Image copyright ESO/M. Kornmesser Image caption Astronomers got the result by tracking the movement of a star as it passed through the gravitational field of a black hole

The black hole at the centre of our galaxy has helped astronomers confirm a key prediction of Albert Einstein's ideas.

By observing a cluster of stars near the hole, they were able to confirm a phenomenon known as "gravitational redshift".

It's when the wavelength of light gets stretched out in response to a gravitational field.

The result will help scientists better understand the physics of black holes.

The Very Large Telescope (VLT) in Chile found evidence for Einstein's prediction by observing a star, called S2, that passed through the intense gravitational field of Sagittarius A* - the huge black hole at the heart of the Milky Way.

The effect they observed, gravitational redshift, occurs as particles of light (photons) climb out of a gravitational well like a black hole. As they do, the light's wavelength gets drawn out.

Image copyright Getty Images Image caption Albert Einstein would no doubt be delighted

This shifts the wavelength to the red part of the light spectrum - hence "redshift".

It's predicted by Einstein's theory of general relativity, but has never been observed in an intense gravitational field such as that of a black hole.

Frank Eisenhauer, from the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching, Germany, said the measurement opened the door to more studies of the physics of black holes.

In future, he said, "we will see many more effects of general relativity in the galactic centre black hole. We will see the orbits of the stars change, we will see light go in circles, we will even see space-time rotate together with the black hole."

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Reinhard Genzel, also from MPE, said: "There is still more work to do to really come as close as you can to the event horizon [the "point of no return" of the black hole] where you might expect strong deviations from Einstein's theory."

Françoise Delplancke, from the European Southern Observatory (Eso), which operates the VLT, said that the laws of physics could only be tested here in the Solar System under particular circumstances.

"So it's very important in astronomy to also check that those laws are still valid where the gravitational fields are very much stronger," she explained.

Image copyright ESO / A. Ghizzi Panizza Image caption The observations were carried out with the Very Large Telescope in Chile

S2 is one member of a star cluster that surrounds Sagittarius A*. These stars reach mind-boggling speeds when they approach the black hole - S2 comes very close to Sagittarius A* every 16 years.

Astronomers followed S2 before and after it passed close to the black hole on 19 May 2018, tracking its progress hour-by-hour.

When S2 passed by the black hole at a distance just 120 times that of the Earth from the Sun, it reached an astonishing orbital velocity of 8,000 km/s. That corresponds to about 2.7% of the speed of light.

The astronomers found that light from the star was indeed stretched to longer wavelengths by the very strong gravitational field of Sagittarius A*.

The results were perfectly in line with the theory of general relativity - and not explained by Sir Isaac Newton's ideas - which exclude such a shift.

"In sport, you would say it was 1-0 for Einstein," said Frank Eisenhauer.

Image copyright SPL Image caption Artwork: Astronomers want to test other aspects of physics around black holes

Odele Straub, from the Paris Observatory, in France, said: "What we hope is at some point we will see something in the galactic centre that we can't explain with Einstein's theory - that would be really, really exciting. Because then we could go back to the drawing board and come up with something better."

The astronomers are continuing to observe S2; observations of its trajectory should yield new findings about the extreme conditions around the Milky Way's central black hole.

Gravitational redshift occurs because, in order to escape a gravitational well such as a black hole, particles of light (photons) must expend energy.

However, at the same time, these photons must travel at a constant speed - the speed of light.

Therefore, the photons can't lose energy by slowing down, but must expend it in another way. This lost energy manifests itself as a shift towards the red end of the light spectrum.

The results are published in the journal Astronomy & Astrophysics.

Follow Paul on Twitter.</s>The black hole at the centre of our galaxy has helped astronomers confirm a key prediction of Albert Einstein's ideas.

By observing a cluster of stars near the hole, they were able to confirm a phenomenon known as "gravitational redshift".

This effect applies to sources of light that are in a gravitational field.

The finding could help scientists better understand the physics of black holes.

The Very Large Telescope (VLT) in Chile found evidence for Einstein's prediction by observing a star, called S2, that passed through the intense gravitational field of Sagittarius A* - the huge black hole at the heart of the Milky Way.

The effect they observed, gravitational redshift, describes how the wavelength of light lengthens as it climbs out of a gravitational well like a black hole.

In practice this corresponds to a shift in the wavelength to the red part of the light spectrum - hence "redshift".

