NASA finds water reservoir equivalent to 140 trillion times the world's oceans | Hacker News Reader

NASA finds water reservoir equivalent to 140 trillion times the world's oceans

nasa.gov

143 pointstomeast85 comments

I understand NASA's PR team wants to make these headlines appealing to general audiences, and generate pageviews, but they're making the mistake of overpromising in the headline and underdelivering in the copy.

To normal people -- i.e. Not HackerNews readers -- read reservoir and think of a resource we can tap for our curren needs, a "reserve" of water. It's not that at all. NASA's PR team isn't doing their scientists any favors. It's not some egregious sin or anything but I'd have chosen a different headline altogether. Or maybe I'm just being a nitpicky former PR guy.

The title on HN ("NASA finds water reservoir equivalent to 140 trillion times the world's oceans") is not the title NASA uses on its article ("Astronomers Find Largest, Most Distant Reservoir of Water"). It appears to be have created by mashing together the first two sentences of the article - the first describes it as a reservoir, the second describes its size relative to the earth's oceans.

Don't blame NASA, blame the submitter.

I'd blame NASA for using the word "reservoir".

I really don't think the regular layperson is going to be confused into thinking we can tap into it as needed when NASA describe it as the "Most Distant Reservoir of Water" right there in the headline, the first sentence of the article describes it as the "furthest reservoir of water", and the next explains it is "12 billion light-years away".

And even if this hypothetical layperson doesn't know how far a light-year is, 12 billion certainly gets across the point that it is an awful lot of them.

If we can't tap into it, then it certainly isn't a reservoir. For headline readers like myself, the choice of words is misleading.

Not sure why this comment is being downvoted. It's technically accurate. The definition of "reservoir" implies that a body of water is being collected or stored for later use. A reservoir need not be artificially constructed (i.e., a well or drainage pool), but in order to be a "reservoir," it needs to be put to use or accessible for use.

I am not a PR person myself, but I think the vast majority of laypeople who stumble across the headline "large, distant reservoir" would assume that the source is tappable. They might also ignore or not really understand the issue of the 12 billion light years -- or the inconvenience, to say the least, of the quasar nearby.

I actually think this was a good move by the PR. I think most people understand that space travel is in its newest form and by calling it a reservoir NASA is challenging science so that one day this distant water can become a practical reservoir.

Yes we just need to travel back in time to just after the beginning of the universe to use it. Oh, and it's also a long way away.

And there goes Stephen Hawking's fearmongering about hostile aliens barbecuing us for our water.

Keep in mind it's a huge amount of water, scattered through a mindboggingly huge volume. It's a very tenuous vacuum with more water then the surrounding vacuum, but, still, pretty good vacuum.

Where did he write about that?

http://www.millennium3.info/2010/04/26/stephen-hawking-says-...

http://www.huffingtonpost.com/2010/04/25/stephen-hawking-ali...

Edit: Okay ... I give up. I wasted a lot of time googling for an original source or a video where Hawking actually said these things. My Google search skillz are off this early in the AM and I can't bear to see more ads associated with 1 minute clips. The story that humans should stop trying to contact aliens (attributed to Hawking) became quite popular a few years ago. I even recall someone from SETI saying how this is not what they are doing ... rather, they are merely listening for signals from intelligent life that may exist rather than attempting to initiate contact.

http://news.ycombinator.com/item?id=1291969

That's a HN submission with good comments, where he basically gives the plot of independence day.

I'm more worried about alien life forms due to the Great Filter problem, personally. Other life is bad news for our chances at a cosmic-proportion, galaxy-changing Singularity.

Based on the HN headline, I was hoping it was in the solar system, like they just discovered the asteroid belt contained far more water than they thought before... could be very useful for future space applications.

This is pretty cool too though.

A cloud containing 140 trillion times the amount of water in our oceans would be pretty hard to miss if it was in our solar system! In fact, it might be bigger than our solar system... Anyone care to do the quick estimate math? (I'm on an iPad, impractical...)

That would be a sphere of water with radius <0.25AU: http://www.wolframalpha.com/input/?i=1.3+billion+cubic+kilom...

