Lab 1 - Time and Space
In
this lab, you will investigate the myriad ways of keeping time in the
universe. Measuring the passing of astronomical time is by no means a
trivial task - keep that in mind, as you find the current time according
to various websites. This lab is structured as a series of topics,
followed by questions and suggested websites. Have fun, and take your
time! (Yes, it was time for that pun. On second thought…..)
Local Time
Give
the current local time (whenever you are performing this lab), either
EST or EDT. Specify whether or not we are on EDT, and when (and how)
this will change.
Interested in the time elsewhere? Try this:
http://www.timeanddate.com/worldclock/
Universal Time
UT
is counted from 0 hours at midnight, with unit of duration the mean
solar day, defined to be as uniform as possible despite variations in
the rotation of the Earth. Find the current UT. The clock applet below
may be helpful:
http://tycho.usno.navy.mil/utclock.html
UT is very similar to Greenwich Mean Time
(GMT), though this term is not used often these days. Both are 5 hours
ahead of EST. Is this currently true? If not, why not?
Longitude and Latitude
These
quantities give the location on the surface of the semi-spherical
Earth, by laying a grid atop it. Lines of longitude are measured with
respect to the Prime Meridian. Find the longitude of your hometown:
Lines of latitude are measured with respect to the equator. Find the
latitude of your hometown.
Julian Date (JD)
Julian
Day Number is a count of days elapsed since Greenwich mean noon on 1
January 4713 B.C., Julian proleptic calendar. The Julian Date is the
Julian day number followed by the fraction of the day elapsed since the
preceding noon.
Find the current JD:
Calendar
Which calendar do we currently use?
What calendar was this switched from, and when?
Why was the switch made?
Does all the world use the calendar we do? Explain.
Sidereal Time
ST
is time based on duration of the Earth's rotation with respect to a
point nearly fixed relative to the stars. Local Sidereal Time (LST) is
computed from ST using a longitude correction. Find the current LST.
The Lunar and Solar Cycles
Have
a look at sunrisesunset.com. Determine how the sunrise and sunset
times change from day to day. Also determine how the moonrise and
moonset times change daily.
Etcetera
Discuss any other times and/or calendars that are of interest to you.
Also, give a general conclusion (paragraph or more) about things that were interesting to you in this activity.
No comments:
Post a Comment