Everything about it feels like BFD category for potential microbial life if true. And all the circumstantial details seem to point in the same direction. Potential hydrogen-rich ocean planet in a habitable zone, in alignment with theory about most plausible models for environments that might support life.
It's got no known abiotic process for being generated, but a clearly understood connection to life, and is apparently very reactive and would have to be actively re-generated at mass scale to sustainably show up in an atmosphere.
Nothing should be taken as proven, but it feels staggeringly plausible, and in my opinion would be the biggest of the "big if true" space stories I've ever seen in my lifetime.
I had to finish your comment before realizing you truly meant BFD as such and not (as I think more often the use is) sarcastically BFD. That said I agree.
BFD in this context standing for "Big Fucking Deal" (Urban Dictionary), not "Binary File Descriptor" (V.E.R.A. - Virtual Entity of Relevant Acronyms) I guess?
Surface gravity is a bit higher than Earth (12 m/s2), but totally bearable for humans. The smell of the atmosphere, on the other hand, will be something the first human visitors will never forget ;-).
Assuming unchanged density of tissues, mass is proportional to volume and strength is proportional to muscle/bone cross section. According to the square-cube law[1], to keep the same weight to strength ratio under ≃20% higher gravity, body linear dimensions should be down-scaled by 1/1.2 ≃ 83%.
So I think not many generations would be necessary, given individuals with 83% the average size or smaller are a common occurrence. The trait small body size should just become more common.
I look forward to the dwarf federation gaining independance from the terran hegemony. I only hoping we perfect stasis technology in time for me to sleep a few generations and witness it.
A great question. And one fascinating but maybe disturbing thing we have seen from the ISS is the body seems to be pretty aggressive with bone decalcification in lower-G environments. I don't know if there's a corollary for higher-G, and the mechanism is orthogonal to questions about heritability, but meaningful changes happen even within the life span of a single person.
You can doubt it. If only it was possible to go to these locations in real life and verify it yourself? That's exactly what I did. I went to Dartmoor and the difference is quite noticeable. YMMV
All life is a stack of autonomic systems. My hunch is that a human in a high G environment would make a bunch of adaptations even if they were born in orbit. By 3-5 generations they might even be another species. I am sure there has been some research done on raising mice in a high-g environment.
I'm still trying to wrap my head around why does FTL violate causality (even in the specific case of "space folding", a theoretical instant jump from one point in space to another).
Let's simplify the problem (take a spherical cow in the vacuum), say we have planets A and B, 100 LY away from each other, time flows at exactly the same rate near both, clear path in between them, they move through space at the same speed and relative direction, etc.
I'm on planet A. I send out a signal towards planet B. I jump to planet B and wait 100 years. I observe the signal.
Now my simplistic assumptions probably suggest that this isn't that much different from sending out a carrier pigeon while I take the train to its destination and wait. Very obviously I'm not Einstein. What am I missing?
I didn’t know either, but this article [0] has some thorough explanations.
I think the basic idea is that when two people are experiencing time dilation, FTL communication makes it possible (according to relativity equations) for a recipient to receive a message, reply to it, and have the original sender receive the reply before the point in time (in the original sender’s point of reference) the original sender sent the initial message, which clearly violates causality.
I think your scenario would not break causality because you are assuming both A and B are experiencing time at the same pace, so there would be no way to take advantage of time dilation.
Time is relative in special relativity. Things do not happen at the same time or the same order. Say FTL jumps are instantaneous for the ship in their frame, this means that ship moving fast will have a different view about when the jump happens.
Ship 1 FTL jumps, transmits message to Ship 2 that is moving relativistically, and then Ship 2 FTL jumps back. Ship 2 can arrive before Ship 1 left, creating a paradox if they give them the message.
This assumes that FTL follows relativity where physics are the same in all frames. If it happens in fixed frame, then there isn't a problem. But that would break physics; I guess FTL would break physics too. We would either need to give up on causality and except weird things happen, or give up on FTL and accept light speed as the speed limit.
Because (at least, according to special and general relativity) when two events U,V are simultaneous (in the sense of “the time coordinate is the same) in one frame, then from another frame U is before V (in the sense of the time coordinate in that frame’s coordinate system) , and in a third frame V is before U.
Hm, that’s probably not a very clear explanation..
Ok, suppose you depict time and one dimension of space on a grid, where traveling at c is depicted with a line that makes a 45 degree angle with the space axis.
