Outer Limits
The solar wind "blows a bubble" in the interstellar medium (the rarefied hydrogen and helium gas that permeates the galaxy). The point where the solar wind's strength is no longer great enough to push back the interstellar medium is known as the heliopause, and is often considered to be the outer "border" of the Solar System. The distance to the heliopause is not precisely known, and probably varies widely depending on the current velocity of the solar wind and the local density of the interstellar medium, but it is known to lie far outside the orbit of Pluto. Scientists hope to gain more perspective on the heliopause from data acquired through the Interstellar Boundary Explorer (IBEX) mission, launched in October 2008.
Read more about this topic: Solar Wind
Famous quotes containing the words outer limits, outer and/or limits:
“No one knows better than children how much they need the authority that protects, that sets the outer limits of behavior with known and prescribed consequences. As one little boy expressed it to his mother, “You care what I do.””
—Leontine Young (20th century)
“Take away an accident of pigmentation of a thin layer of our outer skin and there is no difference between me and anyone else. All we want is for that trivial difference to make no difference.”
—Shirley Chisholm (b. 1924)
“As nature requires whirlwinds and cyclones to release its excessive force in a violent revolt against its own existence, so the spirit requires a demonic human being from time to time whose excessive strength rebels against the community of thought and the monotony of morality ... only by looking at those beyond its limits does humanity come to know its own utmost limits.”
—Stefan Zweig (18811942)