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Our Place in Universe
Our Place in Universe

... The constellations lying along the ecliptic are collectively referred to as the zodiac T F The seasons are caused by the precession of Earth’s axis T F The vernal equinox marks the beginning of spring T F The parallax of an object is inversely proportional to its distance T F Rotation is the term us ...
Planetarium_Exercises - Illinois State University
Planetarium_Exercises - Illinois State University

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... accordingly. But, since it was not permissible to ignore, those eight minutes pointed the road to a complete reformation in astronomy.” ...
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titel - Maastricht University

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... It also rare because of the elliptical (oval) shape of the Moon's path, or orbit, around the Earth, meaning the Moon is sometimes further away from us. Additionally the Moon's orbit is on a tilt, making it even more rare when the Sun, Moon and Earth align. We haven't had a full solar eclipse since 1 ...
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Brock physics - Brock University

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... after the Roman goddess of love and beauty its surface is veiled by thick clouds. Beside the Sun and Moon, Venus is the brightest celestial object, shine with steady bright white light. Its physical dimensions are rather similar to that of Earth and is referred to as the Earth's sister planet. Venus ...
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... Usually the new moon passes the sun from above or from beneath and doesn’t hit the sun. The insertion of the annual orbit of the sun (ecliptic) and of the monthly orbit of the moon into the image shows, that a solar eclipse only happens, if the new moon is situated in the intersection of both orbits ...
What are constellations? - Red Hook Central Schools
What are constellations? - Red Hook Central Schools

... and mane make up an upside-down question mark called the Sickle. One of the brightest spring stars, Regulus (Latin for "little king"), is at the base of the question mark. The rest of Leo's body, legs, and tail extend to the east. During the dry season in ancient Egypt, the lions of the desert came ...
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Tropical year

A tropical year (also known as a solar year), for general purposes, is the time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice. Because of the precession of the equinoxes, the seasonal cycle does not remain exactly synchronized with the position of the Earth in its orbit around the Sun. As a consequence, the tropical year is about 20 minutes shorter than the time it takes Earth to complete one full orbit around the Sun as measured with respect to the fixed stars (the sidereal year).Since antiquity, astronomers have progressively refined the definition of the tropical year. The Astronomical Almanac Online Glossary 2015 states:year, tropical:the period of time for the ecliptic longitude of the Sun to increase 360 degrees. Since the Sun's ecliptic longitude is measured with respect to the equinox, the tropical year comprises a complete cycle of seasons, and its length is approximated in the long term by the civil (Gregorian) calendar. The mean tropical year is approximately 365 days, 5 hours, 48 minutes, 45 seconds.An equivalent, more descriptive, definition is ""The natural basis for computing passing tropical years is the mean longitude of the Sun reckoned from the precessionally moving equinox (the dynamical equinox or equinox of date). Whenever the longitude reaches a multiple of 360 degrees the mean Sun crosses the vernal equinox and a new tropical year begins"". (Borkowski 1991, p. 122)The mean tropical year on January 1, 2000, was about 365.2421897 ephemeris days according to the calculation of Laskar (1986); each ephemeris day lasting 86,400 SI seconds. By 2010 this had decreased to 365.2421891 (365 ephemeris days, 5 hours, 48 minutes and 45.14 seconds). This is about 365.242181 mean solar days, though the length of a mean solar day is constantly changing.
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