supernovae visibility

[ratchetmouth]

In arguing with creationists, you hear a lot of bizarre claims, and reasoning that is completely unburdened by fact or reason. I was recently talking with a creationist who liked to delve into arguments that had more bearing on astronomy than biology (they are quite fond of this, as I`m sure many of you know). He said that if the universe was really billions of years old, the whole night sky should be lit up with supernovae. Of course, I told him that the light from those supernovae takes tens or hundreds of millions of years to reach earth (sometimes longer) and that in and of itself disproves his claim about a young universe. However, even taking into account how long it takes light to reach the earth from distant supernovae, why is it that we don`t see more than we actually see? I understand that they can often oushine whole galaxies when they are spotted. I certainly don`t think this joker`s claims have any merit, but I would like to present him with more evidence than I have so far.

[Jeff Root]

The first stars to form were extremely massive -- typically, more
massive than the most massive stars existing today. They would
have had very short lifetimes before going supernova. It is possible
that such stars condensed in large numbers in a relatively short
time (perhaps on the order of a hundred million years), once the gas
had cooled enough to collapse gravitationally. If so, a few hundred
million years after that, there would have been a tremendous number
of supernovae in an equally short time period. Maybe thousands of
supernovae per year in a galaxy the size of the Milky Way. That was
so long ago that, if there was such an outburst of supernovae, the
light from them has been redshifted into the microwave part of the
spectrum, and is very faint with extreme distance, so it will be very
hard to detect now, even though it would have been very bright at
the time.

Over the eons, star formation has evened out, and average star
lifetimes have become much longer, so that a galaxy like the Milky
Way only only produces about one new star each year, and only
about one supernova in a hundred years. The vast majority of
stars now are too small to ever go supernova.

All the stars that were born in the first generation went supernova
billions of years ago, spewing out heavier elements which got into
later generations of stars and made them different from the first
generation: Less massive and longer-lived. The average star will
shine for tens of billions of years before gradually shrinking and
dimming. Our own Sun, somewhat more massive than average,
formed about 4.5 billion years ago, and is at about the middle of
its lifetime right now. A total expected life of between eight and
ten billion years. It will not go nova, but will puff off outer layers
of its atmosphere, making a planetary nebula, before it collapses
into a white dwarf. It will then slowly cool off over hundreds of
billions of years. Only the very few most massive stars can go
supernova.

-- Jeff, in Minneapolis

[astromark]

Yes, I to enjoy a good discussion. My best advise to you is to explain the frequency of super nova is such that you may never see one. Yes the Universe is a very big field. Just estimating the number of galaxy present is a daunting task. A very large number. With the stars per Galaxy set at about 300 - 500 million stars. ( Thats just a guess ) You would think that we might see more Nova.
No, because the time scale of a human life is such a small part of the time line of the universe. This is not a bad thing as these super nova things could be the last thing you see. Astronomers tell us that we are safe. There is no or very little chance of a too near to us nova. Phew!

I trust the following does not offend; It's not intended to. . .

After a public viewing session at the local observatory. A distractingly attractive young woman stepped up to us as we were closing the observatory and asked,
" The splendor of it all must leave you pondering why ?" Without getting into the subject because to do so might offend. How would you have answered her.

A colleague of mine whom is not known for diplomacy was about to answer.
I interrupted him with.
" We are interested in imparting our knowledge of the science of astronomy. To Speculate why , who or how will simply do your head in. Leave those big questions to the elders among st your group."
Even she saw the mirth of it.

[ss002d6252]

Its basically a re-wording of Olbers Paradox.

Basically, a lot of distant light in red shifted beyond the visible.

http://en.wikipedia.org/wiki/Olbers'_paradox

[grant hutchison]

He said that if the universe was really billions of years old, the whole night sky should be lit up with supernovae.

Yes, Olbers' argument was that, if the Universe is infinitely old and homogeneous, any sightline would eventually reach the surface of a star, so the sky should be very bright indeed. Your co-discussant seems to have narrowed this down to just supernovae, but the same refuting arguments apply:
1) The Universe is billions of years old, not infinitely old, so the amount of supernova light that can reach our eyes is limited by the number of supernovae that have had time to occur since the Universe began.
2) The huge majority of such supernovae occur in parts of the expanding Universe that have high red-shifts relative to our own location, so their light is very much dimmed relative to nearby supernovae.

