Monday, February 27, 2017

When a Physicist Needs to Consult an Economist

As a physicist, I never expected to turn to the results of economics to advance my research. And I never have. But the death this past week of Kenneth Arrrow, a Nobel-Prize winning economist, reminded me of one occasion on which I had to invoke Arrow's work in my role as department chair to settle a dispute. Or rather, to show that it could never be settled. Arrow proved some mathematical results concerning elections that are so bizarre and so disturbing that it's difficult to believe them -- and these results are still largely unknown to most people.

Tuesday, February 21, 2017

Is Technology Taking Us Back to a Victorian Lifestyle?

Imagine making a telephone call in the early 20th century:  you'd just tell the operator the name of the person you wanted to reach, and the operator would connect you. This all changed with the development of automatic switching. It was progress of a sort -- no need to go through a human operator. Instead, you had to memorize a host of phone numbers and dial up (or later, punch in) the number you wanted. But now smart phones have taken us full circle. Just like our forebears, you can simply speak the name of the person you want to talk to (or, at worst, pull up a name on your screen), and the phone does the rest. Telephone numbers (and the need to remember them) are going the way of the buggy whip.

Tuesday, February 14, 2017

A Most Peculiar Holiday

Almost all physics departments host a weekly colloquium, at which an outside speaker presents a talk on a current research topic -- it's traditional to take the speaker out to dinner afterwards. When I began my first appointment as a junior faculty member (at Ohio State), this task often fell to the single faculty members -- our schedules were more open, and we were grateful for the free meals and the company.

One Tuesday evening, a group of five of us (all guys) took the speaker out to a local restaurant, only to discover that they didn't have a free table. This was a bit odd for a Tuesday night, but we simply went to our second-choice restaurant, only to discover that it was full as well. Finally, one of us realized that it was Valentine's Day! That's right, none of us, including the speaker, had remembered that Feb. 14 was of any significance. (This story has a happy ending -- we found a Chinese restaurant with available seating).

Friday, February 3, 2017

Confessions of a Cowboy Cosmologist

We recently watched The Magnificent Seven (the original, not the remake). It's a good movie, even if Yul Brynner, with his bald head and vaguely Eastern European accent, sometimes gives the impression that he wandered in by mistake from an adjacent movie set.

Which way to The King and I?
There's an odd similarity between the closing of the western frontier and my own research field of cosmology. In the early 1980s cosmology was the crazy no-holds-barred Wild West of science.  Cosmologists knew that the Big Bang theory was correct: the universe started out incredibly hot and dense and then expanded and cooled to form the space we inhabit today. But there was so much that we didn’t know. What was the universe made of?  Would it expand forever, or collapse back down and crush us all into an atomic soup? Where did all of the galaxies come from? We didn’t even know how fast the universe was expanding: the two groups measuring the expansion rate kept getting answers that differed by a factor of two! But life on the lawless frontier was great fun for theoretical physicists like me. With so little data to go on, we were free to speculate endlessly -- no theory was too outlandish to publish. We roamed the scientific landscape like cowboys, drifting from one new idea to the next. And theories sprouted like tumbleweeds, only to blow away when the next hot idea came along.

But then the experimentalists came to town and started fencing us in. First came the astonishing discoveries by astronomers mapping out the expansion of the universe on the largest scales. These investigators used distant supernovae, so far away that the light from these cosmic explosions took billions of years to reach us. These supernovae allowed the scientists to peer back in time and measure the expansion rate of the universe billions of years ago.  And they made a shocking discovery: the expansion of the universe isn’t slowing down under the force of gravity; instead, it’s speeding up! Next came the precision measurements of the radiation left over from the early stages of the Big Bang. This radiation contains tiny ripples that encode information about the universe:  its age, how much matter it contains, and what kind of matter it’s made of.

Friday, January 27, 2017

Life Under a Double Star

You've all seen the iconic image: Luke Skywalker on Tatooine, gazing into the sky at two suns. That's George Lucas's way of whacking us over the head with a two-by-four -- "Toto, I've a feeling we're not in Tunisia anymore."


Could life actually exist on a planet orbiting a binary star? Ivan Shevchenko has recently made an extraordinary claim -- he argues, in this paper, that life is actually more likely to develop around binary stars than around a single star like our Sun. In Shevchenko's view, we are the weird ones, while life on planets like Tatooine should be common. 

