Squeezing light to detect more gravitational waves

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This article appeared in the fall print issue of Popular Science, but I missed that this article had also been published online.

Something called ‘squeezed light’ is about to give us a closer look at cosmic goldmines

Gravitational wave detection is going through an even tighter squeeze.

For Popular Science:

In 2015, scientists caught evidence of a ­cosmic throwdown that took place 1.3 billion light-​years away. They spied this binary black-hole collision by capturing gravitational waves—­ripples in spacetime created when massive objects ­interact—​for the first time. But now physicists want to see even farther. Doing so could help them accurately measure waves cast off by colliding neutron stars, impacts that might be the source of many Earthly elements, including gold. For that, they need the most sensitive gravitational-wave detectors ever.

The devices that nab waves all rely on the same mechanism. The U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) and its European counterpart, Virgo, fire lasers down two mile-plus-long arms with mirrors at their ends. Passing waves wiggle the mirrors less than the width of an atom, and scientists measure the ripples based on when photons in the laser light bounce off them and come back. Ordinarily, photons exit the lasers at random intervals, so the signals are fuzzy.

[Read the rest at Popular Science]

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Looking for the fifth dimension with wrinkles in spacetime

[ This blog is dedicated to tracking my most recent publications. Subscribe to the feed to keep up with all the science stories I write! ]

Are We Closer to Finding a Fifth Dimension?

For The Daily Beast:

In Madeleine L’Engle’s classic novel A Wrinkle in Time, the characters travel from one place to another in space using a hidden fifth dimension, which they use to “wrinkle” the fabric of space and time. In the book and upcoming movie, this travel is more mystical than it is science. However, some scientists think there might be extra dimensions beyond the four (three space plus one time) that we’re familiar with—and those dimensions might affect the way gravity works.

But how can we know for sure? One way to check uses the collision of two neutron stars, as detected by the gravitational wave observatories LIGO and Virgo in 2017.

While they found no sign of a fifth (or sixth or seventh or…) dimension, researchers—who recently posted their work on the website arXiv—were excited.

That’s because looking for extra dimensions is difficult. We only see three dimensions in space (length, width, and depth) and one in time on the scale of the everyday; if a fifth dimension exists, it has to be hiding from us. That pushes any detectable consequence into the realm of the very small—the regime of particle physics and string theory—or the very large, where LIGO and other astronomical measurements come in.

[Read the rest at The Daily Beast]

Nuclear pasta and neutron stars

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The Inside of a Neutron Star Looks Spookily Familiar

Exotic ultra-compressed matter can look like pasta, among other things

Two phases of matter found in neutron stars are featured in this recent Dinosaur Comic; click to see the whole thing. (Slightly naughty language included.) [Credit: Ryan North]

Two phases of matter found in neutron stars are featured in this recent Dinosaur Comic; click to see the whole thing. (Slightly naughty language included.) [Credit: Ryan North]

For Nautilus:

Hot fluids of neutrons that flow without friction, superconductors made of protons, and a solid crust built of exotic atoms—features like these make neutron stars some of the strangest objects we’ve found in the cosmos so far. They pack all the mass of a star into a sphere the size of a city, resulting in states of matter we just don’t have on Earth.

And yet, despite their extreme weirdness, neutron stars contain a mishmash of vaguely familiar features, as if seen darkly through a funhouse mirror. One of the weirdest is the fact that deep inside a neutron star you can find a whole menu full of (nuclear) pasta. [Read the rest at Nautilus…]

Be very very quiet, we’re hunting gravitational waves

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Gravitational waves and where to find them

Advanced LIGO has just begun its search for gravitational waves

For Symmetry Magazine:

For thousands of years, astronomy was the province of visible light, that narrow band of colors the human eye can see.

In the 20th century, astronomers pushed into other kinds of light, from radio waves to infrared light to gamma rays. Researchers built neutrino detectors and cosmic ray observatories to study the universe using particles instead. Most recently, another branch of lightless astronomy has been making strides: gravitational wave astronomy.

