Why does the sun burn us?

The sun keeps our planet warm enough for living things to thrive. It gives us light so we can see. But it can also burn us. What causes these burns?

All About Energy

The sun sends lots of energy toward us all the time. There are a few different kinds of energy. There is infrared radiation, which is heat. There is visible light, which is what our eyes can see. There is also ultraviolet light. We can’t see ultraviolet with our eyes, but it’s there. And it can burn our skin.

Waves, Waves, Waves

Infrared radiation, visible light, and ultraviolet light are all types ofwaves in the electromagnetic spectrum. They’re all energy. But these energy waves aren’t all the same. Some have more energy than others.

Infrared waves have less energy than visible light waves. Infrared waves are longer with more space between each high and low. Ultraviolet waves have more energy than visible light does. It’s this energy that can hurt us.

Feel the Burn

If too much ultraviolet light hits our skin, over time it can hurt our skin cells. The cells can die, and our bodies react. The skin gets red, and it can hurt a lot.

Ultraviolet light comes from the sun, but it can also bounce off of other surfaces like water, snow, and concrete. That means that even if you’re under an umbrella, you can still get a sunburn. Ultraviolet light can also go through clouds, so you can get burned on an overcast day. No fair!

You can protect your skin by doing things that keep ultraviolet waves from reaching you. Clothing and hats are a great way to keep away those waves. Sunblock contains chemicals that can reflect or absorb the ultraviolet light, leaving your skin sunburn free.

That way you can enjoy the other energy from the sun, visible light and infrared warmth.

Interstellar Space

Where does interstellar space begin?

At first glance, the answer seems simple. ‘Inter’ means between. ‘Stellar’ refers to stars. “Easy!” you think, “Interstellar space is the part of space that exists between stars.”

Not so fast! Wouldn’t that pretty much mean that all of space is interstellar space?

For interstellar space to be something different, then there must be some defined boundary between the space near a star and the space in between stars. But what is that boundary?

Look to the solar wind!

The sun creates this heliosphere by sending a constant flow of particles and a magnetic field out into space at over 670,000 miles per hour. This stream is called the ‘solar wind.’Scientists define the beginning of interstellar space as the place where the sun’s constant flow of material and magnetic field stop affecting its surroundings. This place is called the heliopause. It marks the end of a region created by our sun that is called the heliosphere.

Like Earth wind, this wind pushes against the stuff around it. What it pushes against are particles from other stars. —pretty much anything that doesn’t come from our own solar system.

How would we know when we’ve arrived in interstellar space?

When it comes to the sun it’s all about detecting the concentration and temperature of the particles around you.

Inside the heliosphere, the solar particles are hot but less concentrated. Outside of the bubble, they are very much colder but more concentrated.

Once you arrive in interstellar space, there would be an increase of “cold” particles around you. There would also be a magnetic field that does not originate from our sun. Welcome to interstellar space!

Paper Quilling Flower Basket

Paper Quilling Flower Basket done by Me 

Human Body Facts

1. There are 2.5 trillion (give or take) of red blood cells in your body at any moment. To maintain this number, about two and a half million new ones need to be produced every second by your bone marrow.That's like a new population of the city of Toronto every second.

2. Considering all the tissues and cells in your body, 25 million new cells are being produced each second. That's a little less than the population of Canada - every second !

3. A red blood cell can circumnavigate your body in under 20 seconds.

4. Nerve Impulses travel at over 400 km/hr (249 mi/hr).

5. A sneeze generates a wind of 166 km/hr (100 mi/hr), and a cough moves out at 100 km/hr (60 mi/hr).

6. Our heart beats around 100,00 times every day or about 30 million times in a year.

7. Our blood is on a 60,000-mile journey per day.

8. Our eyes can distinguish up to ten million colour surfaces and take in more information than the largest telescope known to man.

9. Our lungs inhale over two million litres of air every day, without even thinking. Their surface area is large enough to cover one side of a tennis court.

10. We give birth to over 200 billion red cells every day.

11. When we touch something, we send a message to our brain at 124 mph

12. We exercise at least 36 muscles when we smile.

13. We are about 70 percent water.

14. We make around 1 to 1.6 litres of saliva a day.

15. Our nose is our personal air-conditioning system: it warms cold air, cools hot air and filters impurities.

16. In one square inch of our hand we have nine feet of blood vessels, 600 pain sensors, 9000 nerve endings, 36 heat sensors and 75 pressure sensors.

