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!