It may look like something you’d see on a continental breakfast table.

This artist, who is depicted as a croissant-shaped mantle, is actually what scientists think our solar system looks like. And now they could have an answer.

A new study has suggested that hydrogen particles from outside might be playing an important role in shaping the shape of the bubble around the sun and planets.

The heliosphere (or the bubble) acts as a shield for objects in the solar systems from the powerful cosmic radiation emitted by supernovas.

Scientists warn that without it, there would be an increase in risk for life on Earth as well as astronauts living in space. 

From the outside looking in: This croissant-shaped artist's interpretation is actually how scientists believe our solar system is shaped, and now they may have the answer as to why

The outside is looking in. This artist who resembles a croissant may be able to explain how scientists think our solar system was formed.

Twin jets of material – known as heliospheric jets – emanate from the sun's poles but, rather than shooting straight out, they curve round to form the solar system's tails and look like the points of a croissant (pictured)

Twin jets of material – known as heliospheric jets – emanate from the sun’s poles but, rather than shooting straight out, they curve round to form the solar system’s tails and look like the points of a croissant (pictured)


Solar wind is a continuous flow of solar material that the sun emits to the earth. This bubble surrounds the planets and creates the heliosphere.

The shield of the heliosphere protects planets against interstellar radiation.

Voyager 2 of NASA’s spacecraft was seen passing the outer edge in November 2018.

The heliopause is the boundary where the hot, dense solar wind meets interstellar material.

Wind and radiation from sun create the heliosphere, which flows outwards into interstellar spaces. 

Twin jets of material – known as heliospheric jets – emanate from the sun’s poles but, rather than shooting straight out, they curve round to form the solar system’s tails and look like the points of a croissant.

Boston University’s study now reveals the reasons why the heliosphere forms into pastry-like shapes. This is due to interstellar hydrogen particles.  

Because they are equal in positive and neg charge and therefore have no charge whatsoever, the particles cause the heliospheric aircraft to become unstable and bend inwards.

“How does this relate to society?” James Drake of University of Maryland said the bubble, which is produced by the Sun, provides protection from cosmic rays. It can also influence how the radiation enters the heliosphere.

‘There’s lots of theories but, of course, the way that galactic cosmic rays can get in can be impacted by the structure of the heliosphere — does it have wrinkles and folds and that sort of thing?’ 

The heliosphere acts to shelter objects in the solar system from powerful cosmic radiation emanating from supernovas, the final explosions of dying stars across the universe

The heliosphere shields solar system objects from the powerful cosmic radiation emitted by supernovas (the final blasts of star-dead stars)

Now a study led by Boston University has found the reason why this heliosphere is shaped into a pastry-like form, and it's all to do with neutral hydrogen particles from interstellar space

Boston University’s study now reveals the reasons why this heliosphere forms into a puffy-like shape. This is due to interstellar hydrogen particles.

Drake was part the team that conducted a Boston University study on astrophysicists led by Merav Opher. 

This boundary of solar influence cannot be seen because we are in the heliosphere. It is therefore difficult to see.

Scientists initially thought the shape was like a comet with a long tail at its back and an edge that turned round.

But data from three spacecraft that have travelled to the far reaches of the solar system – two Voyager probes and New Horizons – found that it is more like a croissant.

It is a question Opher wanted to find out why it was shaped in this way, and how unstable heliospheric Jets are.  

‘Why do stars and black holes – and our own sun – eject unstable jets?’ Opher said. 

“We perceive these jets as projecting irregular columns. [astrophysicists]I have wondered for many years about the causes of these instabilities.

Using a computer model, researchers found that when the neutral hydrogen particles were taken out of the simulation, the jets coming from the sun became 'super stable'

Researchers used a computer simulation to find that the solar jets became “super stable” after the neutron hydrogen particles were removed from the model.

But when they were put back, 'things start bending, the centre axis starts wiggling, and that means that something inside the heliospheric jets is becoming very unstable,' researchers said

Researchers found that when the jets were returned, they began to bend and the centre axis started wiggling. This indicates that something is very unstable within the heliospheric planes.

The researchers used computer modeling to show that jets from the sun become’super-stable’ after the neutral hydrogen particles are removed.

Opher stated that when the jets were returned, ‘things begin bending and the centre axis begins wiggling. This means that something within the heliospheric planes is becoming very instabile.

The researchers said this happens because of the interaction of the neutral hydrogen particles with the ionized matter in the heliosheath — the outer region of the heliosphere. 

Rayleigh-Taylor instability is a result of the interaction between fluids with different densities. The lighter fluid presses against the heavier fluid. 

This creates large-scale turbulent in the tails the heliosphere.

“The universe isn’t quiet.” I have been able to identify the root cause of chaos using our BU model. [of the heliosphere’s instability]…. Opher stated that the neutral hydrogen particles are “the neutron particles”.

“This discovery is really a major breakthrough. It’s set us on a path to discover why our model has its distinctive croissant-shaped Heliosphere, and why others don’t.”

The Astrophysical Journal published the study.


Voyager 1 travels northward through outer space at 14 billion miles per hour.

NASA has received data back from the probe after it entered interstellar space. The information shows that cosmic rays can be four-fold more common in interstellar than near Earth.

The heliosphere is the area of space that holds the planets in our solar system. This could be a shield against radiation.

Voyager 2 continues to travel southward towards interstellar space, at 11.77 Billion miles away from Earth.

Because of their different locations, scientists can now compare two areas of space in which the heliosphere and interstellar medium interact.

Voyager 2’s crossing of the interstellar Medium allows scientists to test the medium simultaneously from two separate locations.