Physics
drorzel | January 7, 2014I'm teaching introductory E&M this term, so it's kind of fun to play around with silly applications of Coulomb's Law. For example, let's imagine that gravity suddenly switched off, but we wanted to keep the Earth in its orbit. How much charge would we need to move from the Earth to the Sun for the electrostatic attraction to take the place of gravity?
The key here is to set the gravitational force, which we can reasonably approximate by Newton's Law of Universal Gravitation:
$latex F_{grav}=G\frac{M_1 m_2}{R^2} $
(where the M's are the masses, R is the distance between them, and G is a…
catdynamics | January 6, 2014You are at university.
Do you like stars, and stuff?
We revisit old ruminations on career paths 'cause it is topical...
Another rehashed blast from the past.
Should you do astronomy as an undergrad? (the following is in part shamelessly cribbed from a colleague’s previous freshman seminar for our majors):
Do you like stars and stuff?
If not, you probably should look for an alternative to astronomy, on the general principle that at this stage of life you should at least try to do things you actually like.
If you do, good for you.
Now, do you have the aptitude?
Professional astrophysics/…
drorzel | January 6, 2014Classes for the Winter term start today, and I'm totally prepared for this. Yep. Uh-huh. Losing a bunch of prep time to snow and ice last week hasn't thrown anything into disarray.
Anyway, for a variety of reasons, I've ended up departing from my plan to not do any new preps while I'm stuck being Chair, and I'll be teaching intro E&M this term. This isn't a completely new class, but the last time I taught it I was very much in traditional lecture mode, and this will be my first pass using more of an active learning approach. Which will mean a lot of time re-working slides and that sort of…
drorzel | January 3, 2014I got a new camera for Christmas, not because there's anything wrong with my DSLR, but because I wanted something that could do high-speed video. So I now have a Casio point-and-shoot camera that will record up to 1000 frames per second, woo-hoo!
To break it in, I got the kids to help out by re-creating a classic slow-mo physics trick: the slinky drop:
Note that when SteelyKid lets it go, the bottom doesn't really move until after the entire length of the spring has relaxed. You can clearly see this in the still frame that's the "featured image" at the top of the post.
And since The Pip has…
carlyo | January 2, 2014By Stacy Jannis
Kavli Science Video Contest Manager
The Kavli Science in Fiction Video Contest challenges Gr 6-12 students to examine the science in fiction, including science fiction movies, TV shows, and games. Our contest advisors include science educators , scientists, and Hollywood scifi visual effects experts. Follow #SciInSciFi on twitter to for contest updates.
Dr. Joanne Budzien is an Assistant Professor of Physics at MacMurray College. Dr. Budzien's research is in materials science simulation and she has been at Frostburg State University, the New Mexico Institute of Mining and…
drorzel | January 2, 2014This past Monday, a lot of people in my social media feeds were passing around this Benjamin Bratton piece about the problems with TED, blasting the whole phenomenon as "placebo technoradicalism." The whole thing, he claims, is shallow pseudo-inspirational bullshit that makes people feel nice, but doesn't actually lead anywhere. As he notes at the opening, most of the grand promises made in TED talks have yet to pan out: "So much potential and enthusiasm, and so little actual change."
I found this kind of amusing, because a day earlier the link being passed around a lot of my social media…
jhalper | January 1, 2014A recent paper by Weizmann Institute scientists suggests that we might be able to break the third law of thermodynamics. This is how that law was originally formulated in 1908 by Walther Nernst: “It is impossible for any procedure to lead to the isotherm T = 0 in a finite number of steps,” (source: Wikipedia). To elaborate, the entropy of a system approaches nil as the temperature closes in on absolute zero, so that extracting further energy becomes increasingly difficult. According to the third law, you can get very close – temperatures of less than a billionth of a degree have already been…
drorzel | January 1, 2014I sent off the complete draft of the book-in-progress yesterday, somewhere between 12 and 36 hours ahead of my contractual deadline. Which I suppose makes it a book-in-process now, maybe. That process may still include re-writes, though, so my work probably isn't done yet.
The final draft, according to Word anyway, comes to 253 pages (space-and-a-half) and 96,807 words. I don't remember the word count from the original contract, but this is more than that. Which is pretty typical of my writing, really.
Because I wrote it down as part of the final checks, here's the approximate table of…
esiegel | December 28, 2013"I had seen birth and death but had thought they were different." -T. S. Eliot
Time passes, and things grow; that's the way of the world, so it seems. 2013 was no exception, and as Joshua Radin (featuring Patty Griffin) would sing,
You Got Growin Up To Do.
Well, the world grew again this year, in a multitude of ways. Approximately 134 million new human babies were born worldwide, and in back in February, the largest extraterrestrial object in more than a century merged with the Earth. It's been quite a year for new additions.
Image via: http://www.zingzoo.com/2013/02/15/falling-meteor-…
esiegel | December 24, 2013"Bethany: Is your house on fire, Clark?
