Ann wrote: ↑
Thu Apr 29, 2021 4:47 am
The link you gave us, Art, took us to a page showing us this infrared image of the Milky Way. There is an important source of some kind to be seen "above" the plane of the Milky Way, to the right.
There are also a few sources "below" the plane of the Milky Way, but I'm more interested in the source above it.
Does anyone know what it could be?
Ann, for all I know your "source
" above the plane of the Milky Way is nothing more than a distant galaxy.
However, there are plenty of potential dust sources "within
" the plane of the Milky Way (e.g., supernova, Bok globules
, etc.) if only there was some mechanism to exile this material to "dust heaven" and keep it there permanently
. (A normal orbiting
dust cloud would have to repetitively pass through the sticky/gaseous "fly paper
" of the Milky Way disk and get trapped.)
Since Wikipedia has so little to say on this matter I will throw out my own Cavorite "dust heaven" hypothesis
H. G. Wells 1901 _The First Men in the Moon
_ story proposed an anti-gravity material called cavorite
Now, there is a somewhat analogous "anti-gravity cavorite
" material called fine dust in the presence of bright starlight
Fine enough dust will absorb starlight and act as a solar sail under
the influence of a (analogous "anti-gravity") repulsive radial Force
- FR= [L d2 - M ρ d3]/R2 ... provided L/(Mρd) > 1
where: L= stellar Luminosity, M= stellar Mass, R= stellar Radial distance, d= dust diameter and ρ= dust density.
Zodiacal light dust particles of diameters (d) less than 10 μm are removed from the inner Solar System by solar radiation pressure.
- Hence, if d<10 μm then L☉/(M☉ρd) > 1
These dust particles continue moving away from the Sun and by the time they are ~10 light-years away
they are joined by many other dust particles of diameters (d) less than 10 μm.
In fact, the sphere of radius 10 ly around the Sun contains ~28 L☉
of luminosity (mostly from Sirius) but only ~7 M☉
of star mass.
Hence, these smaller (<10 μm) dust particles are joined by larger dust particles of diameters (d) up to ~4
This L/M ~ 4
ratio seems about right for the whole (non-dark matter) Milky Way
which has a luminosity of ~ 20 x 1010
and a (non-dark matter) mass of ~ 5 x 1010
Hence, the ~1,000 light-year wide Milky Way disk will shed dust particles of diameters (d) up ~4
until those particles feel the effects of a much wider & more massive dark matter disk
at which point they permanently rest in peace in "dust heaven" (where dark matter pull balances starlight push)
<<Much of the mass of the Milky Way seems to be dark matter, an unknown and invisible form of matter that interacts gravitationally with ordinary matter. Mathematical models of the Milky Way suggest that the mass of dark matter is 1–1.5×1012
. The total mass of all the stars in the Milky Way is estimated to be between 4.6×1010
. The mass of the Milky Way's interstellar gas is equal to between 10% and 15% of the total mass of its stars. Interstellar dust accounts for an additional 1% of the total mass of the gas. In March 2019, astronomers reported that the mass of the Milky Way galaxy is 1.5 trillion solar masses within a radius of about 129,000 light-years, over twice as much as was determined in earlier studies, and suggesting that about 90% of the mass of the galaxy is dark matter.>>