Draw two such lines crossing at the t=0, x=0 point.
If you apply a “hyperbolic rotation” aka a “boost”, keeping the origin fixed, these lines will stay fixed, and each point in one of the 4 quadrants made by these lines will remain in that quadrant.
The upper quadrant consists of all events in the absolute future of the event at t=0, x=0 . The bottom quadrant consists of all events in the absolute past of the event at t=0, x=0 .
These boosts are what happens when one changes one’s reference frame by changing velocity. Of course, changing one’s velocity cannot change what events can have a causal effect on what other events, as it only changes one’s perspective.
Any line segment that you draw that would be faster than light speed can be hyperbolically rotated so that the endpoint has an earlier time coordinate in the boosted frame than the start point.
Whereas, the points in the upper quadrant always have positive time coordinates.
Now, if you only allowed one instance of FTL ever, that might not cause any cycles in causation? Maybe even if you only allow it in one direction? But those don’t seem particularly plausible.
If you have it in both directions, and they aren’t separated enough I guess, then one could combine those line segments with ones that go at 45 degrees (I.e. light speed) in the forward-in-time direction, to make a loop.
Uh.
Ok so specifically these hyperbolic rotations, in units where c=1 , are
t’ = t cosh(theta) - x sinh(theta) and x’ = x cosh(theta) - t sinh(theta)
Uhh…
Ok I think if FTL was only possible if the signals are still forward in time with respect to one fixed preferred reference frame, then there’s no issue. It is just when it is possible in both directions in a variety of reference frames that it results in a loop.
I'd love that, but when we have perfected off-planet orbital habitats in the outer solar system, it'd be an interesting endeavor to add engines, make the trip in 1,000 years and say hello to our cabbage-smelling neighbors (who'll probably think the same about us).
In the meantime, we continue to develop new designs for deep space mobile habitats and the expedition can have the newest design to build a couple in their new system.
I imagine a culture that has developed in a deep space habitat would not feel life on a planetary surface very appealing.
I'm reminded of this wonderful talk from Clara Sousa-Silva[0], a 'quantum astrochemist'.
At one point in this fascinating talk, she mentions that aliens would immediately be able to identify Earth as inhabited by life, because only a stupid and yet advanced civilization would be capable of creating CFCs. I highly recommend this video.
I've been waiting to see atmospheric composition results from JWT. It seems like JWT was first put to work on other tasks. Anyone know of other studies from JWT like this?
> Gases found are the same as those produced by algae on Earth
AIUI, the sensors used for this discover don't look for just _one_ gas, but as many as possible. So Oxygen is probably included in that list.
Life needs more than just oxygen gas in the atmosphere to thrive. The right combination of gasses is a better signal that life could be there versus just the presence of one gas.
Free oxygen combines with other things very readily, so you need a steady source to replenish it. Abiotic sources may not be common/strong enough. It's been a long time since I've kept tabs on that research, however.
For example, the anaerobic bacteria in your gut do not venture out into your other organs because they cannot survive in the presence of so much oxygen. There are of course membranes and such keeping them in check too, but I was surprised to learn that the oxygen gradient played a role.
Everything about it feels like BFD category for potential microbial life if true. And all the circumstantial details seem to point in the same direction. Potential hydrogen-rich ocean planet in a habitable zone, in alignment with theory about most plausible models for environments that might support life.
It's got no known abiotic process for being generated, but a clearly understood connection to life, and is apparently very reactive and would have to be actively re-generated at mass scale to sustainably show up in an atmosphere.
Nothing should be taken as proven, but it feels staggeringly plausible, and in my opinion would be the biggest of the "big if true" space stories I've ever seen in my lifetime.
I had to finish your comment before realizing you truly meant BFD as such and not (as I think more often the use is) sarcastically BFD. That said I agree.
BFD in this context standing for "Big Fucking Deal" (Urban Dictionary), not "Binary File Descriptor" (V.E.R.A. - Virtual Entity of Relevant Acronyms) I guess?
Surface gravity is a bit higher than Earth (12 m/s2), but totally bearable for humans. The smell of the atmosphere, on the other hand, will be something the first human visitors will never forget ;-).
Funny enough, DMS is a fermentation byproduct in beer brewing and it's detectable for us at low concentration. The off-flavor it can cause is indeed "cooked corn" or "cabbage". [https://www.homebrewersassociation.org/how-to-brew/acceptabl...].
