Being that close also offers us a better ability to examine it. The nearer the star, the more arc-seconds (or tiny fractions thereof) the star will appear in telescopes. 12ly is ridiculously close!
It also tells us something interesting. If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitable planets are out there. Only 12ly away and that one has maybe two habitable planets? That tells me the universe is teaming with potential homes for life.
> If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitable planets are out there
I would put a slight caveat to this - I would argue we do know there's something "special" about our little corner of the galaxy, at least - we are in the continuously habitable zone - for example, there are billions of stars at higher densities closer to the core whose planets are likely uninhabitable due to toxic levels of radiation, GRBs, etc. So I actually might expect other planets near us to be more habitable on average than at least some other places in our galaxy.
But I also think it's too soon to know how potentially habitable these planets are, until we have a chance to check a bunch of other things on the checklist, like the long-term stability of the sun's output and the planet's orbits, the frequency of destructive solar flares, the frequency of asteroid bombardments (if there are no Jupiters to absorb them), etc.
Regardless the close distance should make it much easier to answer these sorts of questions than it would be far planets much farther away, and I'm excited to see what we can learn in the coming years.
> Only 12ly away and that one has maybe two habitable planets? That tells me the universe is teaming with potential homes for life.
This seems like the birthday problem in statistics [0] - that if you have 30 people, it's likely that two people have the same birthday.
However, the problem that could also exist (in our corner of the galaxy) that everyone else has a birthday far away from ours, and nobody else shares a birthday on the same day with anyone else. (in other words, we happen to be the two people who share the same corner of the galaxy, but everyone else is far away and separate - i.e. no other clustering).
Not disagreeing with you, and it does give us hope, but randomness is a bch that can make everything look different from how it actually is.
Light Year has a technical meaning, but it is so large that I can't relate to it at all. So I tried to figure out a different unit of measure, and I came up with what I call an "Earth Escape Year" or EEY.
From Earth, the escape velocity for our solar system is 42.1 km/s. EEY is the distance traveled for 1 year at that escape velocity. It is the maximum amount of time it would take to reach an interstellar object directly launching from Earth -- any slower and you can't get there at all. 1 LY = 7,121 Escape Years. The upper bound time to reach these planets is about 85k EEY.
The 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 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?
One thing's for sure - if there's really 2 habitable planets, with liquid water, then we've got a hell of a target to point James Webb at when it launches - an infrared spectrum star should mean any plant life is well optimized to towards the redder end of the spectrum - we should see some type of chlorophyll.
> 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 chance. While finding intelligent life would be great, finding any life is nearly as great. We might not catch them at a comparable technological moment, but over 8 billion years, intelligent life could have come and gone many times. All we need are some biosignatures to confirm that something's out there, and exploration will kick into overdrive.
The note that it's an old star makes me worry though. If they're older than us, and habitable, were they inhabited?
Many dwarf stars have more solar flares than our sun, while their planets are closer. Teegarden's star is supposed to be very calm right now. I have no idea if that is likely to be true over most of the past 8 billion years. The amount of water they gather may be smaller, and their closer planets may not be able to retain water as well.
So if they were inhabited, what happened to them?
Let's say the origin of life is a million to one filter, and the successful development of sentience is another million to one filter. Those are actually pretty high odds for those two events, and the combination of those two togehter is enough to make it likely we're alone in the Milky Way.
One thing's for sure - if there's really 2 habitable planets, with liquid water, then we've got a hell of a target to point James Webb at when it launches - an infrared spectrum star should mean any plant life is well optimized to towards the redder end of the spectrum - we should see some type of chlorophyll.
Since most of the star's energy is emitted in the infrared, which is a more diffuse form of energy, does this limit the potential of photosynthetic organisms to gain a disruptive evolutionary advantage? (Maybe not. It's still free energy from the sky.)
To give a sense of the scales involved - if the sun were an orange and the earth a grain of sand 6 meters away, this star would be a pea about 5000km away.
There would only be another 34 stars / fruit-and-veg within this 10000km wide sphere. It's pretty empty out there!
