Dennis Overbye

This is not typically seen in regular life — with the possible exception of middle-agers who develop a sudden taste for sports cars and young trophy spouses. The question is, why not?

In what amounts to a technological triumph for the aspiring Benjamin Buttons of the virtual world, a team of quantum physicists reported earlier this year that they had succeeded in creating a computer algorithm that acts like the Fountain of Youth.

Using an IBM quantum computer, they managed to undo the aging of a single, simulated elementary particle by one-millionth of a second. But it was a Pyrrhic victory at best, requiring manipulations so unlikely to occur naturally that it only reinforced the notion that we are helplessly trapped in the flow of time.

Most of us already sense that the atoms of a scrambled egg can’t be unscrambled back inside a pristine shell. Now it seems that, under general conditions, even a single particle probably can’t go backward without help and careful tinkering.

“We demonstrate that time-reversing even ONE quantum particle is an unsurmountable task for nature alone,” Valerii M. Vinokur, of Argonne National Laboratory, said in an email message; he is one of the five aspiring time lords led by Gordey B. Lesovik of the Moscow Institute of Physics and Technology. “The system comprising two particles is even more irreversible, let alone the eggs — comprising billions of particles — we break to prepare an omelet.”

Playing Quantum Billiards

On paper, the basic laws of physics are reversible; they work mathematically whether time is running forward or backward. But if time is just another dimension of space-time, as Einstein said, it’s a strange one-way dimension. In the real world we can climb out of the subway and turn left or right, but we don’t have the choice of going forward or back in time. We are always headed toward the future.

We seem to be at the mercy of the second law of thermodynamics, which states that disorder and complexity only increase in a closed system such as, say, the universe. Thus, the atoms in an egg never unscramble themselves, in part because there are countless more ways for them to be thoroughly scrambled than successfully reassembled.

But the arrow of time takes its direction not only from big numbers. According to quantum theory, that paradoxical body of rules governing the subatomic universe, not even a single particle can reverse its own course through time.

The uncertainty principle, which lies at the heart of quantum mechanics, states that, at any given moment, either the location or the velocity of a subatomic particle can be specified, but not both. As a result, a particle such as an electron, or a system of them, is represented by a mathematical entity called a wave function, whose magnitude is a measure of the probability of finding a particle in a particular place or condition.

The wave function extends throughout space and time. The law describing its evolution, known as the Schrödinger equation, after Austrian physicist Erwin Schrödinger​, is equally valid running forward or backward. But getting a wave function to go in reverse is no small trick.

Vinokur likened the challenge to sending a speeding billiard ball back to where it started. Seems easy: Just hit it with a cue stick. But if it’s a quantum ball, the uncertainty principle kicks in: You can know how hard to hit the ball, or in which direction to hit it, but not both.

“Because of the uncertainty principle, the quantum ball will never return back to the point of the origin,” Vinokur said.

Moreover, in quantum mechanics, the ball is actually a wave: Once its location is known, it spreads like ripples on a pond and evolves. Making it go backward takes more than a nudge with a cue stick. It requires reversing the phases of the waves, turning crests into troughs, and so forth, an operation too complex for nature to accomplish on its own.

Yes, No and Maybe

Unlike regular computers, which process a series of zeros and ones, or bits, quantum computers are made of so-called qubits, each of which can be zero and one at the same time. A quantum computer can perform thousands or millions of calculations simultaneously, so long as nobody looks to see what the answer is until the end.

Many of the largest tech companies, including Google, Microsoft and IBM, are racing to build such machines, which eventually could solve problems that regular computers can’t, such as breaking currently unbreakable cryptographic codes. Some scientists argue that nature itself is a quantum computer, and that the greatest utility of such a computer will be in simulating and exploring the paradoxes of quantum weirdness.

Lesovik and his colleagues set out to try to make a wave function go backward, using an IBM quantum computer that is available online to the public.

“It remains to be seen,” the team wrote in their paper posted online in February, “whether the irreversibility of time is a fundamental law of nature or whether, on the contrary, it might be circumvented.”

The IBM computer they used represents a baby step in the direction of what theorists call “quantum supremacy.” It had only 5 qubits (IBM devices with 16 and 20 qubits are also available), compared to Google’s top-of-the-line 72-qubit “Bristlecone” computer. To keep things even simpler, the group only used two or, sometimes, three of the qubits.

The time-reversal experiment was a four-step process. First the qubits were teed up in a simple initial state that mimicked “an artificial atom,” Vinokur said. Moreover, the qubits were entangled, by what Einstein called “spooky action at a distance” — whatever happened to one qubit affected measurements of the other one (or two, depending on how many were deployed).

Then the team tapped the qubits with a series of microwave radio pulses, which nudged the qubits from a simple state into more complexity. After a millionth of a second, the scientists then halted this phase — “the evolution program” — and treated the qubits with another microwave pulse, to reverse their phase and ready them to devolve to their youthful selves.

“In graphic language, we convert spreading rings in the pond into the rings that are ready to go back to their origin,” Vinokur said. That took another millionth of a second.

