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Contents of the Universe: Dark Matter and Dark Energy

Amazingly, 95% of the make-up of the universe is stuff we can't see, according to cosmologists. Find out more about dark energy and dark matter, which far surpasses the amount of visible mass in the universe.

Physics Spotlight10

Tyson on Minorities in Science

Friday April 18, 2014

Neil deGrasse TysonAt a panel on atheism and science, there was a question about why proportionally so few women pursue careers in the hard sciences. The question relates to comments from Larry Summers about whether there is perhaps some neurophysical explanation for the difference between the genders in this area.

Astrophysicist Neil deGrasse Tyson stepped up with a fantastic response, based upon his own experience having to deal with all of the challenges of being a minority in a white-dominated field of study. Though Tyson has never been a woman, he's always been black, and the challenges are somewhat similar in the sorts of hurdles they have to jump. Here's the link to the segment on YouTube (though if you want to back up and watch the whole video, that's fine too).

Of particular interest, though, is Tyson's observation that he looks behind him and laments the overall lack of progress in getting minorities engaged in the hard sciences. Where are the people coming up in his wake, benefiting from the challenges he's had to face and overcome? To be sure, Tyson is not the only black scientist ... not even the only prominent black scientist. Just within theoretical physics, James Sylvester Gates and Clifford Johnson come to mind as not only great scientists, but also great science communicators. (Gates is actually about 8 years older than Tyson and Johnson is English.)

Many of the challenges that these men have had to face are, sadly, still in place even today. Dr. Tyson recounts an experience, for example, where he was targeted for investigation when store alarms went off. One has to wonder if he was perhaps targeted because of his spiffy astronomy-themed vest or because they were concerned that he had stolen Magnum P.I.'s mustache.

So, Tyson concludes, before we begin looking for biological explanations for different demographic representations in the sciences, we need to be sure that the social explanations are completely ruled out.

This panel is from several years ago, but it just got bumped to my attention through a viral treatment through the Upworthy website.

Image: Dr. Neil deGrasse Tyson, astrophysicist, at a 2005 meeting of the NASA Advisory Council in Washington, DC. Public Domain from NASA

White House Shows How Little Money Goes to Scientific Research

Wednesday April 16, 2014

Well before tax day comes around, the federal government already has a pretty good idea how they're going to spend the money. In an effort to make at least token steps toward transparency, the White House website has released a website called Your 2013 Federal Taxpayer Receipt. This website allows you to enter your Social Security, Medicare, and Income Tax amounts and find out how much of your federal tax bill went to various aspects of the federal budget.

Even without entering values, though, the distribution is telling. The category Space, Science, and Technology Programs comes in at a whopping 1.13% of the federal budget, which is broken down between:

  • NASA:  0.64%
  • National Science Foundation and additional science research and laboratories: 0.49%

There are some other line items, buried within other categories, which might arguably contain various science-related expenses:

  • National Defense - Research, development, weapons, and construction: 7.60%
  • Health Care - Health research and food safety: 1.43%
  • Natural Resources, Energy, and Environment 1.92%

And, of course, some percentage of the education-related expenses no doubt go to science education. Excluding the defense-related research, this means that the total of all of the scientific research is - at the absolute maximum - 4.48% of the federal budget. And, in truth, most of this 4.48% goes to aspects of these categories that have nothing to do with actual research.

These funding concerns are at the heart of many of the essays in Space Chronicles: Facing the Ultimate Frontier by Neil deGrasse Tyson. For example, even the 0.64% of the federal budget attributed to NASA is wrong to think of as scientific research-oriented. According to Tyson:

When NASA's manned missions are not advancing a space frontier, NASA's science activities tend to dominate the nation's space headlines, which currently emanate from four divisions: Earth Science, Heliophysics, Planetary Science, and Astrophysics. The largest portion of NASA's budget ever spent on these activities briefly hit 40 percent, in 2005. During the Apollo era, the annual percentage hovered in the mid-teens. Averaged over NASA's half century of existence, the annual percentage of spending on science sits in the low twenties. Put simply, science is not a funding priority either for NASA or for any of the members of Congress who vote to support NASA's budget.

