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MSL Landing Timeline: What To Expect Tonight
An anonymous reader writes "When the Curiosity rover lands on Mars later tonight, it'll be executing a complex series of maneuvers. JPL will be relying on the Mars Odyssey orbiter to relay telemetry back to Earth in time-delayed real-time, and if all goes well, we'll be getting confirmation on the success (or failure) of each entry, descent, and landing phase, outlined in detail here."
During entry.
Telemetry will be continuously relayed back to earth, true, but with not much less than about a 15 minute latency, owing to the fact that Mars roughly a quarter of a light-hour from earth right now.
File under 'M' for 'Manic ranting'
Anyone know if the "Send Your Name To Mars" chip actually made it onto the rover? Would love to be able to tell my wife and kids our names are on Mars.
http://marsparticipate.jpl.nasa.gov/msl/participate/sendyourname/
I showed my son (just turned 4) a couple of the publicity videos made by Nasa including the Shatner narrated landing.and he wanted to know if we could buy the toy of it. I had to explain there was none, but apparently Hotwheels has come out with one (just the rover itself though, not the whole descent package).
http://www.wired.com/geekdad/2012/08/hot-wheels-curiosity/
the amount of engineering, programming and math that went into this... (among other things i'm sure) I hope it goes well
"Time Delayed Real Time"
More like "Real Time as constrained by the Speed of Light", it's not like NASA is doing what NBC is doing with the olympics... :rolleyes:
Real time simply means that there are deadlines on the system (in the technical sense).
Here the deadline is simply so relaxed that using that term becomes useless.
The real question we should be asking is what does time-delayed mean?
Is there some other non-temporal delay that I'm not aware of?
Space delayed? why are they even saying delayed? Doesn't the travel time automatically delay the signal, or are they adding extra delay?
Maybe they are using negative time delay to make the signal "real time".
Telemetry will be continuously relayed back to earth, true, but with not much less than about a 15 minute latency, owing to the fact that Mars roughly a quarter of a light-hour from earth right now.
That IS indeed real time. Relativity tells us nothing can have an effect here in less time. I don't know if you're trolling or just ignorant, but by your definition you can never look at the stars, galaxies or nebulae in the sky in real time either because they're all at varying distances and we're seeing light that originated anything from about 4 to several million years ago. With telescopes you can go back billions.
Meh... really?...
"Time Delayed Real Time"
More like "Real Time as constrained by the Speed of Light", it's not like NASA is doing what NBC is doing with the olympics... :rolleyes:
You're right. No one ever threw an object all the way to Mars as part of the Olympics ;-)
It would kind of suck if all we were getting were digits and shots of the control room.
I don't think NASA pays too much attention to the PR side of things...probably why budgets are being slashed.
I'm seeing conflicting reports... Is it tonight (as in a few hours from now) or tomorrow (27 hours from now)?
Chance favors the prepared mind.
Perfect is the enemy of good.
I'm really excited, but I doubt the live broadcast will measure up to the bitchin' action movie NASA made of Curiosity's "Seven Minutes of Terror!"
http://www.youtube.com/watch?v=pzqdoXwLBT8 Enjoy!
Ask me about my sig!
The Viking landers were about the same size and used classic retro-rockets. Why does the Curiosity use this much more complex arrangement? I couldn't find an easy answer. Is it so the rocket blast doesn't damage the wheels? Is it so the rover doesn't lug around the dead weight of the rockets once it's landed? I really don't get it.
True, but for a blueworlder, the blueworld-received-time is real-time, for any definition of real-time consistent with relativity.
Speaker K'Breel knows the instant the Martian Defense Force succeeds in its mission, or fails, and either way he has enough time to throw a Junior Reporter's gelsac beneath the spot where the Skycrane will crash-land. At the moment of impact/invasion, the most recent transmissions from his spies on the Blue World will show a clock dated 10:14 PDT, but that's irrelevant. As far as the blueworlders are concerned, they find out at 10:31 PDT. Loyal Martian Citizens can start celebrating/covering their gelsacs early, but have to wait another 15 minutes (until their view of the blueworlders' clocks show 10:31) before they can enjoy true schadenfreude at the blueworlders' pain, or have hopefully protected their gelsacs in preparation for the ever-merciful Speaker for the Council's reaction to his view of the blueworlders' whoops of joy.
I haven't seen any gelsac related posts for a while though.
There's NBC with their time delay again.
Me thinks you are missing the important fact that telemetry beamed from spacecraft is *always* impacted by the transmission delays inherent to the speed of light. In this case it's just more pronounced.
The telemetry from Curiosity is 'real-time' in the context of when it is received here on Earth.
The single most important criteria for something to qualify as "real time" in data communications is low latency. 14 and a half minutes is not low.
Then by your definition NOTHING in space is real time. You look up into the sky and everything you're seeing is sending it's light to you from the past.
That IS indeed real time. Relativity tells us nothing can have an effect here in less time. I don't know if you're trolling or just ignorant, but by your definition you can never look at the stars, galaxies or nebulae in the sky in real time either because they're all at varying distances and we're seeing light that originated anything from about 4 to several million years ago. With telescopes you can go back billions.
Unless you live near a big city, in which case most of the light you can see in the sky at night (other than moonlight) originated within the last quarter millisecond.
No, that's just your personal set of criteria that doesn't have anything to do with reality.
Real-Time is without artificial delay. Yes, there's 14 minutes actual delay, but it's not artificial, it is literally the fastest possible time.
If 14 minutes prevents it from being real time, then 14 seconds should too, as should 14 milliseconds, or 14 nanoseconds. All of them are arbitrary amounts of time, all of them are large amounts of latency relative to something.
...be interesting to have a "news" program that only aired news reports which were, say, a year old, that way people could look back with hindsight and see how trivial the things were that seemed so big at the time, thus hopefully giving them some perspective on the world as a whole, but I always thought it was just a pipe dream. This whole thing has me thinking that, "In other breaking news from yesterday..." might become a real catch-phrase.
It's NBC real time.
Warning *Plug*
I was looking for a sidebar gadget for NASA TV and found the ones out there out of date (and not working). For those who care, you can grab my 2 hours of boredom in creating a working sidebar app at: https://docs.google.com/open?id=0BydS_KYWdjtXMVNTbkdjZjdsWE0
It isn't perfect, but I am enjoying it. I hope you do as well.
"When life gives you lemons, don't make lemonade. Make life take the lemons back!" -- Cave Johnson
I found this link on reddit.com/r/science
God spoke to me
Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere, the delay cannot *POSSIBLY* be considered real time because too many events that can or will affect the system will have occurred by then.
File under 'M' for 'Manic ranting'
Never seen the time !! Does anybody really know what time it is ?? Does anybody really care ?? Know what time ??
If you'd have clicked through to the article, you'd see the whole timeline. Though I'm not sure why you were modded down as a troll, it's a valid question and it seems that many news sources only say "late Sunday night" without giving any times. in any case:
The landing stage separates from the cruise stage at 10:14:34pm PST.
Here's the last few seconds of the timeline (again, see the linked article for the full timeline):
10:31:08 PM: At about 20 meters above the surface, MSL keeps decelerating down to 0.75 m/s. /quote>
10:31:14 PM: Less than 20 meters from the surface, the sky crane shuts off four of its eight engines as the rover separates and begins to descend on cables.
10:31:15 PM: MSL releases its "bogie" wheels, getting ready for touchdown.
10:31:30 PM: TOUCHDOWN! WOOHOO!!! Curiosity knows when she's on the ground when the load on the tether that she used to get from the skycrane to the ground goes slack.
10:31:33 PM: Cables connecting Curiosity to the skycrane are cut, and the skycrane flies off for a crash landing.
plain wrong
CLI paste? paste.pr0.tips!
Just noticed a typo in the article -- it's actually PDT, not PST.
