Physics

Over the last couple of years, I've gotten rid of cable and watch most of my television online. In addition to traditional television through streaming sites like Amazon Instant Video and Hulu, I watch a lot of my programming - especially non-fiction and science - through YouTube.

Most of the science programming on YouTube - or at least the science programming that I come across - is focused on the nuts and bolts of a scientific demonstration or explaining a specific scientific idea. As the parent of a science fair-age child (not the one shown in the picture, but you get the idea), I deeply appreciate the accessibility of these sorts of videos. You can really find a wide range of science programming. For example, there's a video with author James Kakalios discussing the science behind how Thor's hammer Mjolnir works, as I discussed in a recent blog post ... but then there's also this guy, who used a Tesla coil to create a replica of Mjolnir that actually generates electrical energy!

Still, though, I feel like there's a real lack of higher-level science programming which focuses on explaining the context of scientific developments. Now I'm  aiming to fix that. Here's the low-down:

Felicia Day's popular Geek & Sundry channel has become one of my favorite sources for great YouTube programming. But while I enjoy Wil Wheaton's Tabletop series on board games, and some great storytelling shows like The Story Board and Written by a Kid, I've been extremely surprised that the channel lacks any science shows. I mean, really, how can you have a geek channel that doesn't have a science show?

Then the Geek & Sundry folks created a new vlog channel and put out a call for new shows. I'm really hoping that they pick at least one show with a science theme. So, with that in mind, I went ahead and created a show of my own, with the hope of gaining a spot on their line-up. And if that doesn't work out, then I'm going to continue with the series as best I can, doing new segments on my own ... often probably linked in with new material we have on the site.

The first episode is just basically an "audition" video, focusing mostly on introducing myself and talking about why I like science in very broad terms. Big plug for evidence-based testing, a slight dig at Aristotle, and a somewhat gratuitous quote from Richard Feynman. (Speaking of Feynman ... if you're interested in him, I highly recommend this great documentary Richard Feynman - No Ordinary Genius which is available on YouTube.)

The goal of the vlog will be, as I indicated, to focus on the conceptual aspects of physics, because the nuts-and-bolts of "how things work" seems to be well covered in existing videos on YouTube. We won't be blowing stuff up, but instead talking about how awesome it is when scientists blow things up. My ultimate goal will be to bring on scientists whose work is worthy of discussion and more in-depth analysis, and possibly even branching outside the realm of physics a bit into other disciplines of science. It should be exciting to see where this new venture ultimately leads!

And of course there is always the About.com YouTube channel, which features not only science videos but instructional videos from across all of the About.com subject areas. As of this writing, the most recent posts appear to be a series about basketball techniques, for example.

What's your favorite science show or channel on YouTube? What subjects would you most like to see covered in upcoming episodes of a science show?

Image Source: Brand X Pictures

Sometimes, even the fantastic world of comic books takes heed of real-world scientific discoveries.

When the Thor film came out a couple of years ago, I posted about how impressed I was by their attempt to make this fantasy story about Norse gods into something that was at least somewhat tractable within our modern scientific worldview. The trailer for the upcoming sequel, Thor: The Dark World, seems to hint at the idea that they'll continue with this trend, as it addresses the question of what existed before our universe. (The answer, it seems, is darkness ... and evil, ugly elves.)

In Indestructible Hulk #8, there's a discussion of the physics related to Thor's hammer, Mjolnir. On an episode of Virtually Speaking Science, James Kakalios (author of The Physics of Superheroes) explained his theory about why Thor could pick up Mjolnir, as has Captain America (who is, apparently, worthy), but neither Juggernaut nor Hulk have ever been able to move it. This has long been a point of debate among comic book fans, and even made its way into an episode of The Big Bang Theory last season. The explanation presented by Kakalios, as laid out in Indestructible Hulk #8 is:

Physicist James Kakalios advanced my favorite science-based theory. That uru metal, forged uniquely by the dwarf Eitri, can emit graviton particles--

--most likely in response to an external stimulus provided by something within the hammer akin to our nanotechnology.

Controlling gravitons, of course, is equivalent to being able to change an object's mass.

If a person whom the dwarven 'nanotech' has determined to be 'unworthy' attempts to lift the hammer--

-- the uru metal will increase the rate of graviton emission to where it can't be budged. That's one theory.

