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A black hole in the heart of our galaxy .. This is its first image



Scientists have succeeded in matching the image of the Sagittarius-A-star black hole based on data collected from eight radio labs distributed around the world.

Scientists have succeeded in matching the image of the Sagittarius-A-star black hole based on data collected from eight radio labs distributed around the world.

Credit: Event Horizon Telescope collaboration

Radio astronomers have captured the image of a giant black hole in the center of the Milky Way. This is the second time that a live image of the black hole has been taken since the first and most historic image of the same group being able to capture the farthest black hole from the black hole released in 2019.

The long-awaited results released by the Event Horizon Telescope Corporation on May 12 show a picture reminiscent of its predecessor: a ring of radiation around a dark disk of the same magnitude predicted by indirect observations and general relativity. By Albert Einstein.

“Today, at this time, we have direct evidence that this object is a black hole,” said Sarah Essen, an astronomer at the Harvard-Smithsonian Astronomical Center in Cambridge, Massachusetts, at a news conference in Corching, Germany. The team published its findings in a special issue of the Journal of Astronomy. Letters from the Journal of Astronomy. (K. Akkiyama And others. Astronomy. J. Let. 930, L12; 2022.)

“We have been preparing for this discovery for a long time,” said Katie Bowman, a former member of the Event Horizon Telescope team and a computational imaging researcher at the California Institute of Technology in Pasadena, at a news conference in Washington. The hole in the heart of our galaxy. “

Planet-sized telescope

During five nights in April 2017, the Event Horizon Telescope Collaboration used eight observatories around the world to collect data from the Milky Way galaxy – scientists named it Sagittarius A * after its discovery. Black hole M87 *, which is located at the center of the galaxy M87.

Observatory locations were distributed across Spain to Antarctica and from Chile to Hawaii (see:
Global effort)

The researchers released the 2019 image of the M87 * black hole, which provides the first direct evidence of the spherical “event horizon” surrounding the interior of the black hole.

But Sagittarius A Star data was very difficult to analyze. The two black holes have the same apparent size in the sky; Although the M87 * black hole is 1,600 times larger than the Sagittarius-A star, it is almost 2,000 times farther away. In addition, clusters of objects orbiting the M87 * black hole – regardless of their nature – are farther away (larger than Pluto’s orbit around the Sun), and unlike any black hole they emit, they are practically stable in the short term. Sagittarius A star, which can change rapidly even within a few hours of EHT monitoring every day.

“In the case of the M87 * black hole, over the course of a week, we see very little change,” said Heinaw Walke, an astronomer at the University of Rodbout in the Netherlands. It changes shape. In 5 to 15 minutes. “

As the shape of Sagittarius changes so quickly, scientists are careful to create thousands of images without even making a single image of it. Jose Gomez, a researcher at the Andalusian Institute for Astrophysics in Granada, Spain, and a member of the team said, “By averaging data from all these images, we can verify common features.

In addition to the radiation ring around a dark disk, the resulting image showed three bright “nodes”. “We see knots in every film we make,” says Asan, but their location is different in each photo. He said these knots often indicate defects caused by the researchers’ interferometry system.

This black hole differs in its shape from the M87 * hole, in that its brightest part was in the shape of a lunar quadrant (half full moon), which may indicate that dense clusters are accelerating along the line of sight.

Using a supercomputer that drives group simulations and compares their data with their results, the Sagittarius-A-star often rotates in the opposite direction, i.e. the axis that points up to the line of sight toward Earth, Gomez says.

Regina Kaputo, an astronomer at NASA’s Goddard Space Flight Center in Greenfield, Maryland, said: “What amazes me is that we see it from the opposite direction. The Sagittarius-A-Star wormhole occurred during intense activity in the past, but these shapes, known as Fermi bubbles, appear to orbit objects around the black hole, not from the front, but from the side when viewed from Earth.

The first signs of a black hole being a “Sagittarius-A-star” appeared in the 1970s, when radio astronomers discovered the source of a point-like radio wave located at the center of the galaxy.

This evidence became unusually opaque; Is dark as a normal star. Nevertheless, decades of observations of the motion of neighboring stars have shown that this object is very large: based on recent observations, scientists have been able to calculate its mass, i.e. 4.15 million solar masses, plus the margin of error. Or subtraction 0.3%. These calculations, made by observing the orbits of Sagittarius-A-stars, provide conclusive evidence that the source of these radio waves is as large and dense as a black hole.

