A 10-Year-Old Asks about Black Holes

I have a 10-year-old cousin who is very curious about the world, and physics in particular.  When his mother sent me two very interesting questions that he asked about black holes, I had fun coming up with some answers for him.  His questions and my answers are reproduced below. (Yes, some of the language isn’t quite as precise as it should be, but I intentionally glossed over a few details. Hopefully I didn’t say anything wrong as a result.)

If a black hole “sucked in” only photons, would it increase in mass?

Photons “die” when they interact with something, but if they do die, then what are they interacting with in the black hole?

These are two great questions, and I had fun coming up with answers to them. I gave a short answer, but any good physics question brings up a lot of related ideas, so I also put a longer answer that brings up some other ideas.

Short answer:
Yes. Einstein taught us that energy and mass are two aspects of the same thing. Even though the photons are massless on their own, their energy can increase the mass of the black hole when they are absorbed. The event horizon prevents any information from escaping a black hole, so we can’t know exactly what the photon interacts with.

Longer answer: Continue reading ‘A 10-Year-Old Asks about Black Holes’


If you’re not a nerd…

… then you’re just admitting that you’re boring.

“Nerds like us are allowed to be unironically enthusiastic about stuff. We don’t have to be like, ‘Oh yeah that purse is okay’ or like, ‘Yeah, I like that band’s early stuff.’ Nerds are allowed to love stuff, like jump-up-and-down-in-the-chair-can’t-control-yourself-love it. When people call people nerds, mostly what they are saying is, ‘You like stuff’, which is just not a good insult at all, like ‘You are too enthusiastic about the miracle of human consciousness’.”

“Saying ‘I notice you’re a nerd’ is like saying, ‘Hey, I notice that you’d rather be intelligent than be stupid, that you’d rather be thoughtful than be vapid, that you believe that there are things that matter more than the arrest record of Lindsay Lohan. Why is that?’ In fact, it seems to me that most contemporary insults are pretty lame. Even ‘lame’ is kind of lame. Saying ‘You’re lame’ is like saying ‘You walk with a limp.’ Yeah, whatever, so does 50 Cent, and he’s done all right for himself.”

– John Green

(via stackmack)

We’d all be better off if we all just admitted that we’re nerds about something. Stop chasing this nebulous idea of The Cool and just like the stuff that we like and do what we want to do unapologetically.

Budget Cuts for US Science

The proposed Republican budget includes huge cuts across the board, especially in health and science areas. The cuts would come halfway through the fiscal year, making them even more onerous. The cuts would have the effect of slashing the remaining balances of the NSF and NIH budgets by almost 10 percent and the DOE Office of Science and NIST by more than 30 percent. For example, the Tevatron, the large accelerator at Fermilab, already due to be shut down in September due to lack of funding, could be shut down almost immediately. There will certainly be layoffs, and national labs may have to shut down completely for some period. President Obama’s proposed budget is much more favorable to science overall.

The House of Representatives has already passed their version of the bill, but the budget battle is far from over.  Click here to write to your legislators to oppose the passage of such huge cuts to American science.

See this post at Cosmic Variance for more on this issue.

Moving Beyond Petroleum — Bike Sharing

In light of the Deepwater Horizon oil spill in the Gulf of Mexico, many Americans are understandably angry at BP, and want to do something about it.  This has led to calls for boycotts of gas stations bearing the BP logo.  However, this would prove ineffective, as BP does not own most of these stations.  In addition, BP is a wholesaler of petroleum products, so you may be buying gas from BP no matter what station you buy from.

The appropriate response if you want to hurt BP, or, more importantly, try to prevent further environmental damage, is not to look for the most moral oil company.  Instead, take BP at their word, and move Beyond Petroleum.

How to do so? I’ve written about this before, here and here.

Maybe you’re not in a position to make a dramatic lifestyle change like going car-free.  But with a little planning, it’s not too hard to replace several car trips per week with bus or bike trips.  And if you’re lucky enough to live in Minneapolis, you have a new option to make bike riding even easier: Nice Ride Minnesota, a new bike-sharing program.

Based on the Bixi model, recently implemented in Montreal, the system allows users to pay a small subscription fee ($5/24 hours, $30/month, $60/year), and then take one of the 700 neon green bikes out for a spin, returning it to one of 60+ docking stations at the end of the trip.  The first half hour is no additional charge, so it encourages short trips, although the density of the stations in the covered areas makes it easy to hopscotch across town.  The system currently covers downtown and surrounding areas, including the University and uptown neighborhoods, and there are plans to expand.

Some have been dubious of how popular the system could be, but I have seen many of the bikes daily since the program was launched less than a month ago.  In fact, over 10,000 rides were taken during the first 20 days of the program.  This is encouraging news, not just for the success of this program and others like it, but also for encouraging bicycling as a common mode of transportation, not just recreation.

