How long does it take our Moon to go around Earth?
It takes 27 days, 7 hours, and 43 minutes for our Moon to complete one full orbit around Earth. This is called the sidereal month, and is measured by our Moon's position relative to distant “fixed” stars. However, it takes our Moon about 29.5 days to complete one cycle of phases (from new Moon to new Moon). This is called the synodic month. The difference between the sidereal and synodic months occurs because as our Moon moves around Earth, the Earth also moves around our Sun. Our Moon must travel a little farther in its path to make up for the added distance and complete the phase cycle.
What causes a Lunar Eclipse?
Pictures of the moon's phases often make it look like there should be a lunar eclipse during each full Moon and a solar eclipse during each new moon. However, two things have to happen for a full lunar eclipse. First, the moon has to be full, so there is only an opportunity for a lunar eclipse about once each month. Second, the Earth comes between the Sun and the Moon, blocking the sunlight from falling on the Moon. There are two kinds of lunar eclipses:
A Total Lunar Eclipse occurs when the Moon and Sun are on opposite sides of Earth.
A Partial Lunar Eclipse occurs when only part of Earth's shadow covers the Moon.
What causes Earth's Tides?
High and low tides are caused by the moon. The moon's gravitational pull generates something called the tidal force. The tidal force causes the Earth and its water to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides.
As the Earth rotates, your region of Earth passes through both of these bulges each day. When you're in one of the bulges, you experience a high tide. When you're not in one of the bulges, you experience a low tide. This cycle of two high tides and two low tides occurs most days on most of the coastlines of the world.
What are Spring and Neap Tides?
A Spring Tide occurs when there’s a new or full moon. Because it follows the moon’s lunar cycle, a spring tide happens twice per month. With the moon and sun roughly aligned the tides of Earth are on average slightly larger than usual. On beaches this can be seen when the water comes further up the shore than it usually does. The tidemark left will be higher.
A Neap Tide follows seven days after a spring tide. Like the spring tide, it’s connected to the lunar phases and takes place after the first and third quarters of the moon. This is when the moon and sun are at right-angles to each other. The effect of this alignment is that there is less difference between high and low water. This means that on a neap tide, the water does not rise or fall to its usual heights. A high tide will be less high and a low tide will be less low, decreasing the difference between them.
Why do we only see one side of the Moon?
Tidal locking is the phenomenon by which a body has the same rotational period as its orbital period around a partner. So, the Moon is tidally locked to the Earth because it rotates in exactly the same time as it takes to orbit the Earth. That is why we only see one side of the Moon.
What are the Different Phases of the Moon?
New Moon - This is the invisible phase of the Moon, with the illuminated side of the Moon facing the Sun and the night side facing Earth. In this phase, the Moon is in the same part of the sky as the Sun and rises and sets with the Sun. Not only is the illuminated side facing away from the Earth, it’s also up during the day! Remember, in this phase, the Moon doesn’t usually pass directly between Earth and the Sun, due to the inclination of the Moon’s orbit. It only passes near the Sun from our perspective on Earth.
Waxing Crescent - This silver sliver of a Moon occurs when the illuminated half of the Moon faces mostly away from Earth, with only a tiny portion visible to us from our planet. It grows daily as the Moon’s orbit carries the Moon’s dayside farther into view. Every day, the Moon rises a little bit later.
First Quarter - The Moon is now a quarter of the way through its monthly journey and you see half of its illuminated side. People may casually call this a half moon, but remember, that’s not really what you’re witnessing in the sky. You’re seeing just a slice of the entire Moon ― half of the illuminated half. A first quarter moon rises around noon and sets around midnight. It’s high in the sky in the evening and makes for excellent viewing.
Waxing Gibbous - Now most of the Moon’s dayside has come into view, and the Moon appears brighter in the sky.
Full Moon - This is as close as we come to seeing the Sun’s illumination of the entire day side of the Moon (so, technically, this would be the real half moon). The Moon is opposite the Sun, as viewed from Earth, revealing the Moon’s dayside. A full moon rises around sunset and sets around sunrise. The Moon will appear full for a couple of days before it moves into the next phase.
Waning Gibbous - As the Moon begins its journey back toward the Sun, the opposite side of the Moon now reflects the Moon’s light. The lighted side appears to shrink, but the Moon’s orbit is simply carrying it out of view from our perspective. The Moon rises later and later each night.
