A discovery that made a thousand scientists burst into cheers and tears

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Part of one of the mirror assemblies that make up the Laser Interferometer Gravitational-wave Observatory (LIGO) at Livingston, Louisiana. I visited the site in 2012 during the upgrade of the lab to Advanced LIGO. [Credit: moi]

Part of one of the mirror assemblies that make up the Laser Interferometer Gravitational-wave Observatory (LIGO) at Livingston, Louisiana. I visited the site in 2012 during the upgrade of the lab to Advanced LIGO. [Credit: moi]

It’s not every day that we get to usher in an entirely new branch of astronomy. Yesterday, members of the LIGO collaboration announced the first direct detection of gravitational waves, which are a way to study the universe we can’t see using light. Much of my PhD research involved gravitational physics, including a bit of gravitational wave work. I even visited LIGO twice because … well, why not? For that reason, yesterday’s announcement brought tears to my eyes, and I’m not the only one. This is the start of a new in the study of the universe. And here’s what I had to say about it for The Atlantic:

The Dawn of a New Era in Science

By announcing the first detection of gravitational waves, scientists have vindicated Einstein and given humans a new way to look at the universe

For The Atlantic:

More than a billion years ago, in a galaxy that sits more than a billion light-years away, two black holes spiraled together and collided. We can’t see this collision, but we know it happened because, as Albert Einstein predicted a century ago, gravitational waves rippled out from it and traveled across the universe to an ultra-sensitive detector here on Earth.

This discovery, announced today by researchers with the Laser Interferometer Gravitational-wave Observatory (LIGO), marks another triumph for Einstein’s general theory of relativity. And more importantly, it marks the beginning of a new era in the study of the universe: the advent of gravitational-wave astronomy. The universe has just become a much more interesting place. [Read the rest at The Atlantic]

Be very very quiet, we’re hunting gravitational waves

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

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…]

 

Listening to the sounds of the cosmos

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

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….]

If we could only build one huge observatory….

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

Q: Suppose we can only build one big telescope. Should we look for life among the stars or the origins of the universe?

I participated in an experts’ roundtable for Aeon Magazine, in which we were asked (more or less facetiously) what single project we would support to settle either questions about the very early universe or the existence of life elsewhere in the cosmos. Of course my real answer is that we should support all the science, because discovery isn’t about looking for one thing, but seeing what new things we can find. Throwing all our money at one big project might accomplish something, but it’s a bad way to do science. But anyway, taking the question for what it is — a fun exercise in wishing — here’s my answer, along with thoughts from Ross Andersen and Caleb Scharf.

The BICEP2 telescope (foreground) with the South Pole Telescope (SPT) behind. [Credit: Steffen Richter (Harvard University)]

The BICEP2 telescope (foreground) with the South Pole Telescope (SPT) behind. [Credit: Steffen Richter (Harvard University)]

Today was an exciting and stimulating day: the BICEP2 collaboration announced the first measurement of the cosmic microwave background that might tell us whether or not inflation happened. Inflation is the hypothetical rapid expansion of the Universe during its first instants, which explains a lot about why the cosmos appears the way it does. However, data on inflation itself, as opposed to its side-effects, are hard to come by. This new observation could help resolve that…assuming we can figure out why some of its aspects don’t agree with prior observations.

While they do not constitute a direct detection of either primordial gravitational waves (the distortions causing the light polarization) or inflation, the BICEP2 results could provide the best evidence for both that could not be easily explained away by other theories. This observation cannot be the end of the story, however. The measurement of polarization is significantly larger that what is seen in the results of prior observations in a way that cannot be immediately dismissed. Whether the problems are with the interpretation and analysis of the BICEP2 data, or if something more subtle is at work, remains to be seen. [Read more….]

New data offer a peek into the Universe’s first instants

How did the biggest black holes form?

X-ray image of two black holes in the galaxy NGC 6240. Binary systems like this are possibly the origin of the most massive black holes in the cosmos. [Credit: NASA/CXC/MPE/S.Komossa et al. ]

X-ray image of two black holes in the galaxy NGC 6240. Binary systems like this are possibly the origin of the most massive black holes in the cosmos. [Credit: NASA/CXC/MPE/S.Komossa et al.]

The most massive known object in the cosmos is the black hole at the center of M87, a huge galaxy in the Virgo Cluster. While most large galaxies (including the Milky Way) harbor supermassive black holes, the very largest are interesting. That’s because galaxies and their black holes seem to share a history, based on the relationship between the mass of the black hole and the mass of the galaxy’s central region. Since large galaxies grew by devouring smaller galaxies, or by two galaxies merging into a larger one, it’s very likely the biggest black holes followed a similar process. My latest piece for Nautilus examines how this process might have taken place, and what it could reveal about the black holes themselves.

Earth emits gravitational waves as it orbits the Sun, though the amount of energy lost is imperceptible over the lifetime of the Solar System. Binary black holes are a different matter: Once they are relatively close, they shed a tremendous amount of energy, bringing them closer together with each orbit. (Binary black stars are thought to emit more gravitational energy as they merge than regular stars emit in the form of UV, IR, and visible light over their entire lifetimes of billions of years.) Eventually their event horizons will touch, and the system emits a lot more gravitational waves in a phase known as “ring-down,” as the lumpy, uneven merged mass becomes a smooth, perfectly symmetrical black hole. [Read more…]

The week in review (October 13 – 19)

I’m at GeekGirlCon this weekend, so I’m busy with non-writing activities as part of the DIY Science Zone. Thanks to our Fearless Leader Dr. “Nick Fury” Rubidium for putting our part of the event together!

  • Where Nature Hides the Darkest Mystery of All (Nautilus): Even though there’s no solid barrier, the event horizon of a black hole provides a boundary through which we can’t see or probe. That leads to a troubling idea: will we ever know what’s really inside that event horizon? Is there any way to learn about the interior by indirect measurements?
  • Black hole hair and the dark energy problem (Galileo’s Pendulum): Building off that article, what happens if our standard theory of gravity is modified? That’s not an entirely crazy idea: several modifications to general relativity have been proposed, inspired by inflation (the rapid expansion during the cosmos’ earliest moments) or dark energy. A recent paper examined that idea, and here’s my take.
  • Strongly magnetic pulsar could explain anomalous supernovas (Ars Technica): Some supernovas are particularly bright, especially some from the early Universe. These, known as “pair-instability” supernovas, are the explosion of very massive stars made of nearly pure hydrogen and helium. However, some of these super-luminous supernovas don’t quite fit that profile, including being too close. A new set of observations may show they are actually driven by a magnetar, a highly magnetized pulsar.
  • Gravitational waves show deficit in black hole collisions (Ars Technica): Mergers of supermassive black holes should happen frequently enough to produce a bath of gravitational radiation permeating the cosmos. While that gravitational wave background (GWB) possesses wavelengths too large for ground-based detectors like LIGO, astronomers realized it might be visible in the fluctuations of light from pulsars. However, they didn’t see what they expected, leading to the big question: why not?