Comments on: AAS #6: Hubble spies interstellar interlopers

By: icemith

icemith — Fri, 09 Jan 2009 18:41:11 +0000

I’m wondering if as Moss says above, (Jan. 7th, 11:28 pm)…

“Are the dust clouds energized dark matter? Highly energetic interactions with dark matter might produce such patterns. “Dust” may be a misnomer…”

Could we be seeing this effect as if somebody threw a “bucket” of flour over the scene’ a la the movie-makers’ device in stories to make the Invisible Man actually visible? Could there be a natural effect employing interacting wavelengths of certain light, differentiating densities in any matter surrounding the object being studied?

I think I am being reminded of the Kerolian (?) effect from the 70 – 80s in pop literature with the so-called halo around objects and only visible in certain conditions and needed a photograph to show it. The scammers and fraudsters probably made a few bucks from it at least. But I’m not suggesting anything scammy here, but the “patterns” produced are reminiscent.

Ivan.

By: Gary C.

Gary C. — Thu, 08 Jan 2009 18:56:58 +0000

Vortex street is what came to my mind immediately too. http://www.space.com/scienceastronomy/planetearth/vortex_street_001213.html

By: Supernova

Supernova — Thu, 08 Jan 2009 18:20:59 +0000

@Jeff Fite: Not a bad guess! Check out this wacky object, which does have a corkscrewing jet: http://www.nrao.edu/pr/2004/ss433corkscrew/

By: Charles Boyer

Charles Boyer — Thu, 08 Jan 2009 15:13:32 +0000

Put your two-cents into a new study “Rationale and Goals of the U.S. Civil Space Program” – looking for public input into US Space policy.

www7.nationalacademies.org/ssb/rationale_goals_civil_space.html

Given the discoveries of Hubble, Spitzer and other space-based observatories, it is always good to point out the benefits of these investments as this group prepares its report.

By: L Ron Hubbub

L Ron Hubbub — Thu, 08 Jan 2009 14:02:10 +0000

Oh Noes!!!1! Interstellar chemtrails!!!!eleven!!

By: Moss

Moss — Thu, 08 Jan 2009 06:28:12 +0000

Are the dust clouds energized dark matter? Highly energetic interactions with dark matter might produce such patterns. “Dust” may be a misnomer. The level of energetic absorption of this type of star as it interacts with dark matter might fall within a range of expectation that fits a dark model. If so, dark matter is revealed.

By: Lars

Lars — Thu, 08 Jan 2009 00:33:31 +0000

Cool! They’re Glider Guns, just like in the Game of Life!

By: Jeff Fite

Jeff Fite — Wed, 07 Jan 2009 23:49:43 +0000

I wonder if the upper-left ‘sperm tail’ represents a corkscrewing jet? The math is beyond me, but this thread seems to have some pretty bright posters. My first guess is that my off-axis jet model would bee too small to account for the back-and-forth appearance of this shock wave, but I thought I’d throw it and see if it sticks.

By: DaveS

DaveS — Wed, 07 Jan 2009 23:01:34 +0000

Ah, but in supersonic flow, you can estimate the local speed of sound based on the angle of the shocks and the velocity of the star. The local M=1 speed implies things about the properties of the fluid, as well. (I have a BS in AeroE, but that was a LONG time ago, and I haven’t used it much since then.)

By: AAS #6: Hubble spies interstellar interlopers | Bad Astronomy … | boathugger.com

Wed, 07 Jan 2009 22:26:47 +0000

[...] AAS #6: Hubble spies interstellar interlopers | Bad Astronomy … [...]

By: Chris A.

Chris A. — Wed, 07 Jan 2009 21:54:57 +0000

I’d be very interested to know what the radial velocities of these stars are, and see if the more distorted tails correspond to near-line-of-sight motion. In that case, a fairly subtle distortion can appear greatly exaggerated, like looking down the length of a 2 x 4 to see if it’s warped.

By: Jeramyk

Jeramyk — Wed, 07 Jan 2009 21:48:17 +0000

Assuming that v = 50km/s and the scale length is ~50e11 meters (very estimated, based on the link) I get a kinematic viscosity of about 2.5e15 m2/s or about 20 orders of magnitude higher than air at room temp.

Phil, I know that the press release says the same thing, but the boat bow wave analogy isn’t really all that great for describing shock waves. They’re two different types of waves that really only resemble each other by their appearances.

By: ndt

ndt — Wed, 07 Jan 2009 20:55:47 +0000

I think you mean “pedal to the metal”.

By: T.E.L.

T.E.L. — Wed, 07 Jan 2009 20:08:28 +0000

Let’s say that we assume it is a vK vortex. In that case, given how the star’s velocity is measurable, it would provide an independent means of determining the fluid properties of the gas itself, which could then be incorporated into astrophysical theory.

By: Jeramyk

Jeramyk — Wed, 07 Jan 2009 19:43:42 +0000

That top left one looks an awful lot a von Karman vortex street to me. Out of curiosity is there reliable data for the density and viscosity of these gas clouds? Can you even have a vK vortex street with a supersonic flow?

By: Skeptic Tim

Skeptic Tim — Wed, 07 Jan 2009 19:40:46 +0000

Re: T.E.L.
A similar thought occurred to me. I wonder at the possibility of local “currents” within the gas cloud, possibly as a result of MHD forces or something similar: the shapes of the shock waves and wakes might result from the local relative velocity of gas + stellar motion.

By: Larian LeQuella

Larian LeQuella — Wed, 07 Jan 2009 19:38:12 +0000

“That is so cool! There is a lot we still don’t know about the Universe, and we learn so much just by keeping our eyes open! That’s one of my favorite lessons of all about science.”

So beautifully said!

By: T.E.L.

T.E.L. — Wed, 07 Jan 2009 19:31:58 +0000

The one at the upper-left might be a binary; but it occurs to me that perhaps it’s passing through gas which is stratified by shearing boundaries. Maybe there are parallel lanes of oppositely-moving gas.

By: PG

PG — Wed, 07 Jan 2009 19:31:06 +0000

Very neat. I imagine that the spatial variations in the density of the gas cloud might have something to do with the resulting shapes of the shock waves?

By: Richard

Richard — Wed, 07 Jan 2009 18:56:57 +0000

Truly a case of Interstellar Overdrive.