WHAT MAKES THE DAY AND NIGHT CYCLES OF EARTH?
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As Earth spins around its axis, the Sun appear to move across the sky (but it really stays in its position in the center of our solar system). Each day the sun appears to rise and set because the Earth rotates on its axis. As the planet turns, different places move in and out of sunlight.
What is universal time?
- Universal Time (UT) is a time standard that reflects the average speed of the Earth's rotation. It is not measured by clocks but by looking at the stars.
- Universal Time is a solar time standard that reflects the average speed of the Earth's rotation. Using the prime meridian at 0° longitude as a reference point (location of Greenwich, England), it shows the actual length of an average solar day on Earth, which is the time from one solar noon to the next.
- During a solar day, our planet completes a full rotation around its axis in relation to the Sun. Because of Earth's slowing rotation, a solar day is a little longer than 24 hours on average.
HOW DOES UNIVERSAL TIME COMPARE WITH OUR LOCAL TIME?
(EASTERN STANDARD TIME/EASTERN DAYLIGHT TIME)
INTERACTIVE TIME ZONE MAP
- UTC stands for Universal Time. EST stands for Eastern Standard Time. EDT stands for Eastern Daylight time.
- EST is 5 hours behind UTC. EDT is 4 hours behind UTC
- So, when it is 12:00 am UTC (midnight) in Greenwich, England, it will be 8:00 pm EDT and 7:00 pm EST in
Check out the website, https://www.worldtimebuddy.com/utc-to-est-converter, to see the conversion for your hometown.
Day-Night Animation
REALLY, how long is a day? FUN FACT
There are two types of days defined in astronomy, a solar day or a sidereal day. What's the difference?
A solar (or synodic) day is the time required for a single rotation of the earth on its axis with respect to the sun, varying slightly
throughout the year due to variations in the earth's orbit and other factors. The mean solar day is 24 hours.
A sidereal day is the time it takes for the sun to return to the same position with respect to the stars. Due to the precession of the equinoxes the sidereal year is about 20 minutes longer than the tropical year. A sidereal day is 23 hours 56 minutes and 4.09 seconds long.
LEAP YEAR- IS THE CORRECTION FACTOR FOR THE DIFFERENCE IN THESE TO MEASUREMENTS! IT KEEPS THE SEASON OCCURRING AT THE SAME TIME EACH YEAR.
A solar (or synodic) day is the time required for a single rotation of the earth on its axis with respect to the sun, varying slightly
throughout the year due to variations in the earth's orbit and other factors. The mean solar day is 24 hours.
A sidereal day is the time it takes for the sun to return to the same position with respect to the stars. Due to the precession of the equinoxes the sidereal year is about 20 minutes longer than the tropical year. A sidereal day is 23 hours 56 minutes and 4.09 seconds long.
LEAP YEAR- IS THE CORRECTION FACTOR FOR THE DIFFERENCE IN THESE TO MEASUREMENTS! IT KEEPS THE SEASON OCCURRING AT THE SAME TIME EACH YEAR.