I'm curious how many generations of natural selection it would take humans to adapt to the new gravity assuming we had no technology to do it.
Assuming unchanged density of tissues, mass is proportional to volume and strength is proportional to muscle/bone cross section. According to the square-cube law[1], to keep the same weight to strength ratio under ≃20% higher gravity, body linear dimensions should be down-scaled by 1/1.2 ≃ 83%.
So I think not many generations would be necessary, given individuals with 83% the average size or smaller are a common occurrence. The trait small body size should just become more common.
[1] https://en.wikipedia.org/wiki/Square%E2%80%93cube_law
I look forward to the dwarf federation gaining independance from the terran hegemony. I only hoping we perfect stasis technology in time for me to sleep a few generations and witness it.
A great question. And one fascinating but maybe disturbing thing we have seen from the ISS is the body seems to be pretty aggressive with bone decalcification in lower-G environments. I don't know if there's a corollary for higher-G, and the mechanism is orthogonal to questions about heritability, but meaningful changes happen even within the life span of a single person.
Gravity strength varies all over Earth so there are areas with slightly higher than normal gravity. eg. Dartmoor. I wonder if people who live there have higher bone density? https://en.wikipedia.org/wiki/Gravity_anomalies_of_Britain_a...
I’d assume any such signal will be buried in the noise. The difference is very small.
You might be interested to know that the difference is quite noticeable! At least on Dartmoor. Walking feels very different.
The variation is about 0.7%. I doubt a human would notice anything different.
You can doubt it. If only it was possible to go to these locations in real life and verify it yourself? That's exactly what I did. I went to Dartmoor and the difference is quite noticeable. YMMV
All life is a stack of autonomic systems. My hunch is that a human in a high G environment would make a bunch of adaptations even if they were born in orbit. By 3-5 generations they might even be another species. I am sure there has been some research done on raising mice in a high-g environment.
Hypergravity and microgravity exhibited reversal effects on the bone and muscle mass in mice
https://www.nature.com/articles/s41598-019-42829-z
So no dunkin basketballs?
12 m/s² doesn't seem too bad.
just gotta crack that pesky FTL travel
I'm still trying to wrap my head around why does FTL violate causality (even in the specific case of "space folding", a theoretical instant jump from one point in space to another).
Let's simplify the problem (take a spherical cow in the vacuum), say we have planets A and B, 100 LY away from each other, time flows at exactly the same rate near both, clear path in between them, they move through space at the same speed and relative direction, etc.
I'm on planet A. I send out a signal towards planet B. I jump to planet B and wait 100 years. I observe the signal.
Now my simplistic assumptions probably suggest that this isn't that much different from sending out a carrier pigeon while I take the train to its destination and wait. Very obviously I'm not Einstein. What am I missing?
I didn’t know either, but this article [0] has some thorough explanations.
I think the basic idea is that when two people are experiencing time dilation, FTL communication makes it possible (according to relativity equations) for a recipient to receive a message, reply to it, and have the original sender receive the reply before the point in time (in the original sender’s point of reference) the original sender sent the initial message, which clearly violates causality.
I think your scenario would not break causality because you are assuming both A and B are experiencing time at the same pace, so there would be no way to take advantage of time dilation.
[0] https://en.m.wikipedia.org/wiki/Tachyonic_antitelephone
Time is relative in special relativity. Things do not happen at the same time or the same order. Say FTL jumps are instantaneous for the ship in their frame, this means that ship moving fast will have a different view about when the jump happens.
Ship 1 FTL jumps, transmits message to Ship 2 that is moving relativistically, and then Ship 2 FTL jumps back. Ship 2 can arrive before Ship 1 left, creating a paradox if they give them the message.
This assumes that FTL follows relativity where physics are the same in all frames. If it happens in fixed frame, then there isn't a problem. But that would break physics; I guess FTL would break physics too. We would either need to give up on causality and except weird things happen, or give up on FTL and accept light speed as the speed limit.
Because (at least, according to special and general relativity) when two events U,V are simultaneous (in the sense of “the time coordinate is the same) in one frame, then from another frame U is before V (in the sense of the time coordinate in that frame’s coordinate system) , and in a third frame V is before U.
Hm, that’s probably not a very clear explanation..
