A cosmic sackful of black coal

October 14, 2015, ESO
This image from the Wide Field Imager on the MPG/ESO 2.2-meter telescope shows part of the huge cloud of dust and gas known as the Coalsack Nebula. The dust in this nebula absorbs and scatters the light from background stars. Credit: ESO

Dark smudges almost block out a rich star field in this new image captured by the MPG/ESO 2.2-meter telescope at ESO's La Silla Observatory in Chile. The inky areas are small parts of a huge dark nebula known as the Coalsack, one of the most prominent objects of its kind visible to the unaided eye. Millions of years from now, chunks of the Coalsack will ignite with the glow of many young stars.

The Coalsack Nebula is located about 600 light-years away in the constellation of Crux. This huge, dusky object forms a conspicuous silhouette against the bright, starry band of the Milky Way and for this reason the nebula has been known to people in the southern hemisphere for as long as our species has existed.

The Spanish explorer Vicente Yáñez Pinzón first reported theexistence of the Coalsack Nebula to Europe in 1499. The Coalsack later garnered the nickname of the Black Magellanic Cloud, a play on its dark appearance compared to the bright glow of the two Magellanic Clouds, which are in fact satellite galaxies of the Milky Way. These two bright galaxies are clearly visible in the southern sky and came to the attention of Europeans during Ferdinand Magellan's explorations in the 16th century. However, the Coalsack is not a galaxy. Like other dark nebulae, it is actually an interstellar cloud of dust so thick that it prevents most of the background starlight from reaching observers.

A significant number of the dust particles in dark nebulae have coats of frozen water, nitrogen, carbon monoxide and other simple organic molecules. The resulting grains largely prevent visible light from passing through the cosmic cloud. To get a sense of how truly dark the Coalsack is, back in 1970, the Finnish astronomer Kalevi Mattila published a study estimating that the Coalsack has only about 10 percent of the brightness of the encompassing Milky Way. A little bit of background starlight, however, still manages to get through the Coalsack, as is evident in the new ESO image and in other observations made by modern telescopes.

The little light that does make it through the nebula does not come out the other side unchanged. The light we see in this image looks redder than it ordinarily would. This is because the dust in absorbs and scatters blue light from stars more than red light, tinting the stars several shades more crimson than they would otherwise be.

Millions of years in the future the Coalsack's dark days will come to an end. Thick interstellar clouds like the Coalsack contain lots of dust and gas—the fuel for new stars. As the stray material in the Coalsack coalesces under the mutual attraction of gravity, stars will eventually up, and the coal "nuggets" in the Coalsack will "combust", almost as if touched by a flame.

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katesisco
1 / 5 (3) Oct 14, 2015
I have considered that the LMC
katesisco
1 / 5 (3) Oct 14, 2015
I have considered that the LMC and the GMC are the results of a bh collapse. The Coalsack would then be the expelled compressed material given mass. I suggest that our part of the galaxy shows significant Methuselah stars. I suggest that the LMC has inexplicably large stars. I suggest that the collapse was due to an overwhelming magnetic field that warped space time and resulted in material being shifted thru space.
Returners
1 / 5 (5) Oct 14, 2015
This made me wonder how many generations of stars their might be in the future of the universe...how long the Universe might be able to support life.

It occurred to me that dying ~1solar mass stars must one day cool so much that their surface temperature falls below the boiling point of water. They will contain hydrogen, oxygen, nitrogen, Carbon, sulphur, phosphorous, and all the other elements needed for life as we know it, and they will be the right temperature on their surface.

During these eons, The surface layers of the Star will become the new "Goldilocks Zone", and even as the Star cools much more, so that the surface perhaps falls below the freezing point of water, the interior would stay above that temperature for perhaps billions or even trillions of years, although the density and pressure inside may prevent most chemistry as we know it even at "normal" temperatures, but it would depend on the mass of the star and how deep inside you are looking.

