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07/17/2008
Fruity Matters
Last week, I mentioned an old idea about putting a huge solar
collector in orbit and beaming down microwave energy to Earth.
In the column I said that I know of no serious effort or plans to
invest the huge amount of money such a program would require.
Obviously, I hadn’t read carefully my July issue of Scientific
American, which contained an article by Tim Hornyak. The
article, titled “Roping the Sun”, discusses a program by the Japan
Aerospace Exploration Agency (JAXA) aimed at placing just
such a solar power generator in orbit by 2030. This generator
would transmit a gigawatt of energy back to Earth either as
microwaves or as a laser beam. A gigawatt is roughly the same
amount of energy generated by a sizable nuclear power plant!
The generator, consisting of solar panels, mirrors and microwave
transmission equipment, would weigh a mere ten thousand tons
or so and the laser array would weigh some five thousand pounds
and have a hundred lasers. All this stuff would measure several
miles in dimensions. The cost would certainly be in the tens of
billions of dollars. We are assured that this radiation would not
harm the human body, being just about five times the energy of
the sunlight reaching the Earth on a sunny summer day.
However, just to be on the safe side, the beam would be collected
in some isolated spot in an ocean or elsewhere. On a day like
today, about 1 kilowatt of solar energy per square meter shines
down upon me on the golf course. The microwave or laser
energy from the proposed space facility would be about 5
kilowatts per square meter. The energy collector here on earth
will have to be pretty impressive in size to pick up a gigawatt.
All this is too mind-boggling for a hot summer’s day. I’d rather
talk about fruit. Here in New Jersey the blueberries are in season
and, under the watchful supervision of my wife, I managed to
bake a blueberry pie – my first. It wasn’t nearly as good as my
wife’s in the past but for my first attempt it was quite palatable.
Before taking over my care giving role and the shopping that
accompanies it, I could not claim any expertise in choosing fruits
and vegetables. After a notably poor choice of string beans this
past week, my wife would say I have a lot to learn in the
vegetable area.
I’ve done much better in the fruit category, notably in the
blueberry area and surprisingly good white flesh peaches from
California. I find one of the trickiest fruits to judge is the pear.
There’s always the question as to the ripeness of pears and when
to finally cut and bite into them. It’s really disturbing when you
cut into a beautiful looking pear and find that the inside is brown
mush. In my experience there’s much less of a chance of this
happening with an apple. Brian Trumbore recently called to my
attention an article dated July 7 from the BBC News Web site
that explains the science behind the pear versus apple ripening
characteristics.
The article by Jonathan Amos is headlined "Apples beat pears on
crunch issue" and discusses some recent work by Belgian
researchers published in the journal Plant Physiology. Pieter
Verboven and his team at the Catholic University of Leuven
stuck apples and pears inside the European Synchrotron
Radiation Facility (ESRF) in Grenoble. This European facility is
able to deliver powerful X-ray beams that can reveal the inner
structures of apples and pears. Apparently, a conventional
medical CTscan instrument can’t deliver the precise detail that
the Synchrtron device does. I visited the ESRF Web site and saw
the pictures of the inner structures of pears and apples and there
is quite a difference.
I was familiar with the fact that ethylene gas plays a role in the
ripening of various fruits but did not know that, after being
picked, the fruits like to breathe. The fruit needs oxygen to
produce sugars and energy needed for good health. It seems to
me that, from the reproductive standpoint, all the apple or pear
tree cares about is that its fruit decays or rots away exposing the
seeds, which can then be rooted or carried away and deposited
for reproduction of the species. We, on the other hand, want to
maintain the crispness and ripeness of the fruit until we get a
chance to eat it and we don’t give a hoot about what happens to
the seeds.
OK, why does an apple tend to stand up better than a pear so far
as maintaining its desirable edibility characteristics for a longer
period of time? The ESRF facility’s 3-dimensional scans reveal
that in a pear the interior contains a network of interconnecting
microscopic channels. The apple, on the other hand, doesn’t
have these channels but instead there are irregular voids or
cavities scattered among the cells of the apple. The result is that
oxygen has a hard time getting through the microchannels in the
pear but more easily travels through the voids in the apple. The
interior of the pear is more likely to be deficient in oxygen than
the interior of an apple. Hence, I’m more likely to encounter a
mushy brown interior of a pear than I am in an apple.
Hey, if you’re clever (I’m not), you might have already known
that an apple has more voids in it than a pear. If you drop a pear
in a bucket of water, it sinks. Drop in an apple, it floats – more
voids to make it lighter. Speaking of water and continuing our
Phoenix watch, Phoenix has now used its motorized rasp to stir
up some of that presumed ice on Mars. According to a
NASA/JPL press release yesterday, some of the shavings were
scooped up and photos taken, showing that the ice sublimed out
of the scoop in the hours after it was scooped up. The Phoenix
team seemed quite happy with the results and apparently thinks
there will be sufficient material to deliver ice samples into one of
their ovens before it all sublimes away.
Another press release yesterday reported on data from the Mars
Reconnaissance Orbiter published in today’s issue of Nature.
Based on the orbiter’s findings of clay minerals at thousands of
locations on Mars, the picture of Mars as once having large lakes
and flowing rivers is confirmed. The clays were buried by later
volcanic eruptions but impacts of various bodies then opened up
the clay deposits detected by the orbiter. The new data opens up
the selection of future landing sites aimed at the search for
possible remains of life forms if they existed back billions of
years ago when Mars was wet.
Finally, a completely unrelated matter. Some readers may recall
my amazement last year when Brian Trumbore took Harry
Trumbore and me to Ralph Kiner night at Shea Stadium and Bob
Feller was there to honor Kiner. I was amazed again to see
Feller, who must be 89 or close to it, show up for this week’s All
Star game in Yankee Stadium. And no, I did not stay up for the
15 innings!
Allen F. Bortrum
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