This is in contrast to my earlier proposal that this had something to do with the hammer being forged from the substance from a neutron star.

Related Articles

• The Big Bang Theory: episode 6.13, "The Bakersfield Expedition"
• Avengers' Physics, May 7, 2012
• Thor, Science, Magic, and Shameless Self-Promotion, May 15, 2011

Last month, I posted about the release of Time Reborn: From the Crisis in Physics to the Future of the Universe by Lee Smolin. While I found the book extremely enjoyable, I also felt that Smolin was far from making an airtight case about his central thesis: that physics needs to transform into treating time as "real" in order to resolve the "crisis" in which physical cosmology finds itself. The book concludes without it being clear that there really is a crisis, let alone that Smolin's course would resolve the crisis if it did exist.

Now some real physicists have weighed in on the issue, with far deeper insights than I personally can offer:

• Proposterous Universe blog - Time, Born Again by Sean Carroll, author of From Eternity to Here, another book on the nature of time
• BackReaction blog - Book Review: "Time Reborn" by Lee Smolin
• Edge - Think About Nature interview with Lee Smolin (this includes comments from various others, including the earlier Carroll commentary)

These reviews and commentaries all have some really good points. I especially liked the following bit from the Sean Carroll commentary:

Smolin seems quite content to draw sweeping conclusions from essentially philosophical arguments, which is not how science traditionally works. There are no necessary hypotheses; there are only those that work, and those that fail.[...] Use philosophical considerations all you want to inspire you to come up with new and better ideas; but it's reality that ultimately judges them.

This was my biggest issue with the arguments put forth in Time Reborn. I minored in philosophy in college, so fully respect the role philosophy plays in the sciences. That role is primarily in making sure that science is asking the right questions, as Carroll indicates. However, Smolin often goes beyond that, suggesting that well-documented conclusions about the nature of time should be revised, seemingly based upon philosophical principles that he'd like to keep intact, rather than a direct failure of the time understanding.

How, then, can I have such a favorable opinion of the book? The Back Reaction book review sums it up nicely:

Oddly enough however, I enjoyed reading the book. Not despite, but because I had something to complain about on every page. It made me question my opinions, and though I came out holding on to them, I learned quite something on the way.

I do really hope, however, that the ideas in Smolin's book are explored more deeply by a wider group of physicists, including the precise formulation of any falsifiable hypotheses that could come out of Smolin's predictions about the time-evolving nature of scientific laws. As someone who has a healthy respect for the underdog rebel, I find myself hoping that Smolin's fascinating speculations actually achieve their goal of transforming our understanding of physics. Unfortunately, he's been beating drums of this sort for quite a few years without much traction, and I don't anticipate that it will change radically with this book.

In the recent film Star Trek Into Darkness, the crew of the Enterprise uses a warp engine to move faster than the speed of light. This would normally not be allowed by the laws of physics, specifically Einstein's theory of relativity. However, as I've discussed before in our article "Can Anything Move Faster Than the Speed of Light?", the limitations from the theory of relativity make it impossible to accelerate past the speed of light limit, but there do exist some intriguing workarounds (in theory, at least).

One possibility is the Alcubierre drive, which was conceptualized in 1994 as an attempt to create a realistic model for creation of a warp drive. There are now suggestions that NASA may be moving forward to create just such an engine. Dr. Harold White, the NASA physicist who explored Alcubierre's over the last couple of years has come to believe that it was feasible, says that any results that show proof of concept will help push more research in this area. He uses an example he calls the "Chicago Pile" from the middle of the last century:

"In late 1942, humanity activated the first nuclear reactor in Chicago generating a whopping half Watt -- not enough to power a light bulb," he said. "However, just under one year later, we activated a ~4MW reactor which is enough to power a small town. Existence proof is important."

Overall, this does fall in the "I'll believe it when I see it" category ... but I'll confess, this is one radical (and likely over-hyped) scientific announcement that I'd love to be proven wrong on!

