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]

When testing gravity, no news is good news

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Looking for nothing to test gravity

When they look for violations of Einstein’s general relativity, physicists deliberately plan experiments to find nothing at all.

For Symmetry Magazine:

In 1887, physicists Albert Michelson and Edward Morley performed one of physics’ most famous experiments (at Case Western Reserve University, coincidentally, across the street from where this article was written). Unlike other important experiments, they didn’t find what they were looking for, but unexpectedly their “null” result prepared the way for the theory of relativity.

Sometimes researchers deliberately set out to generate null results—while on the lookout for something new. One type of experiment is looking for deviations from Einstein’s general theory of relativity.

“General relativity has been the staple of gravitational understanding for 100 years,” says Katie Chamberlain, a physics student at Montana State University. “We have to rule out the potential for other existing theories to come in and replace [it].”

[Read the rest at Symmetry Magazine]

Looking for the fifth dimension with wrinkles in spacetime

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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]

Doing astronomy using gravity

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Astronomy without light

Gravitational waves let us see the invisible universe in new ways

For Astronomy Magazine:

Humans have always practiced some form of astronomy. For thousands of years, that meant observing only the light our eyes could see — either unaided or with a variety of instruments, such as astrolabes or telescopes. The 20th century brought new types of telescopes, which detect light we can’t see: infrared, X-ray, and so on.

Today, we’re witnessing the genesis of a whole new type of astronomy, and this one doesn’t use light at all. It uses gravitational waves.

Read the rest at Astronomy Magazine

My new series on black holes!

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I’ve just started a new series on black holes for Medium members. The first part is available now, with three more parts to come. And if enough of you read, they may keep me around to write more, so please read and share!

Exploring Black Holes: Frozen Stars and Gravitational Dynamos

Black holes are gravitational superheroes. Here is their origin story, including World War I, magnificent mustaches, and Albert Einstein

For Medium:

February 11, 2016, was a landmark day. After many decades of searching, scientists announced they had detected gravitational waves for the first time: disturbances in the structure of space-time that travel at light speed. But there was a second triumph of physics hiding inside that one. The waves gave us the best evidence so far for the existence of some of the most fascinating objects in our universe: black holes.
Few scientists these days doubt that black holes exist. But in a way, all our evidence for them is circumstantial. Black holes, by their very nature, are difficult to observe. All light falling on them is absorbed, rendering them nearly invisible.
On the other hand, black holes are the strongest gravitational powerhouses possible. When they strip matter off stars or out of interstellar gas clouds, that material heats up and shines brightly. It’s a seeming paradox: invisible objects that end up being some of the brightest things in the universe. The black holes known as quasars can be seen billions of light-years away. [read the rest at Medium…]

Some heavy facts about gravity

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I’m not generally the type of writer who makes listicles, but I’m producing a few for Symmetry Magazine this year. The first covers the OG of fundamental forces: gravity!

Six weighty facts about gravity

Perplexed by gravity? Don’t let it get you down

For Symmetry Magazine:

Gravity: we barely ever think about it, at least until we slip on ice or stumble on the stairs. To many ancient thinkers, gravity wasn’t even a force—it was just the natural tendency of objects to sink toward the center of Earth, while planets were subject to other, unrelated laws.

Of course, we now know that gravity does far more than make things fall down. It governs the motion of planets around the Sun, holds galaxies together and determines the structure of the universe itself. We also recognize that gravity is one of the four fundamental forces of nature, along with electromagnetism, the weak force and the strong force.

The modern theory of gravity—Einstein’s general theory of relativity—is one of the most successful theories we have. At the same time, we still don’t know everything about gravity, including the exact way it fits in with the other fundamental forces. But here are six weighty facts we do know about gravity. [Read the rest at Symmetry Magazine]

BICEP3: Revenge of the telescope

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Dusting for the fingerprint of inflation with BICEP3

A new experiment at the South Pole picks up where BICEP2 left off

For Symmetry Magazine:

When researchers with the BICEP2 experiment announced they had seen the first strong evidence for cosmic inflation, it was front-page news around the world. Inflation is the extremely rapid expansion of space-time during its first split second of existence, proposed to explain a number of puzzling properties of the universe, making the BICEP2 results a really big deal. Over the following months, though, the excitement evaporated: After combining their data with other experiments, the BICEP2 team showed that most or all of the signal attributed to inflation was likely produced by galactic dust inside the Milky Way.

But traces of inflation could still be hiding in the data, and that’s why scientists haven’t given up yet. BICEP3, the upgraded version of BICEP2, began collecting data yesterday. The first observations using the fully updated equipment will run through November. [Read the rest at Symmetry Magazine]