Physics
drorzel | September 15, 2009The ArXiV Blog and several other sources last week linked to a new paper titled Towards Quantum Superposition of Living Organisms:
The most striking feature of quantum mechanics is the existence of superposition states, where an object appears to be in different situations at the same time. Up to now, the existence of such states has been tested with small objects, like atoms, ions, electrons and photons, and even with molecules. Recently, it has been even possible to create superpositions of collections of photons, atoms, or Cooper pairs. Current progress in optomechanical systems may soon…
grrlscientist | September 14, 2009tags: nature, cosmos, streaming video
This amazing video takes us on a fantastic journey from the outer universe down to the earth, then into a leaf and on into submolecular structures, for a look at quarks that make up atoms.
rallain | September 14, 2009I really shouldn't do this. I might be helping someone to set up something dangerous. But, I am going to anyway. Here is a question posted on some forum. (actually, it is from math help forum)
"I'm anticipating a good winter this year, one with lots of snow. My yard is sloped quite a bit and it would be the ideal place for a huge snowboard jump, only problem is I need to calculate how fast I will be traveling when I hit the jump, how high and what angle the jump should be, and the distance and angle of the landing ramp to optimize my range."
So, what am I going to do? I am going to give…
esiegel | September 14, 2009Last week, we got a chance to talk about why the sky is red toward sunset and sunrise but blue everywhere else: the atmosphere. Red light passes through the atmosphere pretty well, but blue light gets scattered more easily. When you look to the horizon at sunset/sunrise, the light passes through a tremendous amount of atmosphere, scattering the blue light all over the sky, but allowing the red light through to your eyes.
But then, I got a very good follow-up question:
Sometimes, either at night or in the morning, not just the horizon but nearly the entire sky turns red! Why does this happen…
drorzel | September 14, 2009Over in Twitter-land, Eric Weinstein is visiting the AMNH at the same time as a bunch of Orthodox Jews, and takes the opportunity for a little Q&A:
Me: Excuse me, but how is the phylogenetic tree reconciled with Torah.
Modern Orthodox Man: Lorentzian time dilation. It's a head hurter.
This is an interesting attempt to square the six-day creation story with modern science, and raises one obvious question: How fast must God have been moving for the six days of creation to last 13.7 billion years?
This is veering into Built on Facts territory, but the relevant formula is:
For six days (5.…
pontiff | September 10, 2009As I discussed a few blog posts ago a serious hole in our apocalypse protection network was about to be compromised with the non-renewal of the website http://www.hasthelhcdestroyedtheearth.com/. But it seems that Domenic has come to the rescue! See comment in the above blog post and the RSS feed update:
Domenic (a true fan of this site) was so distraught at the thought of missing out on further reassurances of the earth's continued existence that he's ponied up the registration cost for another year. So, we're not going anywhere after all.
1. The world has not ended. 2. The website is…
drorzel | September 9, 2009One of the odd things about the C-list celebrity life of a semi-pro blogger is that I get a bunch of requests to review books on physics-related topics. Some of these take the form of a book showing up out of the blue, others are preceded by a polite request from the author. Aaron Santos's How Many Licks? is one of the latter, which helps bump it up the list of things to do...
This is a short little book-- 176 pages total-- built around the idea of Fermi Problems, the order-of-magnitude estimates that Enrico Fermi was famous for. The idea is that, with a little basic knowledge and some really…
drorzel | September 9, 2009We did the far right column of the periodic table, so here's one for the left: the coolest-chemistry-demo-ever column, the alkali metals:
What's your favorite alkali metal?(surveys)
While you can make heteronuclear alkali dimers, at least in a transient way, we're talking atoms here, not molecules. Choose only one.
pontiff | September 8, 2009Over at the most uncertain blog, he of uncertain principles (aka Chad) takes up a challenge posed by @EricRWeinstein on twitter concerning Paul Krugman's recent article on why economists got the economic crisis so wrong. Since I know even less economics than anyone around here this seems like a great opportunity for me to weigh in (this is, after all, the blogosphere!)
Krugman's article is deceptively enticing, yet I find it disturbingly inadequate. In particular the critique is very much written as a just-so story, and there is very little in terms of concrete claims made nor of actual…
pontiff | September 8, 2009One RSS feeds I subscribe to is the one at http://www.hasthelhcdestroyedtheearth.com/. I mean, if the world is going to end, I certainly want Google reader to be the first to tell me. But today's RSS update is, instead of the traditional "no", different:
Bye bye everyone. This domain is not being renewed. It's been fun.
Which means that soon when you check www.hasthelhcdestroyedtheearth.com, you may not get an answer. Which may or may not mean the LHC has destroyed the world (oh noes!) Or it may just mean that your going to find a web page filled with spam from a domain name squatter.…
esiegel | September 8, 2009Sure, we're all familiar with sunsets, and how they appear to turn the entire sky close to the horizon red at night.
But it turns out it isn't just the Sun, and it isn't just the sky. If you look at the Moon at either Moonrise or Moonset, guess what color it appears to be? (Even in urban settings!)
