Download DaysSeasnsYears

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Orrery wikipedia, lookup

History of Solar System formation and evolution hypotheses wikipedia, lookup

Aquarius (constellation) wikipedia, lookup

Astronomical unit wikipedia, lookup

Extraterrestrial skies wikipedia, lookup

Timeline of astronomy wikipedia, lookup

Tropical year wikipedia, lookup

Extraterrestrial life wikipedia, lookup

Comparative planetary science wikipedia, lookup

Dialogue Concerning the Two Chief World Systems wikipedia, lookup

Formation and evolution of the Solar System wikipedia, lookup

Rare Earth hypothesis wikipedia, lookup

Geocentric model wikipedia, lookup

Copernican heliocentrism wikipedia, lookup

Astronomy on Mars wikipedia, lookup

Why do we have Days,
Seasons, and Years?
What on Earth is a day?
• “The time it takes for the Earth (or any planet/moon)
to make one complete rotation.”
• 24 hours
• Part of each 24-hour day is lighted (daytime), part is
dark (night).
• The length of daytime and nighttime varies
depending on how the Earth is tilted.
Earth Orbit (Revolution)
The Earth orbits (revolves) around the sun once every 365 days. This is
where our year comes from. In fact, for every planet a year is the time it
takes to orbit it’s star one time. Our orbit is not a perfect circle. It is an
ellipse. When do you think we are closer to the sun - in our summer our
our winter?
Summer: 152,000,000 Km Winter: 147,000,000 Km
Earth’s Tilt
Reason for
The earth’s axis
is always tilted
at 23.5. When
a hemi-sphere
tilts towards the
sun it gets more
direct sunlight so
it experiences
(summer). The
opposite is true
when the tilt is
away from the
sun (winter).
Spring - March 21st
• Spring Equinox
• First day of Spring
• Equal length of daytime
& nighttime
• Sun directly over
• Fall in southern
Summer - June 21st
• Summer Solstice
• First day of Summer
• Longest daytime in N
• Longest nighttime in S
• Sun over Tropic of Cancer
• Winter in southern hemisphere.
• 24 hours of daytime above the Artic
Circle & 24 hours of nighttime below the
Antarctic Circle.
Fall - September 22
• Fall/Autumnal Equinox
• First day of Fall
• Equal length of daytime and
• Sun directly over equator
• Springtime in southern
Winter - December 21
• Winter Solstice
• First day of Winter
• Longest nighttime in N
• Longest daytime in S
• Sun over Tropic of
• 24 hours of nighttime above the Artic
Circle & 24 hours of daytime below the •
Antarctic Circle.
Summer in southern