Sunday, January 22, 2017

Gilligan's Island: Time-Shifting your Children's Popular Culture

A bit off the topic of this blog, but I have an article at National Review Online about raising children in the current cultural milieu; you can read it here. Neither my background in science nor in science fiction qualifies me to write the article; it's based on my experience in raising six children.

Wednesday, January 18, 2017

Television Science Fiction Trivia Question

Lost in Space premiered when I was six, which is probably the optimal viewing age for that show. (Talking vegetables, anyone?)  So naturally I was hooked. I was a bit too young for Star Trek when it appeared the following year, but, like many others, I became a fan of the show after it went into syndication -- it remains my favorite television SF series.

So here's today's trivia question: one of the main actors from Lost in Space and one from the original Star Trek appeared together as regulars in a later science fiction television series. Which one was it?





The answer is Babylon 5 (1994-98).  Bill Mumy (danger, Will Robinson) appeared as a sort of acolyte for the main character from one of the alien races, while Walter (nuclear wessels) Koenig played a rather sinister telepath. The latter was a much more interesting role than Koenig's character on Star Trek. (And just where, exactly, did Koenig get his Russian accent? He was constantly pronouncing his v's as w's -- "wodka" instead of "vodka" -- while a real Russian would do just the opposite.  And don't get me started on the name "Chekhov." When I later studied Russian literature, I could never take that particular writer seriously).

Babylon 5, unusually for television at the time, had a long-term story arc, although unlike many SF shows, the writers appear to have planned ahead and did not end up writing themselves into an unresolvable corner (see, e.g., Lost). The final resolution of the story arc seemed a bit too abrupt, and the last of the five seasons felt very much tacked-on (it was tacked-on -- there was doubt whether the show would be renewed for a final season), but all in all it's an excellent series -- my second-favorite SF television show.

Bonus:  June Lockhart, who played Will Robinson's mother, also appeared in a single episode of Babylon 5. And there were several other shows employing actors from both Star Trek and Lost in Space. One was The Twilight Zone, which featured quite a few actors from both series, but then again, everyone and his brother appeared on that show. And another was Bonanza, which featured, at various times, Leonard Nimoy, James Doohan, and DeForest Kelley from Star Trek and the actors who portrayed Zachary Smith and Will Robinson's father from Lost in Space. Now that's just weird.

Friday, January 13, 2017

A Relic of the Big Bang (Not)

Helium is the only element produced in large quantities in the early universe. About 25% of the "ordinary" matter in the universe is in the form of helium, and it was almost all produced when the universe was only a few minutes old and very, very hot (about a billion degrees).

So does this mean that when you buy a helium balloon at the grocery story, you're holding a bit of the Big Bang right in your hands? Unfortunately, no. The helium for our balloons doesn't come from the early universe at all -- it comes from Texas.

Tuesday, January 3, 2017

Vera Rubin and Dark Matter

Somewhat lost amid all of the publicity over the deaths of Carrie Fisher and Debbie Reynolds was the death, on Christmas day, of Vera Rubin. Vera was one of the most influential cosmologists of her generation, and a legitimate contender for the Nobel Prize. I only met her once, at a conference at Irvine in the early 1990s.  (Tom Hanks was there as well -- evidently he was thinking of making a movie about cosmologists but decided we were too boring.  A wise decision).

Friday, December 9, 2016

The Marvelous Museum of Science and Industry

When I was 7 years old, my parents took my brother and me up to Chicago for a short visit -- it's one of my most vivid childhood memories. We visited all of the Chicago museums, but the one that made the deepest impression on me was the Museum of Science and Industry. I can't honestly claim that this was the single experience that set me on my path to a career in science, but it was certainly a major influence. We don't always appreciate the huge impact that apparently trivial experiences have on young children.

What was exhibited at the museum back in 1966? We walked through the German WWII submarine, but I didn't particularly like it. My favorite was a nuclear physics exhibit sponsored by the Atomic Energy Commission. It included a large push-button map that allowed you to "prospect" for uranium, a mock-up of a "hot cell" manipulator for handling radioactive materials, and screen with a dial for producing images of atoms with various numbers of electrons. (The last of these must have made a deep impression -- I later authored a textbook on quantum mechanics). A dive through Google determined that this exhibit was called "Atomsville, USA," and it was presented first at the 1964 New York World's Fair, and then made a brief stop in Chicago for a few months in 1966. Remarkably, you can see a video of it (in its World's Fair incarnation) here.