17. We have copper, zinc, cobalt, calcium, manganese, phosphates, nickel and silicon in our bodies.

18. It is believed that the main purpose of eyebrows is to keep sweat out of the eyes.

19.  A person can expect to breathe in about 45 pounds of dust over his/her lifetime.

Space Facts

• The Sun is over 300000 times larger than earth. More Sun facts.
• Halley’s Comet was last seen in the inner Solar System in 1986, it will be visible again from Earth sometime in 2061 (get your camera ready). More comet facts.

• Venus is the hottest planet in our solar system with a surface temperature of over 450 degrees celcius.
• Many scientists believe that an asteroid impact caused the extinction of the dinosaurs around 65 million years ago. More asteroid facts.
• The Solar System formed around 4.6 billion years ago. 

• The Moon appears to have more craters and scars than Earth because it has a lot less natural activity going on, the Earth is constantly reforming its surface through earthquakes, erosion, rain, wind and plants growing on the surface, while the moon has very little weather to alter its appearance. More Moon facts.

• Saturn isn't the only ringed planet, other gas giants such as Jupiter, Uranus and Neptune also have rings, they are just less obvious.

• Footprints and tyre tracks left behind by astronauts on the moon will stay there forever as there is no wind to blow them away.

• In 2006, astronomers changed the definition of a planet. This means that Pluto is now referred to as a dwarf planet. Learn more dwarf planet facts.

• Because of lower gravity, a person who weighs 200 pounds on earth would only weigh 76 pounds on the surface of Mars.

• The only planet that rotates on its side like a barrel is Uranus. The only planet that spins backwards relative to the others is Venus.
• Some of the fastest meteoroids can travel through the solar system at a speed of around 42 kilometres per second (26 miles per second). Check out more meteoroid facts or learn the difference between comets, asteroids and meteoroids.

• The first man made object sent into space was in 1957 when the Russian satellite named Sputnik was launched.

• Jupiter's 4 biggest moons are named Europa, Ganymede, Callisto and Io. MoreSolar System moon facts.

• It is because of the Sun & Moons gravity that we have high & low tides.
• For a list of important space definitions take a look at our glossary of easy space and astronomy definitions for kids.

Facts on the human eye

• Eyes detect light and allow us to see.
• The information our eyes receive is sent to our brain along the optic nerve. This information is then processed by our brain and helps us make appropriate decisions, for example if you can see an object flying in your direction then you will probably move quickly out of the way.
• Around 95% of animals have eyes. Some are very simple, just picking up light and dark conditions while others are more complex, allowing for the recognition of shapes, color and depth.
• Like humans, some animals have eyes placed close together that allow for improved depth perception, others have eyes spread further apart (often on opposite sides of their head, as in horses) to allow for a greater field of view and an early warning against potential predators.
• The light sensitive tissue lining the inner surface of your eye is known as the retina, acting in a similar way to film in a traditional camera.
• Cone cells in the retina detect color while rod cells detect low light contrasts.
• The part of the eye that allows us to focus on different things in known as the lens, it changes shapes so we can focus on objects at various distances.
• The cornea is the transparent covering of the iris and pupil, along with the lens it refracts light so it can be projected onto the retina.
• The central opening of your eye is known as the pupil, it changes size depending on the amount of light.
• The colored area around the pupil is called the iris, it controls the size of the pupil and can be colored brown, blue, green or other colors and shades depending on the person.
• Scientists believe that animal eyes evolved around 500 million years ago, beginning in simple form (perhaps just distinguishing light and dark) but giving a distinct advantage. This advantage led to eyes evolving quickly among animals (by evolutionary standards) as those without the ability to see struggled to survive against those that could.
• Throughout the animal kingdom there are many different types of eyes, for example the human eye is very different to the compound eye of a fly which is better at detecting fast movements.
• Human eyes contain a small blind spot where the optic nerve passes through the retina. Our brains use information from the other eye to fill in the vision gap so it is rarely, if ever, noticed.
• Glasses and other protective equipment are often worn by humans to protect the eyes from UV rays or during various dangerous activities such as welding.
• Glasses and contact lenses are worn to correct common sight conditions such as short and long nearsightedness.