Look into Project Orion. With thermonuclear bombs you could hit 8% c, which would get you there in "only" 150-200 years including acceleration and deceleration time.
That is still beyond humans with present day life spans, but extend life span to ~1000 years or go full AI and you can totally ride the "devil's pogo stick" to stars <=20ly or so awat.
Fusion rockets would probably be better. I mention Orion because we sort of know how to build it today... at ludicrous cost. No new physics and not that much fundamentally new engineering is needed. Orion is a fabulous and quite valid counter to the folks that seem to like to repeat the canard that interstellar flight is impossible. Hard as hell, sure, but not impossible by any means.
To a fully Kardashev type I civilization it might be around Apollo moon shot difficulty.
I smiled as well but with a slowly but steadily accelerating ship we can reach half the light speed and get there in 50 years. It put things in the realm of "possible" which is amazing.
With current tech spread thinly an alpha emitter like Po (2% mass ejected at 5% c) on the backplate and you’ll get 100km/s with 10% payload. Adding an electromagnetic “nozzle” to axially redirect sideway alphas would make it past 200km/s, ie. less then 20k years. Spread thinly enough for the decay leftover - Pb - to be ejected too and you can get to something like 600 km/s, just 6000 years.
Time for the travelers will go slower, for earth time will be 450k years but for travelers will be less.
Can someone explain this situation, what if the travelers reach almost speed light, they will reach on 12 years from earth perspective but for them how long will it take?
there is an effort to put super mini spaceships on missions to other solar systems, and they would travel at something like 20% the speed of light. I think it works by having the probes be like the size of a cellphone or something, and being attached to a solar sail, then using an incredibly high powered laser to pump the solar sail full of energy to get it going so fast. I think if that architecture works they could reach ... proxima centauri? ... in something like 20 years.
just pointing that out to say that i think we have technology that would take less time than 450k years :)
And to think that there is likely an Easy Mode system out there.
A habitable planet on the low end of the mass spectrum needed for a stable atmosphere with other habitable planets in-system. And all that close to another star with habitable planets, possibly in the sub-lightyear range.
Basically everything ripe for a spacefaring civilization to grow without too much trouble and with plenty of motivation.
The Earth is hard to leave and everything else in our system is dead rocks with hellish environments as far as we know with the nearest alternative at least dozens of lightyears away
How common are "life-friendly" planets (Let's say: on a ratio of Life-Friendly Planet:Non Life-Friendly Planet)? And is there any way to check if life-friendly planets contain life without actually going there?
I saw a study recently, unfortunately I can't locate it now.
It discussed the possibility of there having been past civilizations on Earth, hundreds of millions or even billions of years ago. The conclusion was that this can't be entirely ruled out. It noted how few actual fossil remains we have for what we know of dinosaurs, and that there's a lot of space left in those gaps for all the evidence to have been destroyed.
Gavin A. Schmidt, Adam Frank: The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record?, https://arxiv.org/abs/1804.03748
I found it through an article in The Atlantic that may or may not have been linked on HN recently.
It's amazes me a little that we have as much from the dinosaurs as we do, considering how long ago they lived. For many of them it's less than 100x the time between us and them, to go back to the beginning of the entire universe.
It's incredibly improbable. While much of the planet's surface is recycled constantly, there are also huge swaths of land that are billions of years old and haven't changed enough to hide evidence of complex society. Dinosaur fossils are rare, but not that rare. Tiny ones are abundant. If all life on earth ceased today, you could come back here in a billion years and find plenty of evidence everywhere. Maybe it's not 100% impossible, but it's so improbable that it belongs alongside other fringe theories.
I am not a geologist, but it seems improbable for a technical civilization (like our current one) to not leave a global geological mark. For example, our use of fossil fuels changed global carbon isotope composition: our atmosphere now has less portion of C13, because photosynthesis favors the lighter C12 atoms, and all our fossil fuels ultimately derives from photosynthesis.[1]
The changed isotope ratio will be detectable in every carbon-containing sediment layer ever produced in our age. And this is just one example.
Waiting for the moment where we actually find a habitable planet with intelligent life. Next thing you know, we'll be developing ways in order to communicate with them, not just observing them.
