1. This is a hummingbird’s nest, with two jellybean-sized eggs, from the collections of the Milwaukee Public Museum. The nest is made with soft plant fibers, lichen, and spider silk.
Yes, spider silk.
How crazy is that?
I got to see this amazing specimen and lots of other neat behind-the-scenes items used for scientific research, while writing a story about efforts at the museum to preserve the egg collections for future generations of scientists.

With nimble fingers, Julia Colby gingerly lifts a hummingbird’s tiny nest made from soft plant fibers, lichen and spider silk. Nestled inside are two eggs the size of small jelly beans.

But these Lilliputian eggs will never hatch — they are more than 100 years old and are part of the Milwaukee Public Museum’s bird egg collection.

Read it here.

    This is a hummingbird’s nest, with two jellybean-sized eggs, from the collections of the Milwaukee Public Museum. The nest is made with soft plant fibers, lichen, and spider silk.

    Yes, spider silk.

    How crazy is that?

    I got to see this amazing specimen and lots of other neat behind-the-scenes items used for scientific research, while writing a story about efforts at the museum to preserve the egg collections for future generations of scientists.

    With nimble fingers, Julia Colby gingerly lifts a hummingbird’s tiny nest made from soft plant fibers, lichen and spider silk. Nestled inside are two eggs the size of small jelly beans.

    But these Lilliputian eggs will never hatch — they are more than 100 years old and are part of the Milwaukee Public Museum’s bird egg collection.

    Read it here.

  2. You can now download Particle Fever, a documentary about the discovery of the Higgs Boson, on iTunes!

    If you’re interested in particle physics, you need to watch this. The story is told so well — it’s dramatic, thoughtful, and personal.

    Not to mention the fact that it chronicles the making of the biggest discovery in physics in recent memory!

    Edit: For those of you outside the US, if you can’t get it on iTunes, keep an eye on the Particle Fever website. It may be showing at a film festival near you.

  3. A Diamond in the Sky

A Milwaukee astronomer and colleagues have discovered a precious find: a star so old, and so cold, that it is made up of crystallized carbon — better known as diamond.
David Kaplan, an astronomer at the University of Wisconsin-Milwaukee, and colleaguesreported the discoveryof this remarkable star in the Astrophysical Journal. The star is a white dwarf — the dying remains of a once-active star. White dwarfs are no longer able to fuel reactions that generate light and heat, meaning that the star cools as it ages.
"What’s particularly interesting in this case is that the white dwarf is extremely, extremely cold," Kaplan said.
Cold, that is, for a star. Such stars can start out around 100,000 degrees Celsius, but this one is less than 3,000 degrees — the coldest white dwarf star ever discovered. Scientists know the star must be very cold because it is invisible to their telescopes, implying that it is radiating little light or heat. But how does one detect an invisible star? By its effects on the stars around it, it turns out.

From a new article by me at the Milwaukee Journal Sentinel. Read the rest.
It turns out that it’s only “sort of” like a diamond, but either way, it’s definitely cool — in more ways than one!

    A Diamond in the Sky

    A Milwaukee astronomer and colleagues have discovered a precious find: a star so old, and so cold, that it is made up of crystallized carbon — better known as diamond.

    David Kaplan, an astronomer at the University of Wisconsin-Milwaukee, and colleaguesreported the discoveryof this remarkable star in the Astrophysical Journal. The star is a white dwarf — the dying remains of a once-active star. White dwarfs are no longer able to fuel reactions that generate light and heat, meaning that the star cools as it ages.

    "What’s particularly interesting in this case is that the white dwarf is extremely, extremely cold," Kaplan said.

    Cold, that is, for a star. Such stars can start out around 100,000 degrees Celsius, but this one is less than 3,000 degrees — the coldest white dwarf star ever discovered. Scientists know the star must be very cold because it is invisible to their telescopes, implying that it is radiating little light or heat. But how does one detect an invisible star? By its effects on the stars around it, it turns out.

    From a new article by me at the Milwaukee Journal Sentinel. Read the rest.

    It turns out that it’s only “sort of” like a diamond, but either way, it’s definitely cool — in more ways than one!

  4. Neutrino oscillation: the Cinderella analogy from Carel Fransen on Vimeo.

    Neutrino Oscillations — a Cinderella Story

    Cinderella’s carriage morphed into a pumpkin when the clock stuck midnight. It turns out that elementary particles can do a similar switcheroo. Strange but true!

    The phenomenon of neutrino oscillations describes a process by which one type of particle gradually morphs into another — just like Cinderella’s carriage morphed into a pumpkin. This animation explains the process using a neutrino oscillation analogy I wrote for a contest in symmetry magazine.