(Ocean volume figure is from http://en.wikipedia.org/wiki/Ocean )

Not as good as the giant cloud of alcohol http://www.spacedaily.com/reports/Jodrell_Bank_Astronomers_S...

I'm holding out for the giant cloud of beer.

There's water vapor in the Milky Way, although the total amount is 4,000 times less than in the quasar, because most of the Milky Way’s water is frozen in ice.

How could they possibly know this?

It's phrased oddly, and I haven't read the original paper; but I assume they just measured the spectra of its infrared blackbody radiation.

http://en.wikipedia.org/wiki/Black_body

Just like how a noncontact infrared thermometer works, except you have to use a space-based telescope, due to the water in our atmosphere.

I am not an astronomer but I would guess they know this the same way they know what anything in distant space (that does not give off light of its own) is made-up of: they observe the light shining through it and see which part of the spectrum is/is not filtered by it.

aka empirical evidence, yes, that is the basis of science.

Exactly. They "know" but they don't "know". You know?

isn't it also means there was that much water xx billion light years ago, it could be all gone now!

Nope. "Right now, over there" is a phrase which has no meaning on astronomical scales. There is no defined order for events which don't have a causal connection.

http://en.wikipedia.org/wiki/Relativity_of_simultaneity

There exists a frame of reference in which the state that we see in that image takes place at the same time as we read about it today. There's another frame of reference where it happens billions of years ago, before the formation of the Earth; another in which it happens in our future, long after our Sun has evaporated into nothingness (Ed: There isn't actually, see below). All of these perspectives are literally, completely equally valid. They're all real.

There was a good discussion about this last time it came up here: http://news.ycombinator.com/item?id=1907271

Your parent's point was simple and practical, not bound up in relativity. Parent was merely observing that even though we see it (please do not launch off into a metaphysical discussion about "what is seeing"), if we were to go visit it, it could no longer be there for use to "use".

You seem to think I'm quibbling over pedantry. I want to make it clear I'm not talking about wacky theoretical physics here, let alone metaphysics— this is hard science. You can't avoid getting "bound up in it"; relativity is, definitely is, how our world works.

In our universe, "It could all be gone by now" not only isn't true, it doesn't even make logical sense. There is no one such thing as "now".

Now, "It could all be gone by the time we get there" is a different, totally practical and valid statement. But that's just because of the amount of time it would take us to cross that distance; it has nothing to do with the distance that light has already traveled.

I understand relativity is hard science.

While I agree you are not talking about wacky unproven theory, I am not sure I agree that you are not being a pedant. Your parent's assertion is most definitely plausible from the right frame of reference, and mainly written to elicit amusement, but you insist on getting bogged down in the details discussing how it is NOT plausible in other frames of reference, which is quite frankly, besides the point.

I guess I disagree it's beside the point. You say my parent's assertion is plausible from the right frame of reference— what frame of reference are you assuming my parent was referring to? Certainly not the one we're all in, where we can see there remains plenty of water.

I'm inferring you understood it as something like "a frame of reference which agrees with the theoretical frame of reference of a spaceship we launch today, at the time it arrives at the reservoir". That seems far from obvious to me— I find it much more likely that xhuang (like many other commenters on this article, I should add, not to mention the public at large) has been misled by pop-science into the thinking that something being twelve billion lightyears away means that right now, whatever we're seeing is actually twelve billion years in the past.

But that's exactly wrong! There is no actually, and what we see is as valid to call "right now" as anything else. And this is the universe we live in! Maybe I am a pedant, but this stuff is mind-bogglingly amazing when you can actually wrap your head around it, so I try not to miss out on a relativity teaching moment.

Anyhoot, we obviously both get it, so I'll wait on xhuang to say whether my comment was relevant to his point or not.

I would take the frame of reference of an observer at the location of the water because that is your goal - it's what is meant by "over there".

Could you resolve the "right now" issue if you took a picture of the event to said observer, who then compared it to a history of images and then said "oh yeah, 5 minutes later it was all gone, never to return"?

These seem like a closer representation of what people mean when they say "it's all gone now."

See, you're making the same mistake— an observer at the location of the water when? You want to say "now", but there is no such thing. Taking a picture doesn't help the issue— you only wind up tangling yourself up in it.

