If Science Fiction has taught me anything then going to a planet named Wolf {alphanumeric sequence} is a really great idea that won't get most of your crew horribly killed.
Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
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Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#62If Science Fiction has taught me anything then going to a planet named Wolf {alphanumeric sequence} is a really great idea that won't get most of your crew horribly killed.
"ALL THESE WORLDS ARE YOURS, EXCEPT EUROPA. ATTEMPT NO LANDING THERE."
We should throw a huge party to coincide with the Europa Clipper landing. You know, in case it pisses G-d/advanced aliens/&c off and they wipe us out.
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#63Earlier quoted context omitted.
Mars and Venus are not tidally locked. Earth, Jupiter and Ganymede have magnetic fields, and Mars used to. Do we know that these exosolar planets don't have moons, don't have magnetic fields, and are tidally locked?
Mercury and Venus are very near to being tidally locked, despite being thousands of times farther from the sun than the planet cited is from its star. Mars is a good distance off. Earth got its moon via a nearly , but not quite, fatal collision. Probably most other planets did not. Ganymede's magnetic field is news to me. I don't think we know exactly what gives a body a magnetic field, or how it is maintained, but r…
> I don't think we know exactly what gives a body a magnetic field, or how it is maintained, but rotation seems to be important.
The magnetic field on Earth is caused by electrical currents flowing in the rotating molten metal of the outer part of our planet’s core. You’re right, rotation is an important factor.
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#64Earlier quoted context omitted.
Yes, astrobiologists distinguish between direct detection of life and biosignatures. The latter are things for which we don’t have non-biological explanations at this time, but which we don’t consider adequate evidence by themselves for life. FWIW we’ve already detected bio signatures for life in the atmosphere of Mars (seasonal methane emissions). And maybe Venus, though that is less clear. (Thanks!)
Thanks for this, your phrasing makes the concept more clear. Can you give a (fictitious as necessary) example of what would constitute "direct detection of life", from an astrobiological perspective? Given our window to the universe is through telescopes I'm having difficulty imagining/distinguishing how to draw the line between "observed data for which we don't have any non-biological explanation" and something even…
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#65Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#66So I thought this would be big news, so I did some reading. Turns out that in like the past 5-6 years we've gone from "who knows how many habitable zone planets there are" to "we're finding them all freaking over the place!" Does anyone have a good blog/news site that covers topics like this? Because evidently I'm missing out.
Over the course of the past 2 decades we've gone from "perhaps some day we'll find extra solar planets" to "most if not all stars have planets". JWST's already found water. At this point it's no longer a matter of if but when extrasolar life will be confirmed, and with which instrument. Might be JWST, might be WFIRST, might be HabEx.
> At this point it's no longer a matter of if but when extrasolar life will be confirmed
There is absolutely no data to confirm this, simply because no matter what equations or variables you throw around, we have no way of knowing the probability of life. We have only earth, and we still don't fully understand how that all worked out. We do not know what (or if!) any filter is present that prevents complex life. From a philisophical perspective, we'd be much better off as a species that the harder we look, we should hope to find _no_ life: https://nickbostrom.com/extraterrestrial.pdf
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#67Earlier quoted context omitted.
(again) Spin–orbit resonance means that "Tidally-locked" doesn't equate to "always presents the same face. which leads to: > But it is much farther from the sun than announced planets are from theirs. a) So? b) Is it really? I mean sure, in an absolute sense - but what about in an appropriately scaled sense, allowing for the 1/sixth decreased sun mass and the inverse square force relationships, etc. c) Even so, see a…
Literally all moons in the solar system are tidally locked, 1:1, to their parent body. That is the norm for tidal locking. Mercury, lacking ocean or even atmosphere, and mostly frozen solid, is accorded leeway a putatively-habitable planet does not get. Word games are tiresome. Mercury's 2:3 spin-orbit resonant "lock" is interesting but off topic.
It's not about word games, it's about how high the prevalence of 1:1 locking is. Especially when you use words like "all" and "can't spot".
Looking at the moons in our solar system is evidence but not definitive.
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#68"nearby" = 30ly
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#69Earlier quoted context omitted.
Thanks for this, your phrasing makes the concept more clear. Can you give a (fictitious as necessary) example of what would constitute "direct detection of life", from an astrobiological perspective? Given our window to the universe is through telescopes I'm having difficulty imagining/distinguishing how to draw the line between "observed data for which we don't have any non-biological explanation" and something even…
https://astrobiology.nasa.gov/research/life-detection/ladder...
Yeah.
I found and read that before my above comment (and skimmed some of the associated paper[1]) but all that says is direct detection hasn't been attempted since Viking, and that most good signals require in situ or sample return.
It still doesn't answer my question! "astrobiologists distinguish between direct detection of life and biosignatures".
The highest methods in terms of strength of evidence obtainable with remote sensing would be finding "deviations from thermodynamic equilibrium and/or kinetics" of "co-located reductant and oxidant" or "element or isotope fractionations indicative of metabolism". Which sound a whole lot like a detection of a biosignature, which "astrobiologists distinguish" from direct detection . :)
I suspect direct detection in an astrobiological context must mean either "direct, as in we physically touched it" or maybe "a signature found using direct imaging".
Definitions are hard. :)
1: https://www.liebertpub.com/doi/full/10.1089/ast.2017.1773
Re: Wolf 1069B: Earth-mass planet in the habitable zone of a nearby, low-mass star
#70Earlier quoted context omitted.
Literally all moons in the solar system are tidally locked, 1:1, to their parent body. That is the norm for tidal locking. Mercury, lacking ocean or even atmosphere, and mostly frozen solid, is accorded leeway a putatively-habitable planet does not get. Word games are tiresome. Mercury's 2:3 spin-orbit resonant "lock" is interesting but off topic.
It's not about word games, it's about how high the prevalence of 1:1 locking is. Especially when you use words like "all" and "can't spot". Looking at the moons in our solar system is evidence but not definitive.
Looking at the hundreds of moons defines "locked" without qualification to imply 1:1.
Mercury is literally the only body in the whole solar system in any sort of more complicated "lock". So, no, it really is about word games.