Last Quarter - The Moon looks like it’s half illuminated from the perspective of Earth, but really you’re seeing half of the half of the Moon that’s illuminated by the Sun ― or a quarter. A last quarter moon, also known as a third quarter moon, rises around midnight and sets around noon.
Waning Crescent - The Moon is nearly back to the point in its orbit where its dayside directly faces the Sun, and all that we see from our perspective is a thin curve.
Here are some definitions to help you in your Grades 3 - 5 Lesson 1 investigation.
Rotate – when an object spins around an axis or center of the object
Axis – an imaginary line about which an object spins
Revolve – to move in a curved path around another object
Orbit – the curved path of an object revolving around another object
Moon Phase – the shape of the lit portion of the moon as viewed from Earth
Horizon – the line where Earth’s surface and the sky appear to meet
Here are some definitions to help you in your Grades 3 - 5 Lesson 2 investigation.
Rotate – when an object spins around an axis or center of the object
Axis – an imaginary line about which an object spins
Revolve – to move in a curved path around another object
Orbit – the curved path of an object revolving around another object
Moon Phase – the shape of the lit portion of the moon as viewed from Earth
Horizon – the line where Earth’s surface and the sky appear to meet
Solar Eclipse – when light from the sun is blocked from reaching Earth by the moon
Lunar Eclipse – when light from the sun is blocked from reaching the moon by Earth
Here are some definitions to help you in your Grades 3 - 5 Lesson 3 investigation.
Rotate – when an object spins around an axis or center of the object
Axis – an imaginary line about which an object spins
Revolve – to move in a curved path around another object
Orbit – the curved path of an object revolving around another object
Moon Phase – the shape of the lit portion of the moon as viewed from Earth
Horizon – the line where Earth’s surface and the sky appear to meet
Here are some definitions to help you in your Grades 3 - 5 Lesson 4 investigation.
Rotate – when an object spins around an axis or center of the object
Gravity – a force of attraction between two or more objects
Revolve – to move in a curved path around another object
Orbit – the curved path of an object revolving around another object
Moon Phase – the shape of the lit portion of the moon as viewed from Earth
Here are some definitions to help you in your Grades 3 - 5 Lesson 5 investigation.
Rotate – when an object spins around an axis or center of the object
Gravity – a force of attraction between two or more objects
Revolve – to move in a curved path around another object
Orbit – the curved path of an object revolving around another object
Moon Phase – the shape of the lit portion of the moon as viewed from Earth
Tide – the natural rise and fall of the waters of the ocean
Range – the difference between the highest and lowest values
Have you noticed that sometimes the moon looks like a beautiful circle in the night sky? Other times it is a tiny sliver of light in the night sky. The moon has many different looks during the month. In this investigation, you will study the correspondence between the moon's position in its orbit, its phase, and its position in an observer's sky at different times of day.)
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Waxing Crescent - This silver sliver of a Moon occurs when the illuminated half of the Moon faces mostly away from Earth, with only a tiny portion visible to us from our planet. It grows daily as the Moon’s orbit carries the Moon’s dayside farther into view. Every day, the Moon rises a little bit later.)
First Quarter - The Moon is now a quarter of the way through its monthly journey and you see half of its illuminated side. People may casually call this a half moon, but remember, that’s not really what you’re witnessing in the sky. You’re seeing just a slice of the entire Moon ― half of the illuminated half. A first quarter moon rises around noon and sets around midnight. It’s high in the sky in the evening and makes for excellent viewing.)
Waxing Gibbous - Now most of the Moon’s dayside has come into view, and the Moon appears brighter in the sky.)
Full Moon - This is as close as we come to seeing the Sun’s illumination of the entire day side of the Moon (so, technically, this would be the real half moon). The Moon is opposite the Sun, as viewed from Earth, revealing the Moon’s dayside. A full moon rises around sunset and sets around sunrise. The Moon will appear full for a couple of days before it moves into the next phase.)
Waning Gibbous - As the Moon begins its journey back toward the Sun, the opposite side of the Moon now reflects the Moon’s light. The lighted side appears to shrink, but the Moon’s orbit is simply carrying it out of view from our perspective. The Moon rises later and later each night.)
Last Quarter - The Moon looks like it’s half illuminated from the perspective of Earth, but really you’re seeing half of the half of the Moon that’s illuminated by the Sun ― or a quarter. A last quarter moon, also known as a third quarter moon, rises around midnight and sets around noon.)
Waning Crescent - The Moon is nearly back to the point in its orbit where its dayside directly faces the Sun, and all that we see from our perspective is a thin curve.)
