Wednesday 9 October 2019

The planets in the Solar System - Interactive lesson

Part 1

Part 2

In the course of the lesson we are going to sort all the planets in their correct places.

The first planet is Mercury. I will find it in the the movable objects and place it in the slot near the Sun.What is interesting to know about Mercury is that it is the closest planet to the sun.
It have the shortest year of all planets, which is equal to 88 Earth days, that is the time Mercury goes around the Sun. But its own rotation is by far very slow. It takes 58 days for Mercury to turn around itself once. In other words, one year on Mercury is almost half a day there too. This slow rotation makes another interesting event. Facing the sun for a long period, makes the planet very hot on one side, and extreme cold on the other shaded side.

The second planet is Venus. Its distance from the Sun is almost in the sweet spot, like Earth, making it suitable for life. So why there is not life there? Well, may be Venus did have life, but it was destroyed due to a runaway greenhouse effect.
What is most bizarre about Venus, is that it is the only planet in the Solar System, to rotates clockwise. The reason for this may by a hit by another space object, which have changed its rotation. Venus also have the longest day of all planets - 243 Earth days.

The third planet is the Earth, our home planet. Its distance from the Sun, not very hot, not very cold, the available water, and the iron core magnetic field(the shield against Sun radiation), makes it a perfect place for carbon based live forms to thrive.
The Earth also have one natural satellite - the Moon. The moon is orbiting around with one side always facing at the Earth. So from here, we always see only one side and the other side is a secret for the Earth's telescopes.
The moon is also getting far end far from us. One day we may lost in in space.

The forth planet is Mars. It is one of the most explored planets, as its atmosphere is not very violent. Mars have 2 moons, but they are not planets, just some pieces of rocks captured in its orbit. First one is Deimos. It is probably part of the asteroid belt, detached from the hive. The other one is Phobos. If we spent one day on Mars, we will see Phobos passing through the skies 3 times.

Here goes the Asteroid Belt. It is not considered a planet and often is neglected when studying the Solar system. The asteroid belt is a living example, how a planet failed to form in its natural way. The reason is believed to be the huge gravity of Jupiter. There is one notable dwarf planet in the asteroid ring - Ceres is the largest planetoid having a real round shape.

The fifth planet is Jupiter. It is a gas giant and is the biggest planet in the Solar system. As it sounds, gas giants are mainly composed by gases. And only the core consist of rock or ice. Jupiter also play very important role for the life on Earth. With its huge gravity, it attracts space travelling objects, and do not allow them to reach other planets. Like all gas giants, Jupiter have a lot of moons. 67 objects are circling around it, and some of them are well developed planets, like Io, Europa, Ganymede and Callisto.

The sixth planet is Saturn. Another gas giant famous with its visible ring of space objects moving around it. It is 24 times bigger than Earth and have 62 natural satellites, some of them very small in size. The biggest moon is Titan, the second largest moon in the system.

The seventh planet is Uranus. A pale blue gas giant, 10 times bigger than Earth. What is most odd about Uranus, is that its axis of rotation is approximately parallel with the plane of the Solar System. In other words, it rotates around itself like top-down, and not like the rest of the planets left - right. Uranus have 27 natural satellites. The most notable one is Titania.

The eighth planet is Neptune. An ocean blue gas giant with almost the same size as Uranus. One year on Neptune is 164 Earth years. It has 14 known moons, the most notable being Triton.

And this is the point where Heliosphere ends. The rest of the planets are called trans-Neptunian objects and are at a great distance from the Sun. Also their orbits are so elliptical, that they may appear in or out of the Oort Cloud. They are caught in the Sun's orbit in a range called Interstellar Space.

The ninth planet is Pluto. It is double dwarf planet, as the latest discoveries show, that Pluto have a brother planet Charon. Pluto and Charon are considered a binary planet because the barycenter of their orbits does not lie within either body. This means that they both looks like circling each other. Pluto have another 4 natural satellites - Styx, Nix, Kerberos and Hydra.

The tenth planet, considered in this fun astronomy game is the dwarf planet Haumea. The planet has an ellipsoid shape and even have 2 moons - Hiiaka and Namaka.

The far most planet is Sedna. It is a minor dwarf planet in the outer reaches of the Solar System. Little is still confirmed about where did this planet came from, or how was formed. Some of those distant space objects may as well be satellites for some of the gas giants. It takes a lot of years to see where actually one orbit leads, as some of them need more than 100 years to complete one side cycle. For Sedna, "she" goes one time around the sun, for 12 000 years! So this planet haven't completed even one cycle, while human have evolved from iron age, to modern times.

Hope you hand fun with this exciting lesson.

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