NASA has a convenient countdown timer here:
http://www.nasa.gov/mission_pages/msl/index.html
No, the computing definition of "real time" means guaranteed latency, not necessarily low latency. What the guarantee is depends on the specific system. An industrial controller may require a one second response guarantee while a radar system may require millisecond response.
Would it really be so much to ask for a link to the Countdown?!?
Try making an os that is defined to take 14 minutes to respond to interrupts and see if you can pass it off as "real time"
File under 'M' for 'Manic ranting'
NSFW
Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere, the delay cannot *POSSIBLY* be considered real time because too many events that can or will affect the system will have occurred by then.
But since the information reaches us as quickly as reasonably possible it can still be considered real-time. (I said "reasonably possible", since there's some finite processing time that's incurred when an event is recorded, encoded for transmission to the earth, received, decoded, then broadcast to the world which means that it will take longer to receive the information at home than is physically possible if we all had telescopes that could resolve the landing in "real time").
Otherwise, where would you draw the line?
Does a solar satellite give us "real time" information about the sun even though any data it receives is already 8 minutes old? Do we have "real time" communications with a lunar lander, even though everything it sends has a 1.28 second radio delay? Can we watch events at the London Olympics in "real time" even if codec and satellite delays delay the signal by a second or two? If you watch a sporting event live, are you really seeing it in "real time" since you're not seeing the action 100m away for 833ns.
Here in NZ, we've already seen it descend. Can't tell you how it came out, owing to a non-disclosure agreement but ...
Can one of the rocket scientists on here explain why, when every gram to orbit is accounted for, 150kg of dead weight was the only way to do this? Couldn't they have at least put some kind of small stationary experiments, retroreflectors for earth-based lasers (like on the moon), or radio repeaters in the things that would be no big loss if they didnt survive re-entry?
Well great... publicize the time and location and you are just making the formidable Mars Homeland Security's job easy. Loose lips sinks ships.
Just give it in GMT and let us worry about daylight saving time conversions.
When our name is on the back of your car, we're behind you all the way!
You draw the line at any signal latency that is too slow to meaningfully respond to in the context that the signal was originally sent from. There's a reason why interrupt handlers in real-time OS's need to finish their job in as few computing cycles as possible.
File under 'M' for 'Manic ranting'
If so I can't imagine why.
Go Sounders! Oh, wait. *MSL*.
Trolling. How is that not obvious?
You draw the line at any signal latency that is too slow to meaningfully respond to in the context that the signal was originally sent from. There's a reason why interrupt handlers in real-time OS's need to finish their job in as few computing cycles as possible.
So in the event of a fully autonomous landing that wasn't designed for any human input or control, is a 15 minute delay "real time" or not? Once the landing sequence starts, there's no going back or adjusting the sequence until the entire 15 minute landing sequence is over, even if a human was orbiting Mars.
An interrupt handler in a Real-Time OS doesn't need to finish its job in as few computing cycles as possible, it only needs to finish within the guaranteed interrupt latency time, which could be a few microseconds or could be 15 minutes. Real time doesn't mean fast, it means it meets hard deadlines.
I don't mean to be arrogant or rude, but this is a common misconception about what a "real time" OS would be.
http://en.wikipedia.org/wiki/Real-time_operating_system
It has nothing to do with getting things done fast, it's more about when getting things done.
An interesting definition of "all going well"...
Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere
Relativity says that there is a 14 minute delay in *some* frames of reference. In other frames of reference, the delay is longer. For others (those occupied by the radio signal photons, for example), the landing events and our reception of the signals happen simultaneously.
Getting hung up over what you imagine is the "time delay" between two points in spacetime that are outside of each others' light cones is kind of pointless.
This is the year 2012, no 3D animation on what the MSL is doing right now? Jeez!
Given this post, and all the other by you below, I think they should have just told you (and only you, as the rest of us have no problem with this) that the landing was happening about 15 minutes later than it is. I bet you'd be happy then :)
(Meant in good fun!)
I can respect the geek appeal of the engineering. However I compare it to writing a console app in java when a bash,perl or python script would have gotten it done without including 400 jar files.