    Carel Fransen, a graphic design student at AKV St. Joost in the Netherlands made the animation as part of his graduation project. He also made a “visual language” representing each of the elementary particles we know of. 

    See the whole project here.

  5. 
For the past few months, physicists have been arguing among themselves. The source of the disagreement?
Dust.
It may sound insignificant, but resolution of the debate is essential to our understanding of the birth of the universe.
A recent measurement, which provided evidence for a theory describing the first instants after the Big Bang, has come under fire from physicists. The universe, the theory goes, began with an extreme kind of growth spurt, known to scientists as “inflation,” in which the universe expanded exponentially before slowing to a more reasonable pace.
The new evidence for the theory was presented with great fanfare, but, in the grand tradition of science, the experimenters’ colleagues have been questioning the results. The importance of galactic dust — small particles in the space between stars — is the sticking point.
Now, after peer review and extensive scientific debate, the experimenters acknowledge that, although it is unlikely, the possibility that dust is providing false evidence of inflation cannot be completely ruled out.
[[MORE]]
Inflation is a well-loved theory among physicists. It does a spectacular job of explaining the observations that physicists have made of the universe. A definitive confirmation of the theory, however, has been elusive. Such a result, scientists say, would be the kind of major discovery that comes along once in a lifetime and an achievement likely worthy of a Nobel Prize. Despite the criticisms of the new result, physicists are optimistic that it will stand the test of time.
"I’ve hoped for this to happen for probably 15 years, so it’s quite exciting," says Daniel Chung, associate professor of physics at the University of Wisconsin-Madison.
In March, BICEP2, a collaboration of physicists led by John Kovac of the Harvard-Smithsonian Center for Astrophysics, announced that it had found evidence of primordial gravitational waves, ripples in space and time that are considered a “smoking gun” for a period of inflation in the early universe.
"This really is an extraordinary claim," says Xavier Siemens, associate professor of physics at the University of Wisconsin-Milwaukee. If confirmed, the result would give scientists a wealth of information about the early universe.
"It’s hard to see how you could have a window onto the universe that is much earlier than that," he said.
To detect primordial gravitational waves, scientists measure the oldest light in the universe, remnants of the Big Bang. This light, known as the Cosmic Microwave Background, is like a baby picture of the universe, revealing how it behaved in its infancy.
The evidence for inflation is a swirling pattern in the polarization of this light. The Cosmic Microwave Background is polarized just as light can be polarized by scattering off the surface of water (a fact that makes polarized sunglasses useful for cutting glare). Such swirls were reportedly seen by BICEP2, using a specially designed telescope stationed at the South Pole.
But scientists are questioning whether the result might be due to another effect — namely, dust.
Much as dust on a camera lens can ruin a photograph, dust in our galaxy could create misleading effects in the data. The BICEP2 scientists accounted for this in their analysis, but evidence has been accumulating that perhaps the accounting was not complete.
On Thursday, the BICEP2 collaboration published their results in the journal Physical Review Letters. They stand behind their result but acknowledge that the possibility the signal is due to dust cannot be fully excluded.
The skepticism about the result, scientists say, is part of the normal operation of a healthy scientific method.
"We’re seeing the process work, people are questioning the result as they should, and luckily we have a really good prospect for verification in the near term," said Peter Timbie, professor of physics at UW-Madison.
That verification could come from the European Space Agency’s Planck satellite, which should have results in October. Like so much of science, unraveling the mystery will be a waiting game.

From an article I wrote for the Milwaukee Journal Sentinel. Read the rest.

    For the past few months, physicists have been arguing among themselves. The source of the disagreement?

    Dust.

    It may sound insignificant, but resolution of the debate is essential to our understanding of the birth of the universe.

    A recent measurement, which provided evidence for a theory describing the first instants after the Big Bang, has come under fire from physicists. The universe, the theory goes, began with an extreme kind of growth spurt, known to scientists as “inflation,” in which the universe expanded exponentially before slowing to a more reasonable pace.

    The new evidence for the theory was presented with great fanfare, but, in the grand tradition of science, the experimenters’ colleagues have been questioning the results. The importance of galactic dust — small particles in the space between stars — is the sticking point.

    Now, after peer review and extensive scientific debate, the experimenters acknowledge that, although it is unlikely, the possibility that dust is providing false evidence of inflation cannot be completely ruled out.

    Read More

  6. I officially got my PhD this weekend!

    I officially got my PhD this weekend!

  7. See that bird? It looks kind of like birds you’re used to seeing. But what’s up with those claws on its wings?
That’s a bird that lived in the Cretaceous period, about 125 million years ago, shortly after birds evolved from dinosaurs. The birds that were around back then looked and behaved differently than modern-day birds. 
In particular, prehistoric bird species were not nearly as diverse as modern-day birds, according to research by scientists at the University of Chicago and the Field Museum. The birds were mostly similar to crows and sparrows — living in the forests and feeding on seeds and insects — possibly because they had so recently evolved that they hadn’t had time to fill all the ecological niches they do today.
The findings could tell scientists a bit more about how and when birds evolved from dinosaurs, a topic under some scientific debate.
For more information, check out the article I wrote on the subject.

