Related topics: solar wind · solar system

NASA Voyager 2 could be nearing interstellar space

NASA's Voyager 2 probe, currently on a journey toward interstellar space, has detected an increase in cosmic rays that originate outside our solar system. Launched in 1977, Voyager 2 is a little less than 11 billion miles ...

The Sun's magnetic field is about to flip

( —Something big is about to happen on the sun. According to measurements from NASA-supported observatories, the sun's vast magnetic field is about to flip.

Voyager 1 hits new region at solar system edge

( -- NASA's Voyager 1 spacecraft has entered a new region between our solar system and interstellar space. Data obtained from Voyager over the last year reveal this new region to be a kind of cosmic purgatory. ...

Data from Voyager 1 point to interstellar future

( -- Data from NASA's Voyager 1 spacecraft indicate that the venerable deep-space explorer has encountered a region in space where the intensity of charged particles from beyond our solar system has markedly increased. ...

Voyager 2 illuminates boundary of interstellar space

One year ago, on Nov. 5, 2018, NASA's Voyager 2 became only the second spacecraft in history to leave the heliosphere—the protective bubble of particles and magnetic fields created by our Sun. At a distance of about 11 ...

NASA's IBEX observations pin down interstellar magnetic field

Immediately after its 2008 launch, NASA's Interstellar Boundary Explorer, or IBEX, spotted a curiosity in a thin slice of space: More particles streamed in through a long, skinny swath in the sky than anywhere else. The origin ...

Voyager 1 encounters new region in deep space, NASA says

(—NASA's Voyager 1 spacecraft has entered a new region at the far reaches of our solar system that scientists feel is the final area the spacecraft has to cross before reaching interstellar space.

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The heliosphere is a bubble in space "blown" into the interstellar medium (the hydrogen and helium gas that permeates the galaxy) by the solar wind. Although electrically neutral atoms from interstellar volume can penetrate this bubble, virtually all of the material in the heliosphere emanates from the Sun itself. It was thought for decades that it extends in a long comet-like heliotail, but in 2009 data from the Cassini and IBEX show a different shape. However, depiction of the heliotail is still common. Another change is that the heliosheath area is not smooth but filled with magnetic bubbles.NASA 2011

For the first ten billion kilometres of its radius, the solar wind travels at over a million km per hour. As it begins to drop out with the interstellar medium, it slows down before finally ceasing altogether. The point where the solar wind slows down is the termination shock; then there is the heliosheath area; then the point where the interstellar medium and solar wind pressures balance is called the heliopause; the point where the interstellar medium, traveling in the opposite direction, slows down as it collides with the heliosphere is the bow shock.

As of June 2011, the heliosheath area is thought to be filled with magnetic bubbles (each about 1 AU wide), creating a "foamy zone". The theory helps explain in situ heliosphere measurements by the two Voyager probes.

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