Finally, the team turned the “evolution” program back on. And the qubits went back to their original alignment — back to their own past. In effect, they got a millionth of a second younger.

The algorithm almost always worked. It succeeded in returning the qubits to their youthful states 85 percent of the time when the calculation involved two qubits, but only half the time when three qubits were used. The authors attributed the reduced reliability to imperfections in the quantum computer, and to the tendency of qubits to fall out of sync when their numbers increase.

Ultimately, it will take machines with hundreds of qubits to achieve the ambitions of quantum mathematicians. When such computers become available, the team’s time-reversal algorithm could be used to test them, Andrey V. Lebedev, a physicist at ETH Zurich in Switzerland and an author on the paper, said in a news release from the Moscow Institute of Physics and Technology.

In the meantime, anyone with a quantum computer can play Benjamin Button, using their algorithm. “Now everybody can make qubits younger,” Vinokur said.

At least, they can in the many worlds of cyberspace. In real life, the aging of even a single particle remains too complicated for nature to undo. We’re stuck getting older, hurtling down the river of time.

This article originally appeared in <a href="https://www.nytimes.com/2019/05/08/science/quantum-physics-time.html" id="b29c2f2b-ecdf-3e82-a053-4a8458d7874f">The New York Times</a>.

For a Split Second, a (Simulated) Particle Went Backward in Time

In “The Curious Case of Benjamin Button,” a story by F. Scott Fitzgerald and then a movie starring Brad Pitt, a man ages backward: He is born an old man, regresses over the years and dies an infant.

For years, and for all the mounting scientific evidence, black holes have remained marooned in the imaginations of artists and the algorithms of splashy computer models of the kind used in Christopher Nolan’s outer-space epic “Interstellar.” Now they are more real than ever.

“We have seen what we thought was unseeable,” said Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, and director of the effort to capture the image, during a Wednesday news conference in Washington.

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from Earth, resembled the Eye of Sauron, a reminder yet again of the implacable power of nature. It is a smoke ring framing a one-way portal to eternity.

To capture the image, astronomers reached across intergalactic space to Messier 87, a giant galaxy in the constellation Virgo. There, a black hole several billion times more massive than the sun is unleashing a violent jet of energy some 5,000 light-years into space.

The image offered a final, ringing affirmation of an idea so disturbing that even Einstein, from whose equations black holes emerged, was loath to accept it. If too much matter is crammed into one place, the cumulative force of gravity becomes overwhelming, and the place becomes an eternal trap. Here, according to Einstein’s theory, matter, space and time come to an end and vanish like a dream.

On Wednesday morning that dark vision became a visceral reality. As far as the Event Horizon team could ascertain, the shape of the shadow is circular, as Einstein’s theory predicts.

The results were announced simultaneously at news conferences in Washington and five other places around the world, befitting an international collaboration involving 200 members, nine telescopes and six papers for the Astrophysical Journal Letters. When the image was put up on the screen in Washington, cheers and gasps, followed by applause, broke out in the room and throughout a universe of astrofans following the live-streamed event.

“Einstein must be totally chuffed,” said Priyamvada Natarajan, an astrophysicist at Yale. “His theory has just been stress-tested under conditions of extreme gravity, and looks to have held up.”

Kip Thorne, an astrophysicist at the California Institute of Technology, and who shared a Nobel Prize in 2017 for the discovery of gravitational waves from colliding black holes, wrote in an email: “It is wonderful to see the nearly circular shadow of the black hole. There can be no doubt this really is a black hole at the center of M87, with no signs of deviations from general relativity.”

Janna Levin, a cosmologist and professor at Barnard College in New York, said, “What a time to be alive.”

A telescope the size of Earth

The image emerged from two years of computer analysis of observations from a network of radio antennas called the Event Horizon Telescope. In all, eight radio observatories on six mountains and four continents observed the galaxy in Virgo on and off for 10 days in April 2017.

The telescope array also monitored a dim source of radio noise called Sagittarius A* (pronounced Sagittarius A-star), at the heart of our Milky Way galaxy. There, 26,000 light-years from Earth, and cloaked in interstellar dust and gas, lurks another black hole, with a mass of 4.1 million suns.

The network is named after the edge of a black hole, the point of no return; beyond the event horizon, not even light can escape the black hole’s gravitational pull.

The mystery of black holes has tantalized astronomers for more than half a century. In the 1950s, astronomers with radio telescopes discovered that pearly, seemingly peaceful galaxies were spewing radio energy from their cores — far more energy than would be produced by the ordinary thermonuclear engines that make stars shine.

Perhaps, astrophysicists thought, the energy was being liberated by matter falling onto supermassive, dense objects — later called black holes. Since then, scientists have devised detailed models of how this would work. As hot, dense gas swirls around the black hole, like water headed down a drain, the intense pressures and magnetic fields cause energy to squirt from either side. As a paradoxical result, supermassive black holes can be the most luminous objects in the universe.

