The Reason for Seasons

Seasons change on the Solstices and Equinoxes

These dates are only approximate…

SOLSTICES AND EQUINOXES Time Zone: 6h 00m west of Greenwich Vernal Summer Autumnal Winter

Equinox Solstice Equinox Solstice Year Date Time Date Time Date Time Date Time2005 Mar 20 6:33 Jun 21 0:46 Sep 22 16:23 Dec 21 12:352006 Mar 20 12:26 Jun 21 6:26 Sep 22 22:03 Dec 21 18:222007 Mar 20 18:07 Jun 21 12:06 Sep 23 3:51 Dec 22 0:082008 Mar 19 23:48 Jun 20 17:59 Sep 22 9:44 Dec 21 6:042009 Mar 20 5:44 Jun 20 23:46 Sep 22 15:19 Dec 21 11:472010 Mar 20 11:32 Jun 21 5:28 Sep 22 21:09 Dec 21 17:382011 Mar 20 17:21 Jun 21 11:17 Sep 23 3:05 Dec 21 23:302012 Mar 19 23:14 Jun 20 17:09 Sep 22 8:49 Dec 21 5:122013 Mar 20 5:02 Jun 20 23:04 Sep 22 14:44 Dec 21 11:112014 Mar 20 10:57 Jun 21 4:51 Sep 22 20:29 Dec 21 17:032015 Mar 20 16:45 Jun 21 10:38 Sep 23 2:21 Dec 21 22:482016 Mar 19 22:30 Jun 20 16:34 Sep 22 8:21 Dec 21 4:442017 Mar 20 4:29 Jun 20 22:24 Sep 22 14:02 Dec 21 10:282018 Mar 20 10:15 Jun 21 4:07 Sep 22 19:54 Dec 21 16:232019 Mar 20 15:58 Jun 21 9:54 Sep 23 1:50 Dec 21 22:192020 Mar 19 21:50 Jun 20 15:44 Sep 22 7:31 Dec 21 4:022021 Mar 20 3:37 Jun 20 21:32 Sep 22 13:21 Dec 21 9:592022 Mar 20 9:33 Jun 21 3:14 Sep 22 19:04 Dec 21 15:482023 Mar 20 15:24 Jun 21 8:58 Sep 23 0:50 Dec 21 21:272024 Mar 19 21:06 Jun 20 14:51 Sep 22 6:44 Dec 21 3:212025 Mar 20 3:01 Jun 20 20:42 Sep 22 12:19 Dec 21 9:03

When is the Earth closest to the Sun?

A. July

B. October

C. January

D. April

When is the Earth closest to the Sun?

A. July

B. October

C. January

D. April

So what causes the seasons on Earth?

When is the Earth closest to the Sun?

A. July

B. October

C. January

D. April

Why are there seasons on Earth? The tilt of the Earth’s axis

Effect 1: Sunlight strikes the surface more directly in summer More energy per square meter is absorbed

Why are there seasons on Earth? The tilt of the Earth’s axis

Effect 2: The Sun is above the horizon longer in the summer More heating time each day

So are the summers hotter in the Southern Hemisphere?(and winters colder?)

Notice much more land mass in the

Northern Hemisphere

Much more water in the Southern Hemisphere

Water moderates temperature changes for two reasons:1) The Sun warms water to a greater depth

2) Water has a higher specific heat

Precession

The Earth is a giant top, and it wobbles just like one.

Precession takes 26,000 years to go through one full circle.

It’s winter in the northern hemisphere in January because

A. The southern hemisphere is then closer to the Sun than the northern hemisphere.

B. The Earth is furthest from the Sun in January.

C. The northern hemisphere gets no sunlight in January.

D. Sunlight strikes the northern hemisphere at a shallower angle in January.

E. Sunlight strikes the northern hemisphere more directly in January.

Astro-Cash Cab!

Connor Voelkel

Erin Henderson

Carl Cook

Michael Downs

Joseph Sanchez

1) The first day of spring is called the is called the _______

2) What value states your position on Earth east or west of the prime meridian?

Latitude

Longitude

Altitude

Azimuth

Elevation

3) True or False?

At 37º north latitude, the north celestial pole would be 37º above the northern horizon.

4) What season is it in the northern hemisphere in the diagram below?