Seasons and the Sun

Seasons

A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of Earth's orbit around the Sun and Earth's axial tilt relative to the ecliptic plane.

Seasons

In many parts of the world, the year is made up of four different seasons. These seasonsare spring, summer, fall, and winter. Each has its own pattern of weather and varying hours of sunlight during the days. The northern and southern parts of Earth have different seasons at the same time.

Earth's tilt

Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere.

earth rotation

Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, and 4 seconds with respect to other, distant, stars (see below). Earth's rotation is slowing slightly with time; thus, a day was shorter in the past.Earth's rotation is the rotation of planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north pole star Polaris, Earth turns counterclockwise.

Multiple Choice

In winter, the axis of the earth is pointed away or toward the sun?

• towards
• up
• down
• away

Multiple Choice

Which  of the following best describes the tilt of the earth during the spring and fall equinoxes?

• The earth is tilted away from the sun (Northern hemisphere)
• The earth is tilted neither toward or away from the sun (tilt is side to side)
• The earth is tilted toward the sun (Northern hemisphere)
• The earth is not tilted during spring and fall

Multiple Choice

Which of the following best describes equinoxes?

• The earth is tilted neither toward or away from the sun
• The norther hemisphere is tilted toward the sun
• The northern hemisphere is tilted away from the sun
• The southern hemisphere is tilted toward the sun

Multiple Choice

The earth is a tilted planet.  What is the degree of tilt?

• Approximately 25 degrees
• Exactly 25 degrees
• 23.5 degrees
• 90 degrees with respect to the sun

Multiple Choice

The Arctic Circle receives several days each year where the sun not seeing.

• True
• False

Multiple Choice

Which of the following best describes the tilt of the earth when it is summer in the southern hemisphere?

• The northern hemisphere is tilted toward the sun
• The northern hemisphere is tilted away from the sun
• The norther hemisphere is tilted neither toward or away from the sun
• Why are you talking about the northern hemisphere when you asked about the southern hemisphere?

earth revolution

Revolution of Earth

Earth revolves in orbit around the sun in 365 days, 6 hours, 9 minutes with reference to the stars, at a speed ranging from 29.29 to 30.29 km/s. The 6 hours, 9 minutes adds up to about an extra day every fourth year, which is designated a leap year, with the extra day added as February 29th.

Multiple Choice

Earth does a complete revolution every _______

• 10 years

• 12 hours

• 24 hours

• 365 days

Multiple Choice

Which layers of Earth are mostly made of solid material?

• inner core and outer core
• crust and inner core
• crust and mantle
• mantle and outer core
  

Solar eclipse

A solar eclipse happens when the moon gets in the way of the sun’s light and casts its shadow on Earth. That means during the day, the moon moves over the sun and it gets dark. Isn’t it strange that it gets dark in the middle of the day?

This total eclipse happens about every year and a half somewhere on Earth. A partial eclipse, when the moon doesn’t completely cover the sun, happens at least twice a year somewhere on Earth.

solar eclipse

But not everyone experiences every solar eclipse. Getting a chance to see a total solar eclipse is rare. The moon’s shadow on Earth isn’t very big, so only a small portion of places on Earth will see it. You have to be on the sunny side of the planet when it happens. You also have to be in the path of the moon’s shadow.

On average, the same spot on Earth only gets to see a solar eclipse for a few minutes about every 375 years!In a solar eclipse, the sun gets darker.

Luner eclipse

During a lunar eclipse, Earth gets in the way of the sun’s light hitting the moon. That means that during the night, a full moon fades away as Earth’s shadow covers it up. 

The moon can also look reddish because Earth’s atmosphere absorbs the other colors while it bends some sunlight toward the moon. Sunlight bending through the atmosphere and absorbing other colors is also why sunsets are orange and red.

During a total lunar eclipse, the moon is shining from all the sunrises and sunsets occurring on Earth!

Why don’t we have a lunar eclipse every month?

