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[wierd]

I dont know about you guys, but I find this very exciting.

https://www.nature.com/articles/nature24659

(and a fluff article about the paper)
https://www.washingtonpost.com/news/speaking-of-science/wp/2017/11/29/cells-with-lab-made-dna-produce-a-new-kind-of-protein-a-holy-grail-for-synthetic-biology/?utm_term=.2591c40aa383

Remember those artificial base pairs created some time back, the ones that didn't do anything other than take up space in the genome?  Well--- NOW they DO something, and produce a novel protein in a living organism! (Very exciting! Even just one more functional base pair increases the number of transcribable amino acids by many times!)

[Trekkin]

I dont know about you guys, but I find this very exciting.

https://www.nature.com/articles/nature24659

(and a fluff article about the paper)
https://www.washingtonpost.com/news/speaking-of-science/wp/2017/11/29/cells-with-lab-made-dna-produce-a-new-kind-of-protein-a-holy-grail-for-synthetic-biology/?utm_term=.2591c40aa383

Remember those artificial base pairs created some time back, the ones that didn't do anything other than take up space in the genome?  Well--- NOW they DO something, and produce a novel protein in a living organism! (Very exciting! Even just one more functional base pair increases the number of transcribable amino acids by many times!)

I never thought I'd see you posting Nature articles given your disapproval of their fees, but anyway: no. No it does not. You still need to engineer in the tRNA synthetases to actually accommodate the expanded codon set, and that still means dealing with whatever weird chemistry you want to incorporate. Otherwise it's just a de facto stop codon. There's a reason most ncAAs are close to canonicals chemically, and it's not because we don't have uses for the other ones.

Yes, this is a better way to add noncanonicals than the standard, but it's hardly revolutionary. Making novel proteins is nothing new, and ncAAs aren't really news either; this is just a lot more overhead to do something with marginally more utility in certain cases given an entirely separate engineering project. Much like CRISPR/Cas9, it's exciting until you read the fine print.

[wierd]

While it certainly is no secret that I greatly dislike paywalls, that does not make my interest in science any less, Trekkin. They published in Nature, so that is where I linked.

While they have not fully integrated the synthetic components, (as you point out, it requires artificially added transcription factors), the demonstration that the base pairs are theoretically functional should additional features be incorporated into their sample's genome (said tRNA frameworks) is still a big thing. The devil lives in the details, yes-- but that is what they are showing here-- one of the details claimed to be a devil has been shown to not be. (Specifically, the different bond structure of this base pair, since it is not based on hydrogen bonds. It was argued that it would cause problems with transcription. This is now shown to not be the case.)

You dont win a marathon by jumping to the finish line, you do actually have to run the race. This is exciting, because the runner is still running, and has made a significant distance down the racetrack.  The goal of synthetically assigned amino acids being added to a cell's vocabulary is just a little bit closer today. That is still pretty damn exciting.

[Trekkin]

While it certainly is no secret that I greatly dislike paywalls, that does not make my interest in science any less, Trekkin. They published in Nature, so that is where I linked.

While they have not fully integrated the synthetic components, (as you point out, it requires artificially added transcription factors), the demonstration that the base pairs are theoretically functional should additional features be incorporated into their sample's genome (said tRNA frameworks) is still a big thing. The devil lives in the details, yes-- but that is what they are showing here-- one of the details claimed to be a devil has been shown to not be. (Specifically, the different bond structure of this base pair, since it is not based on hydrogen bonds. It was argued that it would cause problems with transcription. This is now shown to not be the case.)

You dont win a marathon by jumping to the finish line, you do actually have to run the race. This is exciting, because the runner is still running, and has made a significant distance down the racetrack.  The goal of synthetically assigned amino acids being added to a cell's vocabulary is just a little bit closer today. That is still pretty damn exciting.

...no it doesn't, which might be why I never said it did -- and I'd appreciate you not putting words in my mouth in future, especially when you can't get them right. aminoacyl tRNA synthetases are not transcription factors. They do two completely different things.

