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A study has revealed how cosmic objects are sending accelerated particles through space.
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Jets from quasars and supernovae can launch dangerous cosmic rays that strike Earth.
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For the first time, a study has shown how cosmic rays are accelerated to close to the speed of light.
A tiny black hole is helping scientists understand how mysterious cosmic rays can barrel through the universe and hit Earth at nearly the speed of light.
High-energy cosmic rays are constantly raining down on us from space, but scientists don’t know much about them. How cosmic rays can reach our planet at such speeds has long been a mystery.
For the first time, researchers looking at the black hole have observed a naturally occurring particle accelerator that is accelerating the cosmic rays that threaten our planet.
“In recent years, we could say: ‘yes, there is an acceleration of particles. How? impossible to tell. But it is’,” Laura Olivera-Nieto, author of the paper and researcher from the Max-Planck-Institut für Kernphysik in Heidelberg, said Business Insider.
“Now we’re entering an era where we can really answer where and how,” she said.
Fast cosmic rays come from black holes and exploding stars
Our planet is swimming in a sea of cosmic rays. These charged particles bounce around the universe, bringing with them a lot of energy.
If these rays to our planet were unfiltered, life on earth would not be possible. Cosmic rays travel at almost the speed of light – so fast that they can pass through our bodies like air, imparting enough energy to spin our DNA into ribbons.
Thankfully for us, our planet’s atmosphere protects us from the worst of the radiation. But it is still important for us to understand how it appears in our Universe, especially as more countries invest in making humans a multiplanetary future species.
And one of the things we don’t really understand is how they get to the speed they do.
Peering in the heart of a jet
When scientists look at cosmic rays coming from quasars and supernovae, they usually see just a big blob.
High-energy cosmic rays come from distant quasars — anything closer and they’d blow up the Milky Way, so they’re hard to see in detail. Supernovae can be closer nearby, but they emit low-energy rays, which are really faint when seen from a telescope on Earth.
But a nearby cosmic object called SS 433 has provided a rare opportunity to observe cosmic rays in unprecedented detail.
SS 433 is a microquasar, meaning it is a small black hole about ten times the mass of the Sun. It is located in the Manatee Nebula, a cloud of gas left behind by an exploding star some 18,000 light years away.
“It’s called a microquasar because it’s like a small version of these things,” Olivera-Nieto said.
That means it’s weak enough to get close but strong enough to spit out particles of higher energy than a supernova.
There’s another reason this microquasar is so “special,” Olivera-Nieto said. These objects usually have jets that last for a day or two.
“There have been jets on this one for the last 50 years, which is amazing because it’s the only one we know of that’s been stranded in a state,” she said.
When Olivera-Nieto and his colleagues looked at this object, they discovered that there was a large gap in the jets. They could see small spirals around the black hole, about 0.1 parsecs away, then nothing, and the jets reappeared about 75 light-years away.
Scientists think that the gap is where the particles are being accelerated to close the speed of light.
The location of the accelerator tells us how it works
Scientists have three theories to explain how this natural particle accelerator works.
One is that magnetic field lines around the black hole carry these particles, and they become so tense that they collapse violently, propelling the particles into space.
But in that case, the accelerator would be quite close to the black hole.
Another thing is that the black hole creates tunnels that feed the particles as they bounce off the sides. But then the particles would gradually get faster.
The observation, for the first time, favors a third hypothesis: the particles run into an invisible wall, a so-called discontinuity, which suddenly stops the particles in their path.
That change in speed causes energy to gather around the particles, giving them that speed when they break through.
The question now is: what causes that shock?
“We don’t know because it’s quite interesting because it’s happening on both sides symmetrically,” said Olivera-Nieto
“So this means that it is connected in some way to the system itself,” she said.
The result was published in the peer-reviewed journal Science.
Read the original article on Business Insider