    See that bird? It looks kind of like birds you’re used to seeing. But what’s up with those claws on its wings?

    That’s a bird that lived in the Cretaceous period, about 125 million years ago, shortly after birds evolved from dinosaurs. The birds that were around back then looked and behaved differently than modern-day birds.

    In particular, prehistoric bird species were not nearly as diverse as modern-day birds, according to research by scientists at the University of Chicago and the Field Museum. The birds were mostly similar to crows and sparrows — living in the forests and feeding on seeds and insects — possibly because they had so recently evolved that they hadn’t had time to fill all the ecological niches they do today.

    The findings could tell scientists a bit more about how and when birds evolved from dinosaurs, a topic under some scientific debate.

    For more information, check out the article I wrote on the subject.

  8. My Dissertation for Non-Physicists, Part II: Neutrino Oscillations

    Here’s part II of the explanation of my PhD thesis. Part I is here

    Remember from part I that there are 3 charged leptons (the electron’s extended family): the electron, muon, and tau. There are also three neutrinos, each associated with one of those charged leptons: the electron neutrino, the muon neutrino, and the tau neutrino.

    Here’s the whole gang in stuffed-animal form:

    image

    What hams they are! Look at those mugs! Say cheese, little leptons! (If you want your own stuffed lepton, you can find them here.)

    So why do we name the neutrinos this way? It’s because each neutrino is always produced in association with the charged lepton in its name.

    A good example is beta decay. You might remember this from chemistry—it’s one of the main kinds of radioactivity. In this type of radioactive decay, an unstable atom changes from one element to another, and an electron is emitted. But a neutrino is also emitted at the same time. You didn’t know that part about the neutrino, huh? Well, at first, physicists didn’t know about the neutrino either, and it caused a huge scientific hullabaloo. But radioactive man was unfazed!

    image

    Ahem. Anyway, back to beta decay. Since the neutrino we get from beta decay is produced in conjunction with an electron, that means it’s an electron neutrino. (OK, actually it’s an electron antineutrino, the antimatter version of the particle, but that’s not super-important for our purposes.) And when an electron neutrino interacts and creates a charged lepton, it will always always always produce an electron. It will never produce a muon or a tau. That’s how we know these are three different particles.

    OK. We’re now finally ready to tackle the subject of my thesis: neutrino oscillations. Phew. Stay with me!

    Read More

  9. My Dissertation for Non-Physicists, Part I: The Standard Model

    As promised, here’s an explanation of my PhD thesis research! This is the first of two parts.

    I’m a particle physicist. That means I study the smallest things that we know of — elementary particles. So, in order to understand my dissertation, I first need to introduce you to a whole zoo of elementary particles. You’re probably familiar with at least one elementary particle, the electron.

    Some of you atom-enthusiasts are probably itching to blurt out, ”I know about protons and neutrons, too!” Actually, protons and neutrons are not elementary particles. Protons and neutrons are made up of even smaller particles, called quarks. That means protons and neutrons aren’t elementary, although they are important! Most of the time, quarks are bound up into protons or neutrons, which then make up atoms. Yay, atoms!

    image

    Nature, it turns out, has given us a whole host of elementary particles you may never have heard of. But don’t be alarmed — physicists were surprised when they detected these particles, too! The model that physicists have come up with to describe all these elementary particles and their interactions is called the Standard Model. It can’t explain why these particles exist, or why they have all the properties they have. But it can describe them mathematically and make predictions, to an incredibly precise level. That’s why the Standard Model has been called “the most successful theory ever.”

    OK, enough fanfare, here it is, the Standard Model:

    image

    Kinda reminds me of a giant gobstopper… Yum.

    Read More

  10. It’s been a bit quiet on Weak Interactions recently. That’s because I’ve had some big stuff brewing! First — I successfully defended my PhD! 

    This is a photo of me with my advisor, just after my defense. Traditionally, we have champagne after the defense, but we had to schedule mine early in the morning, so we mixed it with orange juice for some mimosas! Cheers!

    I hope I’ll have a chance to write up a summary of my PhD research for the blog. Stay tuned!

    Second, I found out that I was lucky enough to be chosen as a recipient of the AAAS Mass Media Fellowship. This program places scientists at media organizations across the country, where they spend a summer communicating science to the public. I’ll be writing for the Milwaukee Journal Sentinel! It should be a fun summer and I expect to learn a lot. I’m really excited to get started!