It's predicted by Einstein's theory of general relativity, but has never been observed in an intense gravitational field such as that of a black hole.

S2 is one member of a star cluster that surrounds Sagittarius A*. These stars reach mind-boggling speeds when they approach the black hole.

Astronomers followed S2 before and after it passed close to the black hole on 19 May 2018, tracking its progress hour-by-hour.

When S2 passed by the black hole at a distance just 120 times that of the Earth from the Sun, it reached an astonishing orbital velocity of 8,000 km/s. That corresponds to about 2.7% of the speed of light.

The astronomers found that light from the star was indeed stretched to longer wavelengths by the very strong gravitational field of Sagittarius A*.

The results were perfectly in line with the theory of general relativity - and not explained by Sir Isaac Newton's ideas - which exclude such a shift.

The astronomers are continuing to observe S2; observations of its trajectory should yield new findings about the extreme conditions around the Milky Way's central black hole.

The results are published in the journal Astronomy & Astrophysics.</s>Astronomers conduct successful test of Einstein’s general theory of relativity near supermassive black hole.

The massive black hole at the heart of the Milky Way is an ideal cosmic laboratory for all kinds of physical tests. Its extremely strong gravitational field influences the surrounding area and has an impact on the motion of stars passing by. Scientists at the Max Planck Institute for Extraterrestrial Physics (MPE) have now observed an effect that had been predicted by Albert Einstein with his general theory of relativity more than 100 years ago. The discovery of this gravitational redshift represents the climax of a 26-year-long observation campaign using telescopes of the European Southern Observatory (ESO) in Chile.

The closest supermassive black hole to the Earth lies 26,000 light-years away at the centre of the Milky Way. This gravitational trap, which has a mass four million times that of our Sun, is surrounded by a small group of stars orbiting around it at high speed. This region, with the strongest gravitational field in our galaxy, is the perfect place to explore gravitational physics, and particularly to test Einstein’s general theory of relativity.



 This artist’s impression video shows the path of the star S2 as it passes very close to the supermassive black hole at the centre of the Milky Way. As it gets close to the black hole the very strong gravitational field causes the colour of the star to shift slightly to the red, an effect of Einstein’s general theory of relativity. In this graphic the colour effect, speed and size of the objects have been exaggerated for clarity.

In order to observe the galactic centre, the astronomers use sensitive instruments such as Gravity, Sinfoni and Naco. All these belong to the ESO’s Very Large Telescope, were constructed under the leadership of the Max Planck Institute for Extraterrestrial Physics (MPE), and scrutinise the sky in an infrared light. Now, researchers have turned their attention to a star called S2 and followed it on its orbit around the black hole, to which it came particularly close a few weeks ago.

The shortest distance between S2 and the black hole, on 19 May, was approximately 14 billion kilometres. Here, the star moved at a speed in excess of 25 million kilometres per hour – almost three percent of the speed of light. It takes about 15 years to complete its full orbit.

The scientists compared the position and velocity measurements from Gravity and Sinfoni, along with the measurements taken during previous observations of S2, with the predictions of Newtonian gravitational physics, the general theory of relativity and other theories of gravity. In fact, the new results are inconsistent with Newtonian predictions, although they are in excellent agreement with the predictions of the general theory of relativity.

“This is the second time that we have observed the close passage of S2 around the black hole in our galactic centre. But this time, because of much improved instrumentation, we were able to observe the star with unprecedented detail resolution,” explains Richard Genzel, Director of the Max Planck Institute for Extraterrestrial Physics (MPE) in Garching near Munich, and head of the international team of scientists.



 This time-lapse view shows images from the GRAVITY instrument on ESO’s Very Large Telescope as it tracks the progress of the star S2 as it made a close passage past the black hole at the centre of the Milky Way in May 2018.

The new measurements clearly reveal an effect called gravitational redshift. Light from the star is stretched to longer wavelengths by the very strong gravitational field of the black hole, making it appear red. And this change in the wavelength agrees precisely with that predicted by Einstein’s theory of general relativity. This is the first time that the researchers have observed this deviation from the predictions of the simpler Newtonian theory of gravity in the motion of a star around a supermassive black hole.

The team used the Sinfoni instrument to measure the velocity of S2 relative to Earth. Astronomers use Gravity to make extraordinarily precise measurements of the changing position of S2, and thus also of the shape of its orbit. In connection with what is known as interferometry, in which the light of several telescopes is merged and overlaid, Gravity creates extremely sharp images. On these images, the motion of the star can even be followed from night to night as it passes close to the black hole – 26,000 light-years from Earth.