Related Articles:

• io9 - How NASA might build its very first warp drive (May 2013)
• Warp Field Mechanics 101 by Dr. Harold White (2012)
• Warp Drive - A Nice Idea While It Lasted (June 15, 2009)
• Can String Theory Explain Warp Drive (May 10, 2009)
• Institute of Physics - "The warp drive: hyper-fast travel within general relativity" by Miguel Alcubierre (1994 academic paper)

In the physics community, there is no more broadly respected figure than Albert Einstein. Einstein is a transformative figure in the history of physics, comparable only to Isaac Newton in the sheer breadth of how he changed our way of thinking about the physical world. The key insight for which he is credited is his development of the theory of relativity, which allowed physicists to understand the behavior of physical objects in terms of the geometry of the spacetime that they inhabited.

Physics is a progressive discipline, however, and physicists are continually probing the limits of the known in order to expose what is not known. As such, many physics students over the last century have dreamed of finding the next major discovery that would transform physics, making their own contribution to human knowledge and becoming as equally respected.

And, of course, the media would love to report on such a transformation! As such, every so often there comes along a big media flurry around a piece of evidence or new theory that claims to "overthrow Einstein." Usually, I ignore such media hype, because it so far has never panned out.

The last big "Einstein was wrong" news story related to the 2011 announcement that there might have been evidence of neutrinos traveling faster than the speed of light. That turned out not to be the case, despite excitement over reporting what was potentially a revolutionary story. Still, it's useful to occasionally address these things as they happening, if only to understand the way that science works. (See, for example, our article: "Can Anything Move Faster Than the Speed of Light?")

Geometric Unity

The most recent of these seems to be in the works as I type this. I learned about it through an article in Britain's The Guardian, and then read this other Guardian blog post and it was also mentioned on Peter Woit's Not Even Wrong blog.

The fuss is about a guy named Eric Weinstein, who left academia twenty years ago to become a New York economist. In that time, however, he's apparently been peripherally working on mathematics related to solutions to fundamental problems in physics. He is at Oxford today giving a talk about his new theory, which he's calling Geometric Unity.

The problem that Weinstein is trying to tackle is not a new one. It's the well-worn idea that quantum physics and general relativity are exceptional theories for explaining their own domains, but in the cases where they intersect (such as the big bang and black holes), physicists have trouble getting the two theories to work together in a way that really makes sense of the situation, at least without cheating a little bit on one or both of the theories. This has resulted in searches for a theory of quantum gravity, such as the one that Einstein unsuccessfully devoted the latter half of his life to.

Weinstein's approach is to embrace Einstein's intuitions, as evidenced in this tweet (@EricRWeinstein) that Weinstein made yesterday:

Perhaps no university in the world has done more than Oxford both for, and to keep faith with, Einstein's vision for physics as geometry.

Though there are only a couple of reports so fall, and I expect more detail following Weinstein's speech, but so far it seems that the theory involves a 14-dimensional geometry that contains new symmetries above and beyond those already present within the Standard Model of physics. There is some speculation that this might explain current mysteries within physics, such as the problem of dark energy in cosmology.

How Would We Know?

These are the sort of claims that must be treated with a high degree of skepticism. In 2007, physicist and surfer Garrett Lisi made a splash (figuratively, that is, since this was in physics rather than surfing) by putting forth an idea about how to unify physics. Ultimately, though, Lisi's approach was abandoned not because physicists didn't like it, but because it did not make sufficient testable predictions. No matter how great a scientific theory is, if the theory does not make predictions that can come up against analysis in physical reality, it can't go anywhere. Elegance for its own sake is not enough.

Weinstein's ideas will be put forth in front of the world today in his Oxford speech. At that point, physicists will begin looking it over, considering the implications of the theory from a variety of angles. The big tests will come in the following forms:

1. Does it contradict known evidence?
2. Does it explain existing evidence that cannot be explained under current theories and models?
3. Does it make a prediction about new evidence that scientists can search for?

Answers of "No" to the first question and "Yes" to the second two questions are good for the new idea.

And that is how a hypothesis becomes a theory! (Cue Schoolhouse Rock theme song.)

Update: This morning, I stumbled upon this New Scientist article, "Weinstein's theory of everything is probably nothing," which makes things even more interesting ... apparently, Weinstein's Oxford lecture was scheduled at a time when the majority of the Oxford physics department was busy listening to another lecture! As I mentioned above, any internal mathematical elegance that Weinstein's theory may possess is secondary to its ability to actually demonstrate physics results ... which means that physicists have to be centrally involved in the discussion!