And what else was at the museum 50 years ago? I vividly remember the "World of Hardwoods," which included the giant face of Paul Bunyan staring back through a window, and a push-button board under a gigantic light-up globe: you could push each button to see where in the world a particular hardwood tree could be found. The AT&T exhibit had three phone booths, from which you could call someone in another booth or talk to a cartoon character. AT&T also sponsored a video phone linked to the science museum in Philadelphia -- my brother and I were too shy to use it.  (It took 50 years for this technology to become a computer-aided everyday reality). There was the famous walk-through heart, and a bizarre theater with mechanical parts of a cell (or were they molecules?) sliding in and lighting up. An internet search revealed that this exhibit was called "Chemical Man."

What has become of these old exhibits?

Monday, December 5, 2016

Worst. Airline. Ever.

I've been flying for 40 years, and after all this time I've finally discovered the worst airline out there. What's more, I'm confident that most of you will agree with me.

I probably should have suspected a problem when I saw the new signage over the entrance at Midway Airport: "Abandon All Hope, Ye Who Enter Here." I was due to fly out of Chicago on Sunday afternoon. But my flight was cancelled, and I didn't make it back home until 1:00 am. In the end, it turned out to be for the best -- the unexpected layover let me take my daughter to the Museum of Science and Industry, which is one of the world's best science museums. I'll have more to say about the museum in my next post.

So the worst airline ever? That's easy -- it's whichever one you flew on most recently.

Update: My disparaging comment about Midway Airport was, of course, a joke. Midway is not at all like hell. It more closely resembles purgatory -- hordes of people sitting around, with no idea when they are going to get out. Then every so often an angel appears and takes away a large crowd of them into the sky. Definitely purgatory.

Friday, December 2, 2016

A Quantum Limit on How Fast You Can Talk

Is there a fundamental upper limit on how fast we can communicate? If you're like me, that limit is set by your despised cable provider (in my case, Comcast, which avoids being the most disliked company in America only by virtue of being ranked ahead of Time-Warner in most of those surveys).

But recently, Raphael Bousso at the University of California has proposed that quantum mechanics sets an absolute upper limit on how fast information can be transmitted. The limit he proposes in his paper is not all that interesting, but the reason for the limit is rather astonishing.

Monday, November 21, 2016

How will the Universe End? The Big Rip and the Little Rip

Some say the world will end in fire,
Some say in ice.
I say it will end in an infinite-density singularity driven by a scalar field with a negative kinetic term.

Who knew that Robert Frost had such a deep grasp of cosmology?

A couple of weeks ago, New Scientist asked me to comment on a recent paper about the Big Rip. What's that all about?

As the universe expands, all of the ordinary matter becomes less dense. That makes intuitive sense -- if you have a fixed amount of matter in an expanding box, then the amount of mass per unit volume has to go down. But in 1999, Rob Caldwell at Dartmouth made a radical suggestion: suppose that as the universe expanded, the density of the dominant form of energy increased instead of decreasing. This leads to very weird behavior -- the Universe enters a superaccelerated phase, with the expansion factor going to infinity at a finite time, at which point the equations break down at a singularity. It was later pointed out by Caldwell, Marc Kamionkowski, and Nevin Weinberg that as the universe approaches this singularity, it expands so rapidly that all of bound structures in the universe would be torn apart. First galaxies would dissolve, then the solar system would disintegrate, followed by the destruction of the earth, our bodies, and then the atoms in our bodies and the nuclei inside the atoms. And we would be dead by then. Caldwell, Kamionkowski, and Weinberg coined the term "Big Rip" to describe this fate for the universe.

So what was my contribution to this? Nothing, actually. I later worked with Paul Frampton and Kevin Ludwick to come up with the "Little Rip." In what sense is the Little Rip "littler" than the Big Rip?

Friday, November 18, 2016

A Dubious Honor

Today I received my subscriber's copy of the Dec. 2016 issue of Analog, which includes my short story, "Fermi Meets Sagan."  I also received a card in the mail letting me know that as of the next issue, Analog is moving to a bimonthly publication schedule, putting out six issues a year. So I have the dubious distinction of having a story appear in the final monthly issue of Analog. Ever.

Monday, November 14, 2016

Reality Intrudes

Blogging will be light to nonexistent until the beginning of December, as I am working on a grant proposal to the NSF. Given the increasing fraction of time that my colleagues (especially in biomedical research) seem to devote to proposal writing, along with a decreasing success rate, I am beginning to wonder if the research funding system is starting to impede scientific research instead of promoting it. But that's a discussion for another time.