... gravitational pull of the Sun and Moon on the Earth’s
equatorial bulge. (The other planets contribute
slightly.) This causes the vernal equinox to move
slowly westward along the ecliptic by about 50.3 arc
seconds per year. (An arc second is 1/3600 of a
degree.) The precessional period is about 26,80 ...
Fun Facts: Sunshine
... The sun is actually a star.
It is the closest star to earth, which explains
why it looks so big!
Without the sun, there would be no heat or
light on earth.
This means there would be no life either.
It takes 8 minutes for light to travel from the
sun to the earth.
Earth ,Moon,and Sun - Laconia School District
... In addition to the earth rotating on its axis it also
travels around the sun. This is called revolution. It
is the movement of one object around another.
One complete rotation around the sun is a year.
Earth travels on its orbit or its path that leads it
around the sun. Earth’s orbit is not quite a ...
... Equator -- Sun is overhead at equinox
Tropic of Capricorn --
Astronomy = Timekeeping
... • Earth’s axis tilted 23°
• Sun appears higher in
sky in summer
• Longer days
• Sun shines down more
Solstice - East Hanover Township School District
... year is slightly less than 365.25 days.
Years that are integer multiples of 100
are not leap years, unless they are also
integer multiples of 400, in which case
they are leap years. For
example, 1600 and 2000 were leap
years, but 1700, 1800 and 1900 were
not. Similarly, 2100, 2200, 2300, 2500, ...
Study Guide for Earth/ Space Science Test 1. Rotation – The Earth
... from the sun and the direct angle of sunlight hitting the area. Also caused
6. Lunar – Moon – natural satellite – moon cycle is about 28 days long. Moon
means month. Be able to identify phases of moon
7. Solar – sun – only average size star in our solar system that gives us light
Week 3 - Emerson Valley School
... star we call the sun. For thousands of years, astronomers have studied the movements of the
planets across our solar system. These spherical bodies march across the sky in a predictable
way: the length of their days and years remaining reliably constant. Although scientists have
learned a great deal ...
Module 7 Developmental task - Number
... Sun. The planets vary in size – the smallest, Mercury, has a radius of only 2 439 km,
whereas the largest planet, Jupiter, has a radius more than 70 000 km at its equator.
... How do we “see” that the earth is
moving around the sun or v.v.?
• Small discrepancy between sun’s
motion and motion of stars
• Sidereal vs solar day
• At noon, say, the sun is not
exactly in front of the same stars
on the next day.
– It is exactly in the south
– The stars are faster, so a little w ...
Astronomy Unit Study Guide
... hypothesis. (Use the following terms in your description: gravity, accretion, nebula.)
16. What is the reason for Earth’s seasons? How long does it take the Earth to orbit the sun
... • Monitored the movement
of the Sun, Moon and
• Note special events:
eclipses and comets
• Prediction requires
mathematics and record
keeping! (necessitates a
long-lived, stable culture)
... behind their actual Tropical placement when we convert the chart to a Fixed
star or Sidereal Vedic chart. This means that some or all of the planets in a
Tropical chart will move backwards from one sign/house to another, if we
want to convert the Tropical placement of planets to the actual placement ...
... Can measure distance on the sky in
degrees (360 degrees = complete circle)
Horizon -Zenith -Meridian -- line running from north to
south through zenith
(Lecture 3). The Solar System in the Night Sky (cont)
... count 365 days, and exactly 365 mean solar days later, as the Sun crosses the Meridian,
we celebrate the start of the new year. The trouble is, the Sun has not returned to the
same place relative to the stars. It is still 0.25 days away from that point. After the next
year, it is half a day, and the ...
... from a star is shifted towards the
blue end of the spectrum?
The star is moving
... Solstice is when the Sun rises or sets as far North or
South of the equator as it can (days are longest or
Equinox is when the Sun crosses the equator, so the
days and nights are equal in time
... 1. What are the three layers of the sun’s interior? What part is
responsible for fusion?
2. What are the three layers of the Sun’s atmosphere? Be able to
describe them briefly, such as lowest layer, the visible surface, etc…
3. What is the solar wind? What happens when the solar wind gets
trapped in ...
Coordinate System Notes 3 - School District of La Crosse
... A. year- the time necessary for one complete revolution about the sun 365.25 mean
B.Types of years
1. sidereal year- The time necessary for the sun to return to the same position
with repect to the stars.
2. solar year( tropical) is the intreval between the passage of the sun through the ...
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.