BTW: there's an error/omission on the Wiki page that ss002d6252 linked to. I don't know if Mandelbrot ever discussed a fractal Universe as a resolution to Olber's paradox, but the idea significantly predates both fractals and Mandelbrot: Carl Charlier proposed what was called "hierarchical cosmology" as a resolution to Olbers, in the early 1900s.

Grant Hutchison

[Ken G]

Actually, I think it would be a shame to miss the opportunity, in this situation, to seek common ground with the creationist. As long as the debate is couched in terms of a confrontation, you are doomed to fail, if your goal is alter the opinion of the creationist. If you say "you're wrong", they will hear, "your faith is baseless", and you will move them not one iota no matter what the power of your logic. On the other hand, if you recognize that the fact that we don't see supernovae filling the sky is an important piece of scientific evidence, then you have a base for common ground. The issue is really, what can we conclude from this observed fact? The creationist error is not in concept, it is in timescale. You can start by agreeing with them that the observation does indeed set an upper limit on how old the universe can be. What a great place to start--- agreement! Now you turn to the issue of what is that upper limit. At this point, you can talk about supernova rates etc., and point out that astronomers place the limit at the level of many billions of years (probably much longer, but that doesn't really matter). The only real flaw in the creationist's argument is that he/she made the numbers up, but the idea is right. It is quite significant that modern observations support the idea that the age of the universe is finite. So then the debate turns to what the timescale is, and for that issue, the creationist will be woefully ill prepared to debate and will have to admit that they really don't know what the upper age limit is. Then you get them to accept it is many billions of years, and that this is completely consistent with the Big Bang, and you may move their understanding a little.

[grant hutchison]

I suspect the usefulness of the sort of approach Ken recommends is in winning over anyone else who's listening in and undecided. Although it's extremely rude, I confess I'd turn to any such spectators and address my answer to them.
Creationists who offer these little half-digested titbits, in my experience, are parroting them from pamphlets and websites with lists of "Tricky Questions to ask Scientists". They often have little understanding of the point they're raising, and will simply grow defensive (or shift ground to the next question on their list) if you try to enter into debate.

I also wonder about pitching the argument lower. We recognize Olbers when we see him, but most folk don't. You could produce a reasonable analogy by turning the question around: If we've had artificial light for a hundred years, why isn't the whole world brightly lit by now?
1) People turn the lights on and off
2) Light moves fast, so it disappears into the rest of the Universe when the lights are turned off
3) Most of the lights are too far away for us to see, anyway
If anyone says "Yes, but ..." you can turn that into a discussion of Olbers reasonably enough, but I think just that response will knock the whole thing on the head, as far as your average creationist is concerned.
Then you have to brace yourself for the next question on the prepared list ...

Grant Hutchison

[ratchetmouth]

Thanks everyone. Some of the responses were things I didn't have any idea about (such as the kinds of stars being born at different times during the age of the unvierse), and some were embarassingly obvious, and I should have realized them on my own (redshift).
The trouble with debating creationists is that, in my experience, no matter what data you present to them, when they reach the point that they can't answer you with the soundbytes they're fed online and in church, they fall back on, "that's just your opinion," "how do you know, were you there?" and "Science changes all the time, so you can't be sure what you're saying is right." It's difficult nigh unto impossible to get them to admit that any part of their arguments are wrong, because they really believe that they're working from a completely inerrant document, and they're unwilling even to admit to errors in extrapolation from it. However, I don't think that the debates are truly fruitless. After all, as grant mentioned, whether or not you convince your opponent of anything, you may help educate the lurkers. Also, these debates have widened my interest from Philosophy and Biology into astronomy and physics. I started learning about the latter because of the debates I often engage in, and from that start, I've become really fascinated, and am trying to learn as much as I can now. Even if my opponent leaves thinking that I'm a hopeless heathen, I still appreciate the exchange, because it serves as a vehicle for me to learn more about subjects I haven't previously studied.

[Tim Thompson]

When dealing with creationists, always start your search with the venerable Talk.Origins Archive. Therein you will find this: Supernovae, Supernova Remnants and Young Earth Creationism FAQ. I first encountered the SNR argument over a decade ago, and it originated with a Canadian educator who knew far less about astronomy & supernovae than he would ever realize. The bottom line sound bite is that creationists consistently vastly overestimate the visibility of SNR. They have no concept of "confusion" in a crowded sky, a problem that real astronomers deal with regularly. New SNR are still being discovered today, and it is not uncommon for someone to realize that some object we have been looking at for all these years is actually an old SNR.