It’s easy to make gravitational waves: Just flap your arms. Earth’s orbit produces more powerful gravitational waves, but even these are too small to have a measurable effect. This is a good thing: Gravitational waves carry energy, and losing too much energy would cause Earth to spiral into the sun. [Read the rest at Symmetry Magazine…]

 

I Love Q, and now you can too!

I wrote a feature story for Physics World on an interesting little discovery about neutron stars, but unfortunately the article wasn’t in their free online edition. HOWEVER, the editors have kindly let me repost the article here in PDF format for free download! (Here’s the summary I wrote a few weeks ago.)

Physics World is a glossy magazine published by the Institute of Physics (IoP) in Europe. My articles are in the print version, but you can access them online by joining IoP (US$25 per year) and see everything they publish either through the Physics World website (which also has tons of free content) or the app, available on iTunes or Google Play.

The three little words every pulsar wants to hear

[ This blog is dedicated to tracking my most recent publications. Subscribe to the feed to keep up with all the science stories I write! UPDATE: you can now download this article in PDF format! See the follow-up post or the update below.]

I can’t help falling in Love with Q

The first page of my latest print article in Physics World. Unfortunately, there doesn't seem to be an online version.

The first page of my latest print article in Physics World. Unfortunately, there doesn’t seem to be an online version.

From Physics World:

The dancers are an elegant pair. Clothed in the fabric of space–time, they are driven by the music of gravity and make a stately orbit around one another once every two-and-a-half hours. They pirouette as they move – one spins once every few seconds while the other spins many times per second – and each one of their twirls is marked by an intense flash of light. The dancing partners are pulsars – spinning neutron stars that send a regular blip of light our way.

Named PSR J0737-3039, this duo is one of a kind. More commonly known as the “double-pulsar system”, it is the only two-pulsar system where we have observed both partners. Other binary-pulsar systems exist, consisting of a pulsar and, for example, a white dwarf or a (non-radiative) neutron star. However, astronomers find the double-pulsar system particularly valuable because it consists of two flashing beacons rather than one, and the more information they can glean to test their theories, the better.

Unfortunately, this article is currently only available in print, and Physics World isn’t a typical newsstand offering. Update: the editors have kindly let me repost the article here in PDF format for free download! You can also access all the content online by joining IoP (US$25 per year) and see everything they publish either through the Physics World website (which also has tons of free content) or the app, available on iTunes or Google Play.

I am overly proud of the headline, and the concepts I described in the article are very interesting. In brief, measurable properties of neutron star exteriors are independent of the particular physics going on inside. Since neutron stars are some of the most complex objects we know of — they are the density of an atomic nucleus, the mass of a star, and the size of a city on Earth — anything we can learn to help study them is a good thing. A few theorists figured out how to relate observable properties to each other, in particular three parameters labeled I, Q, and the “Love number” (named for a person, not the emotion). The I-Love-Q relations in combination with sophisticated neutron star observations could hopefully help us solve the deep mystery of what’s going inside an object that’s like nothing we can create in the lab.

(If you want some more technical information, here’s the main paper I drew on for background.)

Listening to the sounds of the cosmos

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Last year, I went to a conference in Florida to hear — and in some cases meet — some of the leading thinkers in the study of gravitational waves. These waves are disturbances in the structure of spacetime itself, and could provide information about some exciting phenomena, if we can learn to detect them. The universe as heard in gravitational waves includes colliding black holes, white dwarfs locked in mutual orbits, exploding stars, and possibly chaotic disturbances from the very first instants after the Big Bang. This story marks one of my first big magazine articles, which I wrote for Smithsonian Air & Space magazine.

The Universe is Ringing

And astronomers are building observatories to listen to it

For Smithsonian Air & Space:

Think of it as a low hum, a rumble too deep to notice without special equipment. It permeates everything—from the emptiest spot in space to the densest cores of planets. Unlike sound, which requires air or some other material to carry it, this hum travels on the structure of space-time itself. It is the tremble caused by gravitational radiation, left over from the first moments after the Big Bang.

Gravitational waves were predicted in Albert Einstein’s 1916 theory of general relativity. Einstein postulated that the gravity of massive objects would bend or warp space-time and that their movements would send ripples through it, just as a ship moving through water creates a wake. Later observations supported his conception. [Read the rest at Air & Space….]