There was a paper recently that argued that the habitable zone is smaller than anticipated because either the concentration of carbon dioxide will be too high (and thus toxic at least to life on Earth) or - for small stars like this - there will be (toxic) carbon monoxide in the atmosphere.
Life on Earth lived in CO2-dominated atmosphere for 1.5B years. If anything, CO2-rich world which is not overrun by SO2 and chlorine and phosphoric anhydride and scorching heat, like Venus, is as "potentially life-supporting" as it gets, save for a world with actual oxygen-producing life like ours.
I was under the impression that planets to be life-friendly have to be close to their red dwarf star to a point they'll be tidally locked (one side always light other night), meaning their atmosphere would freeze on the dark side and planet would end up without an atmostphere.
> The team calculates that one of the planets, called Teegarden’s star b, completed an orbit in a mere 4.9 Earth-days; the other world, Teegarden’s star c, has an orbit of just 11.4 days.
I wonder how our understanding of orbital mechanics would have evolved differently had our planet orbited the Sun this fast?
If the planets have long days, then they could potentially see in one night what it takes us a full year to see!
I wonder how different this would make life. Would you experience seasons, or would the temperature be fairly consistent all year around as it wouldn't be long enough for the atmosphere to cool down.
This half-hearted attempt to say that the impressive-looking image of The Nearby Star was in fact an artist's impression of what a Red Dwarf might look like, made me laugh. Is it seen here? Or is it an illustration? I suspect someone changed the copy just before publishing
Wouldn't planets orbiting this close to the star be tidally locked to it? If they are tidally locked to the star, they are also likely to have extreme temperature variations between the two sides. This could rule out life.
As for interesting consequences of a vastly different planetary age: in one SF novel (could be Peter F. Hamilton's, I can't remember right now) humans colonized an Earth-like planet only some 2 billion years old or so. Its uranium ores had so high U235 content (as opposed to Earth's 0.72%, which requires costly enrichment), that you could simply smelt it and put straight in a reactor (cheap nuclear-powered locomotives anyone?).
By the time our technology reaches the point that we could feasibly travel to and inhabit another distant planet, and with all the challenges with that (space travel, terraforming, radiation protection), couldn't we feasibly create or move a planet or gigantic space station built from materials of another planet into whatever orbit we want?
For those that wants to live on another planet, you will unlikely like how things look under another suns sunlight. It is hard to have a planet that will have day light like our sun and be habitable. Think of a yellow-reddish, or a light that is cold blue when you walk out. Human eyes evolved with earths lighting conditions.
[+] [-] mabbo|6 years ago|reply
It also tells us something interesting. If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitable planets are out there. Only 12ly away and that one has maybe two habitable planets? That tells me the universe is teaming with potential homes for life.
[+] [-] joshuahedlund|6 years ago|reply
> If we presume there's nothing special about our little corner of the universe, then the distance to the nearest potentially habitable planets gives us an estimate of how many habitable planets are out there
I would put a slight caveat to this - I would argue we do know there's something "special" about our little corner of the galaxy, at least - we are in the continuously habitable zone - for example, there are billions of stars at higher densities closer to the core whose planets are likely uninhabitable due to toxic levels of radiation, GRBs, etc. So I actually might expect other planets near us to be more habitable on average than at least some other places in our galaxy.
But I also think it's too soon to know how potentially habitable these planets are, until we have a chance to check a bunch of other things on the checklist, like the long-term stability of the sun's output and the planet's orbits, the frequency of destructive solar flares, the frequency of asteroid bombardments (if there are no Jupiters to absorb them), etc.
Regardless the close distance should make it much easier to answer these sorts of questions than it would be far planets much farther away, and I'm excited to see what we can learn in the coming years.
[+] [-] MR4D|6 years ago|reply
This seems like the birthday problem in statistics [0] - that if you have 30 people, it's likely that two people have the same birthday.
However, the problem that could also exist (in our corner of the galaxy) that everyone else has a birthday far away from ours, and nobody else shares a birthday on the same day with anyone else. (in other words, we happen to be the two people who share the same corner of the galaxy, but everyone else is far away and separate - i.e. no other clustering).
