A monthly look at the night skies of the northern Rocky Mountains, written by astronomers Ron Canterna, University of Wyoming; Jay Norris, Challis Idaho Observatory; and Daryl Macomb, Boise State University
November premieres our most beautiful winter constellations, which are rising after
9 p.m.
An hour after sunset on the southwestern horizon, the Milky Way rises to the zenith
accompanied the summer triangle, which will be lost for another season. Overhead are
the two prominent constellations, Pegasus and Cassiopeia. Pegasus, the winged horse,
is slightly to the south of the Milky Way, and is recognized by its famous Great Square.
The queen Cassiopeia, a regular to us northern observers, is easily recognized by
its stretched out W or M star pattern. A few hours later rising prominently in the
east, a definite sign of the arrival of winter, is Taurus the bull followed by Orion
the hunter.
Taurus, this majestic constellation, forms a prominent "V" in the sky and is the location
of the nearest cluster of stars, the Hyades. Aldebaran, the eye of the Bull ,is the
bright orange star. Keep an eye out for these two constellations throughout the month.
This November you will have a fine opportunity to view Jupiter throughout most of
the month. It is in the southeast right after sunset and sets around 3 a.m. About
two hours before sunrise, look for Venus and Saturn on the eastern horizon. As in
every November, the Leonid meteor shower will peak Nov. 17-18, with about 40 per hour.
Look in the east in the constellation Leo but due to the full moon at this time the
fainter meteors may be overlooked
November 2010 Interest: Space-Based Gravitational Wave Detectors
(best URL: http://en.wikipedia.org/wiki/Laser_Interferometer_Space_Antenna)
Last month, we discussed terrestrial gravitational wave detectors, the most state-of-the-art
being the LIGO experiment, comprising two facilities in Louisiana and on the Hanford
Nuclear Reservation, Washington state. These terrestrial detectors are designed to
search for relatively short wavelength gravitational waves. Their space-based counterpart
is the Laser Interferometer Space Antenna. LISA is a NASA mission planned for launch
in 2025.
Gravitational waves are envisioned as "ripples in space-time" -- analogous to waves
produced on a water surface when disturbed by a passing boat-except the material vibrated
by gravitational waves is not water, rather it is the postulated fabric of space-time.
The movement of very massive objects creates these space-time waves. LISA should be
able to detect mergers of binary supermassive black holes in distant galaxies and
binary stellar-sized black holes in our own galaxy.
Both LISA and LIGO are designed detect the space-time disturbances, but in different
wavelength ranges. LISA will be sensitive to wavelengths from 10 billion to 3 million
kilometers-very long waves indeed. LIGO's wavelength range is much shorter, from 300,000
to 300 kilometers.
The LISA experiment will consist of three satellites in an equilateral triangle, with
sides 5 million kilometers in length. The triad of satellites will orbit at the same
distance from the Sun as Earth, but advanced along Earth's orbit by 50 million kilometers.
The passage of very long gravitational waves causes extremely small variations in
the distances between the satellite pairs. Since the satellite distances will change
due to other forces in the solar system -- planetary gravitational forces and the
solar wind -- accurate knowledge of these forces is necessary. A pathfinder mission
to demonstrate aspects of LISA's design is slated for 2013.