Should we be messing with asteroid orbits? | Hacker News Reader

Should we be messing with asteroid orbits?

nautil.us

21 pointslimbicsystem14 comments

"This new advancement is intended for good but might also be used for evil" – this statement describes every invention in history, perhaps going back to the first time a prehistoric human used a rock to crack open a nut. Had online journalism existed back then I'd wager there would have been a "should we be messing with rocks?" article soon after.

Yes there are dangers in changing asteroid orbits. Yes we should be careful. But the argument that we should stop all progress towards diverting extinction-level threats to the planet because a nation might theoretically toss an asteroid at another one day is absurd.

It does sound like a form of ludditism.

All imaginable technologies can be used in more than one way so at the very least some quantification of relative harms and advantages needs to be done for it to be credible.

Realistically, though, we are way bigger danger to ourselves than nature is

That's debatable. Nature has certainly killed more humans in history than humans have. Dramatic climate change or nuclear war could turn the tides, but at the moment nature wins the danger contest.

Any nation that can reasonably build a space program to maliciously divert an astroid can also reasonably build a bomb that could cause the same amount of destruction without the complexity of building a spacecraft. This is a pretty silly argument.

Here's how you can terraform Venus.

1. put a sunshade at the Lagrange point between Venus and Sun. Dim the light coming from the Sun

2. wait for the planet to cool enough until the carbon dioxide (which forms about 97% of the Venusian atmosphere) freezes and falls to the ground. The combination of 30 times less gas in the atmosphere (the remaining gas will be mainly N2) and a lower temperature will lower the ambient pressure to about 1 atm (the pressure on Earth).

3. send some sort of parabolic mirror to one of the icy asteroids like 24 Themis or 65 Cybele. Concentrate the sunlight into a beam that will make a part of the asteroid boil and outgas. That will provide thrust. You can guide the asteroid whichever way you want. Move it to an orbit that will intersect Venus. Slam it into Venus. Now you have the water that you need. Currently Venus is extraordinarily dry, but if you bring water from the asteroid belt, you have a shot.

4. Build greenhouses. Plant trees. In the greenhouses provide artificial light, water and CO2, and let the trees thrive (you need a bit of oxygen to get them going, but after that they'll make more than they'll consume; you'll also need fertilizer, but you have plenty of N2 and now H2 as well; you need other elements like potassium and phosphorus, but in much lower quantities; you will probably be able to mine them locally).

5. The trees will sequester the carbon. They'll also produce oxygen. After a when you have enough oxygen in the atmosphere, you can fold a part of the sunshade and let the temperature go up. The unsequestered CO2 will gassify. Now you'll have an atmosphere with nitrogen, oxygen, CO2 and some water vapors, just like on Earth. Probably much more CO2. But you can control the temperature with the sunshade, so you are not too worried about climate change.

6. Sell tickets to colonists. Profit.

Nice. Thinking big. And long. It’s going to take about a thousand years, but it’ll be worth it.

It might not be one thousand years. It will probably be more than 100 years. Of course, 100 vs 1000 is an unverifiable dichotomy.

But hear me out.

A sunshade big enough to make a difference for Venus would be of the order of 1 billion tons (why? I'm using the sunshield of James Webb, which is about 25 microns thick, and is made of a material called Kepton, which has a density similar to plastic; the rest is just multiplications).

Moving a billion tons in space is not easy, thanks to the tyranny of the rocket equation.

But if you are at the technological level of building a planet side sunshade, then you can probably build a parabolic mirror (made of the same mylar-like material like JWST's sunshield) []6781

Dinosaurs certainly didn't mess with asteroid orbits...

The idea that an individual nation observes someone has accidentally shifted an asteroid to hit their nation, exactly, seems incalculably unlikely.