I came across this intriguing video of a banana being levitated in the air. This isn't the first time I've discussed this strange new technology of quantum levitation, but it's been a while. The last time I brought it up was back in November 2011, when talk show host and comedian Stephen Colbert levitated his ice cream flavor on his show.

These are hardly the most serious examples of how this technology could be used, but they are very cool ... reminding us that scientific discoveries are often leveraged in unexpected (and entertaining) ways. But if you look under the banana (so to speak), you'll find some very deep understanding of the science matter and electromagnetism:

• What is Quantum Levitation (and How Does It Work)?
• Quantum Locking
• The Meissner Effect

Image Source: Tel Aviv University

Physicists like it when things crash together. Okay, not so much when they do so unexpectedly. Just like anyone else, physicists prefer to keep their cars out of the body shop.

But collisions of objects do provide excellent opportunities to use the tools of physics to pull out some of the oldest, most trusted tools in the physics toolbox.

The key to any sort of collision is that it follows the law of conservation of momentum. In most collisions, however, there is a loss of kinetic energy. These collisions are called inelastic collisions, and in the real world this represents most of the types of collisions that we run into. In some collisions, in fact, the objects collide and stick together, losing the maximum amount of kinetic energy possible. These are called perfectly inelastic collisions.

Some collisions, on the other hand, do not lose kinetic energy during the collision ... or, at least, they lose so little kinetic energy that we can treat them as if they didn't lose any. (Recall that in physics we often try to approximate systems with an idealized model if at all possible.) These types of collisions are called elastic collisions, and they are decent first-order approximations for Newton's cradles (as depicted above), billiard balls banging into each other, or bumper cars.

If a collision generates a lot of heat and sound, chances are that it is an inelastic collision, since the original kinetic energy is getting transformed into the vibrating molecules that make up the heat and sound. If you could measure each and every vibration caused by the collision and calculate the total energy, it would of course equal the total energy before the collision. But this is impractical and, fortunately, unnecessary, since conservation of momentum typically gives us a sufficient set of tools to understand what happens in the collision.

When you're dealing with a homework problem that has to do with two objects colliding, a good question to ask oneself is: What type of collision is this? That'll help set you on the road to figuring out which equations you can apply to the situation and how to solve the problem.

Image Source: Tyler Boley/Getty Images

One of the deepest questions in physics is the attempt to provide an answer to the seemingly simple questions: Does time really exist?

Though we all experience time moving in one direction (the "arrow of time" as it is called), the curious thing about the laws of physics don't actually require this. If you tried to apply the equations with time moving the opposite direction, they would actually still make sense. Why, then, do we experience such an unrelenting forward motion in time?

The standard explanation revolves around the concept of entropy. As well explained in Sean Carroll's 2010 book From Eternity to Here: The Quest for the Ultimate Theory of Time, the solution that is most commonly accepted these days is that the arrow of time is an artifact of the initial conditions of the universe. Because the early universe was highly ordered, time moves in the direction of increasing entropy.

This answer doesn't cut it for controversial theoretical physicist Lee Smolin. In the new book Time Reborn: From the Crisis in Physics to the Future of the Universe, Smolin confronts the idea that time is "unreal" and argues instead for treating time as a fundamentally real quantity. His conclusion is that our entire approach to theoretical physics may need to be rethought. Instead of looking for eternal and timeless laws of physics, Smolin believes that we should instead look for laws of physics that themselves evolve throughout time.

It's an intriguing proposal and, if adopted, would certainly revolutionize the approach to physics. This is nothing new to Smolin, who is nothing if not an unconventional thinker. I go into some of the reasoning behind Smolin's approach in the review of the book.

What do you think? Is time real? Does physics adequately address questions about the nature of time?

If you've been paying any attention at all to astrophysics or cosmology over the last couple of decades, you'll be aware that one of the major mysteries science has been exploring is the composition of matter in the universe.