Apparently you missed the part where noncanonical amino acids have been possible for years now. (Synthetic amino acids have been possible for even longer, but there's no real point outside of really weird NMR experiments.)

[wierd]

Trekkin, your argument "We have been able to do that for years", applies specifically to in-vitro, not in-vivo. But sure. disregard an advance. You are welcome to your opinion.

[Trekkin]

Trekkin, your argument "We have been able to do that for years", applies specifically to in-vitro, not in-vivo. But sure. disregard an advance. You are welcome to your opinion.

Wrong again, weird:
https://www.ncbi.nlm.nih.gov/pubmed/21404373
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3278164/

That took me a few seconds to confirm via Google, man. 

And no, I'm not disregarding it. I'm placing it in its proper context: the problem it solves is contingent on solving a much more difficult problem to be of greater utility than our existing solutions to a degree that would justify the added work of implementing it, and actually loading the synthetases gets harder the more unusual an ncAA you want to incorporate. This is a better way to implement those solutions, yes, but in and of itself it's going to be a while before it's worthwhile and it's hardly as revolutionary as you seem to suggest.

But hey, get excited about whatever you want. Just...get informed too, maybe. These aren't things you need any kind of paid access to learn about.

[Max™]

Touching back on the FTL thing, Stephen Baxter plays with this topic regularly, and the entire arc of the book Exultant is built around a situation where a pilot ends up in a sticky situation because they had to follow a trajectory to survive a battle which put them two years into their own past, so they gotta deal with having fled from a battle, AND their younger self gets to deal with pre-emptive corrective actions for something they hadn't done and wouldn't end up doing at all!

[Bumber]

Okay. Assuming the ship travels ~4x the speed of light, the stars are 10 years apart from each other in a line ABCD, and it lingers motionless for five years at each star in a trip going A->B->C->A, (and omitting the actual destruction events to simplify) each of them sees this:

Ship: Depart A, Arrive B, Depart B, Arrive C, Depart C, Arrive A. All good so far.
A: Depart A, Arrive B, Depart B, Arrive A, Arrive C, Depart C. Oh hey, two ships at once.
B: Arrive B, Depart B, Depart A, Arrive C, Depart C, Arrive A. It arrives before it leaves! It leaves before it leaves!
C/D: Arrive C, Arrive B, Depart C, Depart B, Depart A, Arrive A Good grief! The ship's in two places at once and it's arriving before it leaves besides!

See the problem? Mass-energy equivalence isn't conserved, effects precede causes... I can post the diagram if you want.

I'm assuming FTL by Alcubierre drive. I tried working it out by creating a table, but I ended up just confusing myself, and my brain has started shutting down for sleep.

I'm thinking of making some kind of simulation where the ship releases labeled photons as projectiles at each time interval. Then we can know what each point sees by the available photons. Unity engine would be ideal.

[Trekkin]

Okay. Assuming the ship travels ~4x the speed of light, the stars are 10 years apart from each other in a line ABCD, and it lingers motionless for five years at each star in a trip going A->B->C->A, (and omitting the actual destruction events to simplify) each of them sees this:

Ship: Depart A, Arrive B, Depart B, Arrive C, Depart C, Arrive A. All good so far.
A: Depart A, Arrive B, Depart B, Arrive A, Arrive C, Depart C. Oh hey, two ships at once.
B: Arrive B, Depart B, Depart A, Arrive C, Depart C, Arrive A. It arrives before it leaves! It leaves before it leaves!
C/D: Arrive C, Arrive B, Depart C, Depart B, Depart A, Arrive A Good grief! The ship's in two places at once and it's arriving before it leaves besides!

See the problem? Mass-energy equivalence isn't conserved, effects precede causes... I can post the diagram if you want.

I'm assuming FTL by Alcubierre drive. I tried working it out by creating a table, but I ended up just confusing myself, and my brain has started shutting down for sleep.

I'm thinking of making some kind of simulation where the ship releases labeled photons as projectiles at each time interval. Then we can know what each point sees by the available photons. Unity engine would be ideal.

