How Scientists Found an Exotic Black Hole in a 'Needle in a Haystack'
Astronomers have found a needle in a haystack: the first-ever image of an exotic kind of black hole never before seen in our galaxy, and probably others as well. The black hole was spotted at the center of NGC 1332, which lies about 30 million light-years from Earth in the constellation Eridanus.
What is LIGO?
LIGO is the Laser Interferometer Gravitational-Wave Observatory, a scientific observatory that consists of two detectors: one in Hanford, Washington, and the other in Livingston, Louisiana. LIGO's primary purpose is to detect gravitational waves. These are ripples in space-time that are produced by some of the most energetic events in the Universe, such as the merging of black holes.
In 2015, LIGO made its first detection of gravitational waves. Since then, it has made several more detections. The most recent one was made on August 14, 2017. This detection was made by combining data from the two LIGO detectors. It was of a binary black hole merger that occurred about 1.8 billion light-years away from Earth. A few days after this event, LIGO detected another binary black hole merger that happened 2.6 billion light-years away from Earth!
The properties of these two different sources were very different but both would have been difficult to find if we didn't have multiple telescopes like LIGO working together.
For example, the event detected on August 14th gave off more energy than all the stars in our Milky Way galaxy combined! To put this into perspective, if this signal were visible with the naked eye here on Earth it would be easily seen over 5 million times brighter than a typical Venus transit across the sun! What's even more incredible is that scientists found this event just because they had access to data from the two LIGO detectors. One can only imagine how many other signals might be out there waiting for us to find them! In order to help find other signals, LIGO team members use algorithms that process what happens when two black holes merge. They search for occurrences where the observed strain rate at one detector exceeds those expected at the other detector based on background noise alone. Based on their analysis, they estimate how often these kinds of mergers happen within the next year. So far they've determined that every time someone looks through their telescope every six hours or so, they should see a similar type of event. And so far not a single person has looked through any telescope and not seen anything yet! Keep your eyes peeled, you never know what you'll find up there.
The reason why we have such precise measurements is because each detector consists of 4km long tubes (2 in Washington state, 2 in Louisiana) filled with fluid. Any motion in space will result in distortions along these tubes, which are measured using laser light sent down them and then reflected back up again. As gravitational waves pass by, space distorts causing ripples moving both up and down as well as side-to-side along each tube. Using extremely sensitive lasers allows us to measure tiny changes caused by passing gravitational waves. Even though the gravitational waves are weak, LIGO still manages to catch and measure them. This is done by comparing the differences in length of the two arms of a LIGO detector. If one arm gets stretched and the other arm shrinks, this means that gravitational waves passed by. We call this process gravitational wave interferometry.
It is a wonder that, without ever looking through a telescope, we have already discovered something so incredible!
The Hunt for Colliding Neutron Stars
On August 17, 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo detectors picked up the faintest ever gravitational-wave signal. The source: two neutron stars colliding and merging into a black hole about 130 million light-years away. For days after LIGO announced its detection of GW170817 on October 16, astrophysicists around the world scrambled to find this needle in a haystack by combing through data from more than 70 observatories on Earth and in space. They found a burst of gamma rays that matched what LIGO had seen when it sensed GW170817—and also radio waves from hydrogen gas heated to over 1 billion degrees Celsius and heavy elements forged during the violent collision of two stellar objects thought to be 10 times as massive as our sun. It was like looking for a needle in a haystack, says Jim Cordes, a Cornell University astronomer who is co-chair of the LIGO collaboration's science steering committee. But now we've found it. Colliding neutron stars are so far away that they can't be seen directly with telescopes. They're too small, too dim, and too quick to emit their radiation before they fade out again. To detect them, scientists rely on gravitational waves which emanate from these events like ripples across a pond when you toss in a rock.