“Our first observations of S2 with Gravity, about two years ago, already showed that with the galactic centre, we have the ideal black hole laboratory,” says Frank Eisenhauer from the Max Planck Institute in Garching, Principal Investigator of Gravity and Sinfoni. During the close passage, even the faint glow around the black hole could be detected on most of the images. “In this way, we could follow the star on its orbit to an extremely high degree of precision, and could ultimately provide evidence of the gravitational redshift in the spectrum of S2.”



 This animation shows the orbit of the star S2 around the supermassive black hole at the heart of the Milky Way. At its closest approach, which occurred most recently in May 2018, the star is traveling at nearly 3% of the speed of light and is an ideal test object for studying very strong gravitational fields and testing Einstein’s general theory of relativity.

More than 100 years after he published his paper setting out the equations of general relativity, Einstein has been proved right once more – in a much more extreme laboratory than he could have possibly imagined. “In the strong gravitational field around the black hole, we generally expect to see relativistic effects – but only when we are able to conduct sufficiently precise observations”, says Stefan Gillessen from the Max Planck Institute for Extraterrestrial Physics. “For this reason, we had to push the technology to the limits.”

Further measurements will follow, and are already expected to reveal another relativistic effect soon – a small rotation of the star’s orbit known as Schwarzschild precession – as S2 moves away from the black hole.

Paper: Detection of the Gravitational Redshift in the Orbit of the Star S2 near the Galactic Centre Massive Black Hole</s>PARIS - A consortium of astronomers said Thursday they had for the first time confirmed a prediction of Albert Einstein’s theory of general relativity by observing the gravitational effects of a supermassive black hole on a star zipping by it.

The German-born theoretical physicist had posited that large gravitational forces could stretch light, much like the compression and stretching of sound waves we perceive with the change of pitch of a passing train.

Researchers from the GRAVITY consortium led by the Max Planck Institute for Extraterrestrial Physics realised that they had a “perfect laboratory” to test Einstein’s theory with the Sagittarius A* black hole in the centre of the Milky Way.

Black holes are so dense that their gravitational pull can trap even light, and the supermassive Sagittarius A* has mass four million times that of our sun, making it the biggest in our galaxy.

Astronomers followed the S2 star as it passed close to the black hole on May 19 at a speed in excess of 25 million kilometres (15.5 million miles) per hour.

They then calculated its velocity and position using a number of instruments and compared it with predictions made by Einstein that the light would be stretched by the gravity in an effect called gravitational redshift. Newtonian physics doesn’t allow for a redshift.

“The results are perfectly in line with the theory of general relativity” and are “a major breakthrough towards better understanding the effects of intense gravitational fields,” said the research team, whose findings are published in Friday’s issue of Astronomy & Astrophysics.

This is the first time observers have been able to measure such an effect.

The European Southern Observatory, whose Very Large Telescope in Chile was used to make the observations, had watched S2 pass by Sagittarius A* in 2016 but the instruments it was using then were not sensitive enough to detect the gravitational redshift.

“More than 100 years after he published his paper setting out the equations of general relativity, Einstein has been proved right once more - in a much more extreme laboratory than he could have possibly imagined,” said the ESO in a statement. Astronomers already use another effect predicted by Einstein’s theory of general relativity - that a black hole can bend passing light. Called gravitational lensing, researchers have used it to peer behind black holes.

Astronomers hope they can make practical use of the latest confirmation of Einstein’s theory to track shifts in S2’s trajectory due to gravity, which could yield information on mass distribution around the black hole.

“I am always blown away by Einstein’s predictions, by the power of his reasoning which yielded this theory and which has never been faulted,” French astrophysicist Guy Perrin, a member of the GRAVITY consortium, told AFP.

Partnering with the Max Planck Institute in the consortium were French research institute CNRS, the Paris Observatory and several French universities along with Portugal’s CENTRA astrophysics centre.</s>An international group led by Reinhard Genzel at Germany’s Max Planck Institute for Extraterrestrial Physics (MPE) was able to test Albert Einstein’s 100-year-old general relativity theory with a supermassive black hole for first time, proving the latter's theory involving the behavior of stars around black holes. The results of their study have been published in Astronomy & Astrophysics.