It is noteworthy that the black hole “Sagittarius-A star” is practically invisible to optical telescopes; As dust and gas cover the galaxy disk. But since the late 1990s, Polk and others have realized that the shadow of a black hole can be large enough to be photographed by narrow radio waves that can escape from that envelope. However, scientists estimate that this will require an Earth-sized telescope. Fortunately, a technique called interferometry can help scientists in this endeavor. Technology can point multiple telescopes at the same object at the same time, making telescopes practically the same pieces of food.

The first attempts to monitor the Sagittarius-A-star by interferometry relied on radio waves with a wavelength of 7 millimeters, which was relatively long, and the observatories were several thousand kilometers away from each other. Thus, the cloudy space could not be overlooked by researchers.

Later various groups around the world worked hard to improve their methods and re-fit the added observatories into the network. In particular, researchers placed the Antarctic telescope and the $ 1.4 billion Atacama Large Millimeter / Submillimeter Telescope in Chile.

In 2015, research teams teamed up to create the event Horizon Telescope collaboration. The teams took part in a joint space-observation campaign in 2017, the first of which involved observations far enough away to reveal details of an object the size of a Sagittarius A star.

Future plans

The Event Horizon Telescope team collected additional data in 2018, but canceled scheduled observations in 2019 and 2020. Monitoring resumed in 2021 and 2022 with an upgraded network and sophisticated equipment.

Remo Telenos, a board member at the University of Arizona in Duson, said that in March, the team’s last observations could contribute to greater clarity at twice the rate of 2017, often at a wavelength of 0.87 millimeters. The resulting images.

Researchers hope to find out if the Sagittarius-A-star black hole has holes; Many black holes, including M87 *, appear to emit two rays of matter rapidly in opposite directions, and are believed to be caused by the intense heat of the gas falling towards the black hole and to be pushed by its rotation. . The Sagittarius-A-star may have had large jets in the past, marked by heated clouds above and below the galaxy. Its jets are now very weak, but their existence may reveal important details about our galaxy history.

“These eruptions can slow down or induce star formation, and they can push chemical elements around,” says Balk, which affects the evolution of an entire galaxy. “Now we see where all this is happening,” he added.

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After professional testing, the iPhone 15 Pro Max is not the best phone for photography



After professional testing, the iPhone 15 Pro Max is not the best phone for photography

Apple’s new phone, the iPhone 15 Pro Max, has undergone extensive tests for the rear camera to record photos and video clips at the popular DxOMark digital camera testing site.

DxOMark is the leading platform and most important rating site among professional camera testing sites for smartphones and other digital cameras. This site features photography experts and reviews cameras for detailed testing of photography or recording in various modes. Film.

Recently, Apple’s latest iPhone 15 Pro Max underwent extensive camera tests from DxOMark for a real assessment apart from the specification numbers, and the phone has already scored a real hit.

pointed out Final report For the test, Apple’s most expensive phone won the tests, reaching 8 levels of improvement compared to the previous generation iPhone 14 Pro Max, and it took the second place among the best smartphones for photography with the rear camera.

The Huawei P60 Pro is the only device that has given better results than the Apple device and received a higher rating.

iPhone 15 Pro Max

During the evaluation, DxOMark testers were impressed by the brightness and contrast of the iPhone 15 Pro Max’s images, even in low-light (night) scenes, with excellent skin color processing.

The report said that the phone was rated as the best in terms of image brightness, color contrast, shadow rendering, and background isolation mode. According to DxO ratings, it was also said to be the best phone for video shooting.

The report also highlighted that the flaws that didn’t make the iPhone 15 Pro Max the best among all the competition appeared in the tests, where colors differed in low light and the photos taken at night were noisier than some competitors. with dynamic range. A little less in hard outdoor scenes.

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The most important thing that can be distinguished about the phone after the test is that the new telephoto lens, telephoto and 5X zoom on the iPhone 15 Pro Max, which is one of the most important revolutionary changes this year, is not really there. Do what the company says.

Apple confirmed at the phone announcement event that the new zoom lens will work with focal lengths up to 120mm with standard options for 28mm and 35mm, similar to what professional DSLR cameras offer with advanced lenses.

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In practice, the camera results are actually a crop of said image dimensions and not the default focal lengths mentioned earlier, because images are taken through lenses and then cropped to match professional dimensions.

The report confirmed that the new lens provides very impressive results, especially when there is enough light, and it can distinguish backgrounds and isolate targets professionally.

