Nicholas Barnard PHY117 2/5/02
The Planetarium visit was quite insightful after a long cold time spent outside looking at the real stars. The planetarium made it quite easy to see all of the specific items, and provided a great visual tool, that made understanding concepts very easy.
The winter and spring constellations that were mentioned were quite mundane. Every person who describes the stars points out Orion's belt, Sirius, the north star, and the big dipper. This portion of the show did not provide much information.
The celestial sphere made understanding the coordinate system to catalog stars quite simple. It is one thing to be inside of a dome and understand it. It is much easier to understand than a two-dimensional drawing description of the celestial sphere and several auxiliary drawings.
The celestial sphere provides a useful coordinate system to catalog stars. It is quite notable though that this system only works from the earth, or possibly earth orbiting satellites. The celestial sphere is tied to the earth. It would not be useful in space travel as shown on popular television shows.
The Ecliptic, is the most useful for understanding, In essence it maps the non-star bodies through the earth's night sky. The great circle on the celestial sphere that lies in the plane of the earth's orbit (called the plane of the ecliptic). Because of the earth's yearly revolution around the sun, the sun appears to move in an annual journey through the heavens with the ecliptic as its path it is the principal axis in the ecliptic coordinate system. The two points at which the ecliptic crosses the celestial equator are the equinoxes. The obliquity of the ecliptic is the inclination of the plane of the ecliptic to the plane of the celestial equator, an angle of about 23 1/2°.
I found the discussion on pulsars, quite interesting. A pulsar is a neutron star that emits brief, sharp pulses of energy instead of the steady radiation associated with other natural sources. The magnetic field and plasma that surround a neutron star create radio waves. The high-energy electrons of the plasma move around the magnetic field and emit radio waves and other forms of electromagnetic radiation.
A Black hole is another interesting stellar phoneme. A black hole is an object of such extremely intense gravity that it attracts everything near it and in some instances prevents everything, including light, from escaping. In some ways black holes are “burnt out” stars. Because light and matter is permanently trapped inside a black hole, it can never be observed directly. But, black holes can be detected by the effect of its gravitational field on nearby objects, for instance if it is orbited by a visible star; during the collapse while it was forming; or by the X rays and radio frequency signals emitted by rapidly swirling matter being pulled into the black hole.
The Magellenic clouds are satellite galaxies bubbled off of the Milky Way like spray from a fountain. These bright regions of light, observed by Ferdinand Magellan in 1519 and by other early explorers like Amerigo Vespucci and Marco Polo, are also known as Cape Clouds.
Andromeda Galaxy is the closest large galaxy to the Milky Way and the only one visible to the naked eye in the Northern Hemisphere. It is also known as the Great Nebula in Andromeda. It is 2.2 million light-years away and is part of the local group of several galaxies that includes the Milky Way, which it resembles in shape and composition. It has a diameter of about 165,000 light-years and contains at least 200 billion stars. The light arriving at earth from the Andromeda Galaxy is shifted toward the blue end of the spectrum, whereas the light from all other cosmic sources exhibits red shift.
The planetarium visit was very useful for understanding the celestial world in which we live. The examples were clear and aided my understanding immensely.