It’s a double whammy of gravitational waves!

Image: Black hole merger
A computer simulation shows two black holes shortly before they merge into one. (Credit: SXS)

Two detections of gravitational waves, separated by a mere 21 minutes, set off a flurry of excitement among astronomers today.

Was it a binary black-hole merger? A double observation of a single black-hole merger, created by gravitational lensing effects? A glitch affecting the analytical systems at the world’s gravitational-wave detectors? Or merely a coincidence of cosmic proportions?

“This is a genuine ‘Uh, wait, what?’ We’ve never seen that before…….’ moment in gravitational wave astronomy,” Robert Rutledge, a physicist at McGill University, tweeted today. “If you’d like to see how double-checks and confirmations and conclusions occur – pay attention, in real time. Happening now.”

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Did a black hole just gobble up a neutron star?

Neutron star and black hole illustration
An artist’s conception shows a neutron star swirling around a black hole. (OzGrav ARC Centre of Excellence Illustration via Australian National University / Carl Knox)

The Laser Interferometer Gravitational-Wave Observatory, or LIGO,  has detected mergers of black holes, and even a couple of neutron star smash-ups. But it hasn’t yet confirmed the signature of a black hole gobbling a neutron star.

That could soon change.

Over the past week, physicists have been buzzing over an Aug. 14 detection made by the twin LIGO detectors in Hanford, Wash., and Livingston, La., as well as by the European Virgo gravitational-wave detector in Italy. Those L-shaped facilities monitor ever-so-slight fluctuations in laser beams to look for wobbles in spacetime caused by passing gravitational waves.

The types of waves that LIGO and Virgo detect are given off only by violent cosmic events such as supernova explosions and cataclysmic collisions. LIGO’s first black hole detection, made in 2015, earned the Nobel Prize in physics two years later. More such detections have been made since then.

Detecting the first neutron star merger, and matching that event up with multispectral observations from a wide array of telescopes, marked another milestone in 2017. Neutron stars are the super-dense stellar cores that are left behind when stars bigger than our sun burn out and collapse.

Picking up on the collision of a neutron star and a black hole would complete a gravitational-wave trifecta. LIGO’s team thought they might have detected such a smash-up back in April, but the signal was weak and couldn’t be confirmed.

Astronomers say the Aug. 14 detection, known as S190814bv and traced to a source roughly 900 million light-years away, could be the one.

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Cosmic Space

50 shades of black holes for 17 years of Cosmic Log

This week marks 17 years since Cosmic Log was founded, and to celebrate the occasion, here’s the text of a talk I gave this month at Theatre Off Jackson for Infinity Box Theatre’s “Centrifuge” production of science-oriented one-act plays. My talk, titled “Fifty Shades of Black Holes,” set the scene for a three-actor drama about a black hole expedition. To take a walk down Cosmic Log’s memory lane, check out our archives.

I bet you never thought you’d be learning about black holes, the holographic principle and digital consciousness theory tonight. But you’ll be getting a taste of all of that in just a few minutes, in Harold Taw’s play about the Primrose Protocol.

My name is Alan Boyle. I’m the aerospace and science editor at GeekWire, and you can consider this a prologue to set the scientific scene.

I actually write about black holes every so often – for example, I was in Washington, D.C., last month for the unveiling of the first-ever image of a supermassive black hole. This one is in M87, a galaxy that’s about 55 million light-years away. But our own Milky Way galaxy also has a black hole at its center, a mere 26,000 light-years away.

If you’re up on your science fiction, you probably know that a black hole is a gravitational singularity so dense that nothing, not even light, can escape its grip. But that’s just one of the ways in which black holes bend our conception of reality.

Light waves from stars behind a black hole are bent by its gravitational field, which produces the aura you see around the circular edge of the event horizon.

Oh, the event horizon … This is important. That marks the edge of the region where anything that falls in can’t get out. But if you were heading toward the event horizon, you wouldn’t necessarily know when you crossed it – at least at first. You could keep falling toward the center of a black hole for hours before bad stuff starts happening.

Eventually, though, the gravitational field would become so strong that if you were falling feet first, your feet would be pulled in faster than your head. Your whole body, and all the atoms in it, would be stretched out like a noodle. Stephen Hawking is credited with coming up with the technical term for this effect: spaghettification.

Once an object falls past the event horizon, it’s gone. But for physicists like Hawking, that’s a big problem. In science class, you’ve probably heard it said that energy can neither be created nor destroyed – it can only be transferred or changed in form. Theoretical physicists say the same thing about information: It can neither be created nor destroyed.

So what happens to the information about things that fall in a black hole? Some physicists say that the information is somehow encoded on the surface of the event horizon, perhaps as tiny fluctuations in a black hole’s gravitational field.

It’s similar to the way the information for a 3-D object can be encoded on a 2-D hologram – like the shiny square that’s on the back of a credit card. Physicists call this idea the holographic principle. Some even suggest that at its most basic level, the universe we live in just might be an encoded two-dimensional surface that we decode into our perception of three dimensions.

If that’s the case, it’s not hard to imagine that everything in our reality – including ourselves – can be translated into the code of a deeper reality. And if our descendants ever figure out that code, maybe millions of years from now, could our shades be re-created from the fluctuations we left behind? What is real?

I’m going to stop right here, at the edge of the event horizon. I’ll leave it to the actors of “The Primrose Protocol” to plunge ahead, into the void.


Readings hint at black hole eating neutron star

Scientists work in the LIGO Hanford control room. (Caltech / MIT / LIGO Lab Photo / C. Gray)

The science teams for the Laser Interferometer Gravitational-Wave Observatory, or LIGO, and Europe’s Virgo detector today laid out the details of their recent detections, including a crash between neutron stars, three black hole mergers and what may be the first observed collision of a neutron star and a black hole.

