The sun is the star at the center of our solar system. It gives off heat and light, which warms the Earth and other planets. But how does it do that?
In this post we'll cover:
- 1 Solar Radiation
- 2 Energy Transmission Through Vacuum and Physical Media
- 3 Absorption of Solar Radiation by the Earth
- 4 Reradiating Heat
- 5 What Temperature Does the Sun Reach?
- 6 The Sun’s Heat and Energy
- 7 The Sun’s Toasty Temperature
- 8 The Sun’s Source of Energy: Proton-Proton Chain
- 9 The Sun’s Shiny Rays
- 10 The Sun is a G-Type Star
- 11 Conclusion
Solar Radiation
What is Solar Radiation?
Solar radiation is the energy that comes from the sun and warms the Earth. It’s created by nuclear fusion reactions in the sun’s core, which causes it to emit a large amount of electromagnetic radiation, mostly in the form of visible light.
How Much Solar Radiation Reaches Earth?
The sun’s surface emits about 63 million watts of energy per square meter, but by the time it reaches us, after traveling 93 million miles, it’s only 1,370 watts per square meter at the top of the atmosphere. That’s a lot of energy, but it’s still not enough to make us all break out in a sweat!
Fun Facts About Solar Radiation
- Solar radiation is the only way to get a tan without having to go to the beach!
- Solar radiation is a great way to power your gadgets and gizmos without having to plug them in.
- Solar radiation can be used to make delicious s’mores without having to build a campfire.
Energy Transmission Through Vacuum and Physical Media
Electromagnetic Radiation
- Electromagnetic radiation, like visible light, infrared radiation, ultraviolet light, and X-rays, can travel through the vacuum of space like a ghost.
- Other forms of energy need a physical media to move through, like sound energy needs air or another substance to be transmitted, and the wave energy of the oceans needs water.
- But solar energy is special, it can travel from the sun to the Earth without the need of a physical substance to transmit the energy. This feature of electromagnetic energy makes it possible for the Earth to get all the solar energy, including heat, it needs.
Sound Energy
- Sound energy needs air or another substance to be transmitted, like a whisper in the wind.
- Wave energy of the oceans needs water to move through, like a ripple in a pond.
- But solar energy is different, it can travel from the sun to the Earth without the need of a physical substance to transmit the energy. This feature of electromagnetic energy makes it possible for the Earth to get all the solar energy, including heat, it needs.
Absorption of Solar Radiation by the Earth
The Sun’s Gift
So the sun’s like, “Hey Earth, I got something for ya!” and Earth’s like, “What is it, Sun?” and the Sun’s like, “It’s a whole bunch of energy! It’s gonna be great!” So the sun sends down all this energy in the form of heat, light, and UV rays, and Earth’s like, “Oh wow, thanks Sun!”
Where Does it Go?
So the energy’s all over the place, and it’s like, “Where do I go? What do I do?” and Earth’s like, “Don’t worry, I gotchu!” So the energy gets absorbed by the air, water, rocks, buildings, pavement, and living things, and it’s like, “Oh cool, I’m part of something now!”
Uneven Heating
So some parts of Earth get more energy than others, and it’s like, “Hey, why’s that?” and Earth’s like, “That’s just how it is, buddy!” So the differences in energy cause winds and ocean currents to move all over the planet, and it’s like, “Woah, that’s pretty cool!”
Reradiating Heat
What Would Happen Without It?
- If the Sun kept beamin’ down on us without any way of gettin’ rid of the heat, we’d be toast!
- Luckily, the Earth has a way of coolin’ off – it reradiates heat back into space.
- The amount of heat that gets reradiated depends on the types of gases in the atmosphere. Some gases absorb heat better than others, and can mess with the reradiation process.
- One of these gases is carbon dioxide, which can cause the ‘greenhouse effect’. When the amount of carbon dioxide in the atmosphere increases, more heat gets stored in the atmosphere and less heat gets reradiated.
What Does This Mean For Us?
- If we don’t keep an eye on the amount of carbon dioxide in the atmosphere, the Earth’s gonna get a lot hotter!
- We need to make sure we’re keepin’ the Earth cool by managin’ the amount of carbon dioxide in the atmosphere.
- That means reducin’ our use of fossil fuels, plantin’ more trees, and generally bein’ more mindful of our impact on the environment.
What Temperature Does the Sun Reach?
Surface Temperature
So, you’re wondering how hot the sun is? Well, let me tell ya, it’s hot! Hotter than a day at the beach, hotter than a hike in the summer, and even hotter than your house on the hottest day of the year when the AC’s broken. We’re talking temperatures of 90°F to 100°F (32°C to 38°C). But that’s nothing compared to the hottest temperature ever recorded on Earth – 134°F (56.7°C) in Death Valley, California on July 10, 1913.
The Sun’s Core
The sun, the star at the center of our solar system, is way hotter than anything we can imagine. The surface of the sun is scorching, but the core? Well, that’s a whole other level of heat! Here’s a few things you can expect to find in the sun’s core:
- Temperatures reaching up to 27 million degrees Fahrenheit (15 million degrees Celsius)
- A pressure so intense it’s 250 billion times greater than the pressure at sea level
- Nuclear fusion reactions that produce energy and light
Conclusion
So, there you have it. The sun is hot. Like, really hot. Hotter than anything you can imagine. So, next time you’re out in the sun, remember – it’s hotter than you think!
The Sun’s Heat and Energy
Temperature
- In space, molecules far from the Sun are warmed solely by light left over from the Big Bang. Absolute zero is -273.15°C, -459.67°F, or 0K.
- The gas between stars may reach a temperature of only about 3K.
- The Sun’s surface, or photosphere, has an average temperature of about 6000K.
- Sunspots are cooler, at about 4500K.
