Seen in space: Supermassive black hole swallows star, ejects 'jet' of matter
This image provided by NASA shows particle jets erupting from a supermassive black hole. (AP/NASA)
Emily Chan, CTVNews.ca
Published Thursday, November 26, 2015 2:01PM EST
Last Updated Thursday, November 26, 2015 2:03PM EST
A team of scientists has witnessed a supermassive black hole swallowing a star and spitting out a "jet" of matter.
Researchers reported the findings in the journal Science on Thursday.
"Seeing this jet and these events was something that was never seen before," Sjoert van Velzen, the Johns Hopkins University scientist who led the research team, said in a phone interview with CTVNews.ca. "(Before) people were starting to give up hope and think 'maybe these jets are not there.' "
A black hole is so dense that its gravitational force attracts matter, gas, and even light, creating "the effect of a void in the fabric of space," a Johns Hopkins University statement says.
According to van Velzen, this void pulls in matter in the same way the moon tugs at ocean tides on the Earth.
"The oceans are always being pulled toward the moon," he said. "Similarly, the same tidal force is at work when a black hole and star are close together … but in this case, the black hole is so big that it really pulls the star apart."
As the star is pulled apart, it breaks up into what van Velzen describes as "spaghetti streams" of gas.
The streams orbit the black hole and interact with each other, releasing light, he said.
When this light sinks into the black hole, van Velzen said some matter shoots back out, forming a "laser"-like jet.
Supermassive black holes, the largest type of black holes, are believed to exist at the centre of most massive galaxies, including the Milky Way Galaxy that Earth calls home.
Despite this, it's rare for a black hole to be close enough that its gravity pulls a star off course and into the void, van Velzen said.
In fact, it's so unlikely to happen that, just months before he witnessed the phenomenon for himself, van Velzen predicted it would take years for scientists to find and watch a supermassive black hole emitting a jet.
"Even though a black hole is a big thing, a supermassive black hole is still very small compared to the whole galaxy. You basically need to have a very, very unlucky star."
That's why he figured it would be "at least four years" before researchers would witness a black hole suck in a star and emit a jet. But it didn't take that long for his prediction to be proven wrong.
"It shows how fast this field is moving," he said. "We're really excited about this."
It was a tweet by a research team at Ohio State University that ultimately guided van Velzen and his team to the black hole.
In December, 2014, mere months after Velzen defended his dissertation, the Ohio State scientists spotted a black hole in a galaxy approximately 300 million light years from Earth.
The black hole, which was about a million times the mass of the sun, appeared to be destroying a star about the same size as the sun.
When Van Velzen read about this discovery online, he teamed up with scientists at the University of Oxford to set up a radio telescope and tune into the astronomical event.
They tracked the star's destruction, and watched as the black hole sent out a jet of matter, travelling at about the speed of light.
Now, scientists are on the hunt, hoping to catch another black hole in action.
They're also continuing to monitor the supermassive black hole and jet van Velzen's team reported on. According to him, that jet could remain visible for "many" more months.
"It's sort of like a train that's going through a snowstorm," Van Velzen said. "If you keep going, you accumulate snow … This jet can keep going at the speed of light for probably half a year."
Through further observation, van Velzen said researchers hope to better understand how black holes work, and how they influence the galaxy around them.
And while there's still much left to learn about the "beautifully complicated" way black holes destroy stars, he said scientists are sure of at least one thing:
"We can be sure that our own sun is safe," he said. "We won't fall into our own black hole any time soon."