Got Code?
Damn straight. It's Zulu time.
Happy viewing! Fingers crossed!
:)
p.s. watching the simulation while listening to the beautiful blue danube is kind of fun
while [ 1 ]; do echo -n -e "\xe2\x95\xb$((($RANDOM&1)+1))"; done
Then by your definition NOTHING in space is real time. You look up into the sky and everything you're seeing is sending it's light to you from the past.
Duh. Real time is a bit subjective, but it basically is a threshold of control over a system. The strict definition is that a system is real time, if it meets strict time constraints imposed on it (I gloss over some important nuance). So in a sense, one can have real time systems with say, years of lag, for really generous time constraints.
For me, I have an informal definition of real time, namely, a control methodology which wouldn't change, if communication lag were instantaneous.
For example, the human body wouldn't move differently even if human nerves were transmitting signals instantaneously. Walking, running, and such still are the best means for moving. You might be able to try other movement forms (such as cartwheeling), but these wouldn't give you an advantage in normal operation over the usual means of movement.
So in this sense, the human body and its normal means of moving about are "real time". Movement of the MSL and other rovers remotely controlled from Earth have less optimal movement schemes (there's a lot of need to evaluate terrain obstacles, for example, resulting in a lot of move-then-stop operation) than if someone were controlling them from nearby on the Martian surface. So these systems are not real time in my sense.
Now suppose instead of the MSL, one were piloting this fine piece of gear, one of the largest excavators in the world. Suddenly that 15 minute lag time is not so significant and the machine probably wouldn't operate all that differently, if the operator was sitting in a cockpit directly rather on distant Earth.
Since I mentioned systems with extremely long lag still qualifying as real time, consider this example. One could set up vast streams of gargantuan slow moving space vehicles carrying basic crude, bulk resources (water, organic compounds, metals, etc) between different planetary systems, say moving at the speed of the Voyager spacecraft. It might take 50,000 years to make the trip and adjustments in trajectory would be very minimal and glacial. Would it matter if one had instantaneous communication? Not really. The years of communication lag have no real effect on the system.
Stupid discussions like this one arise when perfectly useful expressions are replaced by inferior, more complex expressions merely to make people sound more expert or scientific. In the olden days, they would have said "Live images will be beamed back by the lander". No one would have been in any doubt what that meant and this bullshit discussion would never have needed to take place, in 'real time' or slightly delayed.
Telemetry will be continuously relayed back to earth, true, but with not much less than about a 15 minute latency, owing to the fact that Mars roughly a quarter of a light-hour from earth right now.
So you'll be sitting in the crowd watching one direction (or whatever you kids are into these days) complaining that you should be closer to the front because the light from the stage is taking multiple nanoseconds to reach you, which is unacceptable because you paid full price for a live performance.
Stupid discussions like this one arise when perfectly useful expressions are replaced by inferior, more complex expressions merely to make people sound more expert or scientific. In the olden days, they would have said "Live images will be beamed back by the lander".
I don't believe saying it's a "live image" would be any less likely to be challenged. "How can it be live if it happened 15 minutes ago!?"
No one would have been in any doubt what that meant and this bullshit discussion would never have needed to take place, in 'real time' or slightly delayed.
I'm seeing about 100 msec of latency to Slashdot from here, so this conversation is not taking place in "real time".
I wasn't disputing the term "live"... I was disputing the term "real time", which in data communications has a sort of specific meaning related to the ability to respond to signals within a finite (and very small) time.
File under 'M' for 'Manic ranting'
You're both rude and wrong. GP is correct.
"Relativity tells us nothing can have an effect here in less time." True, but that doesn't mean that it's real time. Here are a few examples that show that it's completely ridiculous to call it real time:
The cosmic microwave background is the glow of the hot early universe, from shortly after the Big Bang. No cosmologist would refer to this as seeing the Big Bang "in real time."
It's possible for a ray of light to travel in a circular orbit around a black hole. That means that it would theoretically be possible for me to face in a certain direction, stick out my tongue, and then turn around 180 degrees, look through a telescope, and, some time later, see myself sticking my tongue out at myself. I'm obviously not seeing myself "in real time."
