There is also a re-thinking of the role that lactic acid plays in muscle fatigue in exercise. It is not the source of burning in your muscles it has long been thought to be.

There are a lot of silly people bemoaning the loss of Pluto as a planet. Get over it. I’m sure there were some stubborn people upset over the loss of the flat Earth. When Pluto was discovered in 1930 by Clyde Tombaugh, planetary science was in its infancy. In the time since, our knowledge of the universe and how it works has improved dramatically.

Let’s role play: Suppose you are an alien observing events on Earth for the first time. You happen upon a burning building and you see a bunch of fireman surrounding the house working furiously and spraying something all over the building. You might reasonably conclude that the fireman created the fire and working to keep it going. Once you learn a bit more about Earth, humans, and fire, it would be ridiculous to continue to believe that.

Pluto is not and should not be a planet anymore because now we have a very sound definition of what a planet is. To be classified as a planet, a celestial object must meet two criteria:

1. It must have enough mass to pull itself into the shape of a sphere
2. The Sun must be the primary source of its gravitational influence

(By the way, I have a Bachelor of Science degree in Astronomy. Yes, it is true. I used to study stellar bodies, now I help build them.)

The burning in your muscles when you exercise has been attributed to lactic acid ever since researchers experimenting on frogs about 100 years ago attributed muscle fatigue and pain to the lactic acid found in the frog's muscles. Well, people keep doing more research, and yet again, science changes.

Not only does lactic acid not cause burning and fatigue, it actually protects muscles against exhaustion. Some lactic acid actually gets recycled as another fuel source for your muscles and your heart, slow-twitch muscle fibers and the muscles used in breathing – all of which prefer lactic acid as a fuel during exercise.

It is actually hydrogen ions (H+) that cause the burning. These hydrogen ions are formed from lactic acid when it is used for energy. They can interfere with electrical signals in the muscles and nerves, slow energy reactions and impair muscle contractions.

Science – whether it pertains to space or to human physiology – will always change with each new discovery. Accept this as part of reality and skip the frustration when something changes about exercise or nutrition that was previously thought to be true.

Now that you know why Pluto should not be a planet and why lactic acid does not cause muscles to burn, you are sure to impress at the next social event you attend. You will be able to provide lively and intelligent conversation on such seemingly disparate subjects – demonstrating that you have well-rounded knowledge and a willingness to embrace cutting edge research.