of Radio Lab on stochasticity.  Stochasticity is  fifty cent word for randomness.  Most people think they know random when they see it, but frequently find patterns where there is really randomness.

The show starts off with a very interesting story about a young girl letting go a balloon with a note tied to it.  It is found and, at first, the commonalities she shares with the girl who found it seem extraordinary…but only if you look at the things they have in common of course.  A quick examination of their differences makes you wonder a bit more.

They discuss one of my favorite games I did with students occasionally.  They do it with two groups but I would do it with 5-7 depending on class size.  The game is you give one group a coin.  You tell them to flip it 10o times and write down the series of heads and tails (using h and t).  The other groups are just to write down (what they think) is a random series of h’s and t’s without flipping the coin.  I leave the room so I don’t know which group has the coin.  I then come back a few minutes later when they are done and tell them which group was flipping a real coin based on their sequences. What they think is a random sequence has easily recognizable differences from a real random sequence.  I am going to make you listen to the episode to hear one way of doing this (they don’t reveal all the tricks, but the others are similar to the one they use).

We are programmed to see patterns.  That served us well when we were dodging tigers, but now we can see patterns where there are none.  From an evolutionary standpoint, we not recognizing a tiger attack results in death and a false positive results in a change of underwear at worst.  Therefore, we tend to have a lot of false positives when it comes to recognizing patterns.

We see everything from the face of Jesus on a tortilla to Elvis in the Eagle Nebula (recognizing faces has its whole own subcategory).  Gamblers think they recognize patterns (reinforced by bells and flashing lights) that keep them gaming.  They have an interesting statistical analysis of athletes who get the hot hand and find it usually isn’t as hot as you think it is.

People base their lives on patterns that don’t exist.  Everything from who they date and marry to their stock market picks and the lottery tickets they buy.  We all could use a little better understanding of statistics and how to pick out meaningful patterns.

June 23, 2009 Posted by | Fun Stuff, general science | 1 Comment

The Spooky Eyed Spookfish

I like optics so this caught my attention.  The brownsnout spookfish is now the first vertebrate to use mirrors to focus images in its eyesYou can see the strange looking spookfish appears to have four eyes, but since the two on the left and the two on the right are part of the same structure, biologists consider them two eyes.

Spookfish live at a depth of about 1000 meters where there is very little light.  The two eyes pointing upward (the orange spots) use a traditional cornea to focus light much like our eyes (most of the focusing power of our eyes comes from the cornea.  The lens is used to fine tune the focus for nearby or far away objects…as you get older the lens loses flexibility which is why you may be able to see far away just fine but need reading glasses).  The other part of the eye points downward (the black spots in the image).  Light from below is reflected off a mirror like surface in the eyes and onto the retina.  The mirror shows not only what is directly below the fish, but out to about 50 degrees in all directions (which is useful for avoiding predators!)  There is evidence that the fish can slightly change the shape of the mirror to focus the images much like our lens changes shape to help us focus.

Some animals (like housecats) have a reflective layer called the tapetum to help them see in dim light.  The tapetum lies behind the retina and increases the sensitivity to dim light but does not focus the light.

The spookfish has been known for over 100 years.  However, a live specimen was never caught until recently.  The deep sea is truly one of the final frontiers on Earth with lots of odd treasures waiting to be discovered.

February 18, 2009 Posted by | Biology, general science | Leave a comment

The End of the Rainbow

There is an interesting discussion about rainbows going on over that the Orange County Register (a former student of mine sent this to me and asked my opinion) involving a picture that some think shows the end of a rainbow. Some are questioning if the image is photoshopped.  You can see the picture in question on the right.

Okay, rainbows do not have an end. If you have ever been in a plane, you can see rainbows form complete circles! I have seen this and it is pretty cool. What they mean obviously is the point where the rainbow hits the ground. To me, I see what they call the “end” of a rainbow all the time. Sometimes it appears over a mountain, others over the ocean, sometimes over a house.

Let’s back up. In order to get a rainbow, the Sun must be low in the sky. There must be rain on the opposite side of the sky from the Sun from where you are standing. Sunlight passes through the raindrops and reflects off the back. However, as sunlight passes through the raindrops, it also bends due to a phenomena called refraction. Blue light refracts more than red light. Therefore, when the reflected light heads back to you, it has been split up into different colors. You can see the path light takes through a raindrop in the image on the left and notice how the colors separate.

You can fine the center of the circular rainbow by drawing a line from the Sun and through yourself and extend it away on the other side. This will show you the center of the circle somewhere underground (except for rare cases when you see a rainbow right after sunset). The circle forms a cone with you at the tip an an angle of 42 degrees to the rainbow.

So let’s go back to the photo. It was taken on highway 241 North in California at 4:59pm on February 7th. The GPS cooridnates are given on the OCR site. I popped them into my computer and found the Sun was 15 degrees high in the sky at an azimuth of 239 degrees. The center of the rainbow is at 59 degrees putting the left side of the rainbow at about 17 degrees (slightly east of north) which jibes well with someone driving north on 241 seeing this site. Since the Sun is low, we see almost half the circle and this rainbow has a nice steep arc which also agrees well with the time and geometry of the situation.

Some in the discussion argue this is a “sparybow” created by spray kicked up by the car tire (which also gives the nice illusion of the end of the rainbow).  It does appear the tires are kicking up spray that makes the bottom of the rainbow brighter.  However, the person who took the picture says they say an entire arc of the rainbow. That single car could not kick up enough spry to create a rainbow that extends that high in the sky!  I suggest you could call it a hybrid…the bottom part may be a “spraybow” but you definitely have a rainbow there as well.

So what do the people in that car see?  They see a rainbow in front of them!  As you move toward a rainbow, it continually moves away from you.  You can never reach the true end of a rainbow no matter how hard you try.  In fact, everyone sees their own personal rainbow.  The light I see entering my eye comes from a different set of raindrops than a person standing next to me becuase the angles between the person and the Sun change!

So enjoy the rainbows…but don’t go chasing that pot of gold!

February 13, 2009 Posted by | Fun Stuff, general science | Leave a comment

Satellites in Collision

There have been small objects colliding in space before, but now we have two full fledged satellites that have run into each other. An Iridium communication satellite collided with an old Russian Cosmos Communication satellite. This collision created hundreds of new pieces of debris that could in turn collide with other satellites. The collision occurred about 500 miles over Siberia.

The first thing most people are concerned about is the International Space Station or Hubble. Both of these orbit a lot lower, so they are not in immediate danger from this debris. However, there are a lot of satellites in similar orbits to these to that are now at increased risk of collision with space debris.

A company called Analytic Graphics created a pretty neat animation of the collision and the resulting debris cloud (based computer models of course).

You can see the debris spread out fairly quickly. When they add all the other objects up there it starts looking pretty crowded.

You can even listen for radar echos from the debris cloud.  Spaceweather is streaming the Air Force Space Surveillance Radar signals from Texas.  The next time to listen is 11:56pm to 12:07am EST tonight.

February 12, 2009 Posted by | Environment, general science | Leave a comment