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Earth-sized exoplanet ‘habitable zone’

nature.com

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Re: Earth-sized exoplanet ‘habitable zone’

#41

Post by ur-whale »

ppeetteerr wrote: post #16

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 think the reason earth-like exoplanets generate so much interest is not because of the terraforming / colonization potential but rather because they are more likely places where we might find alien life.

Re: Earth-sized exoplanet ‘habitable zone’

#43

Post by kirubakaran »

jcims wrote: post #4

> Astronomers have discovered a world only a little bit bigger than Earth, whirling around a bright star about 31 parsecs from our planet. Parsec is one of those units that is difficult to remember if you just look at the conversion (1 parsec = 3.26 light years). If you remember how it's defined, however, it somehow becomes easier (for me anyway). One parsec is the distance at which one astronomical unit (AU, mean di…

I just imagine 337453805774280 football fields end-to-end when I want to visualize a parsec

Re: Earth-sized exoplanet ‘habitable zone’

#44

Post by VonBraunsGhost »

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. Therefore...

Re: Earth-sized exoplanet ‘habitable zone’

#45

Post by omarhaneef »

jcims wrote: post #4

> Astronomers have discovered a world only a little bit bigger than Earth, whirling around a bright star about 31 parsecs from our planet. Parsec is one of those units that is difficult to remember if you just look at the conversion (1 parsec = 3.26 light years). If you remember how it's defined, however, it somehow becomes easier (for me anyway). One parsec is the distance at which one astronomical unit (AU, mean di…

I think of a parsec as 1/12th of a Falcon Kessel Run

Re: Earth-sized exoplanet ‘habitable zone’

#46

Post by bazeblackwood »

VonBraunsGhost wrote: post #44

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.…

Wow, don't mind me, I've just never seen one of you people in the wild.

Re: Earth-sized exoplanet ‘habitable zone’

#47

Post by AnIdiotOnTheNet »

madrox wrote: post #22
ppeetteerr wrote: post #16

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…

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.

Re: Earth-sized exoplanet ‘habitable zone’

#48

Post by phildenhoff »

ppeetteerr wrote: post #16

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…

Semi-related to this discussion is the novel _Seveneves_ by Neal Stephenson.

Essentially, the premise is that the Moon gets hit by a Very Large Thing, and humanity has to prepare for Earth being hit by some very large bit of the moon. Part of their planning is building a generation-spaceship, designed to last until Earth's hot atmosphere cools to a habitable level, so there is some discussion of "Why live on a spaceship when you can live on a planet?" However, it's not a deep focus.

The book has good reviews [1] and I'd strongly recommend it for those who like hard Sci-Fi. However, I would consider only reading the first two parts. The third part is rather extravagant and, imo, lost the thread of the first two parts. It certainly lost my interest.

[1]: https://www.goodreads.com/book/show/22816087-seveneves

Re: Earth-sized exoplanet ‘habitable zone’

#49

Post by the8472 »

jcims wrote: post #4

> Astronomers have discovered a world only a little bit bigger than Earth, whirling around a bright star about 31 parsecs from our planet. Parsec is one of those units that is difficult to remember if you just look at the conversion (1 parsec = 3.26 light years). If you remember how it's defined, however, it somehow becomes easier (for me anyway). One parsec is the distance at which one astronomical unit (AU, mean di…

Perhaps it is difficult to remember, but the light years are more useful because it directly tells you the communication delay or lower bound for travel time. Arcsecond parallax in the sky doesn't really help much.

Re: Earth-sized exoplanet ‘habitable zone’

#50

Post by VonBraunsGhost »

bazeblackwood wrote: post #46
VonBraunsGhost wrote: post #44

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.…

Wow, don't mind me, I've just never seen one of you people in the wild.

You can direct the 'you people' at yourself. I once believed in the pseudo-science promoted as truth, then I took some time to educate myself. You should do the same.
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