Science Forums 2

[Pyrotex]

Hi guys,
sorry I been away so long. Life was happening.

1st question. The Sun and Solar System are in a void called, "The Local Bubble". This is well documented by astronomers. It is a region about 15 to 25 light years across, roughly spherical, in which the density of gas and dust is much lower than the average density that occurs in most of the Milky Way Galaxy. These "bubbles" are quite common. Photos of the Andromeda Galaxy and the Magellanic Clouds show dozens of these voids, from those about the size of our "Local Bubble" to some that are 100s of light years across. They are typically created by supernovas or the stellar winds of super blue giant stars.

Given our relative velocity, it is likely that the Local Bubble was created long after the Sun was, and that the Sun wandered into the Local Bubble after the LB was formed. So, the LB almost certainly did not get created by our Sun using up all the gas and dust.

Question 2. Excellent question. What affect would a void have on planetary conditions? Could it help trigger the formation of life? Well, we're talking densities that are pretty low to start with. Maybe 100 gas molecules per cubic cm -- on average in the galaxy. In our Local Bubble, maybe 10 or 20 gas molecules /cm^3. So, I rather doubt that this had any affect on life on Earth.