## Supernova Casts Doubt on "Standard Candle" 132

Posted
by
kdawson

from the chandrasekhar's-the-limit dept.

from the chandrasekhar's-the-limit dept.

Krishna Dagli writes,

*"A supernova more than twice as bright as others of its type has been observed, suggesting it arose from a star that managed to grow more massive than theoretically thought possible. The observation suggests that Type 1a supernovae may not be 'standard candles' — all having the same intrinsic luminosity — as previously thought. This could affect their use as probes of dark energy, the mysterious force causing the expansion of the universe to accelerate."*
## Oh really... (Score:5, Funny)

Obviously not a

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## Re:Oh really... (Score:5, Funny)

I don't get it.

## Gravity Lensing? (Score:1, Insightful)

Ryan Fenton

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Or, for that matter, could it be a foreground star and not associated with that galaxy at all?

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...could it be a foreground star and not associated with that galaxy at all?"Simply put, no.

A light spectrum clearly identifies a supernova for what it is. There is nothing else like it. Also, the redshift in the supernova and surrounding stars gives the distance fairly accurately.

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I bet not!

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Especially since the news seems to originate from Nature, and if it took only 6 min to find a slashdot reader with a sensible explanation, I suspect it would not have taken much more time within Nature Readers.

B

## Re:Gravity Lensing? (Score:4, Informative)

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Probably not. Gravitational lensing would cause a noticible shift in the star's spectrum.And why would that be? Wouldn't the light be blueshifted as it fell into the gravitational potential of the lens, and then redshifted as it escaped, for a net spectral shift of zero?

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My gut feeling says that because the light trajectory was altered by gravity, there must be some effect on it's spectrum. But I would have to do some difficult calculations to see if my gut is right (it is, after all, a very dumb organ). Need more coffee...

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## Canada-France-Hawaii telescope? (Score:1, Interesting)

Why is the telescope called "Canada-France-Hawaii" instead of "Canada-France-USA" telescope?

Or did Hawaii separate from the US recently?

Thomas Dz.

## Re:Canada-France-Hawaii telescope? (Score:5, Informative)

## Re:Canada-France-Hawaii telescope? (Score:5, Funny)

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## The universe will out (Score:5, Insightful)

## Re:The universe will out (Score:5, Interesting)

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"Why does 2+3 = 5? Because we said it does...not because it is universally true."While the notion that a mathematical model can be flawed is something that is easily conceivable, the "2+3=5 only true because of consensus" idea paints all of math as merely arbitrary, and I don't think it is. I think most, if not all, of math holds together rather well as an integrated system.

## Re:The universe will out (Score:5, Interesting)

"Why is 2 + 3 = 5?"

Because the arbitrary definitions which we assigned to the symbols 2, 3, 5, +, and = happen to represent real-world concepts that exhibit the behavior that 2 + 3 = 5, and not because there is any abstract universal rule that "2 + 3 = 5" and we simply need to find real-world behavior to prove it. That is, the real-world behavior has always existed, but the mathematical language used to express it was invented by us and assigned to those behaviors specifically to make the mathematics true.

(Or something, it's early.)

--K

## Re:The universe will out (Score:5, Interesting)

Quoted for truth. I want to elaborate (i.e. ramble) on it a bit . . .

Numbers are indeed a

deductivesystem: they are true because they aredefinedto be true. They are true in all conceivable universes. This makes them useful but also hollow: they contain no empirical content, and hence are immune to all conceivable experimental results.Nevertheless, they (and all other deductive symbols) can participate in

inductivestatements, such as "2 algae cells will combine with 3 fungi cells to produce 1 lichen".## Re: (Score:2)

Ooohh... I just made my head hurt.

