Mountain Views News          Saturday, August 23, 2014

B2

THE WORLD AROUND US

Mountain Views-News Saturday, August 16, 2014 


SWIRLING ELECTRONS IN THE WHIRLPOOL GALAXY


The Whirlpool Galaxy Messier 51 (M51) is seen 
from a distance of approximately 30 million light-
years. This galaxy appears almost face-on and 
displays a beautiful system of spiral arms.

 A European team of astronomers was able 
to observe M51 with the International LOFAR 
Telescope in the frequency range 115-175 MHz, 
just above the normal commercial FM radio 
frequency band of 88-108 MHz. The team 
obtained the most sensitive image of any galaxy at 
frequencies below 1 GHz so far.

 With LOFAR’s high sensitivity, the disk of M51 
in the radio regime could be traced much further 
out than before. The astronomers detected cosmic 
electrons and magnetic fields 40,000 light-years 
away from the center of M51. With LOFAR’s 
high angular resolution, the spiral arms are 
clearly visible. Magnetic fields and cosmic rays 
are densest in spiral arms. Compared to higher 
radio frequencies, spiral arms appear broader at 
low frequencies due to the diffusion of cosmic 
electrons away from the spiral arms where they 
have been formed.

 The view of galaxies in the radio regime is 
different to their optical appearance. Whereas 
optical images show predominantly the visible 
light from stars, the radio waves unravel two 
constituents of galaxies that are invisible to optical 
telescopes: electrons and magnetic fields. Their 
role for the stability and evolution of galaxies is 
increasingly under discussion. The electrons are 
“cosmic ray” particles produced in the shock 
fronts of giant supernova explosions. Magnetic 
fields are generated by dynamo processes driven 
by gas motions. When the electrons spiral around 
the magnetic field lines, radio waves are emitted, a 
process called synchrotron emission. Its intensity 
increases with the number and energy of the 
electrons and with magnetic field strength.

 For many decades, radio astronomy has been 
unable to explore low frequencies below 300 
MHz because the ionosphere acts as a barrier of 
low-frequency radio waves (which are completely 
blocked below about 10 MHz). Sophisticated 
methods of data processing and superfast 
computers are needed to recover the emission. 
Due to these technical challenges, spiral galaxies 
have hardly been studied before at these very low 
radio frequencies. The only observations were of 
poor resolution and no details could be made out.

 The target of investigation in David Mulcahy’s 
PhD project was the beautiful spiral galaxy 
Messier 51, which is visible with small telescopes 
in the constellation Canes Venatici (not far from 
the Big Dipper).

 “Low-frequency radio waves are important 
as they carry information about electrons of 
relatively low energies that are able to propagate 
further away from their places of origin in the star-
forming spiral arms and are able to illuminate the 
magnetic fields in the outer parts of galaxies,” says 
Mulcahy. “We need to know whether magnetic 
fields are expelled from galaxies and what their 
strength is out there.”

 The Low Frequency Array (LOFAR), designed 
and constructed by ASTRON in the Netherlands, 
is a brand new radio telescope giving access to 
very low radio frequencies.

 LOFAR explores the relatively unexplored 
frequency range below 240 MHz and consists of 
a multitude of small and simple antennas without 
moving parts. LOFAR consists of 38 stations 
in the Netherlands, 6 stations in Germany and 
one station each in the UK, France and Sweden. 
Signals from all of LOFAR’s stations are combined 
online in a powerful computing cluster located at 
the University of Groningen (Netherlands).

 You can contact Bob Eklund at: b.eklund@
MtnViewsNews.com

FORAGING FOR GINKGO 

By Christopher Nyerges


(Ginkgo biloba)

How to use the 
nuts and leaves of 
this “living fossil”

 

 Botanists 
believed that 
the Ginkgo 
biloba tree was 
extinct, but then 
it was found in a 
Chinese Buddhist 
monastery in 
the 1700s, where 
specimens were being cultivated. 

 Ginkgo is a smooth-barked tree, often growing 
upright in a very vertical fashion when young, and then 
producing a much larger angular crown as it matures. 
Each leaf is fan-shaped, and has the appearance of 
a fern. The leaves turn yellow in the fall. The fruits, 
formed only on the female trees, are covered in a light 
brown fleshy coating that is very odoriferous. The nut 
has a thin shell that is easily cracked. Both nuts and 
leaves are considered edible, if properly prepared.

 Once it was rediscovered, ginkgo has been cultivated 
and spread all over the world as an ornamental 
and street tree. It is popular because of its unique 
appearance, and its relative resistance to insects and 
disease. To Buddhists, the tree is regarded as sacred.