The images released Wednesday bolster the notion of violence perpetrated over cosmic scales, said Sera Markoff, an astrophysicist at the University of Amsterdam, and a member of the Event Horizon team. “Black holes must be the most exotic major disrupters of cosmic order,” she said.

Einstein’s least favorite idea

The unveiling took place almost exactly a century after images of stars askew in the heavens made Einstein famous and confirmed his theory of general relativity as the law of the cosmos. That theory ascribes gravity to the warping of space and time by matter and energy, much as a mattress sags under a sleeper.

General relativity led to a new conception of the cosmos, in which space-time could quiver, bend, rip, expand, swirl like a mix-master and even disappear forever into the maw of a black hole.

To Einstein’s surprise, the equations indicated that when too much matter or energy was concentrated in one place, space-time could collapse, trapping matter and light in perpetuity. He disliked that idea, but the consensus today is that the universe is speckled with black holes furiously consuming everything around them.

Many are the gravitational tombstones of stars that burned up their fuel and collapsed. But others, hidden in the centers of nearly every galaxy, are millions or billions of times more massive than the sun.

Nobody knows how such behemoths of nothingness could have been assembled. Dense wrinkles in the primordial energies of the Big Bang? Monster runaway stars that collapsed and swallowed up their surroundings in the dawning years of the universe?

Nor do scientists know what ultimately happens to whatever falls into a black hole, nor what forces reign at the center, where, theoretically, the density approaches infinity and smoke pours from nature’s computer.

Zeroing in on cosmic monsters

Any lingering doubts about the reality of black holes dissolved three years ago when the Laser Interferometer Gravitational-Wave Observatory, or LIGO, detected the collision of a pair of distant black holes, which sent a shiver through the fabric of space-time.

Now the reality has a face. Peter Galison, a physicist, filmmaker and historian at Harvard, and a member of the Event Horizon team, noted that there is “a wonderful open-ended sense of being able to see something” instead of merely accumulating statistical evidence.

Still, questions about gravity and the universe abound. “We know there must be something more,” Broderick told the audience in Washington. “Black holes are one of the places to look for answers.”

Proving that the monsters in Virgo and the center of the Milky Way were really black holes required measuring the sizes of their shadows. That was no easy job. Both are exceedingly small, at this distance, and resolving their tiny details would be a challenge for even the biggest individual telescope.

Moreover, the view is blurred by the charged particles such as electrons and protons that fill interstellar space. “It’s like looking through frosted glass,” said Doeleman, director of the Event Horizon Telescope.

To see into the shadows, astronomers needed to be able to tune their radio telescope to shorter wavelengths. And they needed a bigger telescope.

Enter the Event Horizon Telescope, the dream-child of Doeleman. By combining data from radio telescopes as far apart as the South Pole, France, Chile and Hawaii, using a technique called very long baseline interferometry, Doeleman and his colleagues created a telescope as big as Earth itself, with the power to resolve details as small as an orange on the lunar surface.

In April 2017, the network of eight telescopes, including the South Pole Telescope, synchronized by atomic clocks, stared at the two targets off and on for 10 days.

For two years, the Event Horizon team reduced and collated the results. The data were too voluminous to transmit over the internet, so they were placed on hard disks and flown back to MIT’s Haystack Observatory, in Westford, Massachusetts, and the Max Planck Institute for Radio Astronomy, in Bonn, Germany.

The data from the South Pole could not arrive before December 2017, Doeleman said in an interview, “because it was Antarctic winter, when nothing could go in or out.”

Last year the team divided into four groups to assemble images from the data dump. To stay objective and guard against bias, the teams had no contact with each other. They readied themselves for an inconclusive or ambiguous result — a blur, perhaps, that they couldn’t quite read.

‘It was a surprise how clear this image is’

Doeleman grew optimistic last year at a dinner attended by some of the younger members of the team, who showed him the first data for M87.

“There were clear signatures of a ringlike structure,” he said. After dinner, he went to his office and made some crude calculations. “That was one of those great moments,” he said. “It was a surprise how clear this image is.”

The ring of light in the new image corresponds to the innermost orbit of photons — the quantum particles that comprise light — around the black hole. By laying a ruler across that ring, astronomers could measure the size of the black hole and see that it met Einstein’s prescription.

The measurement also gave a firm estimate of the mass of the Virgo black hole: 6.5 billion solar masses. That is heavier than most previous determinations, and it suggests that the masses of other big black holes may need to be revised upward.

The observations also revealed that the accretion disk — the doughnut of doom — is on its side with regard to Earth, the hole facing us and spinning clockwise. The image is brighter where gas flows around the hole, toward us.

Doeleman described the black hole in the center of the Milky Way as “a fascinating, interesting object.” But it is much smaller than the Virgo black hole, so its portrait is harder to capture. That task lies ahead for the Event Horizon Telescope.

The telescope network continues to grow. In April 2018, a telescope in Greenland was added to the collaboration. Another observation run was made of the Milky Way and M87, and captured twice the amount of data gathered in 2017. That data was not part of the results released Wednesday, but will be used to confirm them and monitor the behavior of the black holes. Two more antennas are waiting to join the Event Horizon Telescope.

