November 2002 Sky from the Keeble Observatory
Pluto, the embattled 9th planet, has more company. Recall that
Pluto is the most recently discovered of the nine planets, and
that many astronomers would like to downgrade its status. It doesn't
fit the pattern of the outer solar system; it's not a gas giant
like Jupiter. Rather, it seems most closely to resemble the icy
moons found orbiting those gas giants. Triton, one of Neptune's
moons imaged by Voyager 2, is probably a close twin.
Yet, the nostalgic impulse says to let Pluto be considered a planet.
It was discovered 72 years ago by Clyde Tombaugh, who was actually
looking for a planet precisely where he found Pluto. Of course,
he was looking there because of a faulty calculation, and Pluto
is not anything like what he expected.
We now understand that there is a reservoir of short-period comets,
nearly in the plane of the ecliptic and lying at distances beyond
that of Neptune. This so-called Kuiper Belt was formed when the
solar system was very young, as gravitational interactions with
Uranus and Neptune threw many planetesimals into orbits at distances
comparable to Pluto's current orbit. Similar gravitational slingshot
events interacting with Jupiter and Saturn are responsible for the
larger, spherical reservoir of long-period comets, known as the
Once only the stuff of theory, with the capabilities provided
by Hubble Space Telescope, the Kuiper Belt has been observed - or,
at least, sampled. About 500 objects are now identified. The largest
denizen of the belt thus far is about half the diameter of Pluto.
Its official designation thus far is 2002 LM60. Its discoverers
wish to name it Quaoar (pronounced kwa-war) after a southern California
native American creation deity. Quaoar is about 800 miles in diameter,
and is likely composed of the same mix of ice and rock that we estimate
for Pluto and Triton. It's actually not dissimilar from the composition
of comets. Another, known as Varuna, is almost 550 miles in diameter.
Maybe it's time we shift Pluto's designation from planet to Kuiper
Belt Object and let it be the largest known to date.
Lunar phases for November: New Moon at 3:34 pm EST on the 4th;
First Quarter at 3:52 pm on the 11th; Full Moon on the 19th at 8:34
pm; Last quarter on the 27th at 10:46 am.
Early evening planet watchers can take the month off! Saturn rises
at least 3 hours after sunset, Jupiter about an hour later. In the
pre-dawn you'll be able to find both of them; Jupiter is high to
the SSE early in the month, moving to southwest by the end of the
month. Saturn is high to the WSW, moving towards the west by month's
end. Mars is visible low to the ESE.
The Leonid meteor shower should display two distinct peaks, one
at about 11:00 pm on the 18th, the second on the 19th at about 5:30
am. The first is the debris train from the 1767 apparition of Comet
Tempel-Tuttle, the second from its 1866 pass through the inner solar
system. Unfortunately, you'll be contending with a nearly-full moon,
so only the brightest meteors will be visible. For an update on
the meteor shower, check the web site of the International Meteor
Organization at http://www.imo.net.
An overhead view at mid-month finds the Andromeda Galaxy almost
at zenith, with little competition from a waxing crescent moon until
about the 18th or 19th. To find it, try averted vision so that
the more sensitive part of your retina can see the faint smudge
light. This galaxy is similar in size and structure to our own Milky
Way, but it lies at a distance of 2 million light years. As such,
it is the most distant object which is directly visible without
a telescope. The plane of our own Galaxy makes an arc slightly north
of zenith, crossing the horizon at east and west. To the west Cygnus
now shows itself as the Northern Cross, with the upright marking
the plane of the Milky Way. Deneb is the bright star at the top,
the binary Albireo marks the cross's base. To the east we see bright
Capella in the constellation Aurigae. Just clearing the horizon
at this time we see Castor and Pollux in Gemini, and the distinctive
shape of Orion. These constellations will become more prominent
into the winter months.
For your own monthly star chart, you can direct your web browser
You will find extensive descriptions of what's worth looking for,
and you can download and print a single copy for your personal use.