Essay: Questions in Astronomy
Essay: Questions in Astronomy
Consider a star at the upper part of the main sequence (label it Star A) and a star in the lower part of the main sequence (label it Star B). Which is?
2) More luminous?
3) More massive?
5) Moving Faster?
Star A is younger, more massive, more luminous, faster and hotter than star B.
h. What is the definition of a Main Sequence Star? Compare the main sequence life spans of low mass stars and high mass stars. Explain why low mass stars stay on the main sequence much longer than high mass stars.
Main sequence star is one which has achieved hydrodynamic equilibrium. Stars the Main sequence have different lifespan. High mass stars have a significantly less lifespan than low mass ones. Low mass stars stay on main sequence much longer because they burn fuel at much lower rate than high mass stars (Kutner, 2003).
i. What would an imaginary observer on Earth witness as the Sun runs out of hydrogen in its core? If life is confined to Earth when this happens, would life perish from heat or from cold? Explain.
The observer on earth will see the sun turn into a red giant engulfing the nearby planets. Its outlays will expand and drift into space as Nebula. The Sun will then become a white dwarf which will eventually cool off to become a black dwarf. When the Sun will begin to die, it expansion will engulf Venus. With high temperature so close to earth, it will be impossible for any living thing to survive (Pyhajarvi, 2008).
j. What kind of stars eventually become white dwarfs? What kind eventually become supernovae and then possibly black holes? What will be the ultimate fate of the Sun? Why?
All starts when they die become white dwarf. However, if a is massive enough ( its mass is at least 9 times to that of the Sun), its white dwarf will be able to reach a critical mass of 1.44 times that of the Sun and trigger a supernova and later becoming a black hole (Kutner, 2003).
Question #1 100 words
What are Sun Spots and why do they appear in 11-year cycles? Discuss why we on Earth are interested in closely monitoring solar activity such as sun spots? What role does the Sun’s Magnetic field play in the 11 year solar cycle? How is Solar activity and the Earth’s Magnetic field related to the Northern Lights? If the Earth’s field is weakening as suggested in Week-2 what effect might it have on the geographic visibility and intensity of the Northern Lights?
Sun Spots are dark areas that appear on the surface of the Sun which are cooler then their surrounding. They posses strong magnetic fields and appear a groups of two, each spot having a different polarity. They appear because of the change in the Sun’s magnetic field on a roughly 11 year cycle. They capture our interest because phenomenon like sun spots lead to escape of magnetic particles from the Sun’s atmosphere as solar winds which directly affect the earth. Northern lights appear when the particles carried by solar winds collide with particles in earth’s upper atmosphere, when they are accelerate toward earth by earth’s magnetic field. A weakened earth’s magnetic field will result in increase in Northern lights intensity as well as wider area of their visibility (Lewis, 1997).