Solar Activity

The Sun and its Solar System

In this lesson, we will be covering about the sun, and its solar system.

Lesson Outcomes

• To be able to differentiate the six layers of the sun.

• To understand the characteristic of each layer.

• Able to explain different types of solar activities.

• Able to see the big picture of the solar system.

• Know the basic characters of different planets.

The Sun

• The only star in our solar system. It comprises of more than 98% of solar system mass.
• It spins!
• t has 3 inner layers, and 3 external atmospheric layer.
• 3 Inner layers : Core, Radiative zone, Convection zone.
• 3 External layers : Photosphere, Chromosphere, Corona

The 3 Internal layers

• Core - Site for thermonuclear fission (Fusion of 2 hydrogen to form 1 helium). This process releases a lot of energy in the form of heat, and electromagnetic radiation. (15,000,000 degrees Celcius)

• Radiative zone - Site for energy from the core to pass through in order to reach the convective zone. (Take about 170,000 years)

• Convection zone - Energy transfer in the form of convection, involving both heated and cooled gas.

The 3 External layers

• Photosphere - Layer of the atmosphere, what we see from Earth. (6000 degree Celcius). Thin layer. Surface of the sun.

• Chromosphere - Relatively thin layer. Observable during solar eclipse. Hotter than the photosphere. Rosy red color.

• Corona - Hottest external layer reaching 1,000,000 degree Celcius. Extends millions of kilometer into outer space. Only observable during Solar Eclipse.

Rosy red color of the chromosphere during solar eclipse. White color of the corona.

Corona of the sun during solar eclipse. It releases charged particles (electrons and protons) in the form of solar winds.

The 3 Solar Activity

• Solar flare - Sudden flash of increased brightness (Like camera flash), explosions releases burst of energy.
• Prominence - Anchored to photosphere, extending outwards to corona. Projections usually in loop shape. Very bright.
• Sunspot - Cooler parts of the sun. Appear black in color. High concentration of magnetic field causing energy repulsion.

Solar flare at different cameras of different wavelength detections.

Loop shape of the prominence, anchored to the photosphere, extending outwards towards the corona.

Sunspots of the sun. Cooler regions of the sun due to high magnetic field which repels the energy received.

Solar Cycle

11-year calendar of the sun showing solar activity at different levels based on the number of sunspots. High activity is called solar maximum (More sunspots), Less activity is called solar minimum (Less to no sunspots). It fluctuates (go up and go down).

Solar winds

• Solar activities such as solar flares, sunspots, and prominence emit magnetic waves. (Dangerous, can harm astronauts, and interfere radio signals on earth).

  UV radiation is also emitted.

• Corona releases solar winds.

• Earth is protected by a magnetic field, so it is not affected by the sun's magnetic field, and solar winds.

Solar wind deflection on Earth as a result of Earth's magnetic field. The magnetic field protects the Earth, causing aurora upon deflection.

The solar system's 8 planets. The sun is the heaviest comprising of 99.86% of the total mass of the solar system.

Solar system overview

• Consist of planets, moons (natural satellites), dwarf planets (small planets), asteroids, comets, meteorites, and other celestial bodies. This forms the solar system.

Asteroid belts (Between Mars and Jupiter). Smaller than planets and dwarf planets.

Comet. An icy body made of ice and dust. The tails become longer when reaching the sun, due to more ice melted.

Meteoroids (Fragments of asteroid or comets or debris from other planets). When on fire, its called METEORS. If too big and cannot burn completely, it will hit the earth, and its called METEORITE.

The eight planets (4 Terrestial, and 4 Gaseous planets), and the dwarf planet of the solar system.

Mercury.

• It spins very slowly!
• It is the nearest planet to the sun in the solar system.
• The exposed region is very hot, the night region is very cold.
• 88 Days around the sun. Smallest planet.

Venus.

• Hottest planet in the solar system due to extreme global warming.
• Heat is trapped and cannot escape, causing heat accumulation.
• Second brightest in the night sky.
• Surface has many volcanoes and sulphuric acid rainstorms.
• The clouds are so dense that it reflects light. That's why it is bright in the night sky.
• Approximately same size as the earth.

Earth.

• Our home planet.
• Consist of oceans, and land habitable by living things of many different species.
• Human is the most abundant living thing on Earth of almost 7 Billion people.
• Earth is protected by a magnetic field which deflects the solar wind from the Sun's corona.

Mars.

• It has less magnetic field, hence the atmosphere is stripped away by the solar wind,
• causing oxidation of the iron surface, making it appear red in color.
• It has water, at North pole and South pole.
• Half size of the Earth.

Jupiter. Biggest planet in the solar system. It has a biggest storm in the solar system called "Great Red Spot". Jupiter is a "Gas giant", meaning it mostly made out of gas, with a solid icy core.

Saturn. Second largest in the solar system. It is the lightest planet that it can float on the sea. It is also a "Gas giant". Has great storms at the North pole and South pole. The 7 rings are made out of chunks of ice, and rock debris and dusts.

Uranus. It spins on its axis, but tilted sideways, due to collision by another big object according to theory. It is bright blue in color and very cold! It is also a gas giant.

Neptune. Oceanic color. Another gas giant, and it is the 8th planet and furthest planet from the sun. It is very cold. Densest gas giant. Denser than Jupiter! Consist of water, methane, and ammonia, thats why its so blue in color!

Pluto. This is a dwarf planet, but not a true planet. It has 2 moons. Smallest planet and it one of the celestial bodies in the Kepler's belt (Another belt other than asteroid belt between Mars and Jupiter).

Thank you for your attention. Any questions?