Only 70 trillion miles away...
Two potentially life-friendly planets found orbiting a nearby star
361–370 of 391 posts
Re: Two potentially life-friendly planets found orbiting a nearby star
#362Earlier quoted context omitted.
> So if they were inhabited, what happened to them? Are they exactly at our level of development? Earlier? Hopefully. Because later poses some real big questions - does technology top out about where we are now - no FTL travel, no really big radio transmitters or stellar engineering? No probes to nearby star systems? Did they even make it past the nuclear age, or avoid wrecking their climate? You get more than one ch…
> While finding intelligent life would be great, finding any life is nearly as great. That would actually be worrisome. If we found and detected microorganisms on nearby planet e.g 12 light years away from earth, then that means we are probably headed for extinction. The reason is the theory of the Great Filter. Given that we have not been able to observe any kind of activity outside of our solar system, it means tha…
Not necessarily. Live != civilization, so just because many planets may have developed live (or obtained it via panspermia) but only very few (or one) have developed multi-cellular live (which even on earth is quite recent) and even less a civilization comparable to us humans.
Re: Two potentially life-friendly planets found orbiting a nearby star
#363The note that it's an old star makes me worry though. If they're older then us, and habitable, were they inhabited? Our current era is a few hundred years of real, directed technological development. A few thousands years either side of that and who knows what we'd be looking at, but you imagine that - hopefully - the general progression of technology is forward. So if they were inhabited, what happened to them? Are…
> you imagine that - hopefully - the general progression of technology is forward. I think this might be the key myth of our times. Our entire history is a blink of an eye along the timescales Earth normally changes on. But the last couple hundred years really takes the cake - within a couple human lifespans, we've gone from a lifestyle broadly recognizable to any human from history, to some kind of ravenous sci-fi t…
I totally agree. I have in the past gotten into online arguments with people who claim that this kind of exponential change will continue forever, and I just find it so baffling. The only explanation I can come up with is that this is a core ideological precept of our current economic system and people are just not prepared to challenge it. Like asking a medieval person to believe that god is not real. It’s seen as blasphemy.
Re: Two potentially life-friendly planets found orbiting a nearby star
#364Calling than A and B
Re: Two potentially life-friendly planets found orbiting a nearby star
#365The note that it's an old star makes me worry though. If they're older then us, and habitable, were they inhabited? Our current era is a few hundred years of real, directed technological development. A few thousands years either side of that and who knows what we'd be looking at, but you imagine that - hopefully - the general progression of technology is forward. So if they were inhabited, what happened to them? Are…
> you imagine that - hopefully - the general progression of technology is forward. I think this might be the key myth of our times. Our entire history is a blink of an eye along the timescales Earth normally changes on. But the last couple hundred years really takes the cake - within a couple human lifespans, we've gone from a lifestyle broadly recognizable to any human from history, to some kind of ravenous sci-fi t…
> We know this state of affairs cannot possibly last.
Talk for yourself. I personally think this is just the beginning.
Your freefalling similitude has the big flaw of making completely unsubstantiated assumptions. For all we know, we might be elegantly diving into a pool, or having propelled ourselves onto an orbit where we'll forever spin - we just don't know.
Re: Two potentially life-friendly planets found orbiting a nearby star
#366Earlier quoted context omitted.
The benefit of using a cycler rather than a ship that travels orbit-to-orbit is that there is no need to accelerate/decelerate the mass of the ship, just the perishables (people and provisions for the voyage) You would accelerate a small vessel (like a crew dragon or orion), intercept and dock with the much larger cycler, then enter the ship for your x-month trip. When you near mars, you get back into your dragon, an…
> You could presumably look at using a small asteroid to provide the bulk of the "cycler", offering plenty of shielding for the trip, you'd only have to get it into position once - far less fuel requirement. Or maybe even something like, as some have suggested (not me!), Phobos: http://enterprisemission.com/Phobos.html Warning: it's kind of out there. At the very least, it's perhaps interesting as speculative sci-fi.
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Re: Two potentially life-friendly planets found orbiting a nearby star
#367Earlier quoted context omitted.
How confident? Even with an even distribution of birthdays it's possible to have a billion people in the room that don't share your birthday. Very unlikely, but as there's only about 20 million people with your birthday, and 7 billion without, it's quite doable.
"Very unlikely" is a severe understatement. With only 100k people, the odds of no one else having your birthday is 10^-120. With a million people, it is 10^-1192. And with a billion people... apparently, there are over a million zeroes between the decimal place and the first non-zero number. That is a pretty damn small probability. Here is the code I used in python 3: from decimal import Decimal print((Decimal(364) /…
quite, hence "how confident"
There's other things as play. Imagine you, born on July 15th, walked into a room with 1000 people. You'd be fairly confident someone will be born on July 15?
What if I then told you it was the annual astrology get together of Capricorns?
Re: Two potentially life-friendly planets found orbiting a nearby star
#368Earlier quoted context omitted.
I'm talking about the local solar density, not an individual star's density. Obviously that has little effect on the habitable zone of a planet. My question was about the ability of a system's star's own radiation to ward off extra-solar radiation and what kind of limitations we are aware of.
Believe you are thinking of solar wind? That might counteract another source, but don't believe light radiation would be affected.
Solar wind is a type of solar radiation. I thought perhaps a charged field of particles with an outward force could act at least partially as a shield in for some higher frequencies of electromagnetic waves.
Re: Two potentially life-friendly planets found orbiting a nearby star
#369Earlier quoted context omitted.
Electromagnetic radiation from one star does not repel electromagnetic radiation from other stars. If it did, we wouldn’t be able to see stars at night from the Earth.
> If it did, we wouldn’t be able to see stars at night from the Earth. Ha! I love straighforward sanity checks like this. My initial reaction was to ask myself about photon-photon collisions which are im fact possible, but your comment gives a nice Fermi bound on how rare such events actually are. Cool!
Photon-photon collisions are still technically possible... I remember a professor mentioning this as one question he got in grad school... draw out the Feynman diagram and you see a vanishingly small probability of photon-photon interaction.
But yeah. Ionized particles like Galactic Cosmic Rays can be repelled by the local stellar magnetic field, but mostly the lower energy rays are deflected. Higher energy -to-charge-ratio GCRs can punch right through the weak stellar magnetic field, just like do for our Sun’s interplanetary magnetic field.
Re: Two potentially life-friendly planets found orbiting a nearby star
#370Earlier quoted context omitted.
I'm talking about the local solar density, not an individual star's density. Obviously that has little effect on the habitable zone of a planet. My question was about the ability of a system's star's own radiation to ward off extra-solar radiation and what kind of limitations we are aware of.
Electromagnetic radiation from one star does not repel electromagnetic radiation from other stars. If it did, we wouldn’t be able to see stars at night from the Earth.
I should have been more clear in my question. Solar wind is a form of solar radiation, and I was curious about the effect of solar wind + the magnetic field that carries it would have on some frequencies of electromagnetic waves.
I would expect mid-frequency radiation such as visible light to remain largely unaffected, I was thinking more about its effect on high-frequency extra-solar radiation. And it's likely not correct to visualize this as individual photons colliding but rather wave interference.
Here is an article explaining the effect [0]. An excerpt:
"The interplanetary magnetic field, which is embedded in the solar wind, deflects low-energy cosmic rays from us at the outer reaches of our solar system, decreasing the flux of these cosmic rays that reach us at Earth."
[0] https://aasnova.org/2017/12/01/a-shifting-shield-provides-pr...