As a third example, there are distant galaxies whose light hasn't gotten to us yet. I don't think anyone would argue that we are seeing them "in real time" -- we haven't even seen them yet.
It sounds like you're misinterpreting something you heard about the nature of simultaneity in relativity. You can define simultaneity in relativity. You simply have to keep in mind that it's relative, not absolute.
In special relativity, the standard way to do this is Einstein synchronization. The relative motions of the bodies in the solar system, as well as all space probes launched so far, is at velocities much less than c, so it doesn't even matter very much whether you talk about doing your Einstein synchronization in the frame of the earth, of mars, or whatever. This is the sense in which the information from Mars is 15 minutes behind "real time." (There are also gravitational time dilations, and they're also quite small.)
Since you brought up astronomy and cosmological look-back times, it's worth addressing that as well. To describe cosmological scales, you need general relativity, and in general relativity Einstein synchronization doesn't work. However, there is a natural notion of clock synchronization in cosmology that is defined as follows. At any spot in the universe, define a frame of reference that is at rest with respect to the cosmic microwave background (or the local flow of galaxies, which amounts to the same thing). Define a time coordinate as measured by a clock that is at rest in that frame. This is what cosmologists mean when they state the age of the universe as so many billions of years. This time coordinate is also the only reasonable definition of "in real time" for use in cosmology.
Next time, please try being more polite and/or getting your facts right.
Find free books.
Owing to the fact that we will know the lander has already reached the surface (in unknown condition) by the time we get the first signal it has entered the atmosphere, the delay cannot *POSSIBLY* be considered real time because too many events that can or will affect the system will have occurred by then.
Sir, you may want to read up a bit on relativity. Before the signal reaches us, it has not already entered the atmosphere. There is no clock that shows a time that's valid for both Mars and Earth, in which you can say that it has landed "now".
The event cone expands at the speed of light, and until it reaches us, nothing has happened.
"Now" and "while" are purely local phenomena which do not apply across distances. Earth and Mars exist in different time frames. There is no universal clock with a "now" that applies to both places at the same time, so there can not be a "while" that applies either.
What's certain is that when we get information about it entering the Martian atmosphere as it happens in our time frame, it's too late for us to do anything about it. Because by the time a signal from us reaches them, it will be half an hour too late in the Martian time frame.
+1, gelsac
The term "real time" in an operating system context does not have to imply a small (sic) or short response time. Only that the system responds within the specified time. This is not the same thing as interrupt latency. If the system is designed to calculate a landing spot within 15 minutes, it must deliver one within that time, for example.
I want to know what's going to happen This Afternoon.
Ustream NASA JPL ("media" stream) http://www.ustream.tv/nasajpl2
Ustream NASA Public (ie 'media' stream plus inserted clips, talking heads, etc) http://www.ustream.tv/nasahdtv
The Circus starts approx 3pm (Australian Eastern) and the fireworks (or not) around 3:30pm.
Visit CryptoGnome in his home.
Sure there is, there are clocks in both locations, just because we don't receive the information in our light cone does not mean that it has not already happened.
We can know for an absolute fact that at +15min our time information will be received and at -15 our time information will be transmitted by virtue of there being a light cone. Unless the laws of physics suddenly stop and light traveling in the vacume of space changes speed, we know this to be true and those events while being perceived in realitive terms like 'then' and 'now' are still happening and are mutually exclusive of one another.
You sir need to go back and re-read realitivity, because it in no-way implies the sort of anthropic principle you describe, mearly a limitation on the transmission and reception of information from a given frame via the light cone.
I don't believe saying it's a "live image" would be any less likely to be challenged. "How can it be live if it happened 15 minutes ago!?"
The problem is the word "ago", which presupposes that there is a time frame that comprises both here and there.
There isn't. Time is a local phenomenon, and doesn't propagate instantaneously - it's bound by the speed of light too.
