Professor Andrei Linde is among the physicists responding to a recent media story taking aim at inflationary theory. Credit: L.A. Cicero

May 11, 2017 by Amy Adams

From the earliest human civilizations, people have looked to the heavens and pondered the origins of the stars and constellations above. Once, those stories involved gods and magical beings. Now, there's science, and a large research enterprise focused on understanding how the universe came to be.

Squarely in the center of this research enterprise is what's known as inflationary theory. It argues that the universe was born out of an unstable, energetic vacuum-like state then expanded dramatically, spinning off entire galaxies produced by quantum fluctuations. This theory was proposed in 1980 by Alan Guth, presently at MIT. A year later, this theory was improved and extended by Andrei Linde, Stanford professor of physics, who has spent a lifetime modifying and updating it as new data emerged.

See full text

A still image from a simulation that shows a black-hole binary inside a globular cluster. A new study examines how we can tell whether the black holes detected by LIGO were formed hierarchically from mergers of smaller black holes. [Northwestern Visualization/Carl Rodriguez]

By Susanna Kohler on 12 May 2017

The recent successes of the Laser Interferometer Gravitational-Wave Observatory (LIGO) has raised hopes that several long-standing questions in black-hole physics will soon be answerable. Besides revealing how the black-hole binary pairs are built, could detections with LIGO also reveal how the black holes themselves form?

See full text

The stars within and beyond the Pillars of Creation are revealed in the infrared. 

Ethan Siegel, Contributor

While Hubble extends its view out to 1.6 microns, more than twice the limit of visible light, James Webb will go out to 30 microns: nearly 20 times as far again.

It's been a staple of science throughout the centuries: the arrogant thinking that we've almost arrived at the ultimate answers to our deepest questions. Scientists thought that Newton's mechanics described everything, until they discovered the wave nature of light. Physicists thought we were almost there when Maxwell unified electromagnetism, and then relativity and quantum mechanics came along. And many thought the nature of matter was complete when we discovered the proton, neutron and electron, until high-energy particle physics revealed an entire Universe of fundamental particles. In just the past 25 years, five incredible discoveries have changed our understanding of the Universe, and each one holds the promise of an even bigger revolution. There's never been a better time to look into the deepest mysteries of existence.

See full text

Extra dimensions hiding here

Signatures of extra dimensions that don’t normally affect the four dimensions we can observe could show up in the way they warp ripples in space-time

By Leah Crane

HIDDEN dimensions could cause ripples through reality by modifying gravitational waves – and spotting such signatures of extra dimensions could help solve some of the biggest mysteries of the universe.

Physicists have long wondered why gravity is so weak compared with the other fundamental forces. This may be because some of it is leaking away into extra dimensions beyond the three spatial dimensions we experience.

Some theories that seek to explain how gravity and quantum effects mesh together, including string theory, require extra dimensions, often with gravity propagating through them. Finding evidence of such exotic dimensions could therefore help to characterise gravity, or find a way to unite gravity and quantum mechanics – it could also hint at an explanation for why the universe’s expansion is accelerating.

See full text

HEART OF THE MATTER An illustration of the supermassive black hole at the center of the Milky Way.
PHOTOGRAPH BY NRAO, AUI, NSF

By Ron Cowen
PUBLISHED APRIL 11, 2017
WESTFORD, MASSACHUSETTS For the monster at the Milky Way’s heart, it’s a wrap.

After completing five nights of observations, today astronomers may finally have captured the first-ever image of the famous gravitational sinkhole known as a black hole.

More precisely, the hoped-for portrait is of a mysterious region that surrounds the black hole. Called the event horizon, this is the boundary beyond which nothing, not even light, can escape the object’s gargantuan grasp.

As the final observing run ended at 11:22 a.m. ET, team member Vincent Fish sat contentedly in his office at the MIT Haystack Observatory in Westford, Massachusetts. For the past week, Fish had been on call 24/7, sleeping fitfully with his cell phone next to him, the ringer set loud.

See full text

Now we wait to see it.

FIONA MACDONALD 12 APR 2017

Scientists around the world have spent five sleepless nights staring into the abyss, and are hoping they've been rewarded with something that could change physics forever - the first photo of the event horizon at the edge of a black hole.

If their efforts were successful, we might be on the verge of actually seeing the edge of an elusive black hole, allowing us to see if the fundamentals of general relativity hold fast under some pretty extreme conditions. If Einstein was alive, we're sure he'd be excitedly freaking out right now.

See full text

By Leah Crane

Put on the brakes. A spinning neutron star that shifts between two states slows at a faster rate in one of them – and gravitational waves may be responsible.

The neutron star J1023+0038 spins almost 600 times per second. But as its powerful magnetic field dissipates energy, it is slowing by about 76 rotations per second every billion years. This magnetic “spin-down” is normal, but sometimes J1023 slows at a faster rate.

The different rates are associated with two states the neutron star switches back and forth between: one where it emits mostly radio waves and one where it mainly gives off X-rays. No one knows why some neutron stars behave in this way. But when the star is emitting mostly X-rays, it slows down about 30 per cent faster.

See full text

Upholding Einstein, so far
Andrew Brookes, National Physical Laboratory/SPL

By Anil Ananthaswamy

22 March 2017

OUR most accurate clocks are probing a key tenet of Einstein’s theory of relativity: the idea that time isn’t absolute. Any violation of this principle could point us to a long-sought theory that would unite Einstein’s ideas with quantum mechanics.