“The plan is to carry out these observations indefinitely and see how things change,” said Doeleman, embarking on his new career as a tamer of extragalactic beasts.

“It’s astonishing to think humans can turn the Earth into a telescope and see a black hole,” and still more amazing to do it with this team, he said. “That’s the best.”

This article originally appeared in <a href="https://www.nytimes.com/2019/04/10/science/black-hole-picture.html" id="b0df6181-615b-3d80-adde-93dfd324b5ac">The New York Times</a>.

Darkness Visible, Finally: Astronomers Capture First Ever Image of a Black Hole

Astronomers announced Wednesday that at last they had captured an image of the unobservable: a black hole, a cosmic abyss so deep and dense that not even light can escape it.

“We have seen what we thought was unseeable,” said Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, and director of the effort to capture the image, during a Wednesday news conference in Washington, D.C.

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from Earth, resembled the Eye of Sauron, a reminder yet again of the power and malevolence of nature. It is a smoke ring framing a one-way portal to eternity.

The image offered a final, ringing affirmation of an idea so disturbing that even Einstein, from whose equations black holes emerged, was loath to accept it. If too much matter is crammed into one place, the cumulative force of gravity becomes overwhelming, and the place becomes an eternal trap, a black hole. Here, according to Einstein’s theory, matter, space and time come to an end and vanish like a dream.

It would have been easy for the theory to come out wrong, said Avery Broderick of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario: “In April 2017, this was the dog that did not bark.”

The results were announced simultaneously at news conferences in Washington, D.C., and five other places around the world, befitting an international collaboration involving 200 members, nine telescopes and six papers for the Astrophysical Journal Letters. When the image was put up on the screen in Washington, cheers and gasps, followed by applause, broke out in the room and throughout a universe of astrofans who were following the live-streamed event.

“Einstein must be totally chuffed,” said Priyamvada Natarajan, an astrophysicist at Yale. “His theory has just been stress-tested under conditions of extreme gravity and looks to have held up.”

The telescope array also monitored a dim source of radio noise called Sagittarius A* (pronounced Sagittarius A-star), at the heart of our Milky Way galaxy. There, 26,000 light-years from Earth, and buried in the depths of interstellar dust and gas, lurks another black hole, with a mass of 4.1 million suns.

The image provided astrophysicists with the first look at the innards of a black hole and a mystery that has tantalized astronomers for more than half a century.

In the 1950s, astronomers with radio telescopes discovered that pearly, seemingly peaceful galaxies were spewing radio energy from their cores — far more energy than would be produced by the ordinary thermonuclear engines that make stars shine. Quasars are the most extreme examples: distant, pointlike fountains of energy that outshine their source galaxies.

Perhaps, astrophysicists thought, the energy was being liberated by matter falling onto supermassive, dense objects — later called black holes. The process would generate energy the way water pouring over Niagara Falls generates sound and spray.

Since then, scientists have devised detailed models of how this would work. As hot, dense gas swirls around the black hole, like water headed down a drain, the intense pressures and magnetic fields cause energy to squirt from either side. As a paradoxical result, supermassive black holes, which lurk in the centers of galaxies, can be the most luminous objects in the universe.

The images released today bolster the notion of violence perpetrated over cosmic scales, said Sera Markoff, an astrophysicist at the University of Amsterdam, and a member of the Event Horizon team. “Black holes must be the most exotic major disrupters of cosmic order,” she said.

The unveiling, before a crowd at the National Press Club in Washington, D.C., and five other venues around the world, took place almost exactly a century after images of stars askew in the heavens made Einstein famous and confirmed his theory of general relativity as the law of the cosmos. That theory ascribes gravity to the warping of space and time by matter and energy, much as a mattress sags under a sleeper, and allows for the contents of the universe, including light rays, to follow curved paths.

To Einstein’s surprise, the equations indicated that when too much matter or energy was concentrated in one place, space-time could collapse, trapping matter and light in perpetuity.

Einstein disliked that idea, but the consensus today is that the universe is speckled with black holes furiously consuming everything around them.

Many are the gravitational tombstones of stars that burned up their fuel and collapsed. But others, crouching in the centers of nearly every galaxy, are millions or billions of times more massive than the sun.

Nor do scientists know what ultimately happens to whatever falls into a black hole, nor what forces reign at the center, where according to the math we know now the density approaches infinity and smoke pours from God’s computer.

Zeroing in on cosmic monsters

Any lingering doubts about the reality of black holes vanished three years ago when the Laser Interferometer Gravitational-Wave Observatory, or LIGO, detected the collision of a pair of distant black holes, which sent a shiver through the fabric of space-time.

Still, mysteries abound about gravity and the universe. “We know there must be something more,” Broderick told the audience in Washington, D.C. “Black holes are one of the places to look for answers.”