It hasn't happened yet until the information about it can reach us. Any other interpretation breaks causality, which is a no-no.
Has anyone collected all these dispatches from the Martian Council over the years? Every time the Earthlings throw a probe at the homeworld, there'll be an update from the Speaker regarding the success or failure of the defences. I've actually come to anticipate the next entry - they're generally quite funny.
Of course.... but 15 minutes is certainly far too long.
The decent itself will last only 7 minutes. By the time we get a signal that it has just entered the atmosphere, the unit itself may very well have crashed.
File under 'M' for 'Manic ranting'
Suggesting that something hasn't happened yet until the information reaches us is like suggesting that the light we see from distant stars right now was only just emitted by that star. It wasn't.
File under 'M' for 'Manic ranting'
How low is 'low'? Everything you sense in the world is already old news due to delay times in nerve conduction. Even more if you consider actual conscious awareness a necessary element.
Sure there is, there are clocks in both locations, just because we don't receive the information in our light cone does not mean that it has not already happened.
That there are clocks both places doesn't mean that they tick in the same time frame. They most certainly do not.
We can know for an absolute fact that at +15min our time information will be received and at -15 our time information will be transmitted by virtue of there being a light cone.
No, you don't know that. Your problem is thinking the light cone takes 15 minutes to get here. From the point of view of a photon in the light cone, it takes no time at all. Only for a third party observer in rest who gets a signal from Mars when it occurs, and another signal from Earth when we observe it, will it take 15 minutes. In our time frame and the time frame of Mars, that's not true.
You can only measure the round trip time of light - there is no way to measure the time going one way. The problem here is that you measure the round trip times in your frame of reference. Which is a valid frame of reference, but it doesn't apply to elsewhere.
If you bounce light off the moon, it takes no time at all for the photons, but when you get the reflection, sixteen seconds have passed for you. If you reflect it back to the moon, an observer there would see sixteen seconds between the two flashes, but that would be sixteen seconds in a different time frame. It doesn't mean it happens eight seconds "later", because "later" only applies to one of the two places, not both.
From the point of view of a tiny space ship traveling with the photons, the Earth and Moon would have inexplicably aged.
Yes, this is counter-intuitive, and there are many apparent paradoxes due to this - the most famous one being the twin paradox. See http://en.wikipedia.org/wiki/Relativity_of_simultaneity for an explanation of why you can't treat two time frames as they were the same, and have to treat the light cone as "now" for any observer, lest you violate causality.
Suggesting that something hasn't happened yet until the information reaches us is like suggesting that the light we see from distant stars right now was only just emitted by that star. It wasn't.
Correct, it wasn't because "was" makes no sense, because you and the remote star don't share a common frame of reference where "was" makes sense. To not violate causality, the remote event happens as you see it in your frame of reference. You know nothing about the remote frame of reference. You can estimate how many light years away it occurred, but light years is a distance, not a time.
For the farthest objects you see the birth of the universe as it happens , not happened . The universe is 16 billion years old from our point of view, but from our point of view only.
That time is a purely local phenomenon is one of the things that's hardest to accept with conventional thinking. We naturally think of time progressing linearly and applying everywhere. Which isn't the case.
If you send a signal to Mars and it takes half an hour to get a reply, you cannot tell whether it took 15 minutes each way or whether it took 30 minutes one way and 0 the other. Both assumptions are equally valid (or invalid). Because there is no common frame of reference, we have to use ours, and apply Einstein's convention, pretending that there's a delay equalling half the round trip time. That saves us headaches, but it isn't true.
The Curiosity Rover has successfuly landed. Great job people!
In fact, a hard real time system may have a much higher latency than a general purpose system due to the complexity of making sure that it will meet it's deadline every time with certainty.
By that measure we never see anything in real time.
A bit of googling found this:
http://atomfullerene.wordpress.com/dispatches-from-the-red-planet/
Help I am stuck in a signature factory!
That wasn't anywhere even close my point. Perhaps I should have described it more completely.
