Newsgroup: it.scienza.astronomia
Titolo: Però che ci fosse l'acqua ai poli...

...già lo si sapeva...e infatti e quello che hanno detto gli americani ai
loro cugini europei.
Cmq, a parte questi giochetti per farsi (a mio avviso giustamente) un po' di
pubblicità, avanti così.
Spiace parecchio per Hubble...ci sono delle nuove a proposito?
Bye
Ao

 loro cugini europei.
Lo si sapeva da un pezzo...una parte della superficie di Marte è ricoperta
da Permafrost...non capisco tutto questo clamore suscitato dai rilevamenti
di Mars express.
Rappresentano una conferma, non una scoperta.

 pubblicità, avanti così.
Riporto un post di sci.space.policy sull'argomento:
A discovery which America appears to have made over 30 years ago.
Below are some quotes from "On Mars: Exploration of the Red Planet"
http://history.nasa.gov/SP-4212/ch11.html
From a description of MAriner 7, which flew past MArs in 1969.
"Mariner 6 and 7 data did strengthen the earlier conclusion that water was
extremely scarce on Mars and that was a seriously limiting factor for the
search for life. While no clouds, frosts, or fogs had been seen in the new
pictures, minute amounts of water vapor had been detected in the
atmosphere."
(Ch 6 ,Section 180)
From a description of the infrared instrument on the Viking orbiters, which
orbited Mars in 1976.
"A more important contribution from the infrared thermal-mapping experiment
was
the discovery of the nature of the polar ice cap. One of the major questions
posed by the Mariner 9 data was the composition of the residual polar cap
left
when the winter polar cap, made of frozen carbon dioxide, retreated in
midsummer. A major controversy existed over whether this summer cap seas
also
frozen carbon dioxide or was frozen water. According to Viking data, the
temperatures of the residual cap are near -68° to -63°C, making a case for
water frost." (Ch11,Section 373)
" The water-vapor-mapping investigation was designed to map the distribution
of
water vapor over the planet and to determine the pressure of the atmosphere
at
the level where vapor is present. Understanding the distribution of water
vapor
is crucial to understanding the geological features of Mars and the
possibility
of the existence of life. Viking's measurements of water vapor varied,
depending on the location, season, and time of day.
 <snip>
 Interestingly, while the amounts of vapor at some latitudes changed
dramatically, the total global water remained almost constant at the
equivalent
of about one cubic kilometer of ice. The largest amounts observed were found
over the dark polar region, which is inaccessible to Earth-bound observers.
Maximum vapor column abundances of about 100 precipitable micrometers were
measured adjacent to the residual cap itself-a very large amount considering
the temperature of the surface and atmosphere in this region." The Mars
atmospheric water detector also confirmed the conclusion that the residual
cap
is made of frozen water and that the atmosphere above it is saturated with
vapor during the polar summer. 23 "
(Ch11,SEction 374)
And here is a Dec 6, 1998 release from NASA on the results of the laser
altimeter carried by Mars Global Surveyor.
"This first three-dimensional picture of Mars' north pole enables scientists
to
estimate the volume of its water ice cap with unprecedented precision, and
to
study its surface variations and the heights of clouds in the region for the
first time."
http://ltpwww.gsfc.nasa.gov/tharsis/agu_f98.html
MAny people are also aware of the detection of hydrogen ( and hence water)
by
Mars Odyssey's  neutron spectrometer.
I'm not sure wether this story about Europe "discovering " water on Mars is
the
fault of ESA  or clueless journalists. ESA's website and the BBC appear to
have
a clue and don't call this a discovery. However, it does sound as if some
ESA
scientists said it was.
What really concerns me is the apparent inability of European scientists to
conduct a basic literature search. It really make you wonder about the
competence of Europe's Mars reseachers. From this side of the Atlantic they
look like first-class idiots.

 ha scritto nel messaggio
news:FGgQb.178964$_P.62...@news4.tin.it...

Non esattamente, lo si sapeva per metodi indiretti. ME  ha rilevato h2o con
metodi spettroscopici, mentre altri esperimenti avevano dedotto la presenzia
di idrogeno, o di un altro 'moderatore di neutroni', nella forma che poteva
essere h2o. Ma anche altri materiali hanno la stessa proprieta' (metano,
composti con molto idrogeno, concentrazioni di cadmio) ovviamente meno
probabili.
Un rivelatore di neutroni pero' ha il pregio di poter indagare anche a molti
metri di profondita'.
( Info da thred ng uk.sci.astronomy.)
Cia'
Andre

Spiace parecchio per Hubble...ci sono delle nuove a proposito?
I privati si stanno muovendo per salvarlo, e la russia sembra
interessata a dare una considerevole mano.... vediamo che farà l'ESA
adesso.