Starship Asterisk*

VictorBorun wrote: ↑Sat Mar 11, 2023 10:54 pm offtopic on field lines made visible

Chris Peterson wrote: ↑Wed Mar 08, 2023 1:44 am

VictorBorun wrote: ↑Wed Mar 08, 2023 1:38 am gravity field lines must be there, they just do not make a particle to attract to its neighbour in the same line and repulse from its neighbour at another line — like a magnetic field line does, to iron dust particles.

Field lines form closed paths. That is not possible with gravity.

1) not imortant for precipitation and visibility whether the field lines eventually somewhere far off the picture go converge at a mass, electric charge, fantastic magnetic monopole or whatever; as long as in the observed region they tend to repulse from each other while trying to contract. Magnetic lines are the greatest at it: when they align little magnets in the media, they do precipitate to distinct parallel lanes
2) visualisation by iron dust is of the scale of a laboratory table. Visualisation by Sun's chromospheric protuberances is 1 light second long at the longest and so far we have not really seen how two distinct coils were pressed together so hard that the repulsion got overpowered and the two merge with a mighty flash — I mean the flash we can see, but the two coils remain just our best guess so far.

I wonder if magnetic lines can precipitate to dusty lanes in galactic arms

Chris Peterson wrote: ↑Wed Mar 08, 2023 1:44 am

VictorBorun wrote: ↑Wed Mar 08, 2023 1:38 am gravity field lines must be there, they just do not make a particle to attract to its neighbour in the same line and repulse from its neighbour at another line — like a magnetic field line does, to iron dust particles.

Field lines form closed paths. That is not possible with gravity.

Ann wrote: ↑Wed Mar 08, 2023 5:22 am The only problem with Gaia images is that all stars are represented by a tiny dot of a fixed size. This means that, according to Gaia, Alpha, Beta and Proxima Centauri are all represented by a dot of the same size:

AVAO wrote: ↑Tue Mar 07, 2023 9:15 pm

Spif wrote: ↑Tue Mar 07, 2023 5:52 pm What really struck me about this image is how MANY foreground stars there are. Even the dim dots are solar systems (though some of those could be noise). Just about every other pixel is a system, it seems.

Great work!

"The Large and Small Magellanic Clouds are satellite galaxies of the Milky Way Galaxy. The parallax data in the Gaia EDR3 dataset allows the foreground stars to be removed for clarity. Color saturation has ben enhanced 8x to show relative temperature differences between the stars using a white balance temperature of 4550K. This image was rendered by bsrender (https://github.com/kevinloch/bsrender) using the star records from the Gaia EDR3 dataset (https://www.cosmos.esa.int/web/gaia/earlydr3). The original 16k rendering has been scaled down to 8k."

LMC and SMC rendered from Gaia EDR3 data with foreground stars removed:

in biggg: https://upload.wikimedia.org/wikipedia/ ... -s1-s8.png
https://en.wikipedia.org/wiki/Magellani ... -s1-s8.png

VictorBorun wrote: ↑Wed Mar 08, 2023 1:38 am

Chris Peterson wrote: ↑Tue Mar 07, 2023 1:31 pm

madtom1999 wrote: ↑Tue Mar 07, 2023 8:48 am When you drop iron filings onto a bit of paper over a magnet they tend to clump into 'rays'. It seems reasonable to assume gravity will have a similar effect and tend to turn putative disks into arms. I'm betting this happens at solar system levels too and this would mean planets could easily form before the star ignites and thus not require mind-boggling interventions of planets changing orbits and water thats been blasted away by the solar wind magically returning.

Iron filings line up the way they do because of the polar nature of magnetic fields. Field lines form between poles. The same thing happens with electric fields. Gravity is not bipolar, so its behavior is very different. There are no field lines as such. Arms in spiral galaxies form because of interactions between moving masses.

There is nothing we know of to suggest a mechanism for planets to form except in accretion discs around large concentrations of mass. Concentrations of solar or larger mass.

Why, gravity field lines must be there, they just do not make a particle to attract to its neighbour in the same line and repulse from its neighbour at another line — like a magnetic field line does, to iron dust particles.

Chris Peterson wrote: ↑Tue Mar 07, 2023 1:31 pm

madtom1999 wrote: ↑Tue Mar 07, 2023 8:48 am When you drop iron filings onto a bit of paper over a magnet they tend to clump into 'rays'. It seems reasonable to assume gravity will have a similar effect and tend to turn putative disks into arms. I'm betting this happens at solar system levels too and this would mean planets could easily form before the star ignites and thus not require mind-boggling interventions of planets changing orbits and water thats been blasted away by the solar wind magically returning.

Iron filings line up the way they do because of the polar nature of magnetic fields. Field lines form between poles. The same thing happens with electric fields. Gravity is not bipolar, so its behavior is very different. There are no field lines as such. Arms in spiral galaxies form because of interactions between moving masses.

There is nothing we know of to suggest a mechanism for planets to form except in accretion discs around large concentrations of mass. Concentrations of solar or larger mass.

Spif wrote: ↑Tue Mar 07, 2023 5:52 pm What really struck me about this image is how MANY foreground stars there are. Even the dim dots are solar systems (though some of those could be noise). Just about every other pixel is a system, it seems.

madtom1999 wrote: ↑Tue Mar 07, 2023 8:48 am When you drop iron filings onto a bit of paper over a magnet they tend to clump into 'rays'. It seems reasonable to assume gravity will have a similar effect and tend to turn putative disks into arms. I'm betting this happens at solar system levels too and this would mean planets could easily form before the star ignites and thus not require mind-boggling interventions of planets changing orbits and water thats been blasted away by the solar wind magically returning.

bystander wrote: ↑Tue Mar 07, 2023 9:32 am

APOD Robot wrote: ↑Tue Mar 07, 2023 5:08 am
Explanation: Is this a spiral galaxy? No. ... The LMC is classified as a dwarf irregular galaxy because of its normally chaotic appearance. In this deep and wide exposure, however, the full extent of the LMC becomes visible. Surprisingly, during longer exposures, the LMC begins to resemble a barred spiral galaxy. ...

Wikipedia: LMC wrote:
The Large Magellanic Cloud (LMC) ... is classified as a Magellanic spiral. It contains a stellar bar that is geometrically off center, suggesting that it was a barred dwarf spiral galaxy before its spiral arms were disrupted, likely by tidal interactions from the Small Magellanic Cloud (SMC) and the Milky Way's gravity. ...

APOD Robot wrote: ↑Tue Mar 07, 2023 5:08 am
Explanation: Is this a spiral galaxy? No. ... The LMC is classified as a dwarf irregular galaxy because of its normally chaotic appearance. In this deep and wide exposure, however, the full extent of the LMC becomes visible. Surprisingly, during longer exposures, the LMC begins to resemble a barred spiral galaxy. ...

Wikipedia: LMC wrote:
The Large Magellanic Cloud (LMC) ... is classified as a Magellanic spiral. It contains a stellar bar that is geometrically off center, suggesting that it was a barred dwarf spiral galaxy before its spiral arms were disrupted, likely by tidal interactions from the Small Magellanic Cloud (SMC) and the Milky Way's gravity. ...