Ok, suppose you depict time and one dimension of space on a grid, where traveling at c is depicted with a line that makes a 45 degree angle with the space axis. Draw two such lines crossing at the t=0, x=0 point. If you apply a “hyperbolic rotation” aka a “boost”, keeping the origin fixed, these lines will stay fixed, and each point in one of the 4 quadrants made by these lines will remain in that quadrant.
The upper quadrant consists of all events in the absolute future of the event at t=0, x=0 . The bottom quadrant consists of all events in the absolute past of the event at t=0, x=0 .
These boosts are what happens when one changes one’s reference frame by changing velocity. Of course, changing one’s velocity cannot change what events can have a causal effect on what other events, as it only changes one’s perspective.
Any line segment that you draw that would be faster than light speed can be hyperbolically rotated so that the endpoint has an earlier time coordinate in the boosted frame than the start point.
Whereas, the points in the upper quadrant always have positive time coordinates.
Now, if you only allowed one instance of FTL ever, that might not cause any cycles in causation? Maybe even if you only allow it in one direction? But those don’t seem particularly plausible. If you have it in both directions, and they aren’t separated enough I guess, then one could combine those line segments with ones that go at 45 degrees (I.e. light speed) in the forward-in-time direction, to make a loop.
Uh.
Ok so specifically these hyperbolic rotations, in units where c=1 , are t’ = t cosh(theta) - x sinh(theta) and x’ = x cosh(theta) - t sinh(theta)
Uhh…
Ok I think if FTL was only possible if the signals are still forward in time with respect to one fixed preferred reference frame, then there’s no issue. It is just when it is possible in both directions in a variety of reference frames that it results in a loop.
I'd love that, but when we have perfected off-planet orbital habitats in the outer solar system, it'd be an interesting endeavor to add engines, make the trip in 1,000 years and say hello to our cabbage-smelling neighbors (who'll probably think the same about us).
In the meantime, we continue to develop new designs for deep space mobile habitats and the expedition can have the newest design to build a couple in their new system.
I imagine a culture that has developed in a deep space habitat would not feel life on a planetary surface very appealing.
I read it would smell like cabbage.
Like carnies?
I'm reminded of this wonderful talk from Clara Sousa-Silva[0], a 'quantum astrochemist'.
At one point in this fascinating talk, she mentions that aliens would immediately be able to identify Earth as inhabited by life, because only a stupid and yet advanced civilization would be capable of creating CFCs. I highly recommend this video.
[0] https://youtu.be/iN0uyGVNlkQ?si=unBC3Cj228fKJV4i
I've been waiting to see atmospheric composition results from JWT. It seems like JWT was first put to work on other tasks. Anyone know of other studies from JWT like this?
Here is a list of approved programs for JWST - https://www.stsci.edu/jwst/science-execution/approved-progra...
You can filter by cycle & purpose - I think you want GO 4 then look at Exoplanet Atmospheres and Habitability?
Related, but here is the Spectra of K2-18 image - https://webbtelescope.org/contents/media/images/2023/139/01H...
This is cool! Thank you for responding with this! Really neat to see the K2-18 spectra too.
duplicate: https://news.ycombinator.com/item?id=43714203
https://archive.is/bEYGH
What about just looking for oxygen in a planet's atmosphere?
Not all life needs (or wants) oxygen. Plenty of earthlings die quickly when exposed to it.
Third line of the summary:
> Gases found are the same as those produced by algae on Earth
AIUI, the sensors used for this discover don't look for just _one_ gas, but as many as possible. So Oxygen is probably included in that list.
Life needs more than just oxygen gas in the atmosphere to thrive. The right combination of gasses is a better signal that life could be there versus just the presence of one gas.
Plenty of abiotic oxygen sources, even on Earth.
Free oxygen combines with other things very readily, so you need a steady source to replenish it. Abiotic sources may not be common/strong enough. It's been a long time since I've kept tabs on that research, however.
And plenty of life for which Oxygen is a poison.
For example, the anaerobic bacteria in your gut do not venture out into your other organs because they cannot survive in the presence of so much oxygen. There are of course membranes and such keeping them in check too, but I was surprised to learn that the oxygen gradient played a role.
Might be a noise floor from all the interstellar medium oxygen?
[dupe] https://news.ycombinator.com/item?id=43711376
And still there's uncertainty about intelligent life existing in Jersey City.