| |

Mia's notes on nature, astronomy, and the seasons

Constellations and the seasons

The four seasons indicate not only changes in nature but also in the skies. For example, the constellations you see on a night sky change depending on the season you're looking at them in.

Search for these stars in the sky. If you're in the northern hemisphere, look for them above the southern horizon. If you're in the southern hemisphere, take a look above the north horizon.

The spring begins. We can see how nature awakens after the long winter. Flowers start to bloom, and leaves appear on trees. Days become longer and longer.

( Click on the picture to continue! )

Climate and climate change

The weather in one place can be very different. But at the same time, it is predictable. We don't expect snowfalls in the jungles of Colombia, and we know there will be no hot days in the North Pole. The weather predicted in a given area is generally called its "climate." The environment looks differently in the north pole than in the Colombian jungle because these two places are located in two separate climate zones.

The climate of our planet is very complicated, and many scientists study its secrets. Climate has numerous dependables, including the sun's activity, the amount of cloud cover, the concentration of gases in the atmosphere, the speed and temperature of waters in the ocean, forest density in various locations.

Life on our planet adjusts to the climate, but the climate is a very delicate construct itself. We disrupt its balance by deforestation or carbon dioxide emissions to the atmosphere, which is very dangerous to many animal species.

( Click on the picture to watch the animation! )

Day & night: movement of the earth.

When you observe the sky every day, you can see that the morning Sun appears on the horizon close the geographic East. It rises higher and higher, riches the highest point in the sky, and then starts to lower again. At some point it hides below the horizon somewhere in the west and the night begins.

How about the stars in the night sky? Some of them behave exactly the same as the Sun! They rise from behind the horizon in the East, reach their highest point in the sky, and set in the other side.

For many years people thought it results from the fact that the sky revolves above our heads lika a giant ceiling.

Today we know that it is all a result of the Earth spinning around its axis. Being on Earth we do not feel its actual movement, but we see the outcome of it.

( Click on the picture to watch the animation! )

Movements of the Earth

Our planet moves in several different ways. The most important movements are the Earth rotation and orbital motion.

Earth's rotation means spinning around the planet's own axis. It is similar to the ice-skaters' spinning while they do pirouettes. Thanks to this movement of the Earth, we have day and night.

Orbital motion means moving around something else. Earth orbits the Sun (spinning around its axis at the same time!). One orbiting movement takes precisely one year. The route the Earth moves around the Sun on is called an orbit.

( Click on the picture to watch the animation! )

Test it!

Take a ball-shaped item, such as an orange, and try to spin it on the table. Can you see? It is a rotating motion.

Now place any other item on the table and move the orange around it - it is an orbiting motion.

The seasons and the Earth's orbiting motion

The seasons result from the Eart's orbiting movement. The Earth also leans towards the orbit, so sometimes one hemisphere is closer to the Sun, and sometimes the other one.

Let's see how it looks like on the first day of each season.

In June, the northern hemisphere leans towards the Sun. It gets much more sunlight, and that's why we have summer there. At the same in the southern hemisphere, we have winter. Let's wait for about three months. When days pass, the northern hemisphere gets less sunlight, the southern one - gets more of it. Finally, in September - on the first day of astronomical autumn, both hemispheres get an equal amount of sunlight. The Sun shines directly above the equator.

In December in the northern hemisphere, we have winter. That's because then this hemisphere is further from the Sun. At the same time, people who live in the southern hemisphere enjoy the summer months.

In March, on the first day of astronomical spring, both hemispheres once again get equal amounts of sunlight. These moments during the year are called equinox because night and day last for the same time almost on the entire planet.

( Click on the picture to watch the animation! )

Snowflakes

Snowfalls are very characteristic during the wintertime. But did you know that snowflakes have very different shapes? At the right temperature and humidity, you can observe incredible shapes of big snowflakes.

Almost every single snowflake makes a six-pointed star, but there are no identical ones! Snowflakes result from a very complicated natural process, and it is highly improbable that the same process can happen twice.

( Click on the picture to see more snowflakes! )

Whale migration.

Throughout the year, weather conditions change on Earth, even in the same place. This is why many animals migrate in search of areas that are more suitable for them.

Whales belong to such migrating animals. They can travel in the ocean waters even for thousands of kilometers.

Why do they travel like this?

In the cold waters in the polar areas, they can find plenty of food. However, they move towards warm waters when it's time for them to give birth to the littles ones. That's because young whales do not have enough of body fat to survive the cold.

Moving from place to place, whales use the seasons and various climate zones. Therefore, significant climate changes may be very dangerous for the whales' population. They might not be able to adjust to such climate changes.

Do you know any other animals that migrate when the seasons change?

( Click on the picture to watch the animation! )

Autumn and spring

During both autumn and spring, the Earth is similarly lit by the Sun. The first day of each of these two seasons is called the Equinox. That's because a day and a night last for the same amount of time, 12 hours each.

But then why are the two seasons so different?

It turns out that the nature of each season depends on many factors, not just on the sunlight.

Spring follows cold winter, and autumn follows hot summer. This cycle has a significant impact on plants.

When it gets warm enough in spring and the snow melts, the flowers begin to bloom. Leaves appear on trees.

In autumn, when the summer ends, leaves change their color, and plants are getting ready to survive the winter.

( Click on the picture to watch the animation! )