Scientists…suggest that the ribbon of enhanced emissions of energetic neutral atoms, discovered last year by the NASA Small Explorer satellite IBEX, could be explained by a geometric effect coming up because of the approach of the Sun to the boundary between the Local Cloud of interstellar gas and another cloud of a very hot gas called the Local Bubble. If this hypothesis is correct, IBEX is catching matter from a hot neighboring interstellar cloud, which the Sun might enter in a hundred years.
First full-sky maps of the emissions of energetic neutral atoms (ENA), obtained last year by IBEX, showed a surprising arc-like feature called the Ribbon. This astonishing discovery was later announced by NASA as one of the most important findings in space exploration made in 2009….In a paper recently published in the Astrophysical Journal Letters, a Polish-US team of scientists…offers a different explanation. “We observe the Ribbon,” says Professor Stan Grzedzielski “because the Sun is approaching a boundary between our Local Cloud of interstellar gas and another cloud of a very hot and turbulent gas…”
The team of Polish and US scientists suggests that the Ribbon ENA are born by electrical charge exchange between the atoms which “evaporate” from the Local Interstellar Cloud into the nearby Local Bubble of a very hot and fully ionized gas. The Local Bubble is probably a remnant of a series of supernova explosions that occurred a few million years ago and thus is not only very hot (at least million degree Kelvin), but also turbulent. The protons in the Local Bubble nearby to the boundary with the Local Cloud snatch electrons from the neutral atoms and run away in all directions, some of them reaching IBEX…
The model developed by the Polish-US team suggests that the boundary between the Local Cloud and the Local Bubble might be not within a few light years from the Sun, as it was believed earlier, but within just a thousand of astronomical units, a thousand-fold closer. This might mean that the Solar System could enter the million-degree Local Bubble cloud as early as the next century.
“Nothing unusual, the Sun frequently traverses various clouds of interstellar gas during its galactic journey,” comments Grzedzielski. Such clouds are of very low density, much lower than the best vacuum obtained in Earth labs. Once in, the heliosphere will reform and may shrink a little, the level of cosmic radiation entering the magnetosphere may rise a bit, but nothing more. “Perhaps future generations will have to learn how to better harden their space hardware against stronger radiation,” suggests Grzedzielski.
Phew! Had me worried for a minute.
Although it might be fun to forward this to some of the Armageddon types. Revelations and all that.