Special relativity established that the laws of physics are the same for any two observers moving at a constant speed relative to each other, a symmetry called Lorentz invariance. One consequence is that they would observe each other’s clocks running at different rates. Each observer would regard themselves as stationary and see the other observer’s clock as ticking slowly – an effect called time dilation.

Einstein’s general relativity compounds the effect. It says that the clocks would run differently if they experience different gravitational forces.

See full text

Commonly held belief and scientific proof holds true that black holes suck matter in rather than spewing them out. But NASA has just found some curious evidence around a supermassive black hole named Markarian 335.

Two of NASA’s telescopes, including the Nuclear Spectroscopic Telescope Array (NuSTAR), observed what is believed to be a black hole’s corona launching away from the supermassive black hole. That event was then followed by a large pulse of X-Ray energy.

See full text

By Gabriel Popkin

APS April Meeting 2017 —

If the APS April Meeting 2016 was a champagne-soaked celebration for gravitational wave scientists, the 2017 meeting was more like spring training — there was lots of potential, but the real action is yet to come.

The Laser Interferometer Gravitational-Wave Observatory, or LIGO, launched the era of gravitational wave astronomy in February 2016 with the announcement of a collision between two black holes observed in September 2015. "I’m contractually obligated to show the slide [of the original detection] at any LIGO talk for at least another year," joked Jocelyn Read, a physicist at California State University, Fullerton, during her presentation at this year’s meeting.

The scientific collaboration that operates the two LIGO detectors netted a second merger between slightly smaller black holes on December 26, 2015. (A third "trigger" showed up in LIGO data on October 12, 2015, but ultimately did not meet the stringent "five-sigma" statistical significance standard that physicists generally insist on.)

See full text

Kip Thorne (left) and Ronald Drever (middle), with Robbie Vogt, the first director of the LIGO project (1990)

Ronald Drever, one of the architects behind the first detection of gravitational waves, has died aged 85.

The Scottish physicist passed away peacefully in Edinburgh on Tuesday, following a short but rapid deterioration in his health.
Prof Drever is credited with doing some of the key early experimental work.

The sensing in 2015 of ripples in the fabric of space-time generated by merging black holes is seen as one of the major breakthroughs of our time.

His family announced the death with a short statement late on Wednesday: "We are extremely proud of Ronald and his scientific achievements; he was unique and unconventional but very caring with a strong sense of humour. He will be sadly missed by us all."

See full text

Virgo stretches its 3-kilometer arms across the Tuscan plain near Pisa, Italy.
Virgo Collaboration/N. Baldocchi

By Daniel Clery

Feb. 16, 2017 , 2:00 PM

On 20 February, dignitaries will descend on Virgo, Europe’s premier gravitational wave detector near Pisa, Italy, for a dedication ceremony to celebrate a 5-year, €24 million upgrade. But the pomp will belie nagging problems that are likely to keep Virgo from joining its U.S. counterpart, the Laser Interferometer Gravitational-Wave Observatory (LIGO), in a hunt for gravitational wave sources that was meant to start next month. What has hobbled the 3-kilometer-long observatory: glass threads just 0.4 millimeters thick, which have proved unexpectedly fragile. The delay, which could last a year, is “very frustrating for everyone,” says LIGO team member Bruce Allen, director of the Max Planck Institute for Gravitational Physics in Hannover, Germany.

See full text

The EHT team has produced simulations of what Einstein's theories predict the hole should look like

Scientists believe they are on the verge of obtaining the first ever picture of a black hole.

By Jonathan Amos
BBC Science Correspondent, Boston

They have built an Earth-sized "virtual telescope" by linking a large array of radio receivers - from the South Pole, to Hawaii, to the Americas and Europe.

There is optimism that observations to be conducted during 5-14 April could finally deliver the long-sought prize.
In the sights of the so-called "Event Horizon Telescope" will be the monster black hole at the centre of our galaxy.
Although never seen directly, this object, catalogued as Sagittarius A*, has been determined to exist from the way it influences the orbits of nearby stars.

These race around a point in space at many thousands of km per second, suggesting the hole likely has a mass of about four million times that of the Sun.

But as colossal as that sounds, the "edge" of the black hole - the horizon inside which an immense gravity field traps all light - may be no more than 20 million km or so across.

See full text

LISA would use three spacecraft linked by lasers to detect passing gravitational waves. Credit: AEI/MM/exozet 

by Jeff Foust — February 7, 2017

WASHINGTON — A combination of scientific breakthroughs and technical accomplishments are making astronomers optimistic the European Space Agency will proceed with development of a space-based gravitational wave observatory.

A European consortium submitted to ESA in January a proposal for the development of the Laser Interferometer Space Antenna (LISA) mission for ESA’s third large mission, or L3, competition. LISA is widely considered the leading candidate to be selected for that mission for launch likely in the early 2030s.

See full text

 LIGO Detection: Behind the scenes of the discovery of the decade

To celebrate the one-year anniversary of a discovery that changed the face of astronomy, on 7 February we feature the exclusive world premiere of a new documentary.

LIGO Detection reveals what unfolded behind the scenes between the detection of merging black holes on 14 September 2015, and five months later when LIGO announced it to the world

Click here to sign up to our newsletter and find out about exclusive content like this before anyone else.

See full text