One of the greatest minds of humankind predicted that the light of a star would not slow down, but would rather lose some of its energy in powerful gravitational fields such as those created by supermassive black holes; its wavelengths grow longer, which would make a star look redder. The effect, which is an indicator of the general relativity theory, got the name “gravitational red shift.”

Up to now, scientists were unable to test Einstein’s prediction, according to astronomer Frank Eisenhauer.

“This was the first time we could test directly Einstein’s theory of general relativity near a supermassive black hole. At the time of Einstein, he could not think or dream of what we are showing today,” the scholar said.

Astronomers have observed the “red shift” effect monitoring the supermassive black hole Sagittarius A*, which is 4 million times heavier than the sun and is located in the center of the Milky Way galaxy, some 26,000 light years away from Earth.

READ MORE: Told You So: Einstein Proved Right Yet Again as Researchers Measure Star Weight

A team of astronomers at the European Southern Observatory started tracking stars in this area 26 years ago using the Very Large Telescope. They followed the behavior of a star called S2, and with their tools became more accurate: they eventually caught it orbiting around Sagittarius A* at a speed of 24.14 million kilometers per hour. Escaping the extreme gravity of the supermassive black hole, S2’s wavelengths stretched and grew from blue to red.

The team has predicted further confirmations of the theory. More than a year ago, scientists joined forces and telescopes to get a clear rendering of the event horizon of the supermassive black hole — a boundary beyond which even light can’t escape. However, they still haven’t managed to interpret and study the results.</s>BERLIN: A team of international scientists observing a star in the Milky Way have for the first time confirmed Einstein’s predictions of what happens to the motion of a star passing close to a supermassive black hole. Einstein’s 100-year-old general theory of relativity predicted that light from stars would be stretched to longer wavelengths by the extreme gravitational field of a black hole, and the star would appear redder, an effect known as gravitational red shift. “This was the first time we could test directly Einstein’s theory of general relativity near a supermassive black hole,” Frank Eisenhauer, senior astronomer at the Max Planck Institute for Extraterrestrial Physics, told journalists. “At the time of Einstein, he could not think or dream of what we are showing today,” he said. A team of scientists at the European Southern Observatory started monitoring the central area of the Milky Way using its Very Large Telescope to observe the motion of stars near the supermassive black hole 26 years ago. The black hole is 26,000 light years away from Earth and has a mass 4 million times that of the Sun. The scientists selected one star, S2, to follow. With an orbit of 16 years, they knew it would return close to the black hole in 2018.Over 20 years, the accuracy of their instruments has improved and so in May 2018, they were able to take extremely precise measurements in conjunction with scientists from around the world.</s>BERLIN: A team of international scientists observing a star in the Milky Way have for the first time confirmed Einstein's predictions of what happens to the motion of a star passing close to a supermassive black hole.

Einstein's 100-year-old general theory of relativity predicted that light from stars would be stretched to longer wavelengths by the extreme gravitational field of a black hole, and the star would appear redder, an effect known as gravitational red shift.

"This was the first time we could test directly Einstein's theory of general relativity near a supermassive black hole," Frank Eisenhauer, senior astronomer at the Max Planck Institute for Extraterrestrial Physics, told journalists.

"At the time of Einstein, he could not think or dream of what we are showing today," he said.

A team of scientists at the European Southern Observatory started monitoring the central area of the Milky Way using its Very Large Telescope to observe the motion of stars near the supermassive black hole 26 years ago.

The black hole is 26,000 light years away from Earth and has a mass 4 million times that of the Sun.

The scientists selected one star, S2, to follow. With an orbit of 16 years, they knew it would return close to the black hole in 2018.

Over 20 years, the accuracy of their instruments has improved and so in May 2018, they were able to take extremely precise measurements in conjunction with scientists from around the world.

This showed the star's orbital velocity increasing to more than 25 million kph as it approached the black hole.

The star's wavelength stretched as it sought to escape the gravitational pull of the supermassive black hole, shifting its appearance from blue to red, Odele Straub from the Paris Observatory said.

The scientists now hope to observe other theories of black hole physics, she said.

"This is the first step on a long road that the team has done over many years and which we hope to continue in the next years," MPE's Reinhard Genzel, who led the international team, said.</s>Albert Einstein dedicated his life to the pursuit of knowledge, even if he couldn’t always prove that his theories made sense. Many of the things that Einstein wrote about during his life couldn’t even be tested with the technology that existed at the time, which means we’re still trying to figure out just how right he was about how the universe works.

