The Universe is HUGE Everything in the universe depends on the tiniest subatomic particles… But those particles can come together in some huge ways!

In the Beginning there was the Big Bang Occurred over 14 Billion Years Ago The Universe started expanding out from a single point. It was Trillions of Degrees: far too hot for ordinary matter to exist.

Then came Inflation The Universe continued to expand. As it expanded, it cooled down. Once it was cool enough, atoms formed into the first elements. 75% of the first elements were hydrogen. 25% of the first elements were helium. The universe was basically a big cloud of hot, glowing gas. Clouds of gas and dust are called nebulas.

Then Came Stars – 13 Billion years ago As gravity pulled particles of gas together, they collected into nebulas. These nebulas would get dense enough that massive amounts of matter would be in one place. If enough matter was present, the force of gravity could get strong enough to cause fusion. These were the first stars.

Then came Galaxies Groups of millions of stars grouped together form galaxies. The earliest galaxies are called “Globular” because they are loosely shaped like globes (or globs). In these early galaxies, the first stars manufactured the heavier elements. The heavier elements were then scattered when those first stars exploded. Later galaxies would sometimes take a spiral or disc shape.

Then came Solar Systems Once there were clouds of heavier elements (dust) as well as hydrogen and helium (gas), they also formed nebulas. Those nebulas would sometimes come together to form a spinning disc. The center of the spinning disc would sometimes become dense enough for fusion to start, forming a star. The edges of the spinning disc would sometimes come together in clumps to form planets, asteroids, and moons.

The Sun The heart of our Solar System that makes all life possible on Earth is the Sun.

Then came Our Solar System – 4.5 Billion Years Ago The pre-solar system spinning disc nebula gathers into the Sun and planets. Like everything else in the solar system, the Earth is about 4.5 billion Years old. Planets are large spherical objects that orbit the sun and can clear their orbital path. There are 8 in our Solar System. Moons are large objects that orbit planets. Asteroids are smaller, irregularly shaped rocky objects that orbit the sun. Comets are icy objects that orbit the sun at a great distance.

Mercury The closest planet to the sun is Mercury. Mercury is small and rocky. Mercury has no atmosphere. Mercury’s atmosphere probably escaped into space because it overheated and because of the weak gravitational force. Mercury’s year takes 88 Earth days. Mercury’s day takes 58 Earth days. Mercury is the first of the inner planets.

Venus Venus is the second planet from the sun. Venus is slightly smaller than Earth. Venus has an atmosphere 90 times thicker than Earth, but has an atmosphere of 96% carbon dioxide. Venus has a surface temperature of 450 degrees Celsius. Venus’s day is 243 Earth days. Venus’s year is 224 Earth days.

Earth The Earth is the third planet from the sun. The earth has liquid water on its surface and in its atmosphere. It has a magnetic field that keeps its atmosphere from being stripped away by the sun. It has a rocky crust and iron core.

Mars Mars is the fourth planet from the sun. Mars is smaller than Earth. Mars has a thin atmosphere. Mars has frozen water on its surface at the poles. There are some valleys and canyons on Mars’ surface that suggest it might have had liquid water at one point. Mars’ year is 687 Earth days. Mars’ day is almost equal to one Earth day. Mars is the last of the inner planets

Jupiter Jupiter is the first of the outer planets, and the fifth planet from the sun. Jupiter is 1300 times bigger than Earth. Jupiter has a year of 4300 Earth days. Jupiter has a day of about ten hours. Because it is spinning so fast, it has a clear bulge around its equator. Jupiter is mostly hydrogen gas. It is almost totally atmosphere.

Saturn Saturn is the sixth planet from the sun. It is a gas giant, made mostly from gases. It has a thick, dense atmosphere. Saturn is as big as 760 Earths. Saturn’s day is almost 11 hours. Saturn’s year is almost 11,000 earth days. Saturn is surrounded by several equatorial rings made mostly of ice. Saturn has over 60 moons.

Uranus Uranus is also a gas giant. Uranus’ axis is tilted to point towards the sun. Because of this, each pole of the planet experiences 42 years of daylight at a time. It is the coldest planet in the Solar System. Uranus’ day is about 17 earth hours/ Uranus’ year is over 30,000 Earth days. Uranus has faint rings.

Neptune Neptune is a gas giant. Neptune is 57 times larger than Earth. Neptune’s day is 16 hours long. Neptune’s year is roughly 60,000 Earth days. Neptune has faint rings. Neptune has 13 moons.

Dwarf Planets These are large objects that orbit the sun, but are not planets because: They do not have enough gravitational force to clear their orbit. Dwarf planets include: Pluto, Ceres, Makemake, Eris, etc.

Planets Memetic Acronym My Very Excellent Mother Just Served Us Nachos Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune