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Earth-sized exoplanet ‘habitable zone’

nature.com

61–70 of 95 posts

Re: Earth-sized exoplanet ‘habitable zone’

#61

Downvote me to oblivion, but riddle me this Neil DeGrasse Tyson. If the Earth is an 'oblate spheroid' (it used to be a perfect sphere, you've seen the pics, right?) with a roughly 25,000 mile circumference, then why do all the curvature calculations fail? The rate of curve on a sphere that size is 8" x the number of miles squared and modern optics have completely debunked that. We can see too far. There is no curve.…

You can literally see the curve by watching ships on the ocean. :D

Re: Earth-sized exoplanet ‘habitable zone’

#62
Not sure on the social norms here, I commented on the post of this news that didn’t rise to the front :

‘completes one orbit every 10 Earth days' Excellent news for fans of the French Revolutionary Calendar. 'The French Revolutionary Calendar, created at the same time as the metric system, was an attempt to create a metric calendar and time system.' https://www.cooksinfo.com/french-revolutionary-calendar https://en.wikipedia.org/wiki/French_Republican_calendar https://twitter.com/sansculotides

Re: Earth-sized exoplanet ‘habitable zone’

#63

Earlier quoted context omitted.

> It would be so much easier just to create the ideal environment in a large, rotating cylinder instead of having adjust a planet's environment to our needs. Yea but people want to go outside.

Artificial outside? If the ship, for lack of a better term, were big enough its conceivable that you could have a larger open area with grass and trees which would feel much like a park. Could even paint the roof blue.

I’m open to it, but I suspect it would be difficult to figure out all the things we’d miss even on a biological level. You don’t think people would read about planets and realize what they’re missing? I think they would curse their ancestors for ever leaving. This feeling of leaving some paradise and forgetting what we’ve even lost is a core theme of genesis, it’s as human as anything in civilization, and it’s only going to get stronger if we explicitly abandon where we came from (I mean this metaphorically, I imagine we’d be happy on earthlike planets, even if we do miss earth’s sun or whatever at first).

Re: Earth-sized exoplanet ‘habitable zone’

#64
post #10
post #5

Earlier quoted context omitted.

These types of planets are known as 'Eyeball planets'. [1] They are hypothesized to have a hot side and a cold side, and potentially a ring around the periphery that is 'just right' where liquid water could form and sustain life. Not sure if this particular planet would meet those criteria. [1] https://en.wikipedia.org/wiki/Eyeball_planet

Even if the planet had a strong magnetosphere, wouldn't atmosphere on the hot side be blown away by heat or solar wind? Thus atmosphere from the whole planet would be depleted.

Astronomers & cosmologists like to play games where they try to sketch out how a tidally-locked world might, just might, be inhabitable. I tend to think it's balancing on a pretty high-dimensional knife's edge on cosmological time scales; there's all sorts of directions that various resources can fall out of the habitable zone and not be able to come back.

For a terrestrial example of the sort of thing I mean, see things like https://www.astrobio.net/biosphere/earths-breathable-atmosph...; it is thought that a lot of resources vital to life on Earth would have left the biosphere before life could even get going if Earth, or before the biosphere could progress very far, were not tectonically active. Trying to put together a habitable eyeball-planet seems like it has that problem to the tenth power to me.

Re: Earth-sized exoplanet ‘habitable zone’

#65
post #6

According to this [1] it's probably tidally locked, which means that despite being in the goldilocks zone, the environment is likely problematic for life. [1] https://www.sciencealert.com/nasa-found-a-tatooine-like-plan...

People keep saying that for extreme climates on Earth and are then constantly surprised by the variety and abundance of life - admittedly sometimes just microbiology - found in those locations. So I wouldn’t write off a planet just for tidal lock.

The problem is that the atmosphere and weather is global. Meaning that snow that falls on the cold side will never melt or evaporate. Therefore there's probably no liquid water.

Liquid oxygen is dense enough for icebergs to float over to the warm side, but there won't be any oxygen before life can start photosynthesizing, and it would boil off long before ice could float close enough to the hot side to melt or evaporate. Liquid nitrogen is less dense than ice, so that doesn't help. Most other plausible liquids (methane, ammonia) are also less dense than ice.