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Is that to say that the additive property of integers exists only because we've defined integers to be what they are? Seems reasonable to me. It makes me wonder how things would be different if we had (or even could have) decided to conceive of things in real numbers always.## Re: (Score:1)

## Re:The universe will out (Score:4, Interesting)

This is a fairly poor summarization of the argument made by Tom Siegfried (used to be chief science writer for the Dallas Morning News, now he's somewhere else) in his book

Strange Matters.Perhaps you are right, and mathematics is just something we came up with. However, where did we come up with it from? Our brains. Our brains are part of the universe, so if the universe is goverrned by laws which can be well expressed in mathematical language, one might predict that brains would invent mathematics.

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There's little need for such an elaborate argument. Mathematics is something we came up with

to describe and quantify the world we see around us. The fact that mathematics is so good at describing## Re: (Score:3, Insightful)

That the area of a triangle inscribed in a circle is equal to the product of its three sides divided by four times the circles radius is a physical fact...Only for perfectly flat space. In reality, all space is curved even if by just a little bit.

We generally discover that what we believe to be a fundamental truth is often dependant on assumptions that we are not aware of. This is where brilliant minds discover more about our world by exposing these hidden assumptions.

Also, we tend to aggregate things for c

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That the area of a triangle inscribed in a circle is equal to the product of its three sides divided by four times the circles radius is a physical fact...Only for perfectly flat space. Inreality, all space is curved even if by just a little bit.So your argument is with the

physical factpart and not the rest, right? The description of the method for determining the area of a triangle is indeed fact where mathematics is concerned. Math, when applied to the real world, loses a certain amount of its ef## Re: (Score:2)

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but that is not what it really is. 2+3 works for most cases, but there will be edges where the simpler math breaks down and if you do not realize that you are dealing with quantum particles instead of a few apples,Case in point: let X be 0.25 critical masses of plutonium. 2X + 3X doesn't equal 5X, at least not for very long.

you may become very frustrated.Or dead.

(And for the nuclear physicists and engineers: yes, I know it's more complicated than that because of factors like shape, etc. substitue "pluton

## Re:The universe will out (Score:4, Interesting)

That is, mathematics is not purely descriptive as it relates to science. As an example, it is my understanding that the phenomenon of time dilation as velocity increases towards

cwas first "observed" as a result of mathematical manipulations of exsiting models, long before it was (or could be) experimentally observed.If math were purely descriptive, this would not be the case - or, if it were, it would be only by sheerest chance; the exception, rather than the rule.

I agree, of course, that math comes out of description; 2+3=5 because those numbers represent specific physical quantities, and when you have real items in those quantities, they behave in that fashion. However, I can't help believing that there is something inherently "real" about math itself, since the logical structure of math agrees so well with physical reality so often - enough so, in fact, that the mathematical understanding of a physical phenomenon can predate observation of that physical phenomenon.

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That is, mathematics is not purely descriptive as it relates to science.Math is just barely descriptive to science, the tables of values in my thermodynamics class was purely descriptive to science. But by the time you've gotten so far that you have mathemathical formula, it's essentially predictive. If we know that f(x) holds for x_min...x_max, the prediction would naturally be that it holds for 0.5*x_min or 2*x_max. If we know two formulas, the prediction would also be that f(x,y) = f(x) + f(y). Of course

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This is logically fallacious. If a mathematical model predicts previously-unknown real-world behavior, it is either

descriptiveof the world or it isprescriptive. While it might## Re: (Score:2)

I am open to suggestions as to what pair of words I should have used instead.

Regardless of my possible misuse of terminology, I maintain that math's predictive power implies a reali

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Aren't there sub-atomic particles which were believed to exist due to a negative square root or something?

:-P

As I recall, they have been borne out by experiments.

That just hurts my head.

Cheers

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To expand o

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"

So why is it that electric fields follow the law of superposition, which is an additive law working precisely as we said addition should thousands of years before we ever imagined electric fields?"Except when you actually do the measurements, you get a slight variance. Why should we get some discrepancy? I thought this was precise mathematics, proven sturdy for thousands of years. 'Well,' the answer goes, 'the measurement

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Real-world measurements don't exactly work out the way you would have us believe.

"So why is it that electric fields follow the law of superposition, which is an additive law working precisely as we said addition should thousands of years before we ever imagined electric fields?"