This stuff was all figured out in the first place through thought experiments, so let's try one to demonstrate what I mean. Let's say there are two real events we can talk about here. Someone at the reservoir poses, the light takes twelve billion years to get here, and we snap a photo. Then say there's a second event, the draining of the reservoir, which happens (at the reservoir) one year from the time the person poses.

What we want to know is, has that event happened yet, even though we observe there to be water? So on your suggestion, as soon as we take the picture, I jump on the spaceship with a copy and fly over there at near to the speed of light. Twelve billion years after they posed, the person at the reservoir will look up and see me lift off from Earth, and then very soon after I will arrive carrying the picture to ask them about. (Of course I'll already have seen the event I want to ask them about, but set that aside for now.)

Okay, so here's the fun part. While I'm travelling there, at very near to the speed of light, time stops for me, or very nearly. I perceive the journey to take a matter of hours, say. I arrive at the reservoir carrying a still-wet photograph to ask them about. They say, "Oh, yeah, that happened about twelve billion years ago— a year before we drained the reservoir, wasn't it?"

"Ah hah!" I exclaim. "I had a hunch the water was already gone when I left."

The reservoir people think I'm nuts. "We drained the reservoir almost twelve billion years ago. You only left Earth a couple of hours ago. Of course the water was gone."*

This is true. From my perspective, I have just taken a picture, flown for a couple of hours, and the reservoir has been gone for billions of years. But, no matter. Bearing my prize, a notarized letter affirming that the picture depicts events one year prior the draining of the reservoir, I hop back in my spaceship and make for Earth. Again, a journey of twelve billion lightyears seems to take a manner of hours. On arrival, I disembark, waving the letter triumphantly.

"See? We were right! The water was gone a mere year after we took the picture."

"We know," says Earth. "We saw it happen one year after you left."

"...I haven't been gone for a year," I say with a sinking feeling in my gut.

"You've been gone for twenty-four billion years. We watched you leave, and one year later the water was gone. A couple of hours ago we saw you arrive at the reservoir, get the notarized letter, and lift off again; now you're here."

"No, no," I protest. "You only think that just happened a couple of hours ago. It takes light twelve billion years to travel that far, it's ancient history by now. This letter is twelve billion years old."

Suddenly, it occurs to me that I am trying to argue that events that I personally witnessed a couple of hours ago are, in fact, ancient history. I am holding a still-drying photograph which Earth insists was taken twenty-four billion years ago, and they have twenty-four billion years of history to prove it; I am also holding a notarized letter which both I and the Earth have just seen signed mere hours ago, and saying that it is twelve billion years old. And yet I know that these objects are only hours apart in age.

I realize that if I flew back to the reservoir to get double-confirmation, hours later they would say that they had just seen me arguing with Earth, and they took my side, although according to their records the letter was actually notarized twenty-four billion years ago and not twelve as I had been claiming. I realize that no matter how many trips I make, I will never be able to make it so that I, the Earth, and the reservoir people agree about the order of events.

"You know," I mention to the Earth, "I could have saved a lot of time if I had just read the Wikipedia article on the Relativity of Simultaneity, couldn't I."

"Yeah, probably," the Earth says. "Sorry about all your friends and stuff."

* cf. "a frame of reference which agrees with the theoretical frame of reference of a spaceship we launch today, at the time it arrives at the reservoir"

You would observe that history yourself, as you traveled toward it.

It's fine to get excited about strongly relativistic arguments but I don't think they have a place in talking about events at distant celestial objects.

The amount of distortion you can have between distances and times is bounded by the amount you let your reference frames differ. Between stars there is not all that much velocity, so time is a relatively stable concept. Sure it'll wander a few percent but nothing nearly as drastic as having no sense of 'now'.

Don't forget that when you bring relativistic speeds into the mix you can't agree on distances either. Are you prepared to argue that it's actually one billion light years away?

I just posted a fun little thought experiment to illustrate why this is actually a thing: http://news.ycombinator.com/item?id=2799908

When you read someone write "as I write this", they mean "simultaneous with the event of this writing in the reference frame that I occupy currently". I mean I doubt anyone conceptualizes it like that, but that's what they mean physically. It just wouldn't make sense any other way.