If you’re in Minneapolis, I encourage you to try it out! It’s a small investment of time and money to see just how bike-able the city is.  It’s an easy and enjoyable way to travel, and helps you feel more connected to the neighborhood than just driving through, windows up, with the radio on.  (Not to mention the health and environmental benefits.) After trying it out, you may find it worth your while to invest in a longer-term subscription and make Nice Ride part of your regular commuting and recreation plans.

Continue reading ‘Moving Beyond Petroleum — Bike Sharing’

Buried by Papers

A recent article in The Chronicle of Higher Education blames the increased number of published scientific articles on “an avalanche of low-quality research,” and claims that this avalanche is damaging academia. I agree that there are certainly problems associated with the large volume of published research, but is it truly the crisis that the article claims?

It becomes more difficult finding articles for a particular area of interest, as the arXiv feed for the limited area of high energy phenomenology dumps 20+ articles into my RSS reader every evening. This is not entirely unmanageable, as I mostly scan abstracts for anything related to my current work, and ignore the rest.  Plus, it is 2010, and a search function can turn up a paper on any topic I desire.  However, the number of articles makes it more difficult to keep abreast of more subfields, and tangentially-related, though helpful, articles in other fields go unnoticed.  Cross-pollination of ideas has been essential throughout the history of science, but it is more difficult in this era of increased specialization.  The increased number of papers in all areas can’t be helping matters.

Continue reading ‘Buried by Papers’

Talent is a Process

With the semester over, I was able to dive into a couple of books that I had been waiting to read.  On the surface, they seem very different in subject matter, but reading them in succession allowed for some interesting insights.

The first book that I read was David Shenk’s The Genius in All of Us, whose thesis is that the usual conception of talent is incorrect.  Rather than being innate, talents are developed over years of sustained practice. (The canonical 10,000 hours of practice to become an expert, popularized by Malcolm Gladwell’s Outliers.)

The book, which is shorter than it looks due to the notes that fill about half of the volume, covers a variety of interesting topics to help debunk the notion that talents and other personal qualities are inborn.  The author describes a new understanding of genetics by throwing out the classic “nature vs. nurture” distinction, and arguing that the two are inextricably linked through the interaction of genes with their environment.  He goes too far with this in the final chapter, discussing the impact of epigenetic material (stuff other than DNA) on gene expression.  While there seems to be some credible and recent research on the effects of lifestyle on heredity, his assertion that “we may well be able to improve the conditions for our grandchildren by putting our young children through intellectual calisthenics now” seems to me to be a gross overstatement of the research.  Although much of the rest of the book is couched in this genetic argument, it isn’t dependent on his perhaps flawed understanding of the biology.

To determine the true sources of talent, Shenk discusses everything from the history of intelligence testing and “gifted” designations to the reasons for the athletic dominance of certain ethnic groups in their chosen sport.  (It is interesting to note that people used to wonder what genetic gifts allowed Jewish players to dominate basketball in the 30s and 40s, in much the same way that people discuss black players today.)  However, it seems that the most important factor for the development of talent is still the same: deliberate practice.

Deliberate practice requires more than just hard work, and it is not achieved by simply “putting in your 10,000 hours,” although both hard work and large amounts of time are certainly required.  Instead, it involves pushing beyond one’s current skill level to the point of failure, then picking up the pieces and trying again.  This type of practice is not necessarily enjoyable, but pushing beyond current limits is the only way to improve.  The practice activities have to be focused on particular aspects of the performance, with appropriate refinement and feedback for improvement.

It’s easy to imagine this deliberate practice as applied by a musician: seeking out more challenging pieces of music to play, focusing on the most technical measures, playing them repeatedly in solo practice, and later for a demanding instructor.  Or we can imagine the chess student, poring over volumes of opening and closing strategies, learning the tricks of the masters through solo study of their games, before testing those skills against ever tougher competition.

And of course, we can see this playing out with athletes, as it did in the other book I read to start my summer: Chris Ballard’s The Art of a Beautiful Game, which has chapters that discuss several of the basic components of basketball.  Though the book is wonderfully written, and a great read for any basketball fan, I couldn’t help but notice a strange battle playing out between the belief in natural athletic talent with the evidence of his descriptions of the players’ relentless practice habits.

Continue reading ‘Talent is a Process’

NCAA Physics Tournament

It’s been a long time since the last NRC rankings of physics departments were published, and it seems like the new rankings have been “two months away” ever since I started looking at graduate schools.  Maybe the NRC should use the NCAA Basketball Tournament to help settle some discrepancies in rankings.

With this in mind, I filled out a bracket based on the rankings of their physics departments.  You should be able to see my full bracket here.  (In the case of schools where I didn’t know about either department, I took the higher seed.)

Things to look for:

Continue reading ‘NCAA Physics Tournament’