For nearly four decades, the Voyager 1 and 2 probes have been spiraling out toward the edge of the solar system. The beginning of their journey was eventful with close flybys of the outer planets, but now they are nearing interstellar space — the farthest away a man made object has ever gotten. Voyager 1 has been sending back some interesting data, and researchers now believe the probe has discovered a previously unknown region of space.
The magnetic field envelope of charged particles produced by the sun is known as the solar wind. These particles stream outward to the very limits of the outer solar system, where the solar wind changes direction as it contacts interstellar space. This is the heliosheath, and it’s where Voyager 1 is encountering some unusual readings.
Scientists expected the probe to detect a clear change between the solar winds within the magnetic field of the sun, and the interstellar cosmic rays emanating from points unknown. Over the course of last summer, charged particles dropped off as expected. However, the magnetic field has changed direction and actually strengthened. At the same time, low-energy cosmic rays have been increasing.
The researchers studying Voyager 1 are now hypothesizing that this previously unknown region of space acts like a highway for charged particles to escape the solar system. The magnetic field of the sun aligns with that of interstellar space and the solar wind slips out. This also allows more cosmic rays to barrel into the solar system, thus explaining why Voyager is seeing more of them.
The previous model of the outer solar system did not predict this feature of the heliosheath, so it’s a pretty big deal if you’re an astronomer. Voyager 2 is a few years behind Voyager 1, so scientists will have an opportunity to confirm these results.
via Ars Technica