Except when you actually do the measurements, you get a slight variance. Why should we get some discrepancy? I thought this was precise mathematics, proven sturdy for thousands of years. 'Well,' the answer goes, 'the measurement tool

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I suspect that most phenomena don't 'measure up' quite as exactly as electrical fields. If that's

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I admit you caught me -- I don't specifically know about "law of [linearj] superposition of electric fields", but any measurement I've seen of the real world has some small degree of divergence from the formulas -- small in orders of magnitude. The official line is that this variance is due to the imperfection of lab setup, imperfection of materials measured, and the imperfection of the measuring equipment.I'm generally agreed. On the other hand, most experimentalists (and many of the

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Furthermore, how is it that we can "prediscover" phenomena? We develop a model to describe existing data, and whoops!, there's another phenomenon implicit in our model, and sure enough when we look for it in reality, there it is!I suspect this is like our response to red traffic lights. We remember the annoyance of having to stop, but rarely remember all the times we sail through a green light. Often, people will complain about 'bad luck' with red lights as a result. But the reality is that the red lights a

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If mathematics were just some invention of ours,

thenthe universe would need a calculator in hand to figure out what to do next. We know the universe follows relatively simple mathematical laws. So, what?--Does it then comply to our whims and inventions? No, of course not! Our mathematics complies to its nature; not just in our use of it, but in the very nature of mathematics.It's absurd how well mathematics models the world. So absurd, it may be impossible to explain

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Why does 2+3 = 5? Because we said it does...not because it is universally true.I don't know about that. I am not a mathematician, but I've always been pretty sure that we defined numbers and addition, but specific instances of their usage, like "2 + 3 = 5" are not defined but instead logically induced (or deduced, I forget) from those base definitions. And given the base definitions, 2+3=5

isuniversally true.## Re:The universe will out (Score:4, Interesting)

And given the base definitions, 2+3=5 is universally true.2+3=5 is not

univserallytrue, it is true within the framework of a common set of axioms. Here is an example of a simple set of axioms which allow us to prove that 2+3 = 5 (within the framework of those axioms):Let s(X) be the successor function applied to the variable X.

Let 0 be a symbol in our algebra.

Let 0 = 0. (1)

Let s(X) = s(X) if and only if X = Y. (2)

We now have equality defined.

Let X + 0 = X. (3)

Let X + s(Y) = s(X) + Y. (4)

Let X + Y = Y + X. (5)

We now have addition defined.

We define a set of symbols such that 2 = s(s(0)), 3 = s(s(s(0))), and 5 = s(s(s(s(s(0))))).

2+3 = 5 is therefore equivalent to s(s(0) + s(s(s(0))) = s(s(s(s(s(0))))).

We can rewrite this by applying our axoims (axiom number given in brackets) so that:

s(s(s(0))) + s(s(0)) = s(s(s(s(s(0))))) (4)

s(s(s(s(0)))) + s(0) = s(s(s(s(s(0))))) (4)

s(s(s(s(s(0))))) + 0 = s(s(s(s(s(0))))) (4)

s(s(s(s(s(0))))) = s(s(s(s(s(0))))) (3)

s(s(s(s(0)))) = s(s(s(s(0)))) (2)

s(s(s(0))) = s(s(s(0))) (2)

s(s(0)) = s(s(0)) (2)

s(0) = s(0) (2)

0 = 0 (2)

This gives axiom 0, and so is true.

Anyone wanting to play with these ideas in a more hands-on way should download a prolog implementation (I recommend SWI Prolog [swi-prolog.org]). You can implement these axioms in prolog as the following program (the first two are implicitly defined):

You can then ask it questions in the following way: Your homework from this post is to extend this system to define multiplication.## Re: (Score:2)

And given the base definitions, 2+3=5 is universally true.You:

2+3=5 is notuniversallytrue, it is true within the framework of a common set of axioms.Now I think it should be obvious that by "base definitions" I pretty much meant your "common set of axioms", though of course I couldn't write out the exact axioms without doing some reasearch. And in my post I forgot that besides numbers and addition we also needed to define equality. So

given the definitions, or the framework of a common set of axiom## Re: (Score:1)

You have to understand, my math teacher only had one hand.

