CAN YOU SEE A BLACK HOLE WITH A TELESCOPE.
Truth be told, the answer to this question is not a simple yes or no. It is more nuanced than that. Yes we can actually see black holes now but not in the way you’d imagine; and certainly not through a regular telescope. But before we can dive into that, let us first understand what telescopes do.
Telescopes are complex instruments that help us see faraway objects which makes it a wonderful equipment to observe the night sky. They do so by incorporating a host of mirrors (and sometimes lenses or both) that align in a particular manner to magnify the image that the lens of the telescope captures.
The amount of light entering the telescope (and thus determining the brightness of the image) is given by its value of aperture and it is generally agreed upon that the bigger the aperture, the further a telescope can look into space without getting distorted images.
But even with the best telescopes you can buy on the market, you cannot observe everything. And the reason for that in the unfathomable distance between these celestial objects. Therefore to observe them, scientists use what is known as a radio-telescope that, instead of traditional lens and mirror systems, employ sophisticated technology to get more accurate readings. But even our most advanced radio-telescopes are not able to see the black holes directly.
The reason for that is two-fold. Firstly, the distance plays a key role. Black holes are not as common as planets or asteroids and therefore are, for the most part, quite far away. The second reason, and more importantly, is that black holes don’t give out any light which makes them incredibly hard to detect. The gravitational powers within a black hole are so strong that even light cannot escape it and goes through total internal reflection. But in being so, it goes against the laws of conservation of energy.
To counter this, Stephen Hawking hypothised that black holes lose the accumulated energy very little at a time but giving out radiation from the poles of its surface, also known as Hawking Radiation. It is through actively searching for this Hawking radiation and observing strong gravitational fields at seemingly empty dark spaces we can successfully locate black holes.
The technology of observing black holes is still very primitive compared to our other technical advancements and generally depend and derive heavily from theoretical science and physics. However, only a few months ago, a team at NASA successfully photographed a black hole for the first time in human history.
We finally know what a black hole looks like.
Video by Seeker
You must have seen the photo which became an international sensation. The image, in which the black hole looks very much akin to a donut, is one of the most shared images of 2019. The orange outside that looks like the ring of the donut is actually Hawking Radiation and the void inside is the actual black hole.
Black holes are difficult to find on the grounds that the enormous ones are generally far away. The nearest supermassive black hole is the one to occupy the focal point of the Milky Way, called Sagittarius A* (articulated as “Sagittarius A-star”), which lies around 26,000 light-years away. This was the main focus for a driven international venture to picture a black hole in more noteworthy detail than at any other time, called the Event Horizon Telescope (EHT).
The EHT consolidated observations from telescopes everywhere throughout the world, incorporating offices in the United States, Mexico, Chile, France, Greenland and the South Pole, into one virtual picture with a resolution equivalent to what might be accomplished by a solitary telescope the size of the separation between the isolated offices.
Be that as it may, zooming in on the black holes was as yet a huge challenge. Black holes pack a massive measure of mass into a shockingly little space. The black hole at the focal point of M87, 55 million light-years away, has gulped the mass of 6.5 billion suns. However its event horizon is just 40 billion kilometers over—around four times the breadth of the planet Neptune.
No current telescope has the resolution to see such a far off, small object. In this way, the EHT group coopted a large portion of the millimeter-wave telescopes worldwide and joined their information to create a virtual telescope the size of Earth through a procedure called long-baseline interferometry.
What’s special about the event horizon telescope.
Video by Astrum
The telescopes they utilized extended from Hawaii to Arizona, Mexico to Spain, and Chile toward the South Pole. “You can consider them silvered spots on a worldwide mirror,” says Shep Doeleman, the EHT’s undertaking chief at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts. “They are so many because even at the point the Earth turns, we can fill in the picture.”
The collaboration had done similar observations before but with fewer telescopes, and 2017 was the first occasion when they had a globe-traversing cluster that incorporated the intensity of the Atacama Large Millimeter/submillimeter Array in Chile with its 64 dishes.
Millimeter waves are influenced by mists, so getting great climate was significant. In April 2017, the climate was just perfect for the observation to be carried out. “It was one of the smoothest parts of the task,” says Feryal Özel of the University of Arizona in Tucson. “A few groups worked 16-or 18-hour shifts, however the whole thing was fortunate,” she says, ending with: “Examining the information was a lot harder.”
That procedure has taken the whole of the time since. The volume of information was great to the point that it couldn’t be transmitted to enormous PCs at the Massachusetts Institute of Technology’s Haystack Observatory in Westford and the Max Planck Institute for Radio Astronomy in Bonn, Germany.