Not disagreeing with you, and it does give us hope, but randomness is a bch that can make everything look different from how it actually is.
[0] - https://en.wikipedia.org/wiki/Birthday_problem
[+] [-] abtinf|6 years ago|reply
From Earth, the escape velocity for our solar system is 42.1 km/s. EEY is the distance traveled for 1 year at that escape velocity. It is the maximum amount of time it would take to reach an interstellar object directly launching from Earth -- any slower and you can't get there at all. 1 LY = 7,121 Escape Years. The upper bound time to reach these planets is about 85k EEY.
[+] [-] iamgopal|6 years ago|reply
[+] [-] XorNot|6 years ago|reply
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 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?
One thing's for sure - if there's really 2 habitable planets, with liquid water, then we've got a hell of a target to point James Webb at when it launches - an infrared spectrum star should mean any plant life is well optimized to towards the redder end of the spectrum - we should see some type of chlorophyll.
[+] [-] caymanjim|6 years ago|reply
You get more than one chance. While finding intelligent life would be great, finding any life is nearly as great. We might not catch them at a comparable technological moment, but over 8 billion years, intelligent life could have come and gone many times. All we need are some biosignatures to confirm that something's out there, and exploration will kick into overdrive.
[+] [-] stcredzero|6 years ago|reply
Many dwarf stars have more solar flares than our sun, while their planets are closer. Teegarden's star is supposed to be very calm right now. I have no idea if that is likely to be true over most of the past 8 billion years. The amount of water they gather may be smaller, and their closer planets may not be able to retain water as well.
So if they were inhabited, what happened to them?
Let's say the origin of life is a million to one filter, and the successful development of sentience is another million to one filter. Those are actually pretty high odds for those two events, and the combination of those two togehter is enough to make it likely we're alone in the Milky Way.
One thing's for sure - if there's really 2 habitable planets, with liquid water, then we've got a hell of a target to point James Webb at when it launches - an infrared spectrum star should mean any plant life is well optimized to towards the redder end of the spectrum - we should see some type of chlorophyll.
Since most of the star's energy is emitted in the infrared, which is a more diffuse form of energy, does this limit the potential of photosynthetic organisms to gain a disruptive evolutionary advantage? (Maybe not. It's still free energy from the sky.)
[+] [-] petercooper|6 years ago|reply
I love the "just". I know it's nearby on galactic scales but it's practically about 450,000 Earth years away with current technology :-)
[+] [-] hanoz|6 years ago|reply
There would only be another 34 stars / fruit-and-veg within this 10000km wide sphere. It's pretty empty out there!
[+] [-] api|6 years ago|reply
That is still beyond humans with present day life spans, but extend life span to ~1000 years or go full AI and you can totally ride the "devil's pogo stick" to stars <=20ly or so awat.
Fusion rockets would probably be better. I mention Orion because we sort of know how to build it today... at ludicrous cost. No new physics and not that much fundamentally new engineering is needed. Orion is a fabulous and quite valid counter to the folks that seem to like to repeat the canard that interstellar flight is impossible. Hard as hell, sure, but not impossible by any means.
To a fully Kardashev type I civilization it might be around Apollo moon shot difficulty.
[+] [-] TeMPOraL|6 years ago|reply
[+] [-] lmm|6 years ago|reply
If we had the political will, the Orion design could get people there in, what, 200 years, and that's with '70s technology.
[+] [-] sametmax|6 years ago|reply
[+] [-] Eupolemos|6 years ago|reply
I wonder how long it'd take, seen from the perspective of the ship, if we had an engine capable of delivering a constant 1g acceleration.
That's the way we'll want to travel, after all.
[+] [-] trhway|6 years ago|reply
With current tech spread thinly an alpha emitter like Po (2% mass ejected at 5% c) on the backplate and you’ll get 100km/s with 10% payload. Adding an electromagnetic “nozzle” to axially redirect sideway alphas would make it past 200km/s, ie. less then 20k years. Spread thinly enough for the decay leftover - Pb - to be ejected too and you can get to something like 600 km/s, just 6000 years.
