Question

1. What occurs on Dec. 21, March 21, June 21, and Sept. 21? What specific names are given to these dates?
2. Distinguish between the milky way and The Milky Way.
3. Every star (including the sun) we see by eye or telescopes belongs to the MWG. What does this mean? What are the only things we observe not in our MWG?
4. About how many stars are in the MWG? About how many galaxies are there?
5. What do we conclude about the shape of our MWG based on the fact we see the narrow milky band of light on very dark nights?
6. Name some nearby galaxies.
7. Some comets return regularly; others never do. What’s different in their orbits?
8. Here is a tide chart for some place along the ocean shore. Fill in the missing times or dates on the eight _______ lines below.

DATE               TIDE and TIME                                   NEXT TIDE and TIME

June 1 Very high at 4:00 AM                       Very low at _______

                        Very high again at_______    Very low again at _______

.

.

_______ Mildly high at 9:30 AM                    Mildly low at _______

                        Mildly high again at _______            Mildly low again at _______

.

.

_______ Very high and very low tides return

Answer 1

1) Dec 21 -> December 21 is usually the shortest day of trhe year and sometimes regarded as the day of the winter. Winter Solstice starts from this day.

March 21-> This day the Sun crosses the equator. Also called March equinox, it marks the moment the sun crosses the celestial equator.

June 21-> It is the longest time of the year in most of the northern hemisphere.Also known as June solstice of Summer and Winter.

Sept 21=>September equinox when the sun appears to cross the celestial equator heading southwards.

2) The milky way is an instance of spiral galaxy having myriads of stars which appears as a band of light from earth and our own solar system resides in this very galaxy.

3) There are about 100-400 billion stars in the milky way galaxy . Astronomers estimate that there are 100-200 billion galaxy in the universe.

5) As high tides occur after every 12 hours 25 minutes ,Very high tide will occur again at 4: 25 PM .

Very low tide occurs at 6 hours 12.5 minutes before and after a high tide.

So very low tide will be at 10:12.5 AM

very low tide again at :11:12.5 AM

and it continues in the same way.