THE NUTS

 In Japan, and other parts of Asia, processed nuts are 
added to rice and stir fry dishes. Ginko nuts are high in 
protein and low in fat. The medicinal properties of the 
nuts, which you get by eating them, are said to include 
the release of stress and hypertension (the result of 
dilating blood vessels and increasing oxygen into the 
blood stream). The nuts are also reportedly good for 
pain and soreness, as well as aid to digestion.

 Yes, I harvest the ripe ginkgo nuts, and yes, I have 
to hold my nose! The fleshy tissue around the seed really 
stinks! Some people have learned to not-mind the 
strong odor, generally reminiscent of fresh feces. Yes, 
you can get used to just about anything, and in time, 
you can learn to not be bothered by the “aroma” of the 
flesh around the ginkgo nuts. 

 My suggestion is that you just get over it. It might help 
if you chew on some aromatic gum, like licorice gum, 
while collecting. 

 Once collected, you can let the nuts and their soft 
outer shell dry, which makes it significantly easier to 
clean. Or you can just clean them right away, as I tend 
to do. I always wash them outside. You can put all the 
fresh ginkgo nuts in a pan of warm water, and roll 
them around between your hands to clean off all the 
outer coverings, which you should then toss into your 
compost pile.

 The cleaned nuts are then best dried, such as in the 
oven at pilot-light temperature. I have dried them with 
their shells, and without their shells. I don’t know if one 
way is right or wrong, and I believe it is just a matter of 
preference. However, ginkgo nuts dried in the shell seem 
to keep a lot longer than the shelled and dried ones. If 
you plan to eat them right away, then it probably doesn’t 
matter how you prepare them.

 Once roasted, you can just eat the ginkgo nuts as-is. 

 (Yes, there are two types of people: Those who like 
ginkgo nuts, and those who do not….)

 I have never eaten these nuts raw because of the foul 
odor. However, there have been some reports that the 
nuts can make you ill if you eat them raw (no doubt!). 
The nuts must be boiled or roasted for about 25 minutes. 
You’ll know they are done when you can easily break 
the thin shell with a nutcracker. They taste is akin to a 
bean. 

 To extend shelf life, they can be simply dried, though 
freezing might be even better. 

 Caution: there have been reports of sickness by some 
people who have eaten about a dozen cooked nuts at 
one time. So my suggestion is to try a few and monitor 
the results. Your body will tell you whether or not you 
should eat more.

THE LEAF

 When you see pills of Ginkgo biloba in health food 
stores, such pills are made from the ground or powdered 
leaf. 

 Leaf extract has been subject to many clinical tests, 
and it apparently increases circulation for the limbs 
and for the brain. This is why it seems to be helpful 
for improving memory and assisting with retaining 
memories. Suggestions that ginkgo can reverse 
dementia don’t seem to hold up to clinical tests. Nor do 
the claims that ginkgo can cure cancer seem to be valid, 
so far.

 A leaf extract has also been found to improve the 
immune system, and to protect the heart by clearing 
plaque from the arteries. In fact, ginko biloba extracts 
are used for many ailments such as headaches, asthma, 
kidney disorders, and more. 

 I have found that when I am experiencing a “slow day,” 
ginkgo pills, or homemade tea from the leaves, seem to 
offer a subtle yet noticeable “pick-me-up” without the 
eventual slowdown that follows drinking coffee. 

 There has been some debate about the safety of 
gathering your own ginkgo leaves for making your own 
tea. From what I have concluded, it seems safe enough 
to brew an occasional cup of tea from the leaves. Also, 
apparently the best time to collect the leaves for tea is 
when the leaves have turned yellow and are falling 
from the tree. This also apparently bypasses any toxic 
properties (e.g. ginkgolic acid) that may be in the leaf.

 Most negative reactions from using ginkgo are not 
from the leaf, but from eating the nuts raw.

FORAGER NOTES 

 Don’t bring raw nuts with the husks into your house 
without warning the family. I remember I brought 
some home once when I was living with my parents. 
They were all in a brown paper bag in the kitchen, since 
I intended to clean them right after dinner. My mother 
insisted that everyone check the bottom of their shoes 
since she was certain someone stepped in dog poop. 
Finally, I remembered the bag and took it outside. It 
seemed like years before I heard the end of that one.

[Nyerges is the author of “Foraging California,” “Guide 
to Wild Foods,” “How to Survive Anywhere,” and other 
books. He leads wild food and natural history walks on 
a regular basis. Contact him at HYPERLINK “http://
www.schoolofself-reliance.com/” www.SchoolofSelf-
Reliance.com, or Box 41834, Eagle Rock, CA 90041]