Dark Energy and the Goldilocks Zone


A (failed) thought in astrophysics.

It is relatively well-known (at least to me) that stars get brighter over time. As such, the "goldilocks zone" (not too hot or too cold) suitable for life-as-we-know-it moves outward. As the Sun gets brighter, it heats up the world more, but we could theoretically fix this by moving Earth farther away. However, Earth does not move farther away from the Sun (enough to matter), so it gets warmer instead. Eventually (in 1.7ish billion years), the goldilocks zone will move out so far that it is entirely outside Earth's orbit, which will be a Very Bad Thing. ("You people all have to learn / this world is going to burn! / Burn! / Burn!" ~ Dr. Horrible)

But hang on a minute here. The universe is expanding. This means that space is sort of "stretching" and everything gets farther apart from everything else. Gravity holds things like Earth itself together, but shouldn't Earth get to be farther away from the sun? Maybe the world doesn't have to burn after all. That would be nice. I like this place - it has trees and sunsets and whatnot.

Unfortunately, it isn't going to work. Apparently the expansion of the universe only stretches out Earth's orbit when it changes. I don't understand why, but the Internet seems quite confident about it. Maybe it has to do with (general) relativity, but I am only saying that because I don't understand either. I guess that's probably not a reason.

To do: Read about relativity again and maybe this time it will make sense. No harm in trying. Insanity means trying the same thing over and over and expecting a different result. I may be getting a padded room soon, but that is OK. Leah tells me you get free marshmallows, although I am not sure how she figured this out.

Hang on another minute. The expansion of the universe is changing. It's even changing the right way (faster). This is due to something called dark energy, which nobody anywhere understands. If you are wondering, "dark" is a special physics term meaning "we have no idea what this is or why it happens but we have to call it something or we couldn't publish our paper about it". So maybe dark energy will save us.

Sadly, this isn't going to work either. The effect does exist, and it does move Earth away from the Sun, but it isn't enough movement to matter. Earth seems to still be stuck in its orbit. Thomas Aquinas (who suggested that the planets were pushed around by angels) would be pleased.

I guess we will have to fall back on the old plan: A big shield in space to block some of the sunlight. This is called a space sunshade for obvious reasons, and gets a lot of bad press from renewable energy advocates. Rest assured, I want to use it to solve a completely different problem. Its not a remotely urgent problem, admittedly, but it still exists. It's also way more interesting.

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