Not actually Erin.
& is used with permission.
(Hi folks! Lokidude is working an extra shift and so we switched days.)
If you're a fan of science fiction, you have heard the term "hard radiation" and wondered what exactly it meant, or if it's a made-up term. But what exactly is hard radiation? And does that mean there's such a thing as soft radiation?
The answers are "Yes, it's absolutely real" and "Yes, soft radiation also exists."
What They Mean
Both hard and soft radiation are ionizing radiation. I still owe you a detailed explanation on what that is, but as I said last week, it's the bad kind of radiation that gives you cancer or kills you with radiation poisoning.
Soft radiation is at the lower end of the ionizing radiation spectrum, which means it is less energetic than hard radiation, which is at the higher end. A good analogy would be the difference between infrared and ultraviolet light; ultraviolet is at the higher end of the light spectrum, and therefore is "harder" than infrared.
Unfortunately, unlike with the light spectrum, there is no clear line of differentiation between hard and soft radiation; it is a colloquial term. It's pretty easy to understand that ultraviolet light, which can cause skin cancer in large enough doses, is soft radiation, and that cosmic rays (which are the most powerful forms of radiation that we've been able to detect) are hard, but things like x-rays and gamma rays are a bit iffy.
This is because gamma and x-rays can be hard or soft, depending on their frequency. Think of this like shades of color: both maroon and scarlet are shades of red, but scarlet is brighter -- a higher-frequency red, if you like.
The Practical Difference
Exposure to either hard or soft radiation outside of a controlled medical environment is usually a bad thing, and is to be avoided (especially since most sources of x-rays and gamma rays within the atmosphere are the result of a nuclear bomb detonation).
Soft radiation exposure is marginally better than hard radiation exposure, in the same way that it is marginally better to be hit by car than it is to be hit by a bus.
When someone says "hard radiation" they generally mean the kind of radiation that burns your skin, cooks your internal organs, and gives you radiation poisoning. In other words, it kills you quickly, rather than killing you slowly via cancer.
NEXT: Ionizing Radiation for Dummies