Do We Live in a Giant Cosmic Bubble?

[Pyrotex]

If the notion of dark energy sounds improbable, get ready for an even more outlandish suggestion.

Earth may be trapped in an abnormal bubble of space-time that is particularly void of matter. Scientists say this condition could account for the apparent acceleration of the universe's expansion, for which dark energy currently is the leading explanation.

Dark energy is the name given to the hypothetical force that could be drawing all the stuff in the universe outward at an ever-increasing rate. Current thinking is that 74 percent of the universe could be made up of this exotic dark energy, with another 21 percent being dark matter, and normal matter comprising the remaining 5 percent.

Until now, there has been no good way to choose between dark energy or the void explanation, but a new study outlines a potential test of the bubble scenario.

More here...

[Turtle]

Not sure if this is the same bubble or not, but the article popped this old post in(to) my caranium.

galactic plane

Originally Posted by americanscientist

...The sun is on the edge of what is sometimes called the Local Bubble, a great void in the distribution of interstellar gas in the nearby galactic neighborhood.

[Pyrotex]

Turtle, me lad!
Excellent association you've made here.
The "local bubble" has been in the literature for at least a decade, maybe two. This refers to the relative lack of gas and dust in our vicinity, has been accurately measured, and is generally blamed on either a supernova, or a cluster of hot blue stars having "cleared out" the area many millions of years ago. It's diameter extends a few tens of lightyears at most. It appears that the Sun accidently wandered into this "void" some time after it was formed.

I don't think the "cosmic bubble" is the same thing. To be effective at changing the ... let's say, "index of refraction" ... of a large enough volume around us, the relative paucity of matter would have to extend --- I'm just guessing here --- out past the nearest galaxies. Say, around 10,000,000 light years.

[RCP/CRT/RRT]

An article in Scientific American (April 09) posses a very similar, if not identical, concept/idea,different authors though.

"Does Dark Energy Really Exist?"

Citation:
"Scenario 1: In the usual interpretation of supernova observations, the rate of cosmic expansion used to be slower than it is now. Consequently, the universe has taken longer to grow to it's present size and supernova light has had more time to spread out, so that it appears dimmer to us. To drive this acceleration requires dark energy"

"Scenario 2: Alternatively, perhaps expansion is decelerating but at different rates in different places. If our neighborhood is emptier than other areas, it has less matter to retard the expansion and decelerates less quickly.
As light from a supernova spreads out, it enters zones of increasingly rapid expansion - which has the same effect as cosmic acceleration but without any need for dark energy."

The above citations are missing the graphics they provided.

[DaddyUnit]

My friend Jerry has a theory (Comedy-Recycling Theory of the Entire Known Universe) that puts our entire universe inside a giant black hole. Bit of a difference in scale and concept than what I hear you saying. Could it be that our solar system has "used up" all the gasses in our 'neighborhood' in its own composition (and that's why it seems like we're in a bubble)?

[lemit]

Could a bubble like ours be one of the things that makes life possible?

--lemit

[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.