Now, one of Einstein’s theories about how light moves in space has been proven correct. Using a telescope more powerful than astronomers of his day could even dream of, researchers peering at a distant black hole have confirmed that Einstein’s assumptions about light wavelengths were spot-on.

The legendary scientist theorized that when light moves within a strong gravitational field its wavelength would actually stretch as though it’s being stretched by the pull of gravity. This quirk of physics is called a “redshift” because it lengthens the light’s wavelength, pushing it closer to the red portion of the light spectrum.

The theory fits well within the accepted framework of modern physics but it had never been observed around a massively powerful gravitational force like a black hole. That’s where Sagittarius A* comes in. Sagittarius A* is thought to be the location of the supermassive black hole at the center of the Milky Way galaxy, where Earth and our Solar System lives, and in a new series of observations using Chile’s Very Large Telescope scientists have finally observed the phenomenon in action.

By following a distant star as it moved around the black hole, astronomers were able to measure the difference in wavelength of its light. This measurement showed exactly what Einstein predicted it would; light shifts towards the red end of the spectrum when it’s being pulled on by gravity, losing a portion of its energy.

Researchers believe that, as observations of how light behaves even closer to a black hole, some of Einstein’s theories may come up short. For now, however, he gets the win.</s>Astronomers have found evidence that the supermassive black hole thought to lurk at the heart of our galaxy displays the gravitational properties dictated by the general theory of relativity.

The news was announced overnight at the European Southern Observatory (ESO), with the work published in the scientific journal Astronomy and Astrophysics.

Read more: Sizes matters for black hole formation, but there's something missing in the middle ground

By accurately tracing the position and speed of a single star (known as S2), astronomers have detected the telltale signature of Einstein’s gravity in action.

Newton’s mathematical description of gravity reigned for 250 years, but a century ago Einstein’s insights into the nature of space and time rewrote our gravitational understanding.

For most places in the universe, where gravitational fields are weak, the mathematics of Newton and Einstein give identical results for the motion of galaxies, stars and planets.

But as the strength of gravity increases, subtle differences between the two theories emerge.

In fact, Einstein was guided by small but significant discrepancies in the orbit of Mercury about the Sun while reworking his vision of gravity.

For more than two decades astronomers have charted the orbits of stars around an apparent nothingness lurking at the heart of our Milky Way. An immense amount of mass, more than four million times the mass of the Sun, must be present to keep the stars on course.

That mass is concentrated into a tiny volume. Astronomers have only one candidate for such a monster: a black hole. This is a region of completely collapsed mass, known to exist as a consequence of Einstein’s vision of gravity.

While the motions of stars at the galaxy’s centre revealed the presence of the black hole, astronomers wondered if they could search for particular signatures of Einstein’s gravity by tracking their orbits.

For most stars this isn’t possible as they are far enough away from the black hole, where the gravitational pull weakens. Their orbits should therefore agree with both Newton and Einstein.

But one star, S2, possessed a tantalising, highly elliptical orbit. It passes close to the black hole every 16 years, at a distance of less than 20 billion km (only three times the orbit of Pluto within our Solar System). That’s a tiny distance on galactic scales.

The star travels at a blistering 7,600km per second, roughly 3% of the speed of light.

If astronomers could accurately trace S2 through the closest approach of its orbit - where the effects of general relativity should be strongest - the differences between the gravitational theories of Newton and Einstein should become apparent.

Observing stars at the centre of the Milky Way is not easy. It’s a dusty and crowded field of view and the blurring of the Earth’s atmosphere introduces too much distortion. Could measurements be made that were precise enough to test the nature of gravity?

Astronomers are not easily daunted and they had time to prepare. They called on the Very Large Telescope (VLT), consisting of four 8-metre telescopes in the mountains of Chile.

The light from the individual telescopes is combined to act as one immense mirror, a technique known as interferometry. This sharpens the resolution of the images and provides much needed fine-level detail.

To improve accuracy even further, the telescopes were fitted with adaptive optics to counter the effect of atmospheric blurring. They are also fitted with sensitive detectors to collect the light from individual stars.

With names such as GRAVITY, SINFONI and NACO, each represents an immensely complex instrument, built through the efforts of large teams of astronomers and engineers over many years.