Astronomers and their fans have been talking about the detections for days, thanks to the fact that LIGO and Virgo are quickly sharing the raw results from their current observing run. But today’s statements provided the most authoritative views from researchers running the two gravitational-wave detectors.

The April 26 detection of a cosmic collision known as S190426c is the most intriguing event. The subtle signal of a far-off disturbance in the gravitational force was picked up by LIGO’s twin detectors at Hanford in Eastern Washington and at Livingston in Louisiana. The Virgo detector in Italy also detected the signal.

The signal is consistent with what might be expected if a black hole were to swallow a neutron star, roughly 1.2 billion light-years from Earth. Such an event has never been observed before.

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Scientists unveil first image of a black hole

Black hole image
This image from the Event Horizon Telescope shows the supermassive black hole in the elliptical galaxy M87, surrounded by superheated material. (EHT Collaboration)

WASHINGTON, D.C. — Scientists today shared the first picture to show the immediate surroundings of a galaxy’s supermassive black hole, captured by a network of radio telescopes that adds up to what could be considered the world’s widest observatory.

A project called the Event Horizon Telescope delivered a fuzzy view of the dark monster at the center of an elliptical galaxy known as M87. The edge of the black hole’s dark circle, known as the event horizon, was surrounded by the bright glare of superheated material falling into the black hole.

“This is a remarkable achievement. … It’s almost humbling in a certain way,” EHT project director Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said during a news briefing here at the National Press Club.

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LIGO and Virgo gear up for gravitational waves

LIGO upgrade
Detector engineers Hugh Radkins (foreground) and Betsy Weaver (background) take up positions inside the vacuum system of the detector at LIGO Hanford Observatory to perform the hardware upgrades required for Advanced LIGO’s third observing run. (LIGO / Caltech / MIT Photo / Jeff Kissel)

Physicists won’t be fooling around on April 1 at the Laser Interferometer Gravitational-Wave Observatory in Washington state and Louisiana, or at the Virgo gravitational-wave detector in Italy.

Instead, they’ll all be bearing down for the most serious search ever conducted for signs of merging black holes, colliding neutron stars — and perhaps the first detection of a mashup involving both those exotic phenomena.

Both experiments have been upgraded significantly since their last observational runs, resulting in a combined increase of about 40 percent in sensitivity. That means even more cosmic smashups should be detected, at distances farther out. There’s also a better chance of determining precisely where cosmic collisions occur, increasing the chances of following up with other types of observations.

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Four black hole smashups added to LIGO’s list

Black hole merger
An artist’s conception shows two black holes merging. (LIGO / Caltech / MIT Illustration)

Four more mergers of black holes, including the biggest one recorded to date, have been added to a catalog generated by gravitational-wave detectors.

The additions were announced today by the teams in charge of the Laser Interferometer Gravitational-Wave Observatory, or LIGO, and the European-based Virgo detector. The full list of stellar-mass binary black hole mergers now stands at 10, with a neutron-star merger thrown in for good measure.

“The release of four additional binary black hole mergers further informs us of the nature of the population of these binary systems in the universe, and better constrains the event rate for these types of events,” Caltech physicist Albert Lazzarini, deputy director of the LIGO Laboratory, said in a news release

The four previously unreported detections came to light during a re-analysis of data from LIGO’s first two observing runs. The third run, known as O3, is scheduled to begin next spring.

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Relativity rules star near our galaxy’s black hole

A 26-year-long observational campaign provides clear evidence of the effect that general relativity has on the motion of a star known as S2 as it boomerangs around the supermassive black hole at the center of our Milky Way galaxy.

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Neutrino trackers solve a cosmic ray puzzle

Blazar and neutrino
In this artistic rendering, a blazar is accelerating protons that produce pions, which produce neutrinos and gamma rays. One neutrino’s path is represented by a blue line passing through Antarctica, while a gamma ray’s path is shown in pink. (IceCube / NASA Illustration)

An array of detectors buried under a half-mile-wide stretch of Antarctic ice has traced the path of a single neutrino back to a supermassive black hole in a faraway galaxy, shedding light on a century-old cosmic ray mystery in the process.

The discovery, revealed today in a flurry of research papers published by the journal Science and The Astrophysical Journal, marks a milestone for the IceCube Neutrino Observatory at the National Science Foundation’s Amundsen-Scott South Pole Station.

It also marks a milestone for an observational frontier known as multi-messenger astrophysics, which takes advantage of multiple observatories looking at the sky in different ways. Thanks to IceCube’s alert, more than a dozen telescopes were able to triangulate on the neutrino’s source.

“No one telescope could have done this by themselves,” said IceCube lead scientist Francis Halzen, a physics professor at the University of Wisconsin at Madison.

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Stephen Hawking gets a cosmic sendoff

Stephen Hawking memorial stone
Stephen Hawking’s memorial stone depicts a black hole as well as an equation that describes the temperature of a black hole’s Hawking radiation. (Westminster Abbey via Twitter)

Famed physicist Stephen Hawking’s ashes were interred among the greats of British science at Westminster Abbey today — and to mark his passing, his message of peace and hope was beamed to the nearest known black hole.

Black holes were a favorite subject for the theorist, who died in March at the age of 76 after dealing with progressive disability for decades. His memorial stone on the abbey’s floor, which is sure to become the site of scientific pilgrimages for decades to come, is engraved with the outlines of a black hole as well as an equation that describes a black hole’s Hawking radiation.

Today’s memorial ceremony was anything but dark. Nobel-winning scientists and Oscar-winning celebrities joined Hawking’s family and more than 1,000 others to pay tribute to the physicist.

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