NASA's WMAP program had given us a great vision of the universe, indicating that only about 5% of our universe is made up of stuff that we actually observe and mostly understand (called "visible matter" ... since we see it all around us and also in space). Another 23% is what's called dark matter, a type of matter that we cannot see and do not fully understand, but which appears to be out there if we're to explain the behavior of many stars and galaxy movements. And then there's the last 72%, which is an amazing substance which we only barely understand called dark energy, which actually seems to be pushing space itself apart, causing an increase in the expansion rate of the universe ... first observed in 1998 and the discovery of which earned the 2011 Nobel Prize in Physics.

For a while, I had been reporting nearly-monthly on various discoveries and reports on this front ... but this is such a cutting edge of research that science writers had a tendency to jump on every single inkling with overblown headlines about the importance of new discoveries. One thing that I really try to avoid on here is to indulge in this sort of unjustified hyperbole, staying focused on reporting science that's well established. It's not that I oppose speculation in science, but I just want to try to be very clear on when the speculation is happening, and a monthly report that was mostly speculation -- and often speculation that didn't pan out -- became stale to me.

That having been said, it's been long enough since I focused on them that there have been a few discoveries (or potential discoveries), mostly from Europe's Planck observatory, and I feel they're worth commenting on ... so here's a new update on the dark stuff that we think makes up our universe.

Updated Numbers for Dark Matter and Energy

The basis for dark matter is the fact that some galaxies and other astronomical objects are moving in a way that indicates there's probably more matter in those galaxies than we can see. The simplest resolution for this is the explanation that there's a type of matter we aren't able to see ... and this is dark matter.

As I mentioned above, the WMAP estimated that about 23% of the universe was composed of dark matter, but the new data from the Planck observatory has pushed that estimate up to about 27% of the universe! The numbers for dark energy is about 68.3%, with ordinary visible matter still coming in a touch under 5%.

Dark Matter Search Continues

The search for dark matter particles is still going strong, and there's even been a hint of evidence - in the form of some extra anti-matter - showing up in the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. Additional research is still looking for evidence of dark matter here on Earth, such as the research taking place at Minnesota's Cryogenic Dark Matter Search (CDMS) lab, looking for Weakly Interacting Massive Particles (WIMPs), which may also explain the AMS detector results.

Alternative Gravity Theories

As I mentioned above, dark matter is predicted because more matter is needed to make the equations of gravity match the motion we observe in the universe. Another explanation is that perhaps our methods of calculating the gravitational influence of matter is somehow flawed. One alternative gravity proposal designed around this idea is Modified Newtonian Dynamics (MOND), and it's recently gotten a bit of press as well, since MOND-based predictions have had some success in areas where dark matter proposals just can't make predictions. The physicist behind this research, Stacy McGaugh, explains it:

The predictive power of MOND in these systems stands in stark contrast to the dark matter paradigm, which makes no comparably clear prediction.[...] At the very least, this unexpected situation is a reminder that there is still plenty we don't understand about the vast cosmos in which we reside.

New Dark Flow Losing Steam?

In addition to dark energy and dark matter, in 2008 research came out that seemed to indicate something that became known as "dark flow" ... a region of space that was accelerating and moving in a way that not consistent with the surrounding regions of space. This bizarre behavior was discussed in some detail in Paul Halpern's recent book The Edge of the Universe.

Unfortunately for those of us who are always looking for new mysteries of the universe, some newer research, based on data taken from the Planck satellite, is making scientists think that dark flow is probably not real. However, there is some suggestion that the researchers who published the paper overestimated the uncertainty in their measurements, which would mean that there's very real data which is being ignored because it looks like statistical noise. The original researchers are doing their own analysis of the data and will no doubt announce as soon as they can whether or not they feel the Planck data is consistent with their earlier observations.

Image source: NASA/WMAP Team

Did you know that every moment, your body is being bombarded by particles with their origin in distant galaxies? These cosmic rays, as they're called, come from supernovas in distant star systems. Upon reaching the Earth's atmosphere, these particles from the "primary cosmic ray" collide with the molecules there and emit other particles that are part of a "secondary cosmic ray." It's these secondary particles that actually reach us on the surface of the Earth.

These are called cosmic rays because scientists originally thought they were electromagnetic radiation, but they're actually charged particles ... mostly nuclei stripped of their electrons.

For years, we've had information on our website about how to build your own cosmic ray detector. Now this great experiment is also available as a new video on the website. Check it out and build your own cosmic ray detector, then let us know how it worked out.