[+] [-] burtonator|6 years ago|reply
Honestly it's far far far better to focus on reaching superhuman intelligence and AGI and then just creating a Dyson sphere around our sun.
At that point we can try to figure out FTL travel...
[+] [-] lelima|6 years ago|reply
Can someone explain this situation, what if the travelers reach almost speed light, they will reach on 12 years from earth perspective but for them how long will it take?
[+] [-] agumonkey|6 years ago|reply
[+] [-] unknown|6 years ago|reply
[deleted]
[+] [-] ggggtez|6 years ago|reply
Physical travel is out of scope, but we could share knowledge in the (extremely) unlikely case that we found intelligent life with radio technology.
[+] [-] joshlegs|6 years ago|reply
just pointing that out to say that i think we have technology that would take less time than 450k years :)
[+] [-] cptaj|6 years ago|reply
A habitable planet on the low end of the mass spectrum needed for a stable atmosphere with other habitable planets in-system. And all that close to another star with habitable planets, possibly in the sub-lightyear range.
Basically everything ripe for a spacefaring civilization to grow without too much trouble and with plenty of motivation.
The Earth is hard to leave and everything else in our system is dead rocks with hellish environments as far as we know with the nearest alternative at least dozens of lightyears away
[+] [-] dheera|6 years ago|reply
[+] [-] skribbj|6 years ago|reply
[+] [-] CWuestefeld|6 years ago|reply
It discussed the possibility of there having been past civilizations on Earth, hundreds of millions or even billions of years ago. The conclusion was that this can't be entirely ruled out. It noted how few actual fossil remains we have for what we know of dinosaurs, and that there's a lot of space left in those gaps for all the evidence to have been destroyed.
[+] [-] hesk|6 years ago|reply
Gavin A. Schmidt, Adam Frank: The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record?, https://arxiv.org/abs/1804.03748
I found it through an article in The Atlantic that may or may not have been linked on HN recently.
https://www.theatlantic.com/science/archive/2018/04/are-we-e...
[+] [-] Nition|6 years ago|reply
[+] [-] caymanjim|6 years ago|reply
[+] [-] yongjik|6 years ago|reply
The changed isotope ratio will be detectable in every carbon-containing sediment layer ever produced in our age. And this is just one example.
[1] https://skepticalscience.com/print.php?r=109
[+] [-] westoque|6 years ago|reply
[+] [-] vkaku|6 years ago|reply
[+] [-] Tepix|6 years ago|reply
https://phys.org/news/2019-03-complex-life-require-narrow-ha... (good article with link to the paper)
[+] [-] nine_k|6 years ago|reply
[+] [-] aflag|6 years ago|reply
[+] [-] TwoNineA|6 years ago|reply
[+] [-] _Kristijan_|6 years ago|reply
[+] [-] clarkmoody|6 years ago|reply
I wonder how our understanding of orbital mechanics would have evolved differently had our planet orbited the Sun this fast?
If the planets have long days, then they could potentially see in one night what it takes us a full year to see!
[+] [-] vkreso|6 years ago|reply
[+] [-] fyfy18|6 years ago|reply
[+] [-] sambeau|6 years ago|reply
This half-hearted attempt to say that the impressive-looking image of The Nearby Star was in fact an artist's impression of what a Red Dwarf might look like, made me laugh. Is it seen here? Or is it an illustration? I suspect someone changed the copy just before publishing
[+] [-] hughes|6 years ago|reply
[+] [-] umeshunni|6 years ago|reply
[+] [-] gattr|6 years ago|reply
[+] [-] wppick|6 years ago|reply
[+] [-] m3kw9|6 years ago|reply
[+] [-] rossdavidh|6 years ago|reply
[+] [-] totaldude87|6 years ago|reply
Shouldn't those be searching for other life supporting planets, vigorously than us since they would be much mature and advanced?
why no one found us?
WHAT IS THE PROBABILITY OF US FINDING AN ALIEN VS AN ADVANCED RACE FINDING US AS ALIEN?
[+] [-] hirundo|6 years ago|reply
Is it too late to change the name to Tyrion Lannister?
[+] [-] wibble10|6 years ago|reply