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Scientists have found the best place to build a lunar base



Scientists have found the best place to build a lunar base

Published: 09/28/2023 (Last Updated: 09/28/2023 at: 08:09)

Bethlehem – together – scientists found the best place to build a lunar base, they explored it and took into account the surrounding conditions.

At the south pole of the Moon, between two craters there is an area with a large body of water and permanent sunlight, providing a good environment for human habitation.

Antarctica has long been considered a good place for colonization because many of its craters are exposed to constant sunlight and shade so that electricity can be generated using solar panels, while there is ice to extract water.

Areas around some of these craters have been explored by lunar rovers, such as India’s recent Chandrayaan-3 mission, but their goal is to collect scientific data rather than search for the primary location.

Five holes are being considered because of their constant sunlight, but the amount of water and other resources must be considered before deciding on a location.

According to New Scientist, scientists from the University of Atacama in Chile analyzed data from five potential craters.

Five craters are called De Gerlach, Henson, Sverdrup and Shackleton, one of which is an unnamed crater.

The scientists took into account the density of carbon dioxide in the frozen water, other energy sources, ease of access and interactions with the Earth, as well as the distribution of water ice, slope angles and the amount of sunlight available to each hole. .

Where is the place located?

Team leader Giovanni Leone told New Scientist that an area of ​​about 5 square kilometers with two craters known as the Sverdrup-Hensen is the best place to install the first platform.

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The area has a relatively flat surface, which makes construction and transportation easier, as well as more ice and minerals in nearby shadowy areas. There are areas exposed to permanent sunlight, for power generation and contact with the ground.

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Simple Ways to Fix Camera Not Working Problem on Mac



Simple Ways to Fix Camera Not Working Problem on Mac

Apple Mac computers have a built-in webcam, which you can use to make video calls with friends and family through the FaceTime application, or participate in online meetings with various applications such as Zoom, Microsoft Teams, Google Meet, and other video conferencing applications. On a MacBook computer.

But sometimes, when using a particular application, the Mac computer camera may suddenly stop working and a message will appear saying that the camera is not connected. In this case, you can easily fix the problem by following the methods we describe below:

1- Close and restart the app:

First, you can close the application you are working on and try launching it again. This will help you fix any problems or errors that prevent the MacBook computer camera from working properly.

Using more than one Mac camera app at the same time can also cause this problem. This can be easily fixed by using the Force Quit option to close apps. To access this option, you can click the Apple menu, choose Force Quit from the bottom to display a list of active apps, and close them.

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2- Update the application and operating system:

Another simple solution to this problem is to update the apps and operating system on your MacBook to the latest version. Sometimes, the problem may be with the app and not with the MacBook camera. So check if the app is updated and if it is up to date then try uninstalling and reinstalling the app.

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On the other hand, make sure that the macOS operating system on your Mac computer is updated to the latest version. The importance of this is that Apple releases software updates to fix bugs and vulnerabilities that can prevent applications on Mac computers from working properly.

Additionally, you can try launching another app that uses your MacBook camera to make sure the camera is working. If it works, the problem is with the app, not the computer’s camera.

3- Grant the app access to the camera:

You may not grant access to the app you want to use the camera. So, to allow this app to access your MacBook camera, follow these steps:

  1. Click the Apple menu and select System Settings.
  2. Choose (Privacy and Security) from the sidebar and click (Camera).
  3. A list will appear with all the applications installed on your MacBook that require access to the camera. From there, turn on the toggle next to the app you want to use the camera for.
  4. After granting the application access to the camera, it must be closed and restarted for it to work properly.

4- Restart your Mac computer:

Restarting your Mac computer is one of the easiest ways to fix many of the most common problems you may encounter while using the computer, and it can also help fix a problem where the camera stops working.

To restart your Mac, click the Apple menu and select Restart from the bottom. After restarting the computer, launch the app you want to use the camera and make sure it works.

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5- Check if the camera light appears:

To check that your camera is working properly, launch any app that uses your MacBook’s camera: FaceTimeThen make sure the camera light is on.

Otherwise, you can check whether your Mac computer detects the camera or not by following these steps:

  1. Go to (System Settings), then (General).
  2. Click About, then System Report.
  3. Select Camera from the Hardware section in the sidebar on the left side.
  4. If you can see information about the camera model: Model ID and Unique ID on the right, it means that your Mac computer can detect the camera. If you don’t see these details, it means your computer is not detecting the camera.

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