Explain how the outward flow of energy from the Earth’s interior drives the process of plate Tectonics
All the earth processes are a result of energy flow and mass circulation in and outside of the earth system. Plate tectonics is an earth process that involves the movement of the lithosphere caused by internal processes inside the earth’s mantle (Kent C 154). This is as a result of convection currents within the earth’s crust caused by the heat in the crust. This heat in the crust is due to the initial heat during the earth’s formation and through the radioactive process. The earth’s core is made of radioactive elements such as uranium which decay and in the process release energy in the form of heat (Jellinek and Michael 50).
The heat that is produced is then released to the earth’s surface by convection. The process creates circulations in the mantle thus creating regions of different densities and temperatures (Richard 120). Gravitational force acts on these regions hence resulting in the vertical movement of the plates on the lithosphere (Richard 120). Horizontal movement results, where the crust is weak, and the fluid is forced out to form a new surface. The plates move in motion with the convection circulation and follow the direction of the currents inside the crust (Kent C 155).
How would you show experimentally that the solar day is longer than the sidereal day?
The period between successive crossings of any observers Celestial Meridian by any reference star is defined as sidereal time (Ambrosio et al 63). It can also be referred to as a star day. The solar day refers to the time between successive crossings of the sun on any observer’s celestial Meridian (Ambrosio et al 63). What is normally used on the day to day life is the solar day and it is measured in hours using clocks and watches.
There is a difference between the sidereal day and the solar day, whereas the solar day has 24 hours the sidereal day is made of 23 hours and 56 minutes (Ambrosio et al 64). This difference can further be shown experimentally.
An observational experiment can be used to show the difference between the two days and it will require concentration and focus from the observer. The experiment is aimed at determining the duration of a sidereal day using solar hours. This will be achieved by measuring the difference in time that a bright star will take to reach some point in the sky on different nights (Ambrosio et al 65).
The following steps are followed to carry out the experiment.
- The observer then identifies a sharp object that is used as a reference point. Measure the exact time at which the selected star reached the reference point identified.
- The measurement of the exact time is crucial to get the difference with different nights. The experiment will be repeated for several nights while recording the exact time with each night;
- The selected star will follow the same path every night, but there will be a variance in time with each night. The start will appear on the spot earlier and earlier each night. The time at which the star reaches the identified position in the sky, and this are repeated for the following days.
- After observing for several nights, we can find out that there is a daily difference of 4 minutes between the side real day and the solar day.
- This relates to the earth’s movement for the complete 360 degrees in its orbit. To move one degree, the earth takes 4 minutes, and since there are 365 days in a year and only 360 degrees. The earth is forced to travel the extra degree before the next cross of the sun on the same meridian in the second position (Ambrosio et al 66).
This accounts for the leap year every four years to accommodate the 366.26 side real days in the calendar.
Describe the collision-ejection theory of the moon and why we believe it to be the best explanation for the presence of the moon?
The collision ejection theory explains the formation of the moon; the theory postulates that the moon were formed from debris from the earth surface after the earth was hit by a large planetary body assumed to be the size of Mars. According to this theory the collision caused the ejection of materials and debris from the earth’s surface, the debris and vaporized rock material cooled to form the moon (Canup and Erik 710).
The theory further explains some of the known facts and composition of the moon, the material ejected from the earth may have condensed in or near the ecliptic plane, rendering the moon in the known orbit it has today. The composition of the moon, which is known to be less rich in iron is attributed to the fact that it may have retained little of the iron core after the collision. This is because the material had sunk deep into the earth before the collision. Additionally the rock materials that were ejected after the collision were vaporized and depleted of volatile elements and water hence the low water content of the moon compared to the earth as established today (Canup and Erik 710).
The theory also explains why the earth’s axial rotation is tilted 23 degrees; it is a result of the collision which resulted in the tipping of the earth hence the different season we experience today. Additionally one substantial evidence supporting this theory is the moon's orbit having similar orientation with the earth’s rotation or spin. This consistency with observation explains two different observations which are composition and properties of the moon, and the tilting of the earth. The theory appeals to most scientists as a theory explaining the formation of the moon (Canup and Erik 710).
How would a planet orbiting a first generation star be different from planets formed today? Could humans exist on that world? Why or why not?
The planets that orbit, a first generation star will contain only hydrogen and helium that were made in the stars (Spencer 20). On the other hand, planets forming today contain elements that were made in the stars these are hydrogen and helium and, in addition, contain those elements made in the big bang (Spencer 20). Humans could not exist in the earlier planets due to the absence of carbon and oxygen needed for life. Silicon and iron are needed for the formation of planets that can support life. These elements were only made in the big bang (Spencer 20). Planets that orbit first generation stars contain only hydrogen and helium and thus cannot support life.
Ambrosio, M., et al. "Search for the sidereal and solar diurnal modulations” Physical Review D 67.4 (2003): 042002.
Canup, Robin M., and Erik Asphaug. "Origin of the Moon in a giant impact near the end of the Earth's formation." Nature 412.6848 (2001): 708-712.
Condie, Kent C. Plate Tectonics. Butterworth-Heinemann, 1997.
Jellinek, A. Mark, and Michael Manga. "Links between long-lived hot spots, mantle plumes, d ″, and plate tectonics." Reviews of Geophysics 42.3 (2004).
O'Connell, Richard J. "On the scale of mantle convection." Tectonophysics 38.1 (1977): 119-136.
Spencer, Wayne R. "The existence and origin of extra solar planets." Journal of Creation 15.1 (2001): 17-25.