Proving that the monsters in Virgo and the center of the Milky Way are really black holes required measuring the sizes of their shadows. But that was no easy job. In a cosmic coincidence, both of them would appear from Earth to be about as big as an orange on the moon. Resolving their tiny details would be a challenge for even the biggest single telescope to achieve.

Moreover, interstellar space is filled with charged particles such as electrons and protons; these scatter the radio waves emanating from a black hole into a blur that obscures details of the source. “It’s like looking through frosted glass,” said Doeleman, director of the Event Horizon Telescope.

To penetrate the haze and see deeper into the shadows of Virgo, astronomers needed to be able to tune their radio telescope to shorter wavelengths. And they needed a bigger telescope. The bigger the antenna, the higher the resolution, or magnification, it can achieve.

Enter the Event Horizon Telescope, named for a black hole’s point of no return; whatever crosses the event horizon falls into blackness everlasting. The telescope was the dream-child of Doeleman, who was inspired to study black holes by examining the mysterious activity in the centers of violent radio galaxies such as M87.

By combining data from radio telescopes as far apart as the South Pole, France, Chile and Hawaii, using a technique called very long baseline interferometry, Doeleman and his colleagues created a telescope as big as Earth itself, with the power to resolve details as small as an orange on the lunar surface.

It has taken a decade for the astronomers to learn how to use it, and to equip some antennas around the world to make observations that they were not built to make. In the end, Doeleman said, they had a telescope capable of reading the date on a quarter in Los Angeles from Washington, D.C.

For two years, the Event Horizon team reduced and collated the results from their 2017 observations. The data — 5 petabyes, equivalent to a lifetime of selfies taken by 40,000 people, said Doug Marrone of the University of Arizona — were too voluminous to transmit over the internet. So they had to be placed on hard disks and flown back to MIT’s Haystack Observatory, in Westford, Massachusetts, and the Max Planck Institute for Radio Astronomy, in Bonn, Germany.

Last year the team divided into four groups to assemble images from the data dump. To stay objective and guard against bias, the teams had no contact with each other.

After years of learning and disappointment, the team was prepared for an inconclusive or ambiguous result, a blur that perhaps they couldn’t quite read, Doeleman said.

The first time indication that this time would be different came last year at a dinner a year ago of the Black Hole Initiative, a Harvard-Smithsonian effort. Some of the younger members of the Event Horizon team were there, and they showed Doeleman the first data for M87. “There were clear signatures of a ringlike structure,” he said.

After dinner he went to his office and made some crude calculations. “That was one of those great moments,” he said. “It was a surprise how clear this image is.”

The ring of light in the new image corresponds to the innermost orbit of photons — the quantum particles that comprise light — around the black hole. Anything closer falls in and disappears. By laying a ruler across that ring, Doeleman said, astronomers could measure the size of the black hole and see that it met Einstein’s prescription.

The ring measurement also gave a firm estimate of the mass of the Virgo black hole: 6.5 billion solar masses. That is heavier than most previous determinations, which suggests that estimates of the masses of other big black holes also may need to be revised upward.

The observations also revealed that the accretion disk — the doughnut of doom — is on its side with regard to Earth, the hole facing us and spinning clockwise. One side of the image is brighter where a blowtorch of gas is aimed toward us; on the other, dimmer side the blowtorch is aimed away.

Doeleman described the black hole in the center of the Milky Way as “a fascinating, interesting object.” But because it is much smaller than the Virgo black hole, its portrait is harder to capture. That task lies ahead for the Event Horizon Telescope.

The telescope network continues to grow. In April 2018, a telescope in Greenland was added to the collaboration. Another observation run was made of the Milky Way and M87, and captured twice the amount of data gathered in 2017. That data was not part of the results released today, but will be used to confirm them and monitor the behavior of the black holes.

Meanwhile, two more antennas are waiting to join the Event Horizon Telescope.

Black Hole Image Revealed for First Time Ever

Astronomers announced Wednesday that at last they had observed the unobserveable: a black hole, a cosmic abyss so deep and dense that not even light can escape it.

It would have been easy for the theory to come out wrong, said Avery Broderick of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario: “In April 2017 this was the dog that did not bark.”

The results were announced simultaneously at news conferences in Washington, D.C., and five other places around the world, befitting a collaboration involving 200 members and nine telescopes around the world. When the image was put up on the screen in Washington, cheers and gasps, followed by applause, broke out in the room and throughout a universe of astrofans who were following the live-streamed event.

“What a time to be alive,” said Janna Levin, a cosmologist and professor at Barnard College in New York.

Einstein disliked that idea, but the consensus today is that the universe is speckled with black holes furiously consuming their surroundings.

Since then, other collisions have been recorded, and black holes have become so humdrum that astronomers no longer bother sending out news releases about them.

The proof that these objects are really black holes would be to find that the darkness at the heart of Virgo was smaller than the mathematical predictions for a black hole. But the more astronomers narrowed it down, the harder they had to work.

Interstellar space is filled with charged particles such as electrons and protons; these scatter the radio waves emanating from a black hole into a blur that obscures details of the source. “It’s like looking through frosted glass,” said Doeleman, director of the Event Horizon Telescope.

