Why Interstellar Spaceflight is Hard

This was initially published in audio form as Burst 7 of the Wow! Signal. As part of the ongoing effort to tie this blog into that podcast and vice versa, we here present a slightly edited text version of the same.

This is a tutorial post, and is largely meant to bring some of our readers up to speed, since we are going to be talking about interstellar space flight more over the next months. If you have ever wondered by we can’t just get on a big rocket and fly to the stars, this is for you. If you already know why we can’t do that, then I think you might want to skip this one. 

4 Pi SETI - Why Not Build the Argus Radio Telescope Full Scale?

Robert Dixon

Update: we need to digest this first. All-sky there could be 2000 FRBs per day.

This  post - like nearly all the others - is about the questions I have. I am not a radio astronomer.I want to know how and how much and when about the radio telescope we will discuss below. This was stimulated by my interview with Robert Dixon last year, in which he discussed the virtues of the Argus concept. I lay awake that night thinking about it, and wondering why it hadn't been built yet.
 
The Search for Extraterrestrial Intelligence (aka SETI) is just that - a search. Like any search, it becomes much more difficult when more dimensions are added to the search space, and far easier when one or more of those dimensions are removed.

For example, if you are looking for an obscure little store with the best barbeque ribs in the West, and all you know is that it's in Los Angeles County, then your search space is quite large. However, if you have the additional information that it's on Santa Monica Boulevard, then you you still have some searching to do, but much, much less. You might even find the joint before it closes.

The problem with the SETI search is that it uses telescopes, and telescopes like the Allen Telescope Array or the Arecibo Observatory, only look at a small part of the sky at any one time. In fact, all the radio observatories in the world put together are only looking at a tiny sliver of the sky. If an ET beacon is transmitted for a short time while you are looking at another part of the sky (which you almost certainly are), you would completely miss it. We can dream about adding more telescopes to the search, but we would need a ridiculous number to cover the whole sky at once - or would we?

Questions about Asteroid Mining

What follows is based closely upon the Wow! Signal Podcast's Burst 8.

Lately, it’s been my sense that it’s time to spin up the asteroid mining conversation in earnest. Our most recent Unseen Podcast episode (#33) covered asteroid mining, and space policy expert James Muncy joined us for the first part of the show. We received a comment on the blog post for this episode by “Khani”, and here it is verbatim:

Question - (case 1) I travel to an asteroid of 100 meters in size. I start extracting materials from the "equatorial" zone. Is the material mine? (case 2) is the asteroid mine? (case 3) I move the asteroid, and now someone else lands on the other side and starts harvesting it. Is that "illegal" ? How much does the asteroid to be moved to be claimable? One meter?

Respectable test cases, I think, but we can go further.