>Bob Jardine said:
>
>>Prominent TACO and mondo observer Dr. David Kingsley is featured in
>>an article in the S.F. Chronicle today (about his day-job research,
>>not his astronomy). Section A, a few pages back.
>
>After a bit of fishing around, I found it on-line:
>
>http://sfgate.com/cgi-bin/article.cgi?file=/c/a/2005/03/25/MNGMPBUKV81.DTL
>
>Mark
This site has some more background information on the recent studies,
and some actual pictures of the fish.
http://hhmi.org/news/kingsley4.html
To make this slightly relevant to observing, one night in January I
set up the 7 inch Starmaster in my backyard. The previous two weeks
had been brutal at work, trying to get a bunch of stuff finished for
the reviewers of the Science article, and to supply some images of
stickleback fish for the journal. One of the illustrations I had
spent all day scanning and highlighting was taken from "Histotoire
Naturelle des Poissons" , an 1829 fish monograph where the famous
French naturalist Georges Cuvier had described a whole series of
different stickleback species, and included nice plates illustrating
the dramatic skeletal differences between marine and freshwater
forms. These 175 year old pictures are the ones that are shown at
the top of the evolution story on the HHMI link above.
Needing a break from the science, I spent an hour or so touring the
first quarter moon from my backyard. Conditions were hazy, but
seeing was actually very good. It was one of the first even clear
nights after nearly two weeks of continuous rain at the beginning of
the year and I was having a great time panning around the fabulous
detail available on the moon. Although I have observed the moon a
lot over the last several years, I was surprised to stumble on a very
unusual feature located between Maurolycus and Maginus near the
terminator. An unusual triple crater structure was so weird
looking that I spent about 45 minutes sketching it and trying to work
out a series of juxtaposition events that could generate a gigantic
double trough between overlapping craters. When I went inside and
looked it up in Rukl and on line, I found a bunch of other comments
about the unusual appearance of this feature:
From Akkana on Hitchhikers guide to the moon:
DC "Chart 73: Described in Rukl as a "ruined crater with central
mountain range", Heraclitus is a strange rectangular structure
stretching between two large craters (Licetus and Heraclitus D). It
appears as though huge twin boulders had slid from one crater to the
other, creating twin furrows, each wider than most normal craters.
It's hard to imagine what natural process actually caused the strange
appearance of this crater. It looks like a gigantic beetle"
From Tom Trusock
"Further south, my eye is drawn to the odd shape of the HERACLITUS
complex. An old pair of twin elongated scrapes that connect LICETUS
in the north to a grouping of smaller craters (sometimes listed as
HERACLITUS D, among others) in the south. The major portion looks to
be about 35 miles by 30 miles. Although listed as a single crater
HERACLITUS has a clearly visible ridge that runs down the center and
makes the crater certainly seem double. I've heard it described as
"a ruined crater with a mountain range running down the center."
Irregardless of weather it was a double or a single crater it is one
of the more distinctive sights on the moon. If you haven't seen it
already, you really owe it to yourself to take a look and speculate
upon what forces caused this odd creature to come into existence."
Here is an image of the area giving some idea of the huge double
furrow connecting other craters.
http://www.astroimaging.com/images/Stofler.jpg (triplet structure
near bottom of image)
On this page, the double trough is colored in yellow
http://www.astrosurf.com/cidadao/crater_heraclitus_01.jpg (lower righ)
While at the eyepiece, I thought I had worked out one possible
sequence of events that could create the double furrow. With the
low lighting on January 17th, the central ridge in the middle of the
trough looked like it could have been formed by a huge landslide
that tore away from the edge of a previous crater rim. There was
even another larger crater squeezed right up against the double
trough, a possible culprit for creating a massive landslide in the
adjacent area.
The adjacent crater wasn't labeled on my initial Rukl chart, because
the whole triple crater complex happens to occur at a border area
between charts. But when I flipped through Rukl to identify the
missing member of the trio, who should I find? It was my old friend
Cuvier himself. One of the craters I had been sketching was named
after the same French naturalist who had published the 175 year old
pictures I had just been working all day for the Science figure. The
same man who had first named the different fish species we have been
catching, probing, and crossing for the last seven years, based on
their dramatic skeletal differences in body armor. And a broad
smile spread across my face as I realized the connections between all
things, and sent off the last parts of the paper describing how the
differences between Cuvier's old fish were actually created at the
molecular level.
Post script: It turns out I am better at figuring out where
different life forms come from than where interesting craters come
from. When the whole lunar area became better illuminated over the
next couple days, it was clear that the landslide appearance on
January 17th was a complete artifact of low angle lighting near the
terminator. With higher illumination, it was also clear that
Cuvier was too worn and tired looking to have been a giant thwump
that stimulated a landslide in an adjacent trough that looked
sharper rimmed and more recent than Cuvier itself. Instead, the
double-laned trough is probably the remains of a large elongated
crater that has a linear mountain range down its middle, rather than
an isolated single peak. (You can see a similar linear central range
in the elongated crater Schiller, but they are rare on the moon
because not many large craters are created by low angle impacts
http://www.lpi.usra.edu/resources/lunar_orbiter/images/aimg/iv_155_h1.jpg).
Whatever generated the interesting structures, I agree with Tom
Trusock's comment above that this really is "one of the most
distinctive sights on the moon" And Tom's final comment is
peculiarly appropriate to both the moon and the sticklebacks:
" If you haven't seen it already, you really owe it to yourself to
take a look and speculate upon what forces caused this odd creature
to come into existence."
-David Kingsley
Received on Fri Mar 25 21:30:31 2005