The network has gained antennas and sensitivity over the last decade. In the spring of 2015 an effort using seven telescopes took aim at the centers of the Milky Way and M87, but bad weather hampered the observations.

Two years later, in April 2017, the network of eight telescopes, including the South Pole Telescope, synchronized by atomic clocks, stared at the two targets off and on for 10 days.

It took the Event Horizon team two years to reduce and collate the results from their 2017 observations. The data were too voluminous to transmit over the internet, and so had to be placed on hard disks and flown back to MIT’s Haystack Observatory, in Westford, Massachusetts, and the Max Planck Institute for Radio Astronomy, in Bonn, Germany.

The data from the South Pole could not arrive before December 2017, Doeleman said, “because it was Antarctic winter, when nothing could go in or out.”

Last year the team divided into four groups to assemble images from the data dump. To stay objective and guard against bias, the teams had no contact with each other, Doeleman said.

In the meantime, the telescope kept growing. In April 2018, a telescope in Greenland was added to the collaboration. Another observation run was made of the Milky Way and M87, and captured twice the amount of data gathered in 2017.

“We’ve hitched our wagon to a bandwidth rocket,” Doeleman said last week. The new observations weren’t included in Wednesday’s reveal, but they will allow the astronomers to check the 2017 results and to track changes in the black holes as the years go by.

“The plan is to carry out these observations indefinitely,” said Doeleman, embarking on his new career as a tamer of extragalactic beasts, “and see how things change.”

Black Hole Picture Revealed for the First Time

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from Earth, resembled the Eye of Sauron.

As hot, dense gas swirls around the black hole, like water headed down a drain, the intense pressures and magnetic fields cause energy to squirt from either side. As a paradoxical result, supermassive black holes, which lurk in the centers of galaxies, can be the most luminous objects in the universe.

“We’ve exposed a part of our universe we’ve never seen before,” said Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, and director of the effort to capture the image, during a Wednesday news conference in Washington, D.C.

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from here, resembled the Eye of Sauron.

To capture the image, astronomers reached across intergalactic space to a giant galaxy known as Messier 87, in the constellation Virgo. There, a black hole about 7 billion times more massive than the sun is unleashing a violent jet of energy some 5,000 light years into space.

On Wednesday morning that dark vision became a visceral reality. When the image was put up on the screen in Washington, cheers and gasps, followed by applause, broke out.

The images provide astrophysicists with the first look at the innards of a black hole. The energy within is thought to be powerful enough to power quasars and other violent phenomena from the nuclei of galaxies, including the jets of intense radiation that spew 5,000 light years from the galaxy M87.

Astronomers announced Wednesday that at last they had seen the unseeable: a black hole, a cosmic abyss so deep and dense that not even light can escape it.

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from here, resembled the Eye of Sauron, a reminder yet again of the power and malevolence of nature. It is a smoke ring framing a one-way portal to eternity.

The telescope array also monitored a dim source of radio noise called Sagittarius A* (pronounced Sagittarius A-star), at the heart of our Milky Way galaxy. There, 26,000 light-years from Earth, and buried in the depths of interstellar dust and gas, another black hole, with a mass of 4.1 million suns, almost certainly lurks.

For some years now, the scientific literature, news media and films such as “Interstellar” and the newly released “High Life” have featured remarkably sophisticated and highly academic computer simulations of black holes. But the real thing looked different. For starters, the black holes in movies typically are not surrounded by fiery accretion disks of swirling, doomed matter, as are the black holes in Virgo and Sagittarius.

Perhaps even more important, the images provide astrophysicists with the first look at the innards of a black hole. The energy within is thought to be powerful enough to power quasars and other violent phenomena from the nuclei of galaxies, including the jets of intense radiation that spew 5,000 light years from the galaxy M87.

Einstein disliked that idea, but the consensus today is that the universe is speckled with black holes waiting for something to fall in.

Interstellar space is filled with charged particles such as electrons and protons; these scattered the radio waves emanating from the black hole into a blur that obscured details of the source. “It’s like looking through frosted glass,” said Doeleman, director of the Event Horizon Telescope.

Like terrified moviegoers seated on the edges of their seats and at the mercy of their imaginations, astronomers expect this week to finally see the monster: a supermassive black hole.

At 9 a.m. Eastern Time Wednesday, a group of astronomers who run a globe-girdling network of radio telescopes called the Event Horizon Telescope are expected to unveil their long-awaited pictures of a pair of putative black holes. One of the objects sits at the center of the Milky Way galaxy, buried in the depths of interstellar dust and gas, and equivalent in mass to 4.1 million suns that otherwise have disappeared from the visible universe.

The other target is in the heart of Messier 87, a giant galaxy in the constellation Virgo, where a black hole 7 billion times the mass of the sun is spewing a jet of energy thousands of light-years across space.

According to calculations, and if all has gone well, either or both of the black holes should appear as a tiny shadow backlit by the glow of radio energy at the galactic center.

