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January 30, 2004
A: FROM MENTOR JOAN LUSK IN
RI
I checked this out at
http://aa.usno.navy.mil/faq/docs/UT.html
You're right, UT does stand for Universal Time - time on the
0th meridian, formerly known as Greenwich Mean Time. (The
BBC still calls it GMT in its news broadcasts.) The navy site
goes into the subtle difference between time as defined by
the earth's rotation and the more regular time kept by atomic
clocks. The atomic clocks are corrected by a "leap second"
to keep them in sync with the earth's rotation. This happens
every one to one and a half years. We want time to stay in
sync with the day as we live it, even though the earth's rotation
is not perfectly constant. (I wonder why not - forces from
other planets? Tidal friction varying? Here's a research project
for one of you.) If you're interested in precise time to know
where to point your telescope, you obviously want to be in
sync with the earth's rotation or you'll point at the wrong
angle. But if you are interested in duration of elapsed time
on earth, and you recalibrate your clock to the earth's rotation,
your duration might be off by a second every 1 to 1.5 years.
Not many measurements need to be _that_ precise!
For the second question listed above read on . . .
The American Wind Energy Association site
http://www.awea.org/faq/instcap.html has a FAQ section
with a nice graph showing the growth in the amount of wind
power in the US, but searching on "geographical distribution"
turned up many state-wide reports rather than any obvious
nation-wide map. You might look individually at the northern
states - many were listed. The simple answer seems to be yes,
there are wind turbines in the northern states.
I did find a set of maps for the US distribution of wind
energy http://rredc.nrel.gov/wind/pubs/atlas/chp1.html
. see http://rredc.nrel.gov/wind/pubs/atlas/maps/chap2/2-06m.html
for the whole US and browse around for more. It could be interesting
to compare the availability of wind with the amount of usuable
power now being generated from it. I also stumbled across
the global distribution of solar energy, for the sake of photovolaic
cells.
http://mmf.ruc.dk/energy/wienPV.htm
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January 29, 2004
A: FROM MENTOR SANDRA SCANLON
IN CO
Yes, in terms of NASA, UT means Universal Time.
Regarding Wind Turbines:
A great website to check out is the Wind Energy Resource Atlas
of the United
States at http://rredc.nrel.gov/wind/pubs/atlas/
Areas of class 3 or higher wind energy potential occur throughout
much of
the Northeast region. The primary areas of good wind energy
resource are the
Atlantic coast, the Great Lakes, and exposed hilltops, ridge
crests, and
mountain summits from Pennsylvania to Maine. Areas of highest
wind energy
potential (class 5 and 6) are the outer coastal areas such
as Cape Cod and
Nantucket Island, offshore areas of Lake Ontario and Lake
Erie, and the
higher mountain summits of the Appalachians. Winter is the
season of maximum
wind power throughout the Northeast region. During this season,
all except
the most sheltered areas have class 3 or better wind resource,
and exposed
coastal areas and mountain summits can expect class 6 or 7
wind resource. In
summer, the season of minimum wind power, class 3 wind resource
can be found
only on the outer coastal areas and highest mountain summits.
Major areas of
wind resource in the Northeast region are described further
on the website.
There are 8 operating wind sites in New England. A great map
showing all
past, present and proposed wind turbine sites can be found
on page 6 of the
document "Status of Current and Future Wind Energy Development
in New
England" by J. F. Manwell, Ph. D. Director, Renewable
Energy Research
Laboratory, Dept. of Mechanical and Industrial Engineering,
Univ. of Mass.,
Amherst, MA available at the following web address -
http://www.glebemountaingroup.org/Articles/StatusFutureNE.pdf
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