If NASA's budget devotes only about 40% toward research, and if this is optimistically similar for other science-related sections in the budget, then it's safe to say that my earlier 4.48% prediction is going to come out to be even less than 40% of that ... or less than 1.78% of the federal budget devoted to non-defense scientific research!

If you're reading this blog, then this likely isn't that much of a surprise to you, but it never fails to amaze me how many people I run into who think that scientific research receives lavish bundles of money handed out by the federal government.

But the lesson from this budget is absolutely clear: aside from defense-related research, an incredibly small percentage of our federal budget is devoted toward investment in scientific research.

Susskind's Theoretical Minimum Coming Out in Paperback

Sunday April 13, 2014

Book Cover of The Theoretical Minimum by Leonard SusskindLeonard Susskind's phenomenal book The Theoretical Minimum: What You Need to Know to Start Doing Physics is slated for a paperback release on April 22, 2014. For anyone who seriously wants to confront the challenge of actually doing physics - instead of just learning about all the cool stuff that physics talks about - this is really an essential book. Every student who has any hope of moving forward into the study of physics or engineering would do well to have this book on their "to read" list. The strong presence of mathematics isn't for the faint of heart, but it's a level of mathematics that anyone with an interest in physics or engineering will need to become familiar with. (See "What Skills Do I Need to Study Physics?")

The sequel, Quantum Mechanics: The Theoretical Minimum, came out at the end of February. A review on it is coming soon ... but if you haven't read the first book yet, then your chance to get it in paperback is coming up.

The Physics of Captain America

Friday April 4, 2014

The Physics of Superheroes coverEver since reading Jim Kakalios' The Physics of Superheroes, I've been intrigued with the science of how superheroes do the things they do. While this usually manifests in the more grandiose elements of the superhero world, with questions like "How can Iron Man fly?" or "What all can Magneto manipulate with his magnetic powers?" it can show up in much more mundane places as well.

Toward that end, the fine folks over at Wired magazine's Dot Physics blog have taken a commercial segment where Captain America catches his thrown shield and turned it into a problem that incorporates friction, Newton's third law of motion, and the principle of conservation of momentum toward an entirely worthy goal: determining the mass of Cap's shield.

The process is available on their blog, along with some nice little free-body diagrams. For those who don't want to work through the calculations, though, the results come out to the shield having a mass of about 19.9 kg. This means a weight of about 43.9 pounds, which is a pretty heavy shield and certainly hefty to throw, though probably not for someone enhanced with super-soldier serum.

The author then goes a step forward to consider the density of the shield, and here I think we run into some problems. Using some additional estimates, he arrives at  a pretty broad range: 87 8767 - 4383 kg/m3. This range extends from a bit more dense than iron to less dense than titanium, so it is a reasonable range, in principle, but the Vibranium alloy that composes Cap's shield may give some additional clues. Here is from The Physics of Superheroes on the subject:

Wolverine's claws are composed of pure Adamantium, but Captain America's shield is a one-of-a-kind alloy of steel and Vibranium. The steel is needed to provide rigidity, so that the shield can ricochet off walls and supervillain minions. Vibranium is an extraterrestrial material brought to Earth when a meteorite crashed in the African nation of Wakanda, which is ruled by the superhero the Black Panther. Vibranium has the ability to absorb any and all sound and convert the energy in the sound wave into some other, not-well-specified form, making it the perfect shock absorber, a quality strongly desired in a shield.

Kakalios doesn't specifically address the density of Vibranium, but I find it unlikely that something with the ability to absorb sound waves would be more dense than iron, so my guess is that this would at the very least be at the lower end of this spectrum. In part this seems justified because the special properties of the Vibranium alloy would indicate that we can stick with the thinner shield estimate and still have an effective shield.

What do you think? Does that shield look like it weighs over 40 pounds?

Discuss in my forum

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