The light we are seeing from distant stars *WAS* emitted by them many years ago . I have absolutely no idea what you're on about saying that "was" doesn't make any sense. It does.
It doesn't violate causality to know that the lander would have reached the surface of mars nearly 15 minutes before we could possibly receive confirmation of the event, because no real knowledge or information would ever moving any faster than the speed of light. Stuff that we see "happening" in space isn't happening right now... it happened long ago. A lot of them happened before this rock we live on even existed... which is plenty relative to our own local time reference frame.
And it has only been my contention that "real-time" in data communications has a particular meaning, which demands sufficiently low latency that any signals can always be responded to in sufficient time such that no other events can have occurred in the interim which might (significantly) affect the system in the interim. In most cases, this is going to be on the order of milli or microseconds. Not 14 and a half minutes. There are almost certainly some types of systems where a period that long can qualify as real time data communication, but not for something like getting data from a vehicle landing on mars, which can complete its entire landing sequence from the time it first touches the atmosphere in less than half the time it takes to get any confirmation of any of the events that occurred during it.
I might almost think you're trying to use some sort of physics variant of the Chewabacca Defense to cloud ths issue, but I have absolutely no idea why.
File under 'M' for 'Manic ranting'
If one of them catches and tries to eat it, it will be a case of the cat killing Curiosity.
* rimshot *
To have a right to do a thing is not at all the same as to be right in doing it
The light we are seeing from distant stars *WAS* emitted by them many years ago.
Again, you use words that lack meaning in this context. "Ago" implies a time frame where this time can have passed. This does not exist.
The remote stars are not in our time frame. There isn't such a thing as a universal time that you can apply to both us and them in which the years could have passed.
In our time frame, the stars are being born as we watch them. In the time frame of the traveling photons, they just left the remote stars and arrived instantaneously in a much older part of the universe. You can't come up with any time frame where the 16 billion years have actually passed.
Also, the distance as seen from us is not the same distance that the radiation traveled. Not even close. As speed approaches c, the distance traveled approaches zero. But at the same time (no pun intended) the universe expands, for the farthest objects, faster than c. When the light hits us, the galaxy isn't anywhere near where or when a simple speed/distance calculation would give. This is precisely why we observe background radiation from the birth of the universe. The radiation hasn't taken any detours - it has gone straight to us in a very short distance. What has happened is time, here. Not there, because "there" isn't part of our spacetime frame of reference. Time passes differently there; much slower than it does here.
I might almost think you're trying to use some sort of physics variant of the Chewabacca Defense to cloud ths issue, but I have absolutely no idea why.
Oh, that one is easily understood. Attempting to ridicule what you don't understand is common enough, and I won't hold it against you. Special relativity and non-Euclidean geometry are often the butt of such jokes.
But I recommend that you read up on it a bit. A good starting point is the relativity of simultaneity. It's not hard to understand, it's just hard to accept that you have to let go the "but it's obvious" belief that you can apply our time to anything not here, or use words like "ago" or "now" about more than one spacetime frame of reference.
I agree; there is a massive opportunity here to capitalize on the synergy of Martian Control and lolcats. I sense an RSS feed in the making.
As the AC pointed out, by your criterion nothing occurs in "real time" (unless it's on your own worldline), thus rendering the term effectively meaningless. Your post is just silly overeducated nitpicking (and I say this as someone who went to grad school for GR). You probably scream "there's no sound in space" at the movie screen, too.
UTC?
Sorry to intrude, but I just mentioned you in a comment. (Also wanted to say that I nitpicked earlier solely to clarify the issue for others.)
But now that I know you're a GR physicist, I wonder if you'd like to read Outlive the stars and leave a comment?
...if the interest is to search for signs of life... what is the rationale of landing in the middle of a CRATER? Isnt it like trying to find signs of cats in a volcano? O_o
But by your measure, any signal that goes through a repeater, fiber optic, or even air is not real time since all of these things are slower than c. For that reason, you better define "real time" using some non-zero delay cutoff, and then it's no longer true that by bcrowell's measure we never see anything in real time. Problem solved!