Bemopolis

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for very large values of 2.

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Or very small values of 5.

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No, if you said he was a carrot, you would be placing a label, "carrot", upon him. That label is external to the actual himness of him.

2 is a label for a quantity. 3 is a label for a quantity. 5 is a label for a quantity

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so, if I said that you were a carrot, it would be correct because I said so?No, but any deductions that you came up with would be true, provided that you accept that he is a carrot.

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Why does 2+3 = 5? Because we said it does...not because it is universally true.Wouldn't it be universally true because it is consistent with what has been defined? That is precisely what is so useful about mathematics in science, it is not dependent on observation, but merely needs to be consistent with simple rules that have been defined. In science, mathematics is used as a reference system.

Certainly mathematics started as a way to describe real world phenomena, but its definition is no longer linked to

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What utter cobblers.

Consider that other animals show the capacity to do maths. Monkeys are surprised when, for example, a box is shown to them containing two apples, then another three apples are put in a box and when the box is opened there are only four in there. They have understanding of addition, subtraction and probably commutation.

A lot of mathematics is stuff the brain (human or animal) has

observed## This is bull... (Score:2)

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consensus.To go against the consensus isn't, ummmmmmmm, well, politics.KFG

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I find that not at all odd, given how mathematics have proven unreasonably effective [wikipedia.org] in describing the universe we find ourselves to be a part of. Or so I feel. Math feels a little bit like magic to those who don't have a firm grasp of it. Hell, I have a decent grasp of mathematics in general, but it still seems a bit mystical to me. Sort of. Disclaimer: My worldview is entirely naturalistic. I'm not describing my reasoned

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Yep yep. Mathematics makes possible the completely astounding feat of being able to build a bridge out of precise amounts of raw materials, knowing

ahead of timeexactly how much wind and weight it will ultimately be able to bear.Of course, any engineer worth his salt will build his bridge out of :)

Rearden Metal. . .## Re: (Score:1)

All models are wrong, but some models are useful.- George Box## Re: (Score:2)

## Platonist viewpoint (Score:1)

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## This is a GOOD thing.... (Score:5, Interesting)

So why do I think this is a 'good thing'? As the article speculates, it is likely that this supernova was different because of some rotational process or perhaps colliding stars, or some other exotic combination. This is exactly the sort of process that can be used as a test of supernova models to see how well they do. Over all I find this a very exciting observation and hopefully it produces more new science!

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## more important than 'probes of dark energy' (Score:4, Interesting)

The observation suggests supernovae of this type are not "standard candles" as previously thought, which could affect their use as probes of dark energy - the mysterious force causing the expansion of the universe to accelerate.If true, this wouldn't just affect their use as probes of dark energy. These standard candles are used to tell how far away things are and how fast they are moving. The age of the universe could be in doubt.

But I have a hunch this particular supernova will turn out to be an anomaly. Not that I'm a astrophysicist or anything.

## Re:more important than 'probes of dark energy' (Score:5, Interesting)

Similarly, Type IA SN are not the only mechanism by which we measure the age of the universe, so I'm not too concerned. The other reason I'm not too concerned is that the age of the universe was already in doubt. Another talk at PASCOS dealt with something else that I can't recall at the moment (curse my memory in the morning!) that cast into simultaneous doubt all or nearly all of our universe age indicators. IIRC, according to his talk, the universe could well be 20% older than our current best estimate.

Of course, since all these are not quite my field (I was at PASCOS for the particle physics), I can't answer for whether or not these guys were just crazies and all the cosmologists were ignoring them, or if these are serious problems that will be dealt with in the next few years. I'd be inclined, however, to assume that they were quite legit.