The hunt for these rare collisions has been challenging because most black holes form quickly and don't last long enough to make any detectable ripples in spacetime. But then something happened that made finding them much easier: Einstein predicted gravitational waves. When he published his theory of general relativity in 1916, he knew there would be an important consequence: Matter in motion produces distortions or waves in spacetime. Today, we call these waves gravitational waves and measure them with instruments called interferometers such as LIGO. We haven't detected very many gravitational waves because few astronomical sources produce sufficient quantities of energy to excite the largest interferometers available today (LIGO). And even if a large enough event occurs, detecting it takes time--the sound doesn't travel instantaneously but at roughly one foot per millisecond; so if the distance between us and the event is greater than 150 km (about 95 miles), it will take about 4 seconds for us to feel it here on Earth.O ftentimes, the only way to see a gravitational wave is in terms of its effects on a passing object. A gravitational wave's passage stretches and squashes the fabric of spacetime, changing the distances between all objects. In LIGO's case, that means lengthening and contracting the arm lengths of each detector. The relative change in length for each arm, known as a strain, can be calculated from the amount of passing gravitational waves and it enables astronomers to calculate how close an event occurred. Knowing that stretchiness alters LIGO’s arm lengths lets scientists use it as a tool to look for gravitational waves from various sources - sometimes using multiple LIGO detectors in different places. LIGO is not the only instrument for searching for gravitational waves. Other methods include observing stars and galaxies that vary in brightness and spectral lines, as well as pulsars (rapidly rotating neutron stars that beam radiation from their poles) and pulsating black holes. But LIGO's detectors were uniquely sensitive to GW170817 because of its particular wavelengths.
Though LIGO is not powerful enough to see the neutron stars collide, it can detect gravitational waves when they pass through Earth from a distant event. The tiny ripples in spacetime distort the distance between two points on Earth, slightly stretching them closer together while simultaneously making them longer. If the stretch and squeeze happen far away, you'll never notice it. If you live near a collision though—as some residents of Las Vegas did during October 2017—you might feel your own body being pushed back against your seat as LIGO detects what seems like a ripple in space-time. For example, I have been feeling this since just after 3 AM Eastern Time on Sunday morning September 17th and still am feeling this now at 11 PM Eastern Time tonight Monday September 18th after 23 hours with no end yet! That’s more than twice the duration recorded by researchers who first noticed this phenomenon on Wednesday night September 13th after approximately 10 hours!
What's inside a black hole?
Black holes are some of the most fascinating objects in the universe. They are incredibly dense, with a gravitational pull so strong that not even light can escape. And they are mysterious, since we can only observe them indirectly. But astronomers have found a new way to explore what is inside black holes—by observing their interactions with gas clouds. One such gas cloud is called G2, and scientists have been watching it closely for years as it hurtles towards Sagittarius A*, which is a supermassive black hole at the center of our galaxy.
The G2 cloud has now reached its closest point to Sagittarius A* and has made history by becoming the first ever object observed to pass through the intense gravitational field around this particular black hole. It's taken scientists years to prepare for this historic event, using radio telescopes across Earth to get detailed observations on how gas behaves in close proximity to a black hole—data which will help us understand these enigmatic objects more deeply than ever before. While astronomers expect G2 to be pulled apart eventually, that may take months or years. In the meantime, data continues to pour in about this incredible discovery. Follow-up observations by NASA’s Chandra X-ray Observatory, Swift satellite, and NSF’s Karl G. Jansky Very Large Array (VLA) confirm that material is falling into the black hole, creating bright flares near the event horizon. And follow-up radio observations show how the powerful jets react when faced with G2′s infalling material. What happens next? No one knows yet! Stay tuned to learn more!
Stay tuned to learn more! The G2 region provides a unique opportunity because we can observe phenomena that are normally hidden from view. As matter falls toward a black hole, it heats up and glows brightly — brighter than an entire galaxy of billions of stars. Normally we would only see such glowing plasma after it passed beyond the event horizon —the boundary beyond which nothing can escape. But by studying G2 as it races past Sgr A*, we are actually watching it fall into a black hole! We'll soon know what happens over that final distance. With each passing day, G2 moves closer to the edge of the black hole's shadow — just 2 million kilometers away now. On Wednesday morning, April 10th, as G2 enters this final stretch, it will either shoot out like a cork from a champagne bottle and fly off into space or else be inexorably drawn down into the abyss. Either way, an era of exploration has ended and another begins.
The G2 region provides a unique opportunity because we can observe phenomena that are normally hidden from view. As matter falls toward a black hole, it heats up and glows brightly - brighter than an entire galaxy of billions of stars. Normally we would only see such glowing plasma after it passed beyond the event horizon - the boundary beyond which nothing can escape.
Where are they located?
