Will Sagittarius A Destroy Earth

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This article is republished from The Conversation nether a Creative Commons license. Read the original article, which was published May 12, 2022.

On May 12, 2022, astronomers on the Event Horizon Telescope team released an image of a black hole called Sagittarius A* that lies at the center of the Milky way galaxy. Chris Impey, an astronomer at the Academy of Arizona, explains how the squad got this epitome and why it is such a big bargain.

one. What is Sagittarius A*?

Sagittarius A* sits at the the center of our Galaxy galaxy, in the direction of the Sagittarius constellation. For decades, astronomers have been measuring blasts of radio waves from an extremely meaty source there.

In the 1980s, two teams of astronomers started tracking the motions of stars most this mysterious source of radio waves. They saw stars whirling around a dark object at speeds up to a third of the speed of calorie-free. Their motions suggested that at the heart of the Galaxy was a black hole 4 1000000 times the mass of the Sun. Reinhard Genzel and Andrea Ghez later shared the Nobel Prize in Physics for this discovery.

The size of a black hole is divers past its result horizon – a altitude from the centre of the black hole inside which zero tin can escape. Scientists had previously been able to calculate that Sagittarius A* is 16 1000000 miles (26 million kilometers) in bore.

The Milky Mode'southward black hole is huge compared to the black holes left behind when massive stars dice. Merely astronomers call up in that location are supermassive blackness holes at the middle of nigh all galaxies. Compared to virtually of these, Sagittarius A* is meager and unremarkable.

2. What does the new image testify?

Blackness holes themselves are completely dark, since cipher, not fifty-fifty light, can escape their gravity. But black holes are surrounded by clouds of gas, and astronomers can measure this gas to infer images of the black holes within. The central dark region in the image is a shadow bandage by the black hole onto the gas. The vivid ring is the gas itself glowing. The bright spots in the band show areas of hotter gas that may 1 day fall into the black hole.

Some of the gas visible in the epitome is actually behind Sagittarius A*. Light from that gas is existence bent past the powerful gravity of the black hole toward Earth. This effect, called gravitational lensing, is a core prediction of general relativity.

3. What went into producing this image?

Supermassive black holes are extremely hard to measure. They are far away and shrouded past the gas and grit that clogs the centre of galaxies. They are as well relatively small compared to the vastness of space. From where Sagittarius A* sits, 26,000 light years away at the center of the Milky way, only 1 in ten billion photons of visible calorie-free can reach Earth – almost are absorbed past gas in the manner. Radio waves laissez passer through gas much more easily than visible light, so astronomers measured the radio emissions from the gas surrounding the black pigsty. The orange colors in the image are representations of those radio waves.

The team used eight radio telescopes spread across the earth to collect data on the blackness hole over the course of five nights in 2017. Every night generated so much data that the team couldn't ship it through the internet – they had to ship physical hard drives to where they processed the data.

Because blackness holes are then hard to see, there is a lot of uncertainty in the data the telescopes collect. To turn information technology all into an accurate image, team used supercomputers to produce millions of different images, each ane a mathematically viable version of the black hole based off the data nerveless and the laws of physics. They then blended all of these images together to produce the final, cute, authentic image. The processing time was equivalent to running 2,000 laptops at full speed for a yr.

4. Why is the new epitome such a large bargain?

In 2019, the Outcome Horizon Telescope team released the first paradigm of a black pigsty – this i at the centre of the galaxy M87. The black pigsty at the center of this milky way, named M87*, is a behemoth ii,000 times larger than Sagittarius A* and seven billion times the mass of the Sun. But considering Sagittarius A* is 2,000 times closer to Earth than M87*, the Event Horizon Telescope was able to observe both black holes at a similar resolution – giving astronomers a chance to learn about the universe by comparing the two.

The similarity of the two images is striking considering small stars and pocket-sized galaxies look and deport very differently than large stars or galaxies. Blackness holes are the merely objects in existence that only answer to ane law of nature – gravity. And gravity does not care about scale.

For the last few decades, astronomers have idea that there are massive blackness holes at the heart of near every galaxy. While M87* is an unusually huge black pigsty, Sagittarius A* is likely pretty similar to many of the hundreds of billions of black holes at the center of other galaxies in the universe.

5. What scientific questions can this answer?

There is a lot more science to exist done from the information the team collected.

1 interesting artery of inquiry stems from the fact that the gas surrounding Sagittarius A* is moving at close to the speed of light. Sagittarius A* is relatively small-scale, and matter trickles into it very slowly – if it were the size of a human, information technology would swallow the mass of a single grain of rice every 1000000 years. Just by taking many images, it would be possible to watch the flow of matter around and into the black hole in real time. This would allow astrophysicists to study how black holes consume matter and grow.

A picture is worth a grand words, and this new paradigm has already generated 10 scientific papers. I expect there will exist many more to come.

Written past Chris Impey, University Distinguished Professor of Astronomy, University of Arizona.