They might be circular, oval or some other shape entirely, depending on whether they are rotating, or if the Einsteinian equations describing them are slightly wrong, or if they are spitting flares of energy, which is how quasars produce fireworks visible across the universe.

In such shadows the dreams of physicists die; time ends; space-time, matter and light disappear into the primordial nothing from which they spring; and the ghosts of Einstein and Hawking mingle with history and memory. For the first time, astronomers will be staring down the pipes of eternity.

If, in fact, astronomers have finally brought the monsters into view at last. The Event Horizon team has been extremely tight-lipped. Nobody knows for certain if either of these black holes, if any, has been imaged.

Shep Doeleman, director of the Event Horizon Telescope, was ebullient but guarded when reached last week at the Harvard-Smithsonian Center for Astrophysics. “The team is working exceptionally hard to quadruple-check all the results,” he said.

But he and his colleagues are acting as if they have something to celebrate. The announcement of their results will take place simultaneously in six places around the world, reflecting the vast international nature of the collaboration. One news conference, at the National Press Club in Washington, D.C., will be presided over by France Córdova, head of the National Science Foundation. The team and their friends have booked the National Air and Space Museum for a party that evening.

The unveiling will take place almost exactly a century after images of stars askew in the heavens made Einstein famous and confirmed his theory of general relativity as the law of the cosmos. That theory ascribes gravity to the warping of space and time by matter and energy, much as a mattress sags under a sleeper, and allows for the contents of the universe, including light rays, to follow curved paths.

Einstein disliked that idea, but the consensus today is that the universe is speckled with black holes waiting to vacuum up their surroundings. Many are the gravitational tombstones of stars that have burned up their fuel and collapsed.

Any lingering doubts as to their existence vanished three years ago when the Laser Interferometer Gravitational-Wave Observatory detected the collision of a pair of distant black holes, which sent a shiver through the fabric of space-time.

Nonetheless, astronomers are thrilled at the prospect of finally, actually seeing the previously unseeable.

“Yes, I’m definitely excited to see the image!” Daniel Holz, of the University of Chicago, wrote in an email. “It’s not really rational, since I know the math works and the theory has been thoroughly tested. But still, this would be a picture of the real thing, up close and personal. That is super cool.”

Priyamvada Natarajan, a Yale astrophysicist who is not part of the project, said, “It’s exciting, even just technically, to get this up close and personal to a black hole.”

Especially when the black hole is no run-of-the-mill stellar corpse, but one of the behemoths that crouch in the centers of galaxies and direct cosmic weather, launching thunderbolts across thousands of light-years.

Even if the new images do not overthrow relativity, they will be invaluable as astronomers’ first glimpses into the hearts of these entities and the way they generate cosmically catastrophic energies.

The center of the Milky Way, 26,000 light-years from Earth, coincides with a faint source of radio noise called Sagittarius A* (pronounced A-star). By tracking the orbits of stars around this hub, astronomers have calculated that whatever sits at the center has the mass of 4 million suns.

But it emits no visible or infrared light. If this is not a black hole, no one knows what it could be. The only way to be sure is to peer through the haze and record the shadow of oblivion.

Which is no small job. According to the standard Einstein calculations, a black hole with the mass of 4.1 million suns would be only about 24 million kilometers, or about 15 million miles, wide — a tiny area to observe clearly from this distance. Luckily, the black hole’s gravity will magnify it to appear twice that size. But discerning even that is like trying to spot an orange on the Moon with the naked eye.

It takes a big telescope to see something so small. Enter the Event Horizon Telescope, named for a black hole’s point of no return; whatever crosses the event horizon falls into blackness everlasting. The telescope was the dream-child of Doeleman, who was inspired to study black holes by examining the mysterious activity in the centers of violent radio galaxies such as M87.

By combining data from radio telescopes as far apart as the South Pole, France, Chile and Hawaii, using a technique called very long baseline interferometry, Doeleman and his colleagues created a telescope as big as Earth itself.

The network has gained antennas and sensitivity over the last decade. In April 2017, the network of eight telescopes, synchronized by atomic clocks, stared at the Milky Way center and at the giant galaxy M87 off and on for 10 days.

Astronomers have taken the last two years to reduce and collate the results. The data were too voluminous to transmit over the internet, and so had to be placed on hard disks and flown back to MIT’s Haystack Observatory, in Westford, Massachusetts, and the Max Planck Institute for Radio Astronomy, in Bonn, Germany.

Last year the team divided into four independent groups to assemble images from the data dump. To stay objective and guard against bias, the teams had no contact with each other, Doeleman said.

“We’ve hitched our wagon to a bandwidth rocket,” Doeleman said. The new observations won’t be included in Wednesday’s reveal, but they will allow the astronomers to check the 2017 results and to track changes in the black holes as the years go by.

This article originally appeared in <a href="https://www.nytimes.com/2019/04/08/science/black-hole-photo.html" id="e2cc97d7-e98d-378a-a2c4-e72530955d46">The New York Times</a>.

