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(meteorobs) Excerpts from "CCNet DIGEST, 30 March 1999"




------- Forwarded Message

From: Benny J Peiser <b.j.peiser@livjm.acdot uk>
To: cambridge-conference@livjm.acdot uk
Subject: CCNet DIGEST 30/03/99
Date: Tue, 30 Mar 1999 10:09:46 -0500 (EST)

CCNet DIGEST, 30 March 1999
---------------------------

There will be no further CCNet mailings before 10 April.


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...

(2) NANOBES AND METEOROIDS
    Michael Paine <mpaine@tpgi.com.au> 

(3) CRATER COUNTS ON MARS
    W.K. Hartmann et al., PLANETARY SCIENCE INSTITUTE

(4) COMPOSITIONAL CHANGES BY MULTIPLE IMPACTS
    Y. Miura et al., YAMAGUCHI UNIVERSITY
...

===============

(2) NANOBES AND METEOROIDS

>From Michael Paine <mpaine@tpgi.com.au> 

Dear Benny,
 
Follow-up on to the CCNET posting on 23/3/99 "SCIENTISTS DISCOVER NEW
LIFE FORMS". Below is an extract from my "Swapping Rocks" web page
http://www1.tpgi.com.au/users/tps-seti/swaprock.html
 
On 20 March the Australian ABC Radio Science Show had a report on
Queensland research into nanobacteria (nanobes) - see
http://www.uqdot edu.au/nanoworld/uwins.html#nano-organisms (particularly
the PDF download)). The findings have implications for:
 
* Interplanetary transfer of organisms via meteoroids - the Nanobes
apparently survived the vacuum and intense radiation of the electron
microscope (c.f. space travel) after being taken from the hot,
pressurised environment 5 km below the seabed (c.f. planetary ejection
due to a cosmic impact and subsequent re-entry) and
 
* "Nanofossils" in Martian meteorite ALH84001. Until now it was thought
by many scientists that "organisms" around 20 nanometres - the size of
the nanofossils - were too small for "life"!
 
Links
 
Press release</A> from Queensland University
http://www2.uqdot edu.au/newsreleases/view.asp?method=byCategory&freeText=&year=&c_
id=&n_id=1271
 
BBC item 
http://news.bbc.codot uk/hi/english/sci/tech/newsid_300000/300949.stm
 
ABC TV Quantum "Deep Bacteria"
http://www.abcdot net.au/quantum/scripts99/9903/rundown.htm
featuring an interview with Paul Davies. Paul's comment on
the Queensland University discovery, if verified - "Mommentous"
 
New Scientist editorial
http://www.newscientist.com/ns/19990327/editorial.html#2
 
Regards
Michael Paine

==================
(3) CRATER COUNTS ON MARS

W.K. Hartmann*), M. Malin, A. McEwen, M. Carr, L. Soderblom, P. Thomas, 
E. Danielson, P. James, J. Veverka: Evidence for recent volcanism on 
Mars from crater counts. NATURE, 1999, Vol.397, No.6720, pp.586-589

*) PLANETARY SCIENCE INSTITUTE,TUCSON,AZ,85705

Impact craters help characterize the age of a planetary surface, 
because they accumulate with time. They also provide useful constraints 
on the importance of surface erosion, as such processes will 
preferentially remove the smaller craters. Earlier studies of martian 
crater populations revealed that erosion and dust deposition are 
important processes on Mars. They disagreed, however, on the age of the 
youngest volcanism. These earlier studies were limited by image 
resolution to craters larger than a few hundred metres in diameter. 
Here we report an analysis, using new images obtained by the Mars 
Global Surveyor spacecraft, of crater populations that extend the size 
distribution down to about 16 m. Our results indicate a wide range 
of surface ages, with one region-lava flows within the Arsia Mons 
caldera-that we estimate to be no older than 40-100 million years. We 
suggest that volcanism is a continuing process on Mars. Copyright 1999, 
Institute for Scientific Information Inc.

===================
(4) COMPOSITIONAL CHANGES BY MULTIPLE IMPACTS

Y. Miura, S. Fukuyama, A. Gucsik: Compositional changes by multiple 
impacts. JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, 1999, Vol.85, 
No.1-3, pp.192-193

YAMAGUCHI UNIVERSITY,FAC SCI,DEPT CHEM & EARTH SCI,GRAD SCH SCI & 
ENGN,YAMAGUCHI 753,JAPAN

Multiple impacts (i.e. progressive impacts) with reduction state 
produce characteristic compositions originated from target rock. Pure 
carbon can be obtained from limestone target rocks by multi-impact 
reaction with reduction state which can be found in natural and 
artificial impact craters. Pure Fe spherules in lunar agglutinates can 
be obtained from FeO-rich basaltic rock by multiple impacts including 
multi-impact reaction on the airless Moon. (C) 1999 Published by 
Elsevier Science S.A. All rights reserved.


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