So what does it mean when someone writes "as I write this, the water is all gone"? That statement is factually false, since in their frame of reference the event in which the water disappears has not yet happened.

Now as I noted in my thought experiment, that statement is true in "a frame of reference which agrees with the theoretical frame of reference of a spaceship we launch today, at the time it arrives at the reservoir". But that's just not what people mean when they say "now".

Commenters on this article, and there are several, aren't saying that because they're mindful of relativity and are using a peculiar implicit reference frame in order to make the point that the water might all be gone by the time our ship gets there. If they were, they would never say "now", because that's nonsensical, and we have a perfectly straightforward way to say that: "It might all be gone by the time our ship gets there." (In fact, isn't "the frame of reference of a spaceship we launch today, at the time it arrives at the reservoir" the same as "the time our ship gets there"?)

They're saying it because they think that there's such a thing as simultaneity. They think conceptually we could travel there instantly. It's just not true.

And it's not not true in the sense that "little g is 10m/s^2" is not true, it's not true in the sense that "The sky is red" is not true. Somebody who says the sky is red misunderstands something fundamental about their universe, and I think that's worth teaching them about.

Now, sure, you could argue that, say, it's stormy out, so it's dangerous to fly, just like it would would be if the sky were red, so practically the statement is ok and I'm just being a pedant. But that would be ridiculous.

But that sort of problem only comes up when you accelerate. If you maintain a frame of reference then you can handle things far more gracefully.

A shared reference frame over two points billions of light years apart can be established. You simply keep the distance between these points roughly constant, which holds the velocity of all points roughly constant, which keeps calculations of simultaneity roughly constant across the whole region.

I can then state that in the combined earth/reservoir plusorminus .01c reference frame that the water is already gone. And this is factually true. You still have to wait for information to propagate but everything works out. The timing has no disputes between any members subscribing to this reference frame.

Relativity doesn't cause major problems until you deal with matter moving at high relative speeds.

P.S. I'm deliberately ignoring the expansion of space in this argument.

I fail to see how "right now, over there" fails to have any meaning when at this very moment that point in space does exist, the assumption is that we are moving between there and here without any lag (instantly) when comparing the sets of areas.

In our minds, where the comparison is taking place, we need not account for how long it takes light to travel. We can simultaneously hold the thought that we are here on Earth, and way over there, there once was a giant cloud of water vapor.

First you should read the Wiki article I linked, since it goes over it much more thoroughly than I can, and then maybe I can help if you still have questions. Here's the introductory paragraph to get you started:

Where an event occurs in a single place–for example, a car crash–all observers will agree that both cars arrived at the point of impact at the same time. But where the events are separated in space, such as one car crash in London and another in New York, the question of whether the events are simultaneous is relative: in some reference frames the two accidents may happen at the same time, in others (in a different state of motion relative to the events) the crash in London may occur first, and in still others the New York crash may occur first.

I emphasize again that this is the actual way the universe works, not theoretical physics. What you say about our brains holding the two ideas simultaneously in our head is true; our brains are wrong, and the statement "There once was a giant cloud of water vapor" is untrue, or rather, undefined.

Also: I fail to see how "right now, over there" fails to have any meaning when at this very moment that point in space does exist, the assumption is that we are moving between there and here without any lag (instantly) when comparing the sets of areas.

To move "instantly" from one place to another presupposes there is such a thing as "over there, right now", which there isn't. Your definition thus has no meaning. Isn't this stuff wild?

So what I take that relativity of simultaneity is showing, is that there is no "universal time" everywhere.

But this is all dependent on the positioning of the observers. The observers painted on the universal graph are all ones waiting for light to reach them. This is what is causing the confusion as to when is "now", as all the observers or points of awareness are separated in space. And I take it that, their separation in space is also what separates them in time... and thus each have different notions of when now is.

But can we not conjure an omniscient observer as our frame of reference? One who exists at all points, at all times.

Would he not be able to observe both the Earth on July 24, 2011 and what exists in the space of the water vapor cloud as Earth time is still July 24, 2011?

Sure you can.

Pick a vector.

Any vector.

You can create an observer moving at this velocity and it'll give you a different idea of simultaneous from an omniobserver at a different vector.