Rather, it had to be recorded on disks and transported, which represented an issue for the South Pole Telescope. It was in lockdown for the austral winter so specialists didn’t get their hands on its information until nearly the end of 2017. An aggregate of 4 petabytes were recorded, each perusing time-stamped information utilizing a nuclear clock. On the off chance that those information were music recorded as MP3s, they would take 8000 years to play.
Einstein loathed black holes. Months after he published his hypothesis of general relativity in 1915, German physicist Karl Schwarzschild suggested that for solving Einstein’s equations, inside a specific separation of a minuscule point of mass, gravity ought to be so strong it would prevent anything from getting away, even light.
Be that as it may, for a considerable length of time, most physicists and space experts thought such a thought was only of numerical interest. It wasn’t until 1939 that U.S. physicist J. Robert Oppenheimer and associates anticipated that a gigantic star could really crumple to a point.
The way forward for the ETH scientists.
Future EHT experiments could reveal extra insight into the idea of black holes. The group plans to gauge the turn and attractive polarization of the black holes. At M87*, a more voracious and dynamic black opening than Sgr A*, the group could find out about the component that results in ejection of material out from the poles of the black hole, similar to beams from a beacon.
Sera Markoff, an EHT colleague and hypothetical astrophysicist at the University of Amsterdam, noticed that M87* is likewise a functioning galactic core whose glow waxes and melts away as it gulps up matter. “We just lucked out,” she says. “On the off chance that it had been flaring we may have seen something altogether different and it might have obstructed the shadow.”
How to take a picture of a black hole – Sera Markoff.
Video by Space Cowboys Podcast
The group’s crusade in 2018 was for the most part a washout due to terrible climate. This year, the observation mission were deserted on the grounds that few telescopes were not working. In any case, the next year’s observations ought to incorporate new telescopes, and they will likewise start to see at shorter wavelengths, which should offer more sharp pictures, Doeleman says. “We’ll have the option to broaden that picture of that shadow out to where it associates with that jet.”
Space experts outside the EHT group will be excited for sudden disclosures that could point to hypothetical leaps forward. When asked about the performance of the team, Avi Loeb, chief of the Black Hole Initiative at Harvard University, says he is most astounded by the absence of surprises. 10 years back, he recreated M87*, and he says his pictures looked much like the EHT’s today.
All things considered, he says, the group’s outcome is a significant achievement. “A picture merits a thousand words, and truth can be stranger than fiction,” he says. We now have a picture of a black hole, hopefully the first of many to come in our near future.
Related questions.
Can you see a black hole?
Yes and no. Not through the lens of an ordinary telescope you cannot, but we have special equipment that allows us to observe black holes. There is general consensus that supermassive black holes exist in the centers of most galaxies. Despite its invisible interior, the presence of a black hole can be inferred through its interaction with other matter and with electromagnetic radiation such as visible light.
What will happen if I jump into a black hole?
Let’s assume that you start outside the event horizon of the black hole. As you look toward it, you see a circle of perfect darkness. Around the black hole, you see the familiar stars of the night sky. But their pattern is strangely distorted, as the light from distant stars gets bent by the black hole’s gravity.
As you fall toward the black hole, you move faster and faster, accelerated by its gravity. Your feet feel a stronger gravitational pull than your head, because they are closer to the black hole. As a result, your body is stretched apart. For small black holes, this stretching is so strong that your body is completely torn apart before you reach the event horizon.
If you fall into a supermassive black hole, your body remains intact, even as you cross the event horizon. But soon thereafter you reach the central singularity, where you are squashed into a single point of infinite density. You have become one with the black hole. Unfortunately, you are unable to write home about the experience.
Do black holes ever die?
Black holes have a finite lifetime due to the emission of Hawking radiation. However, for most known astrophysical black holes, the time it would take to completely evaporate and disappear is far longer than the current age of the universe.
How are black holes formed?
Black holes generally form during the collapse of a massive star’s core, where the spent nuclear fuel ceases to fuse into heavier elements. As fusion slows and ceases, the core experiences a severe drop in radiation pressure, which was the only thing holding the star up against a total gravitational collapse.
While the outer layers often experience a runaway fusion reaction, blowing the progenitor star apart in a supernova, the core first collapses into a single atomic nucleus — a neutron star — but if the mass is too great, the neutrons themselves compress and collapse to such a dense state that a black hole forms. From a gravitational point of view, all it takes to become a black hole is to gather enough mass in a small enough volume of space that light cannot escape from within a certain region.
Every mass, including planet Earth, has an escape velocity, which is defined by the speed you’d need to achieve to completely escape from the gravitational pull at a given distance (e.g., the distance from Earth’s center to its surface) from its center of mass. But if there’s enough mass so that the speed you’d need to achieve at a certain distance from the center of mass is the speed of light or greater, then nothing can escape from it, since nothing can exceed the speed of light.