Category: Cosmic Variance


By Sean Carroll | December 6, 2012 7:00 am

This isn’t an easy post to write, but it’s time for me to leave Cosmic Variance and Discover and go back to blogging on my own. It’s a move I’ve been contemplating for a long time, essentially unrelated to the recent website update here. After having blogged for many years, I’ve decided that I’m happiest when I feel the least amount of responsibility, and the greatest freedom to be personal and idiosyncratic. Even though I’ve always had perfect freedom here, there was inevitably the (correct) feeling that our efforts represented a group, not just my personal quirks. If a month goes by and I don’t feel like blogging, I don’t want to feel that I’m letting anyone down other than myself.

So, I have a new blog at my personal site, which I’ll update as the spirit moves me. I’ve imported copies of all my previous blogging to there, so it doesn’t look completely empty right from the start. Add me to your RSS feeds if you like.

Read More

CATEGORIZED UNDER: Cosmic Variance, Personal

Freshening Up

By Sean Carroll | November 29, 2012 10:09 am

You may have noticed that all the Discover blogs now have a new look. (One that is still being tweaked, so don’t expect to see my headshot up there for very long.) In fact the whole site has been updated, so there may have been some issues in page loading times and so on. All part of the shakedown process, and hopefully things should be back to normal soon.


Comment Policy

By Sean Carroll | June 26, 2012 7:52 am

Editor’s Note: Way back in 2007, we here at the blog were struggling with a vocal minority of obnoxious commenters. I was stuck on a cross-country plane flight with my laptop, and took out my frustrations by banging out this proposed Comment Policy. Upon landing, I sent it to my co-bloggers for judgment. They were mildly amused, but didn’t think it accurately reflected our actual sentiments — and they were probably right. So we never posted it.

But now, since I’ve been busy and those same co-bloggers are pretty silent, we’re looking for content. So I’ve dredged it back up, just to offer as food for thought.

So, to be clear: this is not our comment policy. It’s simply what our comment policy would have been in a different universe, where my co-bloggers weren’t as good at talking me down from my less well-thought-out schemes.

Our current comment policy is that we delete obnoxious crap, and ban repeat offenders. Easy!


Did you know that there are some blogs out there on the internet that don’t have comments at all? Amazing, but true. To us here at Cosmic Variance, comments are a crucial part of the joy of blogging, and we couldn’t imagine doing without them. Nevertheless, we get occasional visitors who don’t always “get” the whole “commenting thing,” at least as we understand and encourage it. But don’t worry, we’re here to help. In order to answer every possible question before it is raised, we have constructed a hierarchical explanation of how we conceive of the role of comments: a set of Deep Underlying Axioms from which all else can in principle be derived; a Fundamental Theorem of Commenting that concisely expresses the upshot of the above axioms; a Grand Explanatory Analogy that should serve to clear up certain common misconceptions; and a set of Specific Examples, Illustrated in an Entertaining Question-and-Answer Format, to guide the thinking of those who prefer concrete imagery to abstract thinking. We close with some inspirational final words on how the comment section is Your Chance to Shine.

All told, we’re pretty sure you will agree that this is the most awesome comments policy in the entire blogosphere. Read More


A Year Well Blogged

By Sean Carroll | December 29, 2011 11:33 am

‘Tis the season when bloggers, playing out the string between Xmas and New Year’s, fill the void with greatest-hits lists from the year just passed. But a question inevitably arises: how does one decide which posts to include? There are many different criteria, and preferring one to another might lead to very different lists. This is what’s known as the measure problem in blogospheric cosmology.

This year I’ve decided to confront the problem pluralistically. Thus: here we have five different Top Five lists, chosen according to completely different criteria. Let us know if your favorite Cosmic Variance post of the year somehow managed to not be on any of the lists.

First, the most crude and common measure, the posts with the most page views this year.

Next up, an equally quantitative and misleading measure of popularity: the top five posts by number of comments. Read More

CATEGORIZED UNDER: Cosmic Variance, Top Posts

A Salon of Ideas

By Sean Carroll | December 7, 2011 10:42 am

Matt Strassler’s post prodded me to look back and notice something: we really have had quite an amazing collection of guest bloggers over the years. There is a page on the site dedicated to keeping track (as well as a category), but nobody every clicks there, so I thought I would just reproduce the list here. We have a few more in the pipeline, keep your eyes peeled!


Milestone Watch

By Sean Carroll | November 17, 2011 8:39 am

Sometime this Monday afternoon, Cosmic Variance welcomed its 10 millionth visitor. Yay us! (And yay all the visitors!)


Donor's Choose 2011

By Risa Wechsler | October 20, 2011 2:57 pm

So, it’s an annual tradition here at Cosmic Variance to participate in the Science Blogger’s Donor’s Choose event.

Donors Choose Science Blog Challenge

Donor’s Choose is an awesome non-profit that allows public school teachers to post their needs for educational materials for their students, and allows donors to choose which projects get funding. This year, like the last three years, science bloggers are participating

A list of projects we suggest is here:

Cosmic Variance Donor’s Choose Page

I’ve chosen a list of physics and astronomy focused projects in low income school districts —
chip in a few bucks (you can donate as little as $5 or as much as you like!), and make a difference inspiring the next generation of scientists!