Oh, and before you ask, no there is no 'unmoving' vector. They're all relative to each other with no reference frame.

But can we not conjure an omniscient observer as our frame of reference?

Yes. We can not. In fact, that is precisely what the theory of relativity states: There is no privileged reference frame.

There is literally, actually no such thing as "what exists in the space of the water vapor cloud as Earth time is still July 24, 2011". As I look at my clock at noon on July 24, I see water. Someone at the reservoir will not see my clock strike noon for twelve billion years, my time, and they'll look around and maybe see no water. We disagree, but we're both right in our own frame of reference. Both perspectives are true.

Which makes sense if you think about it; your omniscient observer would have to agree with one or the other (or some other) disagreeing perspective. What criteria could you possibly use to choose between them?

Tip: "I'd love to explain it, but (I won't)" comes across as extremely elitist, and to some people, quite repugnant. If that's not how you mean to come across, simply omit that first bit before the comma, and you will come across much more amicably.

That's a great tip, thanks. I really meant that I'd love to explain it, but you're right that it doesn't come across that way :)

Have you considered exactly which frame of reference would be required for it to appear to happen in our future?

Whoops, I forgot my own rules. Relativity doesn't violate causality; Obviously no one will observe us to see the reservoir it before it happens.

Okay, so there's a frame of reference in which what we'll observe to happen to the reservoir tomorrow has already happened. It was much punchier the other way, though :(

I am no expert on this, but if you assume the cosmological principle which states that our universe is roughly isotropic, there is a natural set of observers called comoving observers who are at rest with respect to the expansion of the universe. One can define a universal time using the clocks of these observers. Presumably, this is what gives meaning to statements like the universe is 14 billion years old.

Well, again, relativity doesn't violate causality. No one sees an effect before a cause. That translates into the cosmological principle in that all observers will see the big bang happen before anything else, all observers will see stars form before planets, et cetera, so it all comes out in the wash.

Nothing about that privileges a comoving observer with relation to unrelated events, though; they'll have their perspective just like everyone else, and that will be that. There's nothing "universal" about comoving time.

I don't know what to do with these numbers. I can relate to our ocean in some way, 2 times, 5 times, maybe 10 times the amount of water but higher numbers are too much for me.

They should just use liter instead.

Earth holds about 1.26x10^21 liters (source: http://science.howstuffworks.com/environmental/earth/geophys...). So 140 trillion times that would be 1.764x10^35, or about 176 decillion liters.

I don't know what to do with these numbers either.

Given that the difference between our calculations is a result of the margin of error in determining the Earth's ocean's volume, I wonder what the margin of error is for NASA's measurement.

1.918 * 10^35 cubic liters [1]

[1] http://hypertextbook.com/facts/2001/SyedQadri.shtml

Can anyone come up with a good comparison for this? A sphere the size of Mercury's orbit is an order too large (~ 1.4e36L according to Wolfram Alpha).

Edit: Of course Mercury's orbit isn't spherical, but we're talking ballpark here :P

I like the idea of using Mercury's orbit as a comparison. Some more fodder:

Just over 13,583,569.4 times the volume of the Sun. [2]

[2] http://www.smartconversion.com/otherInfo/Volume_of_planets_a...

How the hell they found something that is xx billion light years away? Isn't that xx the amount of time that light (or whatever else) needs to get here so they can see/measure it?

Well, the light (well, x-rays, I think in this case) has been transiting space for billions of years, then astronomers collected it. Astronomers collect light that was produced billions of years ago every day.

Hope that helps!

In particular, this means that 12 billion years ago, there WAS a reservoir of water of such and such size.... :-)

Well, yes and no. See Cushman's comment, above, on the relativity of simultaneity.

In relativistic situations it really doesn't matter which verb tense you use. Verb tenses are not designed for this sort of thing.

Which also means that what we see now is the light that finally reached us and that "image" is old by a billion years.

The universe is roughly 14 billion years old, so events at this distance are near the beginning of it.

Keeping in mind, people 200 years from now may look back on this comment and go "Ha ha, people used to think crazy things like 'the universe is only 14 billion years old'".

