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Earth-like planet spotted orbiting Sun’s closest star

nature.com

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Re: Earth-like planet spotted orbiting Sun’s closest star

#261

Post by minism »

e40 wrote: post #135
vegai_ wrote: post #3

Perhaps it's too soon after reading The Dark Forest, but uh oh.

I just finished the book yesterday. I rank it #1 on my all-time SciFi list. I would say A Fire Upon the Deep is #2 and Dune #3.

I had the same exact thought the moment I finished it.

After a week of reflection, I think it was a slight overreaction -- the book is still very very good but i dont think #1 for me.

But something about the way the story took shape and culminated in the final third of the book was so engaging, and so satisfying. I think I stayed up until 4 or 5AM the night I finished the last 200 pages.

Re: Earth-like planet spotted orbiting Sun’s closest star

#262

Post by spaetzleesser »

mannerheim wrote: post #259
spaetzleesser wrote: post #199

Earlier quoted context omitted.

Then create one in the Sahara or the Atacana desert at 5000m elevation. Still way easier than Mars.

They are certainly easier, but how useful are they? A base on Mars will bring down the fuel requirements to exploring and exploiting the belt and outer planets tremendously. Missions that are impossible or uneconomical to do from Earth could be made possible and cheap if launched from Mars.

If you are concerned about a launchpad for other missions the moon is much better. Lower gravity, easy to reach.

Re: Earth-like planet spotted orbiting Sun’s closest star

#263

Post by mannerheim »

spaetzleesser wrote: post #262
mannerheim wrote: post #259

Earlier quoted context omitted.

They are certainly easier, but how useful are they? A base on Mars will bring down the fuel requirements to exploring and exploiting the belt and outer planets tremendously. Missions that are impossible or uneconomical to do from Earth could be made possible and cheap if launched from Mars.

If you are concerned about a launchpad for other missions the moon is much better. Lower gravity, easy to reach.

How would you produce fuel and propellant on the Moon? SpaceX plans on producing methane and lox from water and CO2 on Mars.

Re: Earth-like planet spotted orbiting Sun’s closest star

#264

Post by ncmncm »

jl6 wrote: post #220
akamoonknight wrote: post #205

Earlier quoted context omitted.

Making an assumption here about Proxima Centauri's own Oort Cloud, but seems like if it's the same size as ours, they'd overlap? Seems like a potentially interesting way for "stuff" to get transferred from one solar system to another.

I believe we are discovering that space isn’t as empty as we once imagined. Rock-hopping could be a viable method of (slow) interstellar travel.

If you take long enough at it, you get comfortable out there and don't need stars anymore.

Re: Earth-like planet spotted orbiting Sun’s closest star

#265

Post by jrumbut »

ncmncm wrote: post #250
ErikCorry wrote: post #241

Earlier quoted context omitted.

Why is it certainly tidally locked when Mercury is not?

Mercury orbits in 88 days. This other place orbits in 5 days. And Mercury is almost tidally locked. Venus will be, before long.

For us kids at the back of the class, how are those two facts related?

Why couldn't something orbit the star fast without being tidally locked?

Re: Earth-like planet spotted orbiting Sun’s closest star

#266

Post by mcbits »

wizzwizz4 wrote: post #76
adflux wrote: post #71

Earlier quoted context omitted.

I will start off by saying I have very little knowledge of physics or astronomy, but reading comments like these feels like I'm watching a 13th century British sailor confidently state what's on the other side of the Atlantic ocean... Do we really know enough to be able to say if a planet is habitable? Or could there be other forms of life that we don't know of yet... We have only recently put a man on the moon, and…

> We have only recently put a man on the moon, and now we're saying we would be able to detect dyson spheres...? A moth doesn't even have electricity, but it can detect a lampshade. A Dyson sphere is basically a stellar lampshade; we can detect it if the laws of thermodynamics hold, and we're pretty sure they do. (A Dyson swarm is similar, though a bit harder to detect.)

Maybe stars are the Dyson spheres, and their emissions are the waste energy that wasn't worth harvesting.

Re: Earth-like planet spotted orbiting Sun’s closest star

#267

Post by ncmncm »

samatman wrote: post #94
BeefWellington wrote: post #89

Earlier quoted context omitted.

There's also the consideration of the host star to take into account. I dislike the term "Earth-like" in these publications because it conjures images of a strange alien world able to support (human) life. Even assuming there were life capable of withstanding the constant flares from the host star, I suspect it would have to look very different in color and likely composition to the plant life here due to needing to…

My education was in chemistry, I've wondered about this topic before. Visible light is actually special after removing the happenstance of DNA-based visual systems from the picture: IR tends to twist or translate bonds (warming) and UV tends to ionize. Visible light being right in the middle is the trick which gives us photosynthesis, and sight, because in both cases a photon can be captured by a photosensitive bond.…

There is a strong selection bias at work: molecules made and operated on by living systems are chosen according to available energy.

A world evolved under lower energies and temperatures would select chemicals with weaker bonds. Other worlds evolved under higher energies and temperatures would select chemicals with stronger bonds.

Visible light is visible to us because it is important for molecules we use.

This is not to say that all points on the energy continuum are equally favorable to potential metabolic processes, but life adapts to conditions, even where they are not optimal. I don't know of any reason to assume the regime where Earth life has landed is optimal, but it has proven more than adequate.

Re: Earth-like planet spotted orbiting Sun’s closest star

#268

Post by edgyquant »

lanstin wrote: post #157
ethbr0 wrote: post #153

Earlier quoted context omitted.

Isn't long term zero-g pretty hostile to our biology?

Hollow out the asteroid and spin it.

This wouldn’t work, asteroids are like gravel there isn’t really anything to hollow out and even if you did when you spun it the asteroid would just shoot these rocks out in all directions.

Re: Earth-like planet spotted orbiting Sun’s closest star

#269

Post by edgyquant »

rntn wrote: post #13

Sadly, as discussed here, the technical problems with propulsion systems for interstellar travel are non-trivial: https://news.ycombinator.com/item?id=29638529 Of course that doesn't necessarily preclude a nearby higher level Kardashev Civilization becoming interested in all the noise we're making and heading over. As we put up systems beyond Webb, it may be possible to observe a hypothetical inbound craft / fleet so…

I don’t think we will or should be trying for interstellar at this time; but something being non-trivial doesn’t mean we shouldn’t do it.

Re: Earth-like planet spotted orbiting Sun’s closest star

#270

Post by ncmncm »

mannerheim wrote: post #213
spaetzleesser wrote: post #64

Earlier quoted context omitted.

Going to Mars seems pretty useless to me at this time. It’s a super hostile environment and we don’t have the technology yet to have a self sustaining base there. Give it a few decades and progress in robotics will make a Mars base much easier. There is plenty of work to be done on Earth. We have to solve clean energy production and in general reduce pollution. These are massive technological challenges that deserve…

Mars can already be useful as a springboard for space exploration. It's a literal stepping stone, both closer to the belt and outer planets in terms of distance, but also in terms of delta-v, since both the gravity well on Mars is smaller, and it's higher up in the Sun's gravity well, too. Any future space exploration and exploitation will be made tremendously easier if you can launch from Mars instead of Earth.

Mars is, even at absolute best, a dump: dry, cold, airless, at the bottom of a gravity well, and subject to dust storms besides.

We can build much better outside of gravity wells. Whatever you would land on Mars is more useful in solar orbit, parked next to any convenient asteroid.

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