It's difficult to say life would be impossible on a tidally locked planet, but it's certainly very unlikely. Remember that it took Earth something like two billion years to develope life, and this place is downright cozy.

Re: Earth-sized exoplanet ‘habitable zone’

#66

Downvote me to oblivion, but riddle me this Neil DeGrasse Tyson. If the Earth is an 'oblate spheroid' (it used to be a perfect sphere, you've seen the pics, right?) with a roughly 25,000 mile circumference, then why do all the curvature calculations fail? The rate of curve on a sphere that size is 8" x the number of miles squared and modern optics have completely debunked that. We can see too far. There is no curve.…

What about pics from space? I see the curve. I don’t think every country is making fake pictures. Also there are plenty of amateurs with balloons and go pros and I don’t think they’re part of some grand conspiracy either. Also gravity.

Re: Earth-sized exoplanet ‘habitable zone’

#67

Downvote me to oblivion, but riddle me this Neil DeGrasse Tyson. If the Earth is an 'oblate spheroid' (it used to be a perfect sphere, you've seen the pics, right?) with a roughly 25,000 mile circumference, then why do all the curvature calculations fail? The rate of curve on a sphere that size is 8" x the number of miles squared and modern optics have completely debunked that. We can see too far. There is no curve.…

What about pics from space? I see the curve. I don’t think every country is making fake pictures. Also there are plenty of amateurs with balloons and go pros and I don’t think they’re part of some grand conspiracy either. Also gravity.

Wasn't there some guy who was crowdfunding a rocket so he could go up and see for himself? Whatever became of that?

Re: Earth-sized exoplanet ‘habitable zone’

#68

I've been pondering this for a while: once we have artificial gravity in space (from rotation, for instance), would we ever want to shackle ourselves to the gravity of a foreign planet? It would be so much easier just to create the ideal environment in a large, rotating cylinder instead of having adjust a planet's environment to our needs. Take this new discovery for instance. Imagine that this planet is 400m years y…

I wouldn't be surprised if we develop brain uploads sometime in the next 400 years, at which point the focus on trying to recreate earth-like environments anywhere will look silly.

There's probably a lot of other advancements over the next few centuries that we can't imagine. Our current view of space colonization is probably going to have as much of a connection to the future as the Tower of Babel had to the Apollo program.

Re: Earth-sized exoplanet ‘habitable zone’

#69
post #22

Earlier quoted context omitted.

Should it ever become practical to do so, the reasons for doing so will look very similar to the reasons Europeans colonized America. The thing about densely populated environments is it requires lots of governance, and populations have a habit of increasing exponentially, which would be difficult for artificial environments to keep up with indefinitely. When you're on the frontier, you have a lot more freedom.

How so? You've already become adept at living in space, working in space, and building things in space out of materials you found in space or else it wouldn't be practical at all to travel to a new star system anyway. At that point, just build new space habitats.

It's an and, not an or. People get good at living in space. Some of them move next to a new planet because it has resources. Some of those people have to go to the planet to exploit those resources. The rest stay in space. Now you've got a populated planet. Maybe they'll do some terraforming. I'm not sure what will be practical, but it's not hard to imagine that at least some basic terraforming is probably feasible just by constructing life forms that can live on the planet and further move it in a direction intelligence likes, even ignoring massive, energy-intensive interventions.

Not all the space people have to move to the planet, just like when North America was populated it didn't depopulate where they came from.

Re: Earth-sized exoplanet ‘habitable zone’

#70

Downvote me to oblivion, but riddle me this Neil DeGrasse Tyson. If the Earth is an 'oblate spheroid' (it used to be a perfect sphere, you've seen the pics, right?) with a roughly 25,000 mile circumference, then why do all the curvature calculations fail? The rate of curve on a sphere that size is 8" x the number of miles squared and modern optics have completely debunked that. We can see too far. There is no curve.…

> why do all the curvature calculations fail?

Please, show a calculation that fails. Or two.

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