[VariableStar]

I see that. My point is that if the captured energy is used, and thus ultimately dissipated as heat, on the planet's surface, that planet is sooner than later going to have climatic imbalance.

[cletus]

There are several possibilities here.

First, the Earth already receives a ton of energy from the Sun that is "wasted". We estimate that at about 10^16 Watts of power, compared to humanity's energy usage, estimated at 10^10-10^11 watts. So Earth has a ton of energy dissipiation "built in" that we're not "using".

Second, there is some inefficiency and thus heat dissipation in converting solar output into usable energy. Doing that in space means a bunch of heat dissipation happens in space rather than on your planet.

Third, it's relatively straightforwward to counter any increased heat dissipation on your planet by reducing that solar output that hits your planet. How? You build something at the EArth-Sun L1 Lagrange point. Reducing that solar output that hits the EArth by 1% would likely be unnoticeable to us but could cool the Earth significantly. Also, what do you build there? Well, lots of things. More orbitals, solar power collectors, etc.

Fourth, how do you get power down to a planet? There are several candidates. One is to beam it down. This adds a conversion cost. But here's another: you build a n orbital ring [1] 100-150km above the EArth's surface. There are a ton of reasons you'd want to do this: interplanetary travel, cheap travel to and from LEO and easier travel across the planet (ie up to the ring, down to another point on Earth on cable cars, basically). But consider this: it gives you a rigid structure to attach solar power collectors to and you can run power transmission cables down from the ring to the planet's surface.

[1]: https://www.youtube.com/watch?v=LMbI6sk-62E

[ericd]

I wonder how much reaction mass we’d need every year to keep something stationed at a Lagrange point to block 1% of earth’s light, for combatting global warming. 1% of earth’s light would be a heck of a solar sail.

Looks like 1% would be 13.3 watts per meter, cross section of earth yields ~5.4x10^14 watts. Assuming perfect reflective, multiplying by 2/c gives 3.6x10^6 N. So like half of the thrust of one of Saturn V’s engines? So… a lot of reaction mass, or some really powerful ion engines and a ton of power. So maybe not the most practical idea.

[pests]

Are you capitalizing it like EArth for a reason or just a typo? Just wondering as you use it a few times but are flip flopping.

[yreg]

You don't redirect all the energy to the home world. You dissipate the heat into space.

Which is why you can't hide, anyone who aims their instruments on your system will detect the heat and see that the star is obstructed.

[kobalsky]

if a civilization needs so much power they build a dyson sphere they probably have terraforming nailed.

that kind of technology probably takes hundred of thousands of years of technological development and we have had electricity for how long?

[pests]

I think you are overestimating by many orders of magnitude.

[vitiral]

Planet? Dyson swarms orbit a SUN, not a planet

[fikama]

Its not where energy is sourced but wher its used. And assuming it will be civilisation's planet like Earth. The whole energy of the swarm will be used there. - It just has to increase temperature (due to additional energy on the planet)

[kiba]

Earth already do this. We only use some energy for our purpose.

[sdwr]

We are using the sun's energy that hits the earth. Some as light (which turns into heat), some as electricity (which turns into heat), and some as plant food > animal food > oil (which turns into heat)

A Dyson sphere would capture the sun's energy that leaves the sun, not just the fraction that hits earth. Using that energy on earth would release far more heat than our current activities.