You can do that, but a Minkowski diagram gives you exactly that information with much less work. They're well worth learning to draw if you have any interest in this kind of thing.

EDIT: here, I made a quick one.

Spoiler (click to show/hide)

[bloop_bleep]

I'm thinking of making some kind of simulation where the ship releases labeled photons as projectiles at each time interval. Then we can know what each point sees by the available photons.

Hmm....

I'll get back to you on that.

[Bumber]

Finished creating the simulator: https://github.com/Bumber64/FTLsim

Here's the executable: https://github.com/Bumber64/FTLsim/raw/master/FTLsim_x86.zip

[Trekkin]

Nicely done. Is there a way to color or otherwise label the photons according to the ship's position when they were emitted?

Incidentally, it might help you see explicit backwards time travel if you added a selector for reference frames that did the Lorentz transforms for you.

[McTraveller]

To explain what I meant by invoking Morbo: That's not time travel though.  That's just seeing photons arriving from when a ship was at a far place arriving later; a star won't "experience" a ship when the distant photons arrive, it will experience it when the actual ship arrives.  I mean, we're not doing time travel when we use the Hubble - we are just watching a really delayed movie.

It's like when you throw a ball high enough in the air that you can catch your own throw after running for a while - you launched the ball (photon), but you moved faster than the ball so you could be there to catch it.

As for what types of time travel may be possible - I don't know.  I'm not up to speed with that part of general relativity (wormholes and such).

[Trekkin]

To explain what I meant by invoking Morbo: That's not time travel though.  That's just seeing photons arriving from when a ship was at a far place arriving later; a star won't "experience" a ship when the distant photons arrive, it will experience it when the actual ship arrives.  I mean, we're not doing time travel when we use the Hubble - we are just watching a really delayed movie.

It's like when you throw a ball high enough in the air that you can catch your own throw after running for a while - you launched the ball (photon), but you moved faster than the ball so you could be there to catch it.

As for what types of time travel may be possible - I don't know.  I'm not up to speed with that part of general relativity (wormholes and such).

The problem is not only that they're arriving later, but that because the events have spacelike separation their sequence depends on your observation point and that doesn't make sense for causally linked events. If one of us sees a line of dominos fall from A->Z and the other one sees them unfall from Z->A, one of us must be wrong, right? Except relativity says we can't be.

And yes, the star will experience the ship when the photons arrive, because all the other force carriers (gravitons, etc) propagate at the speed of light as well. You can construct a trajectory in which an arbitrary number of the same ship are interacting gravitationally with the same observer, which kind of breaks the conservation of mass, does it not? This is ignoring the energy coming from those photons and its effect on the conservation of energy.

Regardless, would you accept an FTL trajectory that permits photons from the end of its journey to reach it prior to launch to be time travel? Because you can do that, but you need a moving (ideally, relativistic) reference frame. I'll diagram it if you want.

[McTraveller]

Regardless, would you accept an FTL trajectory that permits photons from the end of its journey to reach it prior to launch to be time travel? Because you can do that, but you need a moving (ideally, relativistic) reference frame. I'll diagram it if you want.

I'm not sure what you mean here. "A trajectory that permits photons from the end of its journey to reach it prior to launch" sounds suspiciously like the Bootstrap Problem.

Put another way, your comments about violation of things like conservation of mass are, in fact, tantamount to the reason we say FTL travel is not possible if you remain in the standard confines of spacetime:

Consider this simple thing: if your gravitational and electromagnetic "image", which is the only thing that can interact with other bodies, is limited to the speed of light, how can you "outrun" this?  If you are using something like an Alcubierre drive, which distorts spacetime, then the straight light cones do not apply.  In fact, in your diagram below, what you would see is something like that lines 'Arriving C' and 'Departing C' would bend sharply so they all reached the observer on A exactly when the gravitational and electromagnetic presence of the ship shows up.

Put another way: you are your electromagnetic and gravitational interaction with the rest of the universe.