Returners
1 / 5 (5) Oct 14, 2015
The calculated lifetime of Red Dwarf stars is believed to be trillions of years, during which they will continue to cool gradually. they may therefore be able to have "goldilocks zone" temperatures on their surface for many billions or trillions of years.

The biomass which might be capable of existing on the surface of an extinct star at just the right temperature and composition could make the entire earth biosphere look like nothing in comparison.

This concept was portrayed in the "Star Fox 64" video game, however, as portrayed in the gaem it was unrealistic, because that was on an active star, not an extinct star.

Such a biosphere may be further facilitated by the birth a new, nearby "nth generation" star to further sustain temperature, perhaps from a different gravitational collapse of nebulae and gravity capture, etc.

So it would seem that the universe may be capable of supporting life for several trillion years in at least some locations...
Returners
1 / 5 (5) Oct 14, 2015
Surely, as the star cools and contracts, there would be some "sweet spot" where reactions such as oxygen and hydrogen to re-form water could happen, and where oceans and atmospheres comparable to planets' oceans and atmospheres could form. There are enough trace metals for making the various amino acids and proteins and other structures that life as we know it beyond just the six major life elements (CHONPS).

Has anyone in Exobiology (besides Nintendo with Star Fox) seriously proposed this scenario before?

Dyson Sphere concept? Well that's fine and dandy and stuff, but when the star cools enough, the Dyson Sphere would no longer be able to collect enough energy and mass to sustain a type 2 civilization...but the surface of the star itself would still be warm enough and energetic enough to support "something" which might be capable of living...not necessarily the original intelligent species, but perhaps something "They" seeded from microbial life.
Returners
1 / 5 (5) Oct 14, 2015
I should think that for this scenario you might want a star with much lower mass than the Sun.

1, Burns it's fusion fuel slower, so temperatures are stable for eons, Red Dwarf or even Brown Dwarf.
2, Lower total gravity. Still uninhabitable (directly) to humans, but some form of microbe might be able to survive in 100g environments...and might be able to evolve into something macroscopic eventually which might be viable...even intelligent.
3, a Less massive star is less likely to have head-on collisions with other objects due to lower gravity and cross-sectional area.
4, Less radiation pressure may allow objects beyond it's "snow line" to migrate back inward, delivering water and methane back to the surface of the star or it's immediate surroundings.
Returners
1 / 5 (6) Oct 14, 2015
One day, if humans ever invent relativistic rocket travel, we might one day be the "Master Race" and be able to seed such dying stars' surfaces with microbial life...like the Xel'Naga from Starcraft, or the "Preservers" from Star Trek, only what we would be capable of doing is creating a biosphere descended from our own biosphere, but on the surface of an object capable fo supporting that life for virtually the remainder of the future of the universe.

"in the image and likeness of God."

If we are created in the likeness of God, and God created life, then perhaps we are intended to do the same: create life on all these worlds...
Jeffhans1
not rated yet Oct 14, 2015
Imagine what kind of resolution you could achieve if the entire coal sack was a giant distributed sensor array. Soaking up every stray photon that falls onto it and sending its data through quantum networks to be digested and for pictures to emerge.
Returners
1 / 5 (5) Oct 14, 2015
Imagine what kind of resolution you could achieve if the entire coal sack was a giant distributed sensor array. Soaking up every stray photon that falls onto it and sending its data through quantum networks to be digested and for pictures to emerge.


You are too slow,my friend.

It has been several years since I proposed a future civilization capable of developing galactic scale sensor networks and sharing the data between the various sub-cultures in each star system. Developing resolution and 3-D modelling of the distant universe in a way we can scarcely conceive at the moment.

At 0.1C it would take about a million years to colonize the entire galaxy, and then a few thousand years per planet for populations to grow large enough to support fully functioning industrial economies (maybe less with self-replicating robots)...then you build networks of cmmunication between all colonies, sharing all data and discoveries.

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