You might be wondering why we don’t have a lunar eclipse every month as the moon orbits Earth. It’s true that the moon goes around Earth every month, but it doesn’t always get in Earth’s shadow. The moon’s path around Earth is tilted compared to Earth’s orbit around the sun. The moon can be behind Earth but still get hit by light from the sun.

Why don’t we have a lunar eclipse every month?

Because they don’t happen every month, a lunar eclipse is a special event. Unlike solar eclipses, lots of people get to see each lunar eclipse. If you live on the nighttime half of Earth when the eclipse happens, you’ll be able to see it.In a lunar eclipse, the moon gets darker.

Multiple Choice

How many types of Lunar Eclipses are there?

• a) Three

• b) One

• c) Two

• d) Four

Multiple Choice

When does a lunar eclipse occur?

• at night

• When the moon's shadow is on the earth

• During the day

• when the moon comes between the sun and earth

Multiple Choice

What type of eclipse is in the Diagram?

• Solar Eclipse

• Lunar Eclipse

Multiple Choice

During a solar eclipse, you can look directly at the eclipse.

• True - you can look at a solar eclipse

• False - you cannot look at a solar eclipse

Multiple Choice

For a solar eclipse to occur, what has to happen?

• The sun must be directly between Earth and the moon.
• The moon must be directly between Earth and the Sun.

Multiple Choice

How often does Earth orbit the sun?

• 30 days
• 24 hours
• 365.25 days
• 12 hours

Multiple Choice

What type of eclipse is this?

• Total lunar eclipse

• Total solar eclipse

• Partial lunar eclipse

• Partial solar eclipse

What Is a Galaxy?

We live on a planet called Earth that is part of our solar system. But where is our solar system? It’s a small part of the Milky Way Galaxy.

A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity. Our galaxy, the Milky Way, also has a supermassive black hole in the middle.Sometimes galaxies get too close and smash into each other. Our Milky Way galaxy will someday bump into Andromeda, our closest galactic neighbor. But don’t worry. It won’t happen for about five billion years. But even if it happened tomorrow, you might not notice. Galaxies are so big and spread out at the ends that even though galaxies bump into each other, the planets and solar systems often don’t get close to colliding.

what Is a galaxry

There are many galaxies besides ours, though. There are so many, we can’t even count them all yet! The Hubble Space Telescope looked at a small patch of space for 12 days and found 10,000 galaxies, of all sizes, shapes, and colors. Some scientists think there could be as many as one hundred billiongalaxies in the universe.

Different kind of shapes of galaxies 🌌

Some galaxies are spiral-shaped like ours. They have curved arms that make it look like a pinwheel. Other galaxies are smooth and oval shaped. They’re called elliptical galaxies. And there are also galaxies that aren’t spirals or ovals. They have irregular shapes and look like blobs. The light that we see from each of these galaxies comes from the stars inside it.

Star

A star is an astronomical object consisting of a luminous spheroid of plasma held together by its own gravity. The nearest star to Earth is the Sun. 

Multiple Choice

Nuclear fusion is...

• When two or more elements join together to make a heavier element.
• When two elements separate and form heavier elements.
• When two elements disappear
• that thing that happened to the Hulk

Multiple Choice

A huge ball of very hot gas is a 

• galaxy
• comet
• planet
• star

Multiple Choice

Our galaxy is called the

• Earth Nebula
• The Hubble Galaxy
• The Milky Way
• The Snickers

Multiple Choice

What's the unit of measurement we use when referring to our galaxies?

• light year
• light day
• miles
• kilometers

Multiple Choice

What type of galaxy do we live in?

• Spiral
• Elliptical
• Irregular
• Coaxial

Multiple Choice

What kind of galaxy is this?

• Barred Spiral
• Irregular
• Peculiar
• Ring

Multiple Choice

A galaxy which has a nucleus of bright stars and two or more arms in circular formation is called a ___ galaxy.

• elliptical

• humanoid

• irregular

• spiral

Multiple Choice

A galaxy which is either spherical (ball like) or a flattened disk is a ___ galaxy.

• elliptical

• humanoid

• irregular

• spiral