In May 2018, when S2 was passing closest to the black hole, the team of astronomers were prepared.

The speed of S2 was monitored using Doppler shift, which tracks changes in the speed of the star by detecting small shifts in the wavelength of light emitted by the star.

The Doppler shift increased as the star approached the black hole and its motion initially agreed with the predictions of Newtonian gravity.

But as it drew closer still, the star seemed to increase in speed, peaking at more than 200km/s faster than expected.

This extra speed was not due to an actual increase in motion. Another effect was in play, as the light from the star had to fight against the increased pull of gravity.

Read more: Curious Kids: Where do black holes lead to?

Called gravitational redshift, this effect was predicted by Einstein more than a century ago. The star’s light was being stretched to longer (or redder) wavelengths, and the detected distortion matched expectations of a high-speed star zooming past a black hole.

These new observations are exciting and show that we are entering a new era of black hole research. With ever increasing accuracy, the general theory of relativity can be tested with more precision.

Some astronomers hope that these measurements will become so precise as to eventually show discrepancies that go against the general theory of relativity, ushering in a revolution in our understanding of gravity. Until that day, Einstein’s vision of space and time reigns supreme.</s>More than a century after Albert Einstein proposed it, his theory of general relativity has passed another test.

With giant telescopes pointed at the center of our galaxy, a team of European researchers observed a fast-moving star that got close to a monstrous black hole.

They saw that the black hole distorted the light waves from the star in a way that agrees with Einstein's theory.

This artist's impression provided by the European Southern Observatory in July 2018 shows the path of the star S2 as it passes close to the supermassive black hole at the center of the Milky Way galaxy. As the star gets nearer to the black hole, a very strong gravitational field causes the color of the star to shift slightly to the red, an effect of Einstein's general theory of relativity. European researchers reported the results of their observations in the journal Astronomy & Astrophysics on Thursday, July 26, 2018.

'This was the first time we could test directly Einstein's theory of general relativity near a supermassive black hole,' Frank Eisenhauer, senior astronomer at the Max Planck Institute for Extraterrestrial Physics, told journalists.

'At the time of Einstein, he could not think or dream of what we are showing today,' he said.

The result was reported Thursday in the journal Astronomy & Astrophysics.

Einstein's theory says the fabric of the universe is not simply space, but a more complex entity called space-time, which is warped by the presence of heavy objects.

The one that lies at the heart of the Milky Way is 4 million times as massive as our sun.

'I, just like every physicist in the world, would have loved to finally see a crack in Einstein's relativity,' said Ohio State University astrophysicist Paul Sutter.

But confirming Einstein's work - again, 'feels like we're kind of beating a dead horse,' said Sutter, who wasn't part of the research team led by Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany.

Scientists know that the theory still doesn't explain everything about the universe. So they keep testing it time and again.

So far, nobody has been able to overthrow it.

Although the effects of general relativity have been seen before, this was the first detection made by observing the motion of a star near a supermassive black hole.

'To me, that's what makes this so cool,' said Clifford Will, a University of Florida physicist who did not participate in the research.

Will hopes his colleagues will be able to discover stars even closer to the black hole, where the effects of relativity would be stronger.

This finding 'is really the opening episode,' he said.

'The future, I think, is going to be very exciting.'

The team of scientists at the European Southern Observatory started monitoring the central area of the Milky Way using its Very Large Telescope to observe the motion of stars near the supermassive black hole 26 years ago.

The black hole is 26,000 light years away from Earth and has a mass 4 million times that of the Sun.

The scientists selected one star, S2, to follow.

With an orbit of 16 years, they knew it would return close to the black hole in 2018.

Over 20 years, the accuracy of their instruments has improved and so in May 2018, they were able to take extremely precise measurements in conjunction with scientists from around the world.

This showed the star's orbital velocity increasing to more than 25 million kph (15.5 million mph) as it approached the black hole.

The star's wavelength stretched as it sought to escape the gravitational pull of the supermassive black hole, shifting its appearance from blue to red, Odele Straub from the Paris Observatory said.

The scientists now hope to observe other theories of black hole physics, she said.

'This is the first step on a long road that the team has done over many years and which we hope to continue in the next years,' MPE's Reinhard Genzel, who led the international team, said.
Astronomers say they have observed Albert Einstein's theory of gravitational redshift for the first time while observing a star known as S2 interact with a supermassive black hole using the Very Large Telescope (VLT).