Astronomy Homework
Q1) Last night you saw the star Betelgeuse exactly on your eastern horizon at 5:47 PM. Two students are discussing their answer to the question "At 5:47 PM tonight where will you see Betelgeuse?"
Student #1: The Earth makes once complete rotation about its axis each day so Betelgeuse will rise at the same time every night. It will therefore be exactly on the eastern horizon.
Student #2: No. The constellation Taurus rises earlier each month and so it must rise a little bit earlier each night. Betelgeuse must do the same thing. Tonight it would rise a little before 5:47 PM and be above the eastern horizon by 5:47 PM. You are confusing the sidereal and solar day.
Define a sidereal and a solar day. Based on that information, do you agree with Student #1, Student #2, both, or neither? Explain your answer.
Sidereal: Measured or determined by means of the apparent daily motion of the stars
Solar Day: The time required for a single rotation of the earth on its axis with respect to the sun, varying slightly throughout the year due to variations in the earth's orbit and other factors.
I would have to agree with student #2, with a solar day- as the definition says, “time required for a single rotation of the earth on its axis with respect to the sun, varying slightly throughout… and other factors” Which would explain when the Sun would rise and set in Betelgeuse.
Q2) Define the ecliptic, celestial equator, vernal equinox, autumnal equinox, summer solstice, and winter solstice. How are the last four points (equinoxes & solstices) related to the ecliptic, the celestial equator, the Earth's equator, and the four seasons?
1. Ecliptic: The plane defined by the earth's orbit projected onto the celestial sphere, along which the sun appears to move as viewed from the earth.
2. Celestial Equator: The great circle lying on the celestial sphere the plane of which is perpendicular to the line joining the north and south celestial poles
3. Vernal Equinox: the time when the sun
Student #1: The Earth makes once complete rotation about its axis each day so Betelgeuse will rise at the same time every night. It will therefore be exactly on the eastern horizon.
Student #2: No. The constellation Taurus rises earlier each month and so it must rise a little bit earlier each night. Betelgeuse must do the same thing. Tonight it would rise a little before 5:47 PM and be above the eastern horizon by 5:47 PM. You are confusing the sidereal and solar day.
Define a sidereal and a solar day. Based on that information, do you agree with Student #1, Student #2, both, or neither? Explain your answer.
Sidereal: Measured or determined by means of the apparent daily motion of the stars
Solar Day: The time required for a single rotation of the earth on its axis with respect to the sun, varying slightly throughout the year due to variations in the earth's orbit and other factors.
I would have to agree with student #2, with a solar day- as the definition says, “time required for a single rotation of the earth on its axis with respect to the sun, varying slightly throughout… and other factors” Which would explain when the Sun would rise and set in Betelgeuse.
Q2) Define the ecliptic, celestial equator, vernal equinox, autumnal equinox, summer solstice, and winter solstice. How are the last four points (equinoxes & solstices) related to the ecliptic, the celestial equator, the Earth's equator, and the four seasons?
1. Ecliptic: The plane defined by the earth's orbit projected onto the celestial sphere, along which the sun appears to move as viewed from the earth.
2. Celestial Equator: The great circle lying on the celestial sphere the plane of which is perpendicular to the line joining the north and south celestial poles
3. Vernal Equinox: the time when the sun