My Photo

Tip Jar

Share The Love

Tip Jar
Bookmark and Share

« NASA's Lunar Lunacy Looses Liftoff Capacity | Main | Comet Passing Through Pegasus Square Is Breaking Apart »



Matter can coalesce even while space expands because of the paradoxical nature of entropy in gravitational systems:

Gravity, Entropy, and Coherence --
Given quantity of gas initially concentrated in a small region, the gas will naturally tend to expand to fill a progressively larger volume of space. This is an example of how the entropy of physical systems tends to increase. It is called an irreversible process, because a concentrated region of gas will spontaneously disperse, whereas the reverse does not normally occur, i.e., a dispersed quantity of gas will not spontaneously become concentrated into a smaller region. Or will it? In the treatment of small quantities of gas the gravitational attraction of the gas molecules on each other is negligible, but for a sufficiently large quantity of gas – such as in some regions of interstellar space – there exist large enough regions of gas (of sufficient density) that a cloud of gas will naturally contract due to the mutual gravitational attraction of the molecules. Indeed this is (presumably) how stars are formed. (from

I'm no physicist, do not have a rigorous understanding of these concepts. However, I do think the physics is well described.

Elaine Meinel Supkis

Yes, isn't that so! After our sun "turned on" and began to shine, the planets were bombarded by INCOMING debris. Hugely so.

Isn't that funny?

As I keep saying, huge, gigantic black holes can't be falling into each other's gravitational spirals if they were all shooting away from each other at increasing speed, no?


Again, I'm no expert, but there is a huge difference in scale between the debris in the solar system and gigantic black holes.


Hey, kids! Let's have fun with logic!


"Chandra shows clearly that there are two huge black holes in Abell 400 and they are definitely not only falling into each other, they are spiralling into a mutual jointure. Space is not rapidly expanding and stretching, it is warping and plunging inwards, all black holes are moving in spirals into each other."

Sorry, Elaine! The move from "some black holes are sipralling into each other" to "all black holes are spiralling into each other" is logically invalid: from "all are..." you can infer that "some are...", but not the other way arouind. Thanks for playing!



"I'm no physicist, do not have a rigorous understanding of these concepts."

How would you know whether or not

"... the physics is well described."

Tune in next time for more of Logic 101 with JSmith!

The comments to this entry are closed.