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> Seeing the surface of extrasolar planets Planet. Singular. Not plural. The nature of gravitational lensing is that you would need to build and place a new te

> Seeing the surface of extrasolar planets Planet. Singular. Not plural. The nature of gravitational lensing is that you would need to build and place a new telescope for every different direction you want to look. The relevant quote from the linked wikipedia page is: “FOCAL would be able to observe only objects that are right behind the Sun from its point of view, which means that for every observed object a new telescope would have to be made.” > Compared to settling Mars this seems infinitely more important unless you have some hyper skeptical view of human society. My “hyper skeptical” view of human society is that it is fragile. There are many possible catastrophes which could wipe all of us out, then there are many other possible situations which would not kill all of us but would shunt humanity forever. Settling Mars would make us more resilient in two major ways: The settlement on Mars is a physical off-site backup to human society. And the necessary R&D to achieve a self-sustaining Mars setlement would force us to develop and test for reliability under real world circumstances tech which we could use here on Earth to better survive many of those calamities. It is literally a ticket to raise the probability of the continued existence of humankind. On the other hand a picture of an exoplanet is a picture. An interesting one sure. If we would have it now it would be probably front page news. It would be a blurry pixelated disk with smears of colour. That would be all for 99% of humanity. For the select few they would study the image and analyse it and we would have follow on studies in a few years saying things like: “We are reasonably sure this area is a shallow sea, and we think this colour fluctuation is consistent with an algea bloom.” Iff(!) we got lucky and the exoplanet we aimed the telescope at is not a dead, dry rock. So increasing the chance of our survival vs a blury picture which will pose more question than it answers. How are these two goals in any way comparable? Let alone the second being more important?

dmix 4y ago
I didn't know about the single planet thing thanks for explaining that. I guess I have more hope for the species in the near term and getting those photos seems to be something I personally care more about. But the two things are different you're right.
- krisoft 4y ago
  > I have more hope for the species I don't think that a bolide crashing into our planet and flash-boiling the oceans will care about our hope. Not every danger we are facing is anthropogenic sadly. Some things are just up for luck and happenstance.
shagie 4y ago
If you're interested in a critical review of FOCAL (which is also rather interesting) - https://arxiv.org/pdf/1604.06351.pdf https://arxiv.org/pdf/1604.06351.pdf I am on the "this is a really hard problem - but an interesting one" category. It seems like it will take a number of significant improvements on top of current technology - but it seems like it would be doable in another few decades if we continue to improve (the difference between Pioneer and New Horizons is 35 years... if we can do that much improvement again we might have something). It is still something that if you are a grad student working on it now, it would launch when you retire, and your grad students when you retire - when they retire, it is their grad students who would be doing analysis of the data. I tend to believe this would be a good thing to do because it would be working on that time frame and getting us to think about projects that will run for a century rather than a budget cycle.
- krisoft 4y ago
  > If you're interested in a critical review of FOCAL Thank you. I'm familiar with the general arrangement, but haven't read that one yet. > I am on the "this is a really hard problem - but an interesting one" category. Absolutely! I'm fascinated by these proposals. So much so that I wanted to write a simulator to study the control challenges of a project like this. > I tend to believe this would be a good thing to do I'm with you on that. I just don't think it has the same utility as an off-planet settlement. Luckily, I believe we can and should do both.

dmix 4y ago

I didn't know about the single planet thing thanks for explaining that. I guess I have more hope for the species in the near term and getting those photos seems to be something I personally care more about. But the two things are different you're right.

krisoft 4y ago
> I have more hope for the species I don't think that a bolide crashing into our planet and flash-boiling the oceans will care about our hope. Not every danger we are facing is anthropogenic sadly. Some things are just up for luck and happenstance.

shagie 4y ago

If you're interested in a critical review of FOCAL (which is also rather interesting) - https://arxiv.org/pdf/1604.06351.pdf https://arxiv.org/pdf/1604.06351.pdf I am on the "this is a really hard problem - but an interesting one" category. It seems like it will take a number of significant improvements on top of current technology - but it seems like it would be doable in another few decades if we continue to improve (the difference between Pioneer and New Horizons is 35 years... if we can do that much improvement again we might have something). It is still something that if you are a grad student working on it now, it would launch when you retire, and your grad students when you retire - when they retire, it is their grad students who would be doing analysis of the data. I tend to believe this would be a good thing to do because it would be working on that time frame and getting us to think about projects that will run for a century rather than a budget cycle.

krisoft 4y ago
> If you're interested in a critical review of FOCAL Thank you. I'm familiar with the general arrangement, but haven't read that one yet. > I am on the "this is a really hard problem - but an interesting one" category. Absolutely! I'm fascinated by these proposals. So much so that I wanted to write a simulator to study the control challenges of a project like this. > I tend to believe this would be a good thing to do I'm with you on that. I just don't think it has the same utility as an off-planet settlement. Luckily, I believe we can and should do both.