Science doesn't really work that way; we don't look back at Newton and think what an idiot, nor will future people think so of us. Our measurements get more accurate over time but that doesn't mean our current measurements are wrong or ever will be; they're simply as accurate as they can be now, which is pretty damn accurate. No one in the future is going to suddenly find out the universe is 100 billion years old and we had it all wrong.

Oh, the ego of us humans.

The one constant throughout the history of science is that Nature's imagination is substantially more vast than our own.

What if we discover that "old" has an entirely different meaning after light has traveled for some billions of years?

I can't think of any reasonable examples, except I remember my friend showing me a very old book about Chemistry. It had chapters about how "everything is made of a mixture of earth, water, and fire". And so on.

To your point, someone used the Hubble Effect in the other HN thread on this story to show that this observation is actually closer to 9.5 billion years old, which is significantly different than it being 12 billion years old.

> I can't think of any reasonable examples

Exactly, no one can, because your premise is wrong.

> except I remember my friend showing me a very old book about Chemistry

That was pre-science. If you can't find a modern day example there's a reason for that, the wheel of science only turns one way, forward. New science rarely if ever disproves past science, what it does is give us more accurate theories; the old theories are still correct within the framework they were made in. Einstein for example, didn't prove Newton wrong, he just had a theory that was even more accurate than Newton's.

It's not ego, it's how the process is meant to work.

For some mind-expanding examples of the (probable) insufficiency of our concept of "universe," see:

http://en.wikipedia.org/wiki/Multiverse#Tegmark.27s_classifi...

At various levels, it's possible that our own Hubble volume ("universe") is only a small stable bubble in a much larger physical system.

Well, that is true in 200 years the universe will be 14,000,000,200 years-old ;)

Really? I would have thought since we are expanding outwards, an event could be really far away simply because it is on the other side of the nexus. In other words, the universe is (28 billion) * (speed of expansion) across, rather than 14 billion

I don't follow you. The light from this event traveled 12 billion light years to get to us and current best estimates put the age of the universe at 13.75 billion years, so this light was emitted relatively close to the beginning of the universe. To reach this object now, you would indeed have to travel much farther than 12 billion light years due to the expansion of the universe.

Gah, sorry. You are correct, I was thinking about everything wrong.

The universe is (as far as we know) far larger than that. The thing is that it's literally impossible for us to interact with the parts of it outside one particular sphere.

Additionally, the universe is not expanding from one point - every point is functionally the "center" of the universe.

I do not understand how it is possible for something to expand without having a central locus. In fact, I am at a loss as to how it is possible for anything that posses bounds to fail to have a singular center. Explain?

Who says the universe has bounds? The classic analogy is of an inflating balloon. If you make two marks on the balloon, they'll expand away from each other, but neither one is the center.

Of course AFAIK there isn't any solid proof for the "finite, unbounded" idea, mostly just speculation. But it was Einstein's thing so we (laymen ;) take it pretty seriously.

You're saying that the space inside the balloon is not part of the Universe?

Well, Einstein is ;) But yeah, for the sake of the analogy we're talking about a 2-d universe which is the surface of the balloon, nothing else exists.

So objects in the Universe are not traveling because they have velocity, rather, "space itself" is expanding?

I don't think I understand your question— both are true?

From all I've read on it (the questionable balloon analogy is easily misleading at first), it's less something you can easily understand and almost something you have to trust. I guess there is another dimension involved and as such it's not all something that can be easily visualised when we're so used to dimensions as we experience them.

If NASA is right about where there is water there is life, and or hydrogen drives, then if there are billions of FTL species maybe they would (lol) gravitate to a trillion planets worth of water.

"just saying that it might be a good place to look for more interesting communication signals."

12 billion light years away huh? hmmm

Better get started on the pipeline. LA's residents are thirsty.

LA residents are sitting next to an ocean. If they want water, they should elect a government that will allow them to build desalination plants, as opposed to one which creates artificial scarcity.

That is insane.

Good thing we cut their funding!

Space is web-scale (how has no one else made this joke yet?)

I don't get it. (But I didn't downvote.)

I guess that rules out the plot of "V" ...

https://secure.wikimedia.org/wikipedia/en/wiki/V_%281983_min...

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