Astronomers have discovered why the solar system can be shaped like a croissant

The solar system is in a bubble.

Wind and radiation from the sun flow outward, pushing it into interstellar space. This creates a limit for the sun’s influence, as objects in the solar system are shielded from strong cosmic radiation.

It’s called the heliosphere, and understanding how it works is an important part of understanding our solar system, and perhaps even how we, and all life on Earth, got here.

“How is this relevant to society? The bubble that surrounds us, generated by the sun, provides protection from galactic cosmic rays, and their shape can influence how these rays enter the heliosphere.” Astrophysicist James Drake said: from the University of Maryland.

“There are many theories but, of course, the way cosmic rays enter the galaxy can be affected by the structure of the heliosphere – does it have wrinkles and folds and such?”

Since we’re inside the heliosphere, and its boundaries are actually invisible, figuring out what it looks like isn’t easy. But this is not impossible. The Voyager and New Horizons probes are the three spacecraft that have traveled deep into the solar system. In fact, the Voyager probe has crossed the boundary of the heliosphere, and is currently passing through interstellar space.

With data from these sensors, scientists decided last year that the heliosphere could be shaped like a strange cosmic croissant. Now, find out how: Neutral hydrogen molecules flowing into the Solar System from interstellar space may have played an important role in shaping the shape of the heliosphere.

The team set out to investigate the heliosphere jet. This is a dual emission of material emanating from the Sun’s poles, formed by the interaction of the Sun’s magnetic field with the interstellar magnetic field. And instead of shooting straight, it curves, propelled by the flow between the stars—like croissant dots. This is the tail of the solar system.

Reconstruction of the heliosphere showing the plane. (M.Opher/AAS)

This is similar to other astrophysical radiations observed in space, and like other radiations, solar radiation is unstable. It also seems that the heliosphere, formed by the Sun, is unstable. Researchers want to know why.

“We saw these planes being shot down in irregular columns, and [astrophysicists] I’ve been wondering for years why these forms are so unstable.” Explaining the astrophysicist Merav Over from Boston University (BU), who led the research.

The team carried out computational modeling, focusing on neutral hydrogen atoms – atoms that carry no charge. We know these flows throughout the universe, but not their effect on the heliosphere. When the researchers removed neutral atoms from their model, the sun’s rays suddenly stabilized. Then they brought him back.

“When I put it back in, things started to bend, and the center axis started to vibrate, and that means something in the heliosphere has become very unstable.” Ophir says.

According to the team’s analysis, this is due to the interaction of neutral hydrogen with ionized matter in the heliosphere – the outermost region of the heliosphere. It generates Riley and Taylor Instability, or the instability that occurs at the interface between two fluids of different densities when the lighter fluid pushes against the heavier fluid. This, in turn, results in widespread perturbation of the tail of the heliosphere.

This is a clear and elegant explanation of what the heliosphere looks like, and one that could have implications for our understanding of how galactic cosmic rays enter the solar system. In turn, this could help us better understand the solar system’s radiative environment, beyond Earth’s magnetic field and protective atmosphere.

“The universe is not calm. Our BU model doesn’t try to cut through the mess, which allows me to pinpoint the cause [of the heliosphere’s instability]…. neutral hydrogen particles Ophir says.

“This discovery was really a major breakthrough, and it really led us to find out why our model has a different heliosphere that is shaped like a croissant and why other models don’t.”

Search published in Astrophysics Journal.

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