Expected Soon: First-Ever Photo of a Black Hole

Ridley Scott, eat your heart out.

Which is no small job. According to the standard Einstein calculations, a black hole with the mass of 4.1 million suns would be only about 24 million miles wide — a tiny area to observe clearly from this distance. Luckily, the black hole’s gravity will magnify it to appear twice that size. But discerning even that is like trying to spot an orange on the Moon with the naked eye.

The fragment, made mostly of iron, nickel and other metals, lies 410 light-years from Earth in the constellation Virgo. It could be a mile, or hundreds of miles, in diameter, but to be dense enough to have survived the explosive demise and subsequent evolution of its host star, it likely was part of a large planet with a wider, more distant orbit. Now it circles the white dwarf so closely that it completes an orbit every 123 minutes.

“The fact that we have discovered a body orbiting on a two-hour period is clear evidence that a planetary body can survive this destructive process,” said Christopher Manser, a physicist at the University of Warwick in England, and leader of an international team that reported their results in Science on Thursday.

A white dwarf is the end product left behind when a star as large as the sun or slightly bigger runs out of fuel, expires and eventually shrinks into a dense ember about the size of Earth. The universe is littered with these dense, cooling tombstones.

In the process of dying, however, these stars first puff up into so-called red giants, enveloping and destroying their inner planets. When our sun goes through this process in 5 billion or 6 billion years, it will incinerate everything inside the orbit of Mars and probably disrupt the orbits of planets further out. There is no chance of life on this planet surviving the event, and it’s a toss-up whether the physical object now known as Earth will persevere or be dragged to its doom in the sun.

The newly discovered planetary fragment is only about 320,000 miles from the white dwarf. That is well inside the presumed radius of the original star, and far closer than astronomers would expect to find anything solid. “So if the sun was positioned where the white dwarf is, the planetesimal would be orbiting within the sun,” Manser said.

The original star is estimated to have been about twice as massive as the sun, and it exploded about 100 million years ago, he said.

Manser, along with Boris Gänsicke, also at the University of Warwick, has been studying the disc around a white dwarf known as SDSS J122859.93+10432.9; they have used a variety of telescopes, most recently the Gran Telescopio Canarias in La Palma, in Spain’s Canary Islands. It is one of a handful of white dwarfs known to be encircled by disks of debris.

Within the orbiting debris, the researchers noticed a solid object spraying a cometlike trail of gas. The object, a dense chunk of metal, was probably a remnant of the core of a planet, Gänsicke said. “If correct, the original body was at least hundreds of kilometers in diameter.”

It is only the second solid remnant of a planet to have been discovered orbiting a white dwarf. And it marks the first time such an object has been identified spectroscopically, by analysis of the light emitted by the gas in its “tail.”

It came as a surprise, Manser said. Such debris disks were typically understood to be the remains of a small body, such as an asteroid or comet, that had come near the white dwarf and been torn apart by tidal forces. The newly found fragment would have to be solid metal, perhaps iron, to have withstood the tidal stretching, Manser said. But it now orbits too close to the white dwarf for life as we know it to exist on it.

Nor is there better news to be found elsewhere around the white dwarf. Other planets may exist, orbiting farther out, but the star is now too faint to deliver sustenance at such a distance. “It is unlikely that the system is habitable,” Manser said.

The discovery could yield additional insights into what kind of planetary body this once was, such that it could endure the wall of fire embrace of an expanding star. If a fragment can survive a solar blast furnace, maybe some piece of our own could, too, if only a few inscriptions on some very hard surface.

“We are confident that we will discover additional planetesimals orbiting white dwarfs, which will allow us to learn more about their general properties,” Manser said.

This article originally appeared in <a href="https://www.nytimes.com/2019/04/04/science/white-dwarf-fragment.html" id="f3edb55e-293c-3566-af88-229958ff3c20">The New York Times</a>.

In a shard of galactic archaeology that offers a less-than-inviting hint at our own future, astronomers have discovered a chunk of a former planet orbiting the remains of its former star, now a smoldering cinder known as a white dwarf.

Apocalypse Next? Astronomers Find a Chunk of Planet Around a Distant, Dead Star

The apocalypse has been postponed.

Astronomers have long known that the Andromeda galaxy, aka Messier 31, a swirling city-state of a trillion stars — plus all the accouterments of gas, dust, dark matter and black holes — is rumbling through the cosmos right toward us at 68 miles per second.

Five years ago astronomers using the Hubble Space Telescope calculated that M31 would hit our Milky Way galaxy head on 3.9 billion years from now.

That collision, they said, would initiate a series of do-si-do encounters that would splash streamers of stars and gas across space, and end with the two galaxies merged into a single, supergiant globe of stars.

New data have now revised this forecast. It turns out that the Andromeda galaxy is also going about 20 miles per second sideways. As a result, it will take a more winding path toward us, won’t arrive for another 4.5 billion years and won’t hit so hard, at least not at first, according to a paper in the Astrophysical Journal.

Dennis Overbye

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