[Halcyon Dayz]

Apart from that, don't stars have to reach a certain age, well in excess of
6,000 years, before they can become supernovae?

So, if supernovae are observed, the universe is very old, by human standards.

[Ken G]

It sounds like Tim is raising the issue of objections centered on supernova remnants in our galaxy, rather than the light from very distant supernovae. That would make it an argument about the age of our galaxy, rather than about Olbers' paradox, which is apparently also raised by creationists. In that case as well, the answer rests on the issue of timescale, there can be agreement on the question of finite age. The importance of that agreement is significant, in terms of finding a common ground. But ultimately, I think the key is agreeing in advance whether the search is for scientific, versus faith-based, truth.

[PhysBrain]

In addition to the light from super-novas being red-shifted, there's also the inverse square law to consider. Basically, the intensity of the light which reaches us falls off as 1/R^2 where R is the distance from the source to the observer. Many people do not fully appreciate just how rapidly the intensity diminishes with increasing distance.

[tofu]

Apart from that, don't stars have to reach a certain age, well in excess of
6,000 years, before the can become supernovae?

So, if supernovae are observed, the universe is very old, by human standards.

An interesting little trick of logic just occured to me. I happen to know that if you say to a creationist, "if supernovae are observed, the universe if very old" then the creationist will respond, "no, God created the supernovae remnants and also created old stars that are just about to explode."

Here's my new contribution to this: "why? Why did God create old stars and supernovae remnant?"

I'm guessing the response will be, "so that the universe will appear older."

Now here comes the zinger: "if the universe was created so that it would appear to be billions of years old, then why would expect to see *more* supernovae remnants?? Are you saying that God did an incomplete job, that he made a big booboo when attempting to create an old universe? Do you think that God is up there in heaven saying to himself, 'DOH! I tried to make an old universe but I'm an idiot, I blew it, I totally forgot to make enough supernovae, wow I'm really embarrassed, it's a good thing there are creationists to point out my error.'"

And this logic applies to lots of creationist arguments. "If God purposefully set out to create a universe that appears old, then why is it so easy for you to poke holes in his creation and point out evidence of a young universe?"

[ppaulk]

I have enjoyed reading all of your responses, and follwed everything including visible light shifting to the microwave part of the spectrum (now I see why the evidence of the big bang was found in microwaves). But, if visible light has been shifted to microwaves, wouldn't gamma and x-rays shift to visible light? And, don't supernova produce more gamm and x-rays than any other part of the spectrum?

On the creationist thread, I live in religious right country, North Georgia. I have seen once reasonable people become born again and ironicly embrace intolerance self rightiousness. There seems to be a competition between them to see who can hold the most outragiously unfounded beliefs: it is a badge of honor to be more superstitious and less fact based than the next believer. Once they go, I have never seen them come back, for they cannot allow reason to corrupt or erode their new fact free reality.

Philip

[grant hutchison]

But, if visible light has been shifted to microwaves, wouldn't gamma and x-rays shift to visible light? And, don't supernova produce more gamm and x-rays than any other part of the spectrum?

The thing is that the red-shift doesn't just move the peak frequency to longer wavelengths, it very strongly reduces the received energy content, too. So moderately red-shifted hot objects may brighten, but more strongly red-shifted hot objects grow dimmer. The cut-off point will depend on the detailed shape of the power spectrum.

Grant Hutchison

[Ken G]

And this logic applies to lots of creationist arguments. "If God purposefully set out to create a universe that appears old, then why is it so easy for you to poke holes in his creation and point out evidence of a young universe?"

That is an important argument. Hopefully creationists would not be so foolish as to try to intuit "God's" intentions-- their last line of defense rests better upon "he just did it that way" (assuming they believe in a male creator). Of course they are free to believe that, it just isn't scientific (at all!). But you're right-- they try to sound like they are using logic, so it's important to be able to expose that.

[tofu]

I have seen once reasonable people become born again and ironicly embrace intolerance self rightiousness.

oohhhkay, well I've seen exactly the opposite. I've seen mean and cruel people, basically sociopaths and bullies, find religion and turn their lives around and become nice people who add to society instead of burden it.