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## ultimate fate and scientific knowledge (Score:2)

Aside even from the age of the universe, at stake would be whether the universe is in fact expanding at the widely understood rate, or perhaps whether the universe is expanding at all. IOW at stake again is the question of ultimate fate.

It seems in TFA that astronomers do have some data to reevaluate, toss, and that these fundamental calculations could be in flux. This is exciting, we might not be expanding to oblivion, instead we might be contracting to oblivion like we thought we were before! Knowledgea

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## In astronomy 2=1 (Score:1)

Disclaimers: IRAAA (I really am an astronomer), but I know nothing about using SN as standard candles (other than the fact that they are used...). No, I did not RTFA.

## Micro Supernova simulated in the lab (Score:2)

They simulated a micro super nova here

Producing micro fussion/fission and creation of new materials.

## The observational evidence is surprisingly scanty (Score:5, Informative)

The Nature paper in which this work is published has a figure showing all the measurements of this supernova's brightness; you can see it on Nature's web site at

http://www.nature.com/nature/journal/v443/n7109/f

There are four measurements near time of maximum light, in the red (r) and near-infrared (i) passbands. There are many more measurements starting about 15 days after maximum light in the rest frame, including some in a blue-green (g) passband. Here's what the researchers did to find the maximum brightness of this supernova, so that they could compare it to others:

a) fit models based on the light curves of other supernovae to the r and i measurements,

and the late-time g measurements

b) choose a different passband -- the greenish V passband of the Johnson-Cousins system,

which is closest to their own g passband (the one with no data at max light)

c) use their models to estimate what the light curve in the V filter would have been

This can be a tricky business. Their major conclusion, that this supernova was more luminous than typical ones, is probably correct, but their claim that they can measure the peak magnitude in the V-band to an uncertainty of 6 percent seems a bit bold.

As the press release states, if atypical SNe are very rare, then this probably doesn't have any major impact on the use of Type Ia SNe in cosmology.

## Its all Greek to me (Score:4, Funny)

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## Re:The observational evidence is surprisingly scan (Score:2)

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Type Ia supernovae are indeed one of the last rungs on the distance ladder; they can be used to estimate distances to very distant galaxies.

No, that's an overstatement. Type Ia supernovae are one of several different indicators used to estimate distances to very distant galaxies -- not the only

## This just advances science (Score:3, Informative)

The standard candle was a theory, one that worked well, and now it's in doubt, indicating either that its wrong, or it's incomplete. I'd vote for the latter personally.

That's usually a safe bet...

That's how things move forward.

I shortcut this process. I proved one of my hypothesis wrong even though it had withstood initial tests which indicated correctness. It probably saved a lot of time, but lost me a conference trip, dammit.

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>science.

Sure, just like the ever-changing O.J. defense team theories in response to found evidence were essential to the advancement of justice

Now if you could actually do experiments, that would be pretty cool. I want to don the tinfoil glasses for the first supernova trial in the lab

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## Oh, I get it... (Score:2, Funny)

Dark energy? the mysterious force? Oh, I get it, we found the death star [wikipedia.org]!

That was funny right? *nudge**nudge*

## Lukas Rossi won (Score:1, Offtopic)

## Skeptical... (Score:2, Interesting)

1) Never trust anything you read in New Scientist.

2) Consider the following, discovered on Google:

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2) That email refers to observations in the B filter, which are used for cosmology. Indeed there is not enough data from that g filter (which transforms to B) near peak to constrain this supernova, so it was thrown out from the cosmology partially because the B peak magnitude is a c

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## Re: Supernova casts doubt on "Standard Candle" (Score:1)

## Question (Score:1)

## No, the cat does not "got my tongue." (Score:1)

> has been observed, suggesting it arose from a star that

>

managed to grow more massive thantheoretically thought possibleAssuming the theory is correct...Contact! You heard it here first! [wikipedia.org]

Sci-fi is replete with civilizations that are messing around with black holes and supergiant stars and crap.

## Standard who? (Score:2)

Perhaps they're still miffed that Tommy Lee et al borrowed their name for a reality show recently...

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