Last year 26 of you donated more than $3500, which directly impacted 1,485 students (super impressively, the year before we managed to raise $12,000!) This is our 4th year of participating, but I was woefully slow putting this post up and getting the ball starting. I hope you dear readers will pick up the slack anyways, and give generously to these awesome projects. Luckily, between now and midnight on Saturday, there is a special bonus: the Donor’s Choose Board of Directors is matching all donations with a gift card that you can use to support any project of your choosing, so your money will go double in the next few days. Let’s see if we can beat last year’s numbers in the next 3 days, and help some students get the tools they need to learn science!

CATEGORIZED UNDER: Cosmic Variance, Miscellany

How to Succeed on the Internet Without Really Trying

By Sean Carroll | September 9, 2011 8:24 am

Keen eyes will notice tiny improvements in the look-and-feel of the Discover blogs today, thanks to behind-the-scenes work of our crack website team. One improvement is that the social-media buttons at the bottom of each post are a little more clear and logical. They also let you know how many people have passed along a post via each medium.

Which leads me to an entirely unoriginal observation: the internet loves Top Ten lists. Perusing our home page, it’s easy to be struck by the giant numbers for the Things Everyone Should Know About Time post. It’s true that I like to think the post was actually interesting. (People seem to be divided between whether #4 or #10 is the most striking entry.)

But still, I’ll be honest: being at the conference I hadn’t been able to blog much, so I thought it would be good to write something that would be popular but not too hard to write. Thus: a top ten list. Box office!

So why exactly is that? I’m not disparaging: a good list is a way to convey a substantial amount of information in a well-organized form. But still, would it have been as popular had it been Top Seven? What if each entry were three times as long? What if the exact same words were presented without the numbers and bold-face labels?

No grand theories here, just idle curiosity. Enjoy the tiny aesthetic upgrade.


Chirality and the Positron's Mustache

By Sean Carroll | June 20, 2011 9:09 am

Woke up this morning to the happy news that my post “The Fine Structure Constant is Probably Constant” walked away with the Charm Quark (i.e., tied for third place) in this year’s 3QuarksDaily science blogging prizes. Many thanks to Lisa Randall for judging and Abbas Raza and the 3QD crew for hosting. And of course congrats to the other winners:

  1. Top Quark: SciCurious, Serotonin and Sexual Preference: Is It Really That Simple?
  2. Strange Quark: Anne Jefferson, Levees and the Illusion of Flood Control
  3. Charm Quark: Ethan Siegel, Where Is Everybody?

I already have a great nominee for next year’s contest. One of the most confusing things in particle physics is the notion of “chirality.” The related notion of a particle’s “helicity” is relatively easy to explain — is the particle spinning in a left-handed or right-handed sense when compared to its direction of motion? But a massive particle need not have a direction of motion, it can just be sitting there, so the helicity is not defined. Chirality is the same as helicity — left-handed or right-handed — for massless particles moving at the speed of light, but it’s always defined no matter how the particle is moving. It had better be, since the weak interactions couple to particles with left-handed chirality but not ones with right-handed chirality! (And the opposite for antiparticles.)

It all gets a bit heady, and you can’t give a real explanation without going beyond simple pictures and actually talking about the quantum wave function. But Flip Tanedo at Quantum Diaries has given it an heroic effort, which I insist you go read right now. I don’t want to reproduce the whole thing — Flip was more careful and thorough than I ever would have been, anyway — but I will tease you with this one picture.

Isn’t that the cutest pair of elementary particles you’ve ever seen? I smell a Quark in this lepton’s future.

CATEGORIZED UNDER: Cosmic Variance, Internet, Science


By Sean Carroll | March 24, 2011 4:06 pm

Loyal reader Mandeep Gill points out that I wrote “prevarication” when I clearly meant “equivocation” in the consciousness post. It’s now corrected. Very annoying, as I do like to use words to mean what they’re supposed to mean. I think I have a pretty good track record with “begging the question.”

While I have your attention, fellow loyal reader Richard O’Connell points us to a poem relevant to that post: Robert Browning’s Caliban upon Setebos. It begins:

‘Will sprawl, now that the heat of day is best,
Flat on his belly in the pit’s much mire,
With elbows wide, fists clenched to prop his chin.
And, while he kicks both feet in the cool slush,
And feels about his spine small eft-things course,
Run in and out each arm, and make him laugh:

There’s a lot more.

Also! Flip Tanedo points out that Brian Hill’s transcription of Sidney Coleman’s lectures on quantum field theory have finally been LaTeXed (pdf). Thanks to Bryan Gin-ge Chen and Ting Yuan Sen for undertaking this thankless task. I took that course a couple years after the notes were made, and every student in the class had a photocopy. Yes, Sidney did gripe a bit that nobody laughed at his jokes any more because they had all read them in the notes.

That’s all I got right now. Just trying to lower the bar so our co-bloggers will be encouraged to contribute more frivolous posts.


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