Too difficult to tell? Let's find you a better picture done with time-lapse photography.
What's going on to cause this? Why do things which aren't normally red appear red when you look at them on the horizon, from the Sun to the Moon to the sky itself?
This is all the atmosphere's fault. After…
drorzel | September 8, 2009Like every other blogger with a political opinion, I read Paul Krugman's essay on economics last week, and tagged it for Saturday's Links Dump. And while I appreciate Eric Weinstein calling me out as part of the "high end blogosphere," I'm not sure I have much to say about it that is useful. But, since he asked...
Twitter's interface makes it almost impossible to go back and figure out what the hell was going on even a few days ago, but going through Eric's feed, the crux of the matter seems to be that he takes issue with Krugman's claim that "the economics profession went astray because…
razib | September 5, 2009Sean Carroll points out that physics and math degree holders have the highest LSAT scores. There's the classic chicken or egg issue implied here: does physics make you smart, or do only smart people manage to complete a degree in physics? I think it is more the latter. How individuals in various disciplines do on standardized tests is strongly predicted by mathphobia in said disciplines.
LSAT scores by degree below....
1 Physics/Math 160.0
2 Economics 157.4
3 Philosophy/Theology 157.4
4 International Relations 156.5
5 Engineering 156.2
6 Government /Service 156.1
7 Chemistry 156.1
8 History…
rallain | September 4, 2009I love this story. It is a story of how ideas changed about the nature of the atom. These are the notes (and diagrams) I use when I teach the atomic nature of matter to non-science majors. The best thing about this story is that it is a great example of science. Science (or scientists) build a model. If new evidence comes along, the model gets changed. There are several other websites that describe all of this stuff, I will list a couple at the end of this post.
Typical textbook model of an atom
Look in an intro, non-science majors textbook and you will probably see a picture like this…
drorzel | September 4, 2009I'm clearing out browser tabs before the weekend, which has reminded me that I've been terribly remiss in not passing along information about the Quantum to Cosmos festival being held next month at the Perimeter Institute in Waterloo, Ontario.
For 10 exciting days this October, Perimeter Institute's Quantum to Cosmos: Ideas for the Future (Q2C) will take a global audience from the strange world of subatomic particles to the outer frontiers of the universe. All events will occur on-site in Waterloo, Ontario and online at q2cfestival.com
Q2C's extensive program features more than 50 events --…
esiegel | September 4, 2009Electric charges come in two types, positive and negative. Magnetic poles also come in two types, North and South. In both cases, like charges/poles repel, and opposites attract. The big difference? Electric charges can exist in isolation; you can have just a positive or negative charge by itself. Whereas in a magnet, you always need both a North pole and a South pole; you can't have a magnetic monopole.
Magnetic monopoles have always been a curiosity for physicists, and many of us think that they ought to exist. In the 1970s, there were searches going on for them, and the most famous one…
pontiff | September 4, 2009I'm a pretty optimistic guy. Okay, I'm a really optimistic guy. But even my optimism has its limits when bashing up against the cold hard reality of what experiments plus our understanding of the laws of physics tells us about the universe. Here are my top three most depressing facts about the universe coming from the field of physics and astronomy.
The speed of light. The speed of light is a real bummer, dude. I mean sure, 299792458 meters per second may sound fast, but in comparison to the nearly 40 trillion kilometers to the nearest star, it's not very fast. And considering the…
drorzel | September 4, 2009Physics Buzz has a nice article about Paul Erdos and the Erdos Number Project (mine is 6), which ends with a good question:
I for one, am wondering: who would be the Paul ErdÅs of the physics world?
It's a tough question, complicated further by the existence of really gigantic collaborations in experimental high-energy physics, where author lists can run to hundreds of people. The 511 collaborators that Erdos can boast is more impressive in math than in some fields of physics.
For something really equivalent in spirit to Erdos, you would need to look for a physicist who had a long and…
drorzel | September 3, 2009"...Can you name the six noble gases?"
As this could be no poser for an economic geographer, I rattled them off in their proper aristocratic order. "Helium, Neon, Argon, Krypton, Xenon, and -er- Radon. They were raised to the peerage in the eleventh year of England's George Fifth, and Neon was awarded the Order of the Seraphim by Gustav Sixth of Sweden for its compassionate service in guiding to bars and beaneries guys who roll into towns late at night."
-- from The Moon's Fire-eating Daughter by John Myers Myers
I used that as an opening quote (I can't remember the term for that-- "epigram…
esiegel | September 2, 2009So, I have a small confession for you, my readers. Since I first started writing this blog, I have always solicited questions, and promised to answer the best ones. Recently, this has come back to bite me, as I've started getting more questions than I possibly have time to answer. However, the ones that meet the following criteria:
are of interest to a very broad, general audience,
are clear, well-posed, and straightforward, and
I can actually provide an answer to them,
will, more often than not, get answered right here. This one comes from reader Dan Noyes, who writes:
I have a question…