- Water freezes at 273K (0°C or 32°F) and boils at 373K (100°C or 212°F).
Source of Energy
- Deep inside the Sun, where the temperature is 15 million kelvins, hydrogen atoms zip about and often collide.
- Their energies are so high that a collision strips off the atom’s electrons.
- Hydrogen, which is simply a proton, combines with other protons to form helium.
- This process, called the proton-proton chain, releases energy in the form of gamma rays.
- The gamma rays are converted to heat and light as they travel out of the Sun.
Light
- Special telescopes on Earth and in space can show us the Sun’s surface in exceptional detail.
- The nearly invisible chromosphere, just above the photosphere, is a little hotter than the surface with a temperature reaching a temperature of about 20,000K.
- Above the chromosphere, the corona becomes a wind of thin gas that flows outward through the solar system.
- The corona is remarkably hotter than the surface of the Sun, with temperatures reaching 2,000,000K.
- During a solar eclipse, when the Moon blocks the light of the photosphere, the white glow of the corona is visible to the eye.
Spectrum
- The Sun is a type G star, meaning it emits a spectrum of light that is dominated by yellow-green light.
- The solar spectrum reveals the composition of the Sun, with elements like hydrogen, helium, and oxygen being the most abundant.
- Free solar energy is available to us in the form of sunlight, which can be used to power homes and businesses.
- Sailing in space with sunlight is possible, as spacecraft can use the Sun’s energy to propel themselves.
- Solar wind is a stream of charged particles that is emitted from the Sun and can affect the Earth’s climate.
The Sun’s Toasty Temperature
The Basics
- Absolute zero is a chilly -273.15°C, -459.67°F, or 0K.
- The Earth is kept warm by energy left over from its formation, energy released from radioactive decay, and energy it receives from the Sun.
- The Sun’s surface, or photosphere, has an average temperature of about 6000K.
- Sunspots are cooler, at about 4500K, due to a strong local magnetic field blocking energy flow.
- Water freezes at 273K (0°C or 32°F) and boils at 373K (100°C or 212°F).
The Invisible Parts
- The nearly invisible chromosphere, just above the photosphere, is a bit hotter than the surface with a temperature reaching 20,000K.
- Above the chromosphere, the corona is a wind of thin gas that flows outward through the solar system.
- The corona is much hotter than the surface of the Sun, with temperatures reaching 2,000,000K.
The Inside Scoop
- The average density of the Sun is about 1.4 grams per cubic centimeter.
- The center of the Sun is 15,000,000K and has a density of 150 grams per cubic centimeter.
- Energy from the center of the Sun reaches the surface in about 1,000,000 years and takes 8 minutes to reach Earth.
The Sun’s Source of Energy: Proton-Proton Chain
What’s Happening?
- Inside the Sun, it’s so hot (15 million kelvins!) that hydrogen atoms are bouncing around and often crash into each other.
- This collision strips off the electrons, leaving just protons and electrons.
- The protons have enough energy to overcome their repulsion and fuse together, making deuterium, then light helium, and finally, the helium we find on Earth.
- Every time this process occurs, 4 hydrogen atoms become 1 helium atom.
What’s the Big Deal?
- When the helium is made, some of the mass has disappeared.
- That missing mass has been turned into energy, in the form of gamma rays (100,000 times more energetic than visible light!).
- So, the Sun is converting hydrogen into helium and energy!
The Sun’s Shiny Rays
What are Gamma Rays?
Gamma rays are like tiny little party animals, they get absorbed by atoms, then they get all excited and start dancing around, changing their wavelength according to the energy levels of the electrons in the atoms, and the temperature of the atoms.
What’s the End Result?
By the time these little party animals reach the Sun’s surface, they’ve mostly changed into:
- Visible light (Type G star)
- Ultraviolet light
- Infrared light
- Small amounts of x-rays
- Microwaves
- Radio waves
All of these are forms of Electromagnetic Radiation, which is basically just light, which is made up of photons.
The Sun is a G-Type Star
What is a G-Type Star?
- G-type stars are medium-sized stars that emit mostly visible light, with a little bit of X-rays, ultraviolet, infrared, microwaves, and radio waves thrown in for good measure.
- They’re like the Goldilocks of stars – not too hot, not too cold, but just right!
- These stars are classified based on the light they emit, and those similar to the Sun are labeled type “G”.
What Does This Mean for Us?
- We’re lucky that the Sun is a G-type star, because its electromagnetic radiation is mostly visible light, which is safe for us humans.
- Earth’s atmosphere absorbs the more dangerous X-rays, and the ozone layer blocks out the ultraviolet light.
- The infrared light is felt as heat, and the microwaves and radio waves carry music through space.
Why is the Sky Blue?
- The Sun is a G2 star, which means it has an average surface temperature of 5,780 K, giving it a whitish color.
- The Earth’s atmosphere scatters the shorter wavelength violet and blue light, making the sky appear blue.
- The remaining light makes the Sun look yellow.
Other Types of Stars
- Type O stars are the largest and hottest stars, and they emit mostly ultraviolet light.
- Type M stars are the smallest and coolest stars, and they radiate mostly infrared light.
- Proxima Centauri is a type M star and the nearest star to the Sun, located 4 light years away.
- By analyzing the light emitted by a star, we can learn a lot about it.
Conclusion
In conclusion, the sun is an incredible source of energy that warms us and provides us with light. It’s amazing to think that the same energy that heats up Death Valley to 134°F (56.7°C) can also provide us with a gentle warmth that we can enjoy. To make the most of the sun’s energy, remember to wear sunscreen, stay hydrated, and enjoy the outdoors! And don’t forget the most important rule of all: never look directly at the sun, or you’ll be seeing stars!