Scientists believe that black holes are located in the center of galaxies. In order to find them, scientists look for areas of space where there is a lot of mass concentrated in a small area. This can be done by looking at the light from stars that are located near the black hole. The light from these stars will be bent and stretched as it passes near the black hole. By looking at how much the light from these stars is bent, scientists can determine how massive the object is and whether or not it is a black hole. When this technique was used to locate Sagittarius A*, which is thought to be the center of our galaxy, researchers were able to calculate its mass. They found that this particular black hole has a mass 4 million timestimes greater than our sun's! Scientists have been searching for this elusive thing called dark matter. They believe that dark matter may make up around 27% of all the matter in the universe but they have yet to figure out what it actually is. One theory about dark matter is that it could be made up of exotic particles called axions. Axions would emit gamma rays when decaying into photons and then quickly decay into other particles before ever reaching Earth; so their existence would never been detected on Earth's surface.Scie entists can detect when axions decay into photons because the two kinds of particles would hit molecules differently. For example, if an axion decays into a photon, it could leave behind protons while a photon leaves behind electrons. Experiments like LUX (Large Underground Xenon) experiment search for gamma rays with very specific properties-properties that are not present in ordinary backgrounds sources-in order to identify signs of this hypothetical particle. If there is any chance we will ever learn more about this mysterious particle known as dark matter, scientists need to start with something we know: theoretical models based on current physics knowledgeknowledgeknowledgeknowledgeknowledgeknowledgeknowledgeknowledge
A brief history of black holes
Black holes are some of the most fascinating objects in the universe. These massive objects are so dense that not even light can escape their gravitational pull. Scientists believe that black holes are formed when a star collapses in on itself. This collapse can happen suddenly, or it can take place over millions of years. Over time, the star will get smaller and smaller until it eventually becomes a black hole. The newly discovered black hole is unusual because scientists think it might be really old. It is hard to estimate how old this particular black hole is because there aren't many stars left to help scientists figure out its age.
This rare find was made by using what's called LIGO - which stands for Laser Interferometer Gravitational-Wave Observatory - and looking for the signals caused by these waves. What made this discovery so exciting was that scientists were able to identify the shape of the signal they were seeing from space as a result of two colliding black holes. To put this into perspective, imagine that someone accidentally dropped a glove onto the ground while searching for something under their bed. You could then look under your bed and see if you found anything with a similar pattern as your glove (your potential lost item). In this case, scientists have been scanning the sky for just such a lost object - one like ours but way more distant. Our hope is that we'll be able to make contact with more black holes like ours in order to learn more about them! The last sentence would include information about how people can follow along with discoveries like this one. Maybe link to social media pages where followers can stay up-to-date with posts from the organization. It’s important to remember that new research and new findings often lead to more questions than answers. When scientists first predicted the existence of black holes, no one knew much about them at all. Fast forward 400 years later, and now we're making major breakthroughs that provide us with more insight into these enigmatic cosmic phenomena!
The Future of Research into Black Holes
In recent years, astronomers have made great strides in understanding the nature of black holes. However, there is still much to learn about these fascinating objects. With new technology, scientists will be able to study black holes in greater detail than ever before. This will help us to better understand how they form and how they affect the surrounding environment. Additionally, research into black holes can teach us about the nature of gravity and the origin of the universe itself. The extreme conditions found near black holes could help explain why quantum effects are so significant at very small scales. We might even find answers to some of the most fundamental questions that humans have asked since we first looked up at the stars and wondered what was out there. How did everything begin? What is the fate of our planet? How does our world fit within the rest of the cosmos? Some scientists believe that black holes hold the answer to these questions. They propose that when all other matter and energy cease to exist, only three things remain: space, time, and gravitation. Gravitational forces shape all of space-time like clay from which all forms arise; it may be possible for us to observe this process through the study of black holes. For example, according to one theory, when two black holes collide with each other and merge together, the event generates gravitational waves that ripple throughout space-time. These waves carry information about what happens in their vicinity - including information about the original two black holes. Einstein’s Theory of General Relativity predicts that such ripples should carry signatures from collisions between pairs of supermassive black holes located millions or billions of lightyears away. Future instruments could detect these gravitational waves and measure them for clues as to where the original supermassive pair has gone – and also where such pairs might come from in order to estimate their total number in our Universe. The potential results promise insight into some of the deepest mysteries known to manm.
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