Clark: No, Aunt Bethany, those are the Christmas lights." -National Lampoon's Christmas Vacation
Ahh, Christmas. It's easy to forget how much the invention of the light bulb in 1879 reduced the number of tree fires in people's homes. It was a mere three years later that people began decorating Christmas trees with strings of lights instead of candle flames, and as you can imagine, the reduction in open flames atop fresh kindling had its benefits, and caught on like wildfire. Trees now routinely sport previously unfathomable numbers of lights, limited…
drorzel | December 22, 2013I've seen a bunch of links to this interview with Peter Aldhous, mostly focusing on this quote:
I think for most science journalists, their model of journalism is explanatory. It’s taking the arcane world of the high priests and priestesses of science and translating what they do into language the ordinary mortal can understand. And I think that’s incredibly valuable and very important if we’re to have an informed society. But it is a different mindset from thinking that part of your job is to keep an eye on these guys and check that science isn’t being used and abused, that there isn’t…
esiegel | December 20, 2013"To be is to be the value of a variable." -Willard Van Orman Quine
It's the end of the week once again, and the very end of our Year In Space 2014 Wall Calendar giveaway! So for this week's Ask Ethan column, after dipping into our question/suggestion box, I'm very pleased to let Vera from Italy know that her question was the winning one, as she asked:
I saw the video you posted about the variable star RS Puppis, by the Hubble Space Telescope, and I really would like a post about what exactly are variable stars.
Thank you very much Ethan!! :-)
So -- no burying the lede here -- there was a…
drorzel | December 20, 2013While we were in Florida last weekend, we got a bunch of snow at home, so we came home to the proverbial winter wonderland. It's warmed up quite a bit since, though, and stuff is now melting. When I got home this morning after doing a bunch of revisions to the book-in-progress, I looked out the kitchen window to see the scene in the "featured image" above, which I will duplicate below:
Snow hanging off the edge of SteelyKid's playset.
That's the snowpack from the top of SteelyKid's playset, now melting, just barely hanging on from sliding off the edge of the plastic cloth stretched over…
drorzel | December 17, 2013We spent this past weekend in Florida, visiting Kate's mom and her husband, who moved down there in October. This was a huge hit with the kids, who were very excited to fly on an airplane (four of them, actually, as we changed planes in Baltimore both ways). They also got a big kick out of driving around in a rental car-- The Pip chattered happily about "My new car" for a while-- which we did a lot of, going to a beach and the Mote Aquarium in Sarasota.
Doing all that driving in a rented SUV and a state with a 70mph speed limit got me thinking about optimum driving speed. Particularly on the…
esiegel | December 11, 2013"Where you used to be, there is a hole in the world, which I find myself constantly walking around in the daytime, and falling in at night. I miss you like hell." -Edna St. Vincent Millay
It was just a little while ago that we were all speculating wildly -- and optimistically -- about Comet ISON, as it plunged towards the Sun from its origins in the very, very distant Solar System. As its perihelion date (the moment of closest approach to the Sun) drew near, you may have noticed something interesting about photos of the comet: it's tail appeared to get longer and longer!
Image credit &…
esiegel | December 6, 2013"The results of my observation are best explained by the assumption that a radiation of very great penetrating power enters our atmosphere from above." -Victor Hess
You might think of the largest and most powerful particle accelerators in the world -- places like SLAC, Fermilab and the Large Hadron Collider -- as the source of the highest energies we'll ever see. But everything we've ever done hear on Earth has absolutely nothing on the natural Universe itself! For this week's Ask Ethan, let's take a look at the simple question of our reader David Hurn, who asks:
Ever since I was a young…
esiegel | December 5, 2013"Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice." -Robert Frost
Depending on where you are in the world right now, you might really be feeling the effects of the emerging winter, as cold snaps, freezes and snowstorms take hold across the northern hemisphere.
Image credit: NASA's Scientific Visualization Studio, Goddard Space Flight Center.
But we can all be pretty sure that this is temporary,…
drorzel | December 4, 2013I know I said there weren't going to be physics posts for a while, but yesterday our Communications office passed along a media request about this paper on feedback cooling of BEC, from some sort of communications-person mailing list. I'd seen it talked up elsewhere-- here, for example, so I banged out an email to the reporter in question. Who didn't use any of my stuff in the story that ran late last night.
Having put in the work, though, I may as well get something out of it, so here's the email I sent. Questions in bold are from the original request. The paper is in the New Journal of…
jdupuis | December 2, 2013While browsing through my various social media feeds this morning I noticed that Amazon is having crazy Cyber Monday Kindle sales. Not much science or technology is on offer -- it's mostly popular fiction -- but there is a very nice selection of Einstein books that you can purchase.
They are all $2.82 TODAY!
The World As I See It
Out of My Later Years: The Scientist, Philosopher, and Man Portrayed Through His Own Words
Essays in Humanism
The Theory of Relativity: and Other Essays
Letters to Solovine: 1906-1955
Letters on Wave Mechanics: Correspondence with H. A. Lorentz, Max Planck, and…
esiegel | November 29, 2013“If you see an antimatter version of yourself running towards you, think twice before embracing.” -J. Richard Gott III
It may not occur to you that it's a special thing that the Earth and everything found on it is made of matter; it seems intuitive that it couldn't be any other way. And yet, the very laws of nature themselves haven't yet told us why or how the Universe is this way! For this week's Ask Ethan (and leave your own questions or suggestions here), our regular reader Michael Fisher wants us to get at the heart of this, asking:
Is it true that in the early universe matter &…