Astronomical Cycles and Movements
Period of Revloution
Astronomical Movements and Cycles
-Orbits tend to be in the shape of ellipses(ovals)
-The object that is orbiting will at one point be at its farthest point in its orbit(apogee) and at another point be at its closest point in its orbit(perigee)
Apogee <-------------- 🌎---->Perigee
Differences in orbits
-Astronomers and scientists such as Ptolemy, Kepler(1st to say planets orbit in ellipses), and Newton helped form the basis of our knowledge about orbits and their shapes
Some objects follow a predictable path, while others change direction almost at random
Some objects in space have long,flattened elliptical orbits like comets
-This will not be an exact number
-The time it takes the Earth to revolve around the Sun once is called a year.
-We think of a year as 365 calendar days/366 days every four years(leap year)
-The Earth actually takes 365 days, 5 hours, 48 min., and 45 sec. to orbit the Sun once
-We round to 5:48:45 to 6 hours or 1/4 of a day
Interesting facts
-We can't put 1/4 of a day on the calendar so we save it and every 4 years (4x6hrs=24hrs=1day) we add an extra day to the calendar making it 366/leap year.
-The closer a planet is to the Sun (and the Sun's gravity), the faster it will revolve.
Planetary Years
-The closer a planet is to the Sun, the faster it revolves around it(mercury being the fastest and Neptune the slowest revolving planet.
Period of Rotation
-The Earth rotates around once in 24 hours(23 hours, 56 min.,4 sec.) that's a rate of 1000 miles per hour! The time it takes for the Earth to rotate completely around once is what we call a day. It's Earth's rotation that gives us night and day.
-The combined effect of the Earth's tilt and its orbital motion results in the seasons.