Optical Detection of Anomalous Nitrogen in Comets

In message , Ron Baalke
writes

http://www.eso.org/outreach/press-re.../pr-25-03.html

ESO Press Release 25/03
12 September 2003
For immediate release

Optical Detection of Anomalous Nitrogen in Comets

VLT Opens New Window towards Our Origins


Huge snip


Macromolecules in space

The astronomers think that the new results indicate that the HCN-molecule
cannot be the only "parent" of the CN-molecule; the latter must also be
produced by some as yet unknown parent(s) in which the nitrogen-15 isotope
is even more abundant.

In this connection, it is very interesting that an "excess" of nitrogen-15
is also known to exist in interplanetary dust particles (IDPs), captured by
high-flying aircraft in the Earth's atmosphere. They represent the oldest
material in the solar system that can be subjected to detailed laboratory
analysis. Many of these particles are thought to originate from passing
comets - this possibility is obviously supported by the new measurements.

The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

I can't help feeling that Chandra Wickramasinghe is going to like that
observation.
--
"Forty millions of miles it was from us, more than forty millions of miles of
void"

Jonathan Silverlight wrote in message ...
In message , Ron Baalke
writes

http://www.eso.org/outreach/press-re.../pr-25-03.html

ESO Press Release 25/03
12 September 2003
For immediate release

Optical Detection of Anomalous Nitrogen in Comets

VLT Opens New Window towards Our Origins


Huge snip


Macromolecules in space

The astronomers think that the new results indicate that the HCN-molecule
cannot be the only "parent" of the CN-molecule; the latter must also be
produced by some as yet unknown parent(s) in which the nitrogen-15 isotope
is even more abundant.

In this connection, it is very interesting that an "excess" of nitrogen-15
is also known to exist in interplanetary dust particles (IDPs), captured by
high-flying aircraft in the Earth's atmosphere. They represent the oldest
material in the solar system that can be subjected to detailed laboratory
analysis. Many of these particles are thought to originate from passing
comets - this possibility is obviously supported by the new measurements.

The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

I can't help feeling that Chandra Wickramasinghe is going to like that
observation.


Good point. Also, life is known to be a primary cause of highly
variable isotope fractionation.


Bob Clark

The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)

On 17 Sep 2003 17:54:43 -0400, (Steve Willner)
wrote:

The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

they are well known in incomplete combustion products and heavy oil
tars.
in oil, they are thought to be the reductive breakdown products of
bigger organic molecules like porphryins and structural compounds like
lignins. in space, its probably just UV interaction with simpler
molecules

In message , Steve Willner
writes
The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

That was my point! Hoyle and Wickramasinghe claimed that the spectra
they recorded were biogenic, rather than just organic, for instance. And
the nitrogen-containing macromolecules _are_ suggestive of "interesting"
molecules.
But thinking about hexagonal tiles reminds me of something scary.
Remember the structure of the Andromeda Strain? ;-)
--
"Forty millions of miles it was from us, more than forty millions of miles of
void"

On Thu, 18 Sep 2003 23:53:38 +0100, Jonathan Silverlight
wrote:

In message , Steve Willner
writes
The nitrogen-15 carriers in IDPs have not been securely identified but are
possibly organic macromolecules or polycyclic aromatic hydrocarbons (PAHs).
It is thus possible that the additional parent(s) of cometary CN may belong
to this ensemble of organic substances.

In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

That was my point! Hoyle and Wickramasinghe claimed that the spectra
they recorded were biogenic, rather than just organic, for instance. And
the nitrogen-containing macromolecules _are_ suggestive of "interesting"
molecules.

well, they're interesting to the organic chemist, if nothing else from
the perspective of how they formed. since organic chemists are known
as pot boilers, how you can get complex organic compounds in a vacuum
under all kinds of radiation is even more interesting...

But thinking about hexagonal tiles reminds me of something scary.
Remember the structure of the Andromeda Strain? ;-)

hehe. it sure made for a good story. i saw it as a kid and was
pretty creeped out. i look at it now and just chuckle....

i forget the ep, but McCoy says to Kirk: dammit, i'm a surgeon, not a
bricklayer!

beavith wrote:

i forget the ep, but McCoy says to Kirk: dammit, i'm a surgeon, not a
bricklayer!

Wasn't it in the episode about the Hortha (sp?), silicon-based
creatures who fought back after being disturbed by mining colonists?

--
Odysseus

On Sat, 20 Sep 2003 09:41:54 GMT, Odysseus
wrote:

beavith wrote:

i forget the ep, but McCoy says to Kirk: dammit, i'm a surgeon, not a
bricklayer!

Wasn't it in the episode about the Hortha (sp?), silicon-based
creatures who fought back after being disturbed by mining colonists?

that's the one!

In article ,
Jonathan Silverlight writes:
In article ,
Jonathan Silverlight writes:
I can't help feeling that Chandra Wickramasinghe is going to like that
observation.

I don't see why. PAH's are widely accepted as dust constituents
these days, and there is no indication they are biological. Quite
the contrary, I should think. Their structure is multiple "benzene
rings." (Visualize those small hexagonal bathroom tiles.) Are such
structures known in biology?

That was my point! Hoyle and Wickramasinghe claimed that the spectra
they recorded were biogenic, rather than just organic, for instance. And
the nitrogen-containing macromolecules _are_ suggestive of "interesting"
molecules.

I'm aware of H&W's notions, but I don't understand why you think the
PAH's might be biogenic. The PAH's we know on Earth are not, as
another poster pointed out.

--
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
(Please email your reply if you want to be sure I see it; include a
valid Reply-To address to receive an acknowledgement. Commercial
email may be sent to your ISP.)