Saturday:
School starts next week so it is time for a little geometry review. A square is
a four-sided figure with four equal sides and four right angles. Go outside at
10 p.m. tonight with notebook in hand to sketch one. The Great Square of
Pegasus is balancing on its corner two fists held upright and at arm’s length
above due east. The top corner of the square is two fists above the bottom
corner. The other two corners are to the left and right of the line segment
connecting the top and bottom corners.
Sunday:
Geometry review, part 2. Go outside at 10 p.m. tonight with notebook in hand.
(Good teaching involves a little repetition.) A triangle is a polygon with
three corners and three line segments as sides. A good example is the Summer
Triangle made up of the bright stars Vega, Deneb and Altair. Vega, the
brightest star in the triangle is a little bit west of straight overhead. Deneb
is a little bit east of straight overhead and Altair is five fists held upright
and at arm’s length above the south horizon.
Monday: Tonight’s
moon is new. That means you won’t be able to see it. But that does not mean it
doesn’t exist. Contrary to the belief of toddlers and immature politicians,
just because you can’t see something doesn’t mean it doesn’t exist. (Note a
double negative statement followed by a triple negative statement. I’m not
unsorry about that.) Now, back to the science. What would happen to the earth
if the moon really didn’t exist? In last summer’s blockbuster Oblivion,
aliens destroy the moon and Tom Cruise survives. But the long-term effects on
the earth would be devastating to life as we know it. The moon stabilizes the
spin axis of the earth keeping the seasons fairly uniform over time. For more
information on what would happen to the earth if the moon were destroyed, go to
http://goo.gl/jM1d4. For more
information on Thomas Cruise Mapother IV, go to
http://en.wikipedia.org/wiki/Tom_Cruise.
Tuesday: Saturn
and Mars are brightness twins, fraternal twins, of course. The red planet Mars
is one fist above the southwest horizon at 9 p.m. The yellowish Saturn is less
than a half a fist to the upper right of Mars.
Wednesday:
The Ellensburg Rodeo is a “Top-25” rodeo. What does it take to be a “Top-25”
star? There are many ways to rank stars. The most obvious way for a casual
observer to rank stars is by apparent brightness. The apparent brightness is
the brightness of a star as seen from Earth, regardless of its distance from
the Earth. Shaula (pronounced Show’-la) is the 25th brightest star in the
nighttime sky as seen from Earth. It represents the stinger of Scorpius the
scorpion. In fact, Shaula means stinger in Arabic. Shaula has a visual brightness
rating of 1.62. Sirius, the brightest star has a visual brightness rating of
-1.46. (Smaller numbers mean brighter objects.) The dimmest objects that can be
seen with the naked eye have a visual brightness rating of about 6. There are
approximately 6,000 stars with a lower numbered visual brightness rating than 6
meaning there are 6,000 stars visible to the naked eye. Shaula is a blue
sub-giant star that radiates 35,000 times more energy than the Sun. It is 700
light years away making it one of the most distant bright stars. Shaula is a
challenge to find because it never gets more than a half a fist above the
horizon. Look for it tonight about a half a fist above the south horizon, a
little bit west of due south, at 8:30.
Thursday: The
brightest planet Venus is a half a fist above the east-northeast horizon at
5:30 a.m. Jupiter, the second brightest planet, is about a fist to the upper
right of Venus.
Friday:
Deneb is about seven fists above the east horizon at 10 p.m. When you look at
Deneb, you are seeing light that left Deneb about 1,800 years ago.
The
positional information in this column about stars and planets is typically
accurate for the entire week. For up to date information about the night sky,
go to https://nightsky.jpl.nasa.gov/planner.cfm.
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