Calculation of Solar Motion for Localities in the USA
Issue:
Volume 9, Issue 1, March 2021
Pages:
1-7
Received:
17 December 2020
Accepted:
31 December 2020
Published:
12 January 2021
Abstract: Even though the longest day occurs on the June solstice everywhere in the Northern Hemisphere, this is NOT the day of earliest sunrise and latest sunset. Similarly, the shortest day at the December solstice in not the day of latest sunrise and earliest sunset. An analysis combines the vertical change of the position of the Sun due to the tilt of Earth’s axis with the horizontal change which depends on the two factors of an elliptical orbit and the axial tilt. The result is an analemma which shows the position of the noon Sun in the sky. This position is changed into a time at the meridian before or after noon, and this is referred to as the equation of time. Next, a way of determining the time between a rising Sun and its passage across the meridian (equivalent to the meridian to the setting Sun) is shown for a particular latitude. This is then applied to calculate how many days before or after the solstices does the earliest and latest sunrise as well as the latest and earliest sunset occur. These figures are derived for 60 cities in the USA. The selection was initially based on the most populous urban areas but was extended to ensure that each of the 50 states has a representative city.
Abstract: Even though the longest day occurs on the June solstice everywhere in the Northern Hemisphere, this is NOT the day of earliest sunrise and latest sunset. Similarly, the shortest day at the December solstice in not the day of latest sunrise and earliest sunset. An analysis combines the vertical change of the position of the Sun due to the tilt of Ea...
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On Cosmic Epochand Linear Size/Luminosity Evolution of Compact Steep Spectrum Sources
Ezeugo Jeremiah Chukwuemerie
Issue:
Volume 9, Issue 1, March 2021
Pages:
8-12
Received:
4 March 2021
Accepted:
16 March 2021
Published:
7 April 2021
Abstract: We have used analytical methods in this paper to obtain a mathematical relation that describes relationship between the linear size of compact steep spectrum (CSS) sources and their redshift. Result shows that the source linear size has an inverse power-law dependence on the redshift. Moreover, for the purpose of obtaining an empirical relation that shows relationship between the liner size and the redshift, we carry out simple linear regression analyses on the observed linear sizes of the CSS sources in our sample against their respective observed redshifts. Results of the analyses indicate that the linear sizes of the quasars have direct power law relationship with their respective redshifts; while the converse is the case for their galaxy counterparts. Their correlation coefficients are marginal. In comparison with the obtained theoretical relation, we notice that for the CSS quasars, the linear size–redshift data show an inverse correlation. This is comparable with the theoretical relation. So, it suggests that the dynamical evolution of the source linear sizes may have some cosmological effects on it. However, the converse is the case for the CSS galaxies – the correlation is direct. The possible explanation for this difference is that quasars are observed at higher redshifts than their galaxy counterparts. Hence, the cosmological effects are expected to be more pronounced on the quasars. Furthermore, we use analytical methods again to obtain a theoretical relation that shows relationship between luminosity and redshift. The relation indicates that luminosity of a radio source has an inverse power-law relationship with redshift. This suggestively implies that the intrinsic luminosity of a radio source may be modified by cosmological evolution. Moreover, for the purpose of obtaining an empirical relation for comparison with the theory, we carry out linear regression analysis of observed luminosities against observed redshifts of the CSS quasars and galaxies in our sample. Results show that luminosities have excellent direct power-law relationship with redshifts. However, this is in contradiction to the obtained theory which shows inverse relationship between the two parameters. This excellent direct correlation has been attributable by some authors to strong luminosity selection effects in which samples with high luminosities are found at high redshifts. Therefore, if the selection effects are taken care of, we may be able to see the comparability of the theory with the empirical relation. Hence, we conclude that source radiated power may have some cosmological implications just like we saw in the size/redshift relation.
Abstract: We have used analytical methods in this paper to obtain a mathematical relation that describes relationship between the linear size of compact steep spectrum (CSS) sources and their redshift. Result shows that the source linear size has an inverse power-law dependence on the redshift. Moreover, for the purpose of obtaining an empirical relation tha...
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