Weekend Feature: Do We Live Inside a Bubble in the Interstellar Medium? NASA Astronomers Say "Yes"
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May 05, 2012

Weekend Feature: Do We Live Inside a Bubble in the Interstellar Medium? NASA Astronomers Say "Yes"

 

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We seem to be inside a "local bubble" in a network of cavities in the interstellar medium, probably carved by massive star explosions millions of years ago. The interstellar medium (or ISM) is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space.

The ISM plays a crucial role in astrophysics precisely because of its intermediate role between stellar and galactic scales, with stars forming within the densest regions of the ISM and molecular clouds, and replenishes the ISM with matter and energy through planetary nebulae, stellar winds, and supernovae.

This interplay between stars and the ISM helps determine the rate at which a galaxy depletes its gaseous content, and therefore its lifespan of active star formation.

NASA astronomer's best guess is depicted in the map (below) of the surrounding 1500 light years constructed from multiple observations and deductions. Currently, the Sun is passing through a Local Interstellar Cloud (LIC), shown in violet, which is flowing away from the Scorpius-Centaurus Association of young stars (image above). 

The LIC resides in a low-density hole in the interstellar medium (ISM) called the Local Bubble, shown in black. Nearby, high-density molecular clouds including the Aquila Rift surround star forming regions, each shown in orange. 

The Gum Nebula, shown above and below in green, is a region of hot ionized hydrogen gas. This complex nebula is thought to be a supernova remnant over a million years old, sprawling across the southern constellations Vela and Puppis. Inside the Gum Nebula is the Vela Supernova Remnant, shown in pink, which is expanding to create fragmented shells of material like the LIC. Future observations will aid astronomers to learn more about the local Galactic Neighborhood and how it might have affected Earth's past climate.

Over 13 billion years ago at least one of the domains of life may have begun in nebular clouds. If restricted to the Milky Way, which is 13.6 billion years old, the first chemical combinations would have had billions of years to become a self-replicating organism with a DNA genome long before the existence of Earth.

Nebular clouds are thought to be most likely environment for synthesizing and promoting the evolution of molecules needed for the origin of life. The building blocks for DNA could have been generated or combined within interstellar clouds and DNA would become part of the molecular-protein-amino acid complex. Hydrogen, oxygen, carbon, calcium, sulfur, nitrogen and phosphorus for example are continually irradiated by ions, which can generate small organic molecules which evolve into larger complex organic molecules that result in the formation of amino acids and other compounds. 
Phosphorus, for example, is rare in our solar system and may have been non-existent on the early Earth; phosphorus is essential for the manufacture of DNA.

Polarized radiation in the nebula cloud leads to the formation of proteins, nucleobases and then DNA. The combination of hydrogen, carbon, oxygen, nitrogen, cyanide and several other elements, could create adenine, which is a DNA base, whereas oxygen and phosphorus could ladder DNA base pairs. Glycine has also been identified in the interstellar clouds. 

Fast forward 4.6 billion years, on Earth the steps leading from the random mixing of chemicals to the first nano-particle would likely require hundreds of millions and even billions of years before the first self-replicating molecular compound was fashioned. Even after billions of years, the first replicon may not have possessed DNA.

 

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Originally posted on June, 2011

The Daily Galaxy via sciencemag.org and newscientist.com

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Image credit: With thanks to Greg Bradley 

Comments

Damn... So this is why I feel like I'm living in a bubble :)

1 day we are in a bubble, the next were in a cloud. If the next group looks straight up from the south pole will they see a swirly??

What?

this is so interesting

The article states, "The combination of hydrogen, carbon, oxygen, nitrogen, cyanide and several other elements...", but cyanide is, of course, not an element, but rather a compound of carbon and nitrogen. This is an odd error for a science writer.

No, your right Stephen, it's not an element, and he does not state that it is, but he does state there are several other elements in the mix, capiche?

Amazing piece.
Thanks for the new insight!

I would like to read more about ISM', LIC's, and local nebular clouds, etc...
Any r

"...Any recommended books or accessible articles?"

(to finish my sentence.)


Thank you.
-C

The building blocks for DNA could have been generated or combined within interstellar clouds and DNA would become part of the molecular-protein-amino acid complex. Hydrogen, oxygen, carbon, calcium, sulfur, nitrogen and phosphorus for example are continually irradiated by ions, which can generate small organic molecules which evolve into larger complex organic molecules that result in the formation of amino acids and other compounds.

And now, after such a huge and logical process, the resulting humans (each one unique) are living in a BUBBLE, of all situations. This only reinforces my assertion about the statistical impossibility of such a process being duplicated in the dynamic chaos of the universe(s?) So... we are unique, a truth that is most satisfactory. The latter, due to the resentful part of humanity that is disrespecting nature and intelligence by trying to impose the idea of humans being equal. No? What did Mao achieve by forcing his whole nation to dress the same way, even women? This, when comparing the huge success od China, by integrating the concept of Incentive, into this nation´s society. What about pragmatically analyzing the African American and other "Profiling" concepts, like integrating possibilities of Muslims? Guys who die happily, because 72 VIRTUAL virgins are awaiting their arrival. Then, you have guys eating puppies and unlawfully occupying.... Now, imagine an extraterrestrials, which, if existing, should be something, something, ahhh... really extraterrestrial. No profiling initiative could solve that problem...


The Temporary Local Interstellar Cloud will affect the earth for a thousand years , until the sun carries the solar system out of it in 3012.Most of the oceans will boil away in a few years,leaving an earth surrounded by a protective canopy of mist or water vapor. Those who survived those few "boiling years" will be able to each live for 800-900 years/person. The earth will be repopulated in a short time ,since nobody will die for a thousand years. The misty canopy will shield life in earth from the radiation and poisons that cause aging.


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