[grant hutchison]

oohhhkay, well I've seen exactly the opposite. I've seen mean and cruel people, basically sociopaths and bullies, find religion and turn their lives around and become nice people who add to society instead of burden it.

And I've seen nice people who got religion and stayed nice, and nasty people who got religion and stayed nasty.
We need some decent epidemiology before we can decide whether a specific package of religious convictions has a net good or bad effect on society.
Now that would be an interesting study to try to get through a government funding agency ...

Grant Hutchison

[Ken G]

And connected to that point is, how do you measure someone's religious convictions? If you just ask them, you face distortion due to hypocrisy, brainwashing, etc., but if you instead use their actions as a guide, then you are mixing your categorizations with the data you are trying to correlate. If someone goes to a particular church once a week and memorizes some pat phrases, yet exposes in their actions extremely opposite values, do they even qualify as one of the faithful in a study like that? There may be (at least) two separate types of adherent to religion, one type who is sincere and really tries to apply the tenets, and another type who just goes through the motions like a trained parakeet.

[tofu]

We need some decent epidemiology before we can decide whether a specific package of religious convictions has a net good or bad effect on society.

It's not at all important to me that we have data showing that a particular religion is helpful or not. I just want to make sure that we don't demonize any particular ideology with statements about intolerance self rightiousness. That line of reasoning is too easily abused. "I have seen once reasonable people earn their PhD and ironicly embrace intolerance self rightiousness." See what I mean? It's just not a useful thing to say. That was my whole objection. You'll never see me defend a particular person who shows intolerance etc. but it bothers me to paint a group that way.

[grant hutchison]

See what I mean? It's just not a useful thing to say. That was my whole objection.

That was my whole objection, too.

Grant Hutchison

[ratchetmouth]

Tofu said, ""no, God created the supernovae remnants and also created old stars that are just about to explode."

This is much more in my area of expertise. This is basically the Omphalos argument. People who support this argument actually claim that god created the light that we see from distant stars in transit when he created the universe a few thousand years ago. The problem with this position is that it makes the deity deceitful. It presents Him/Her/It as trying to present all the evidence that one could ask for supporting that the universe is old, and then punishing anyone who believes this evidence. Taken to its extreme, this line of reasoning leads to Last Thursdayism, the proposition that everything in the universe was created Last Thursday, and simply appears to be older. You seem to have memories that go back years or decades, but all of those were simply programmed into you when you were created Last Thursday. Most theists rightly reject this position, as it is so clearly an ad hoc excuse and so easily reduced to absurdity.

[Ken G]

I think the Last Thursday hypothesis is much better used as a device to demonstrate the limitations of the concept of "truth" as applied to science. It is not a terribly good theology!

[tofu]

this line of reasoning leads to Last Thursdayism, the proposition that everything in the universe was created Last Thursday, and simply appears to be older. You seem to have memories that go back years or decades, but all of those were simply programmed into you when you were created Last Thursday.

I wonder if I can use this to challange charges on my credit card?

[ppaulk]

oohhhkay, well I've seen exactly the opposite. I've seen mean and cruel people, basically sociopaths and bullies, find religion and turn their lives around and become nice people who add to society instead of burden it.

If you look to the context of my statement, you will see that I was referring to the " religious right;" you know, the Bob Jonesians, most Pat Roberts discipels, the followers of Faldwell.... And of course, ther are many people that have become better though embracing a superstition: some people need a mystical guide book or a god hanging over their head to act moral: but there is irony in a person who takes from the teachings of Jesus (at the core of which are tolerance, selflessness, and support for the down trodden), and fights for amendment to exclude groups of people from marriage, for marginalizing people based on the country of origin, keeping down minimum wage, and tax breaks for the wealthy, while fighting anything that may push us to be responcible care takers of the planet that we live on. I would say that the institutions that take the afore mentions stances have poor reasoning, lack morality, and are corrupting the teachings of Jesus. There is irony in taking the philosophy of Jesus and using it to support intolerance and greed.

Now, I do know a few christians whose actions and politcal stances corrolate to the teachings of their religion. They are some of the most beautiful people I know: also, they are not inclined to use the bible as a science textbook, they use it a a guide for living ones life. Unfortunately, most of the christians in my neck of the woods are of the "religious right" variety. Sure, they are not "mean, bullies" on the street, but they are in their politics.
Further more, it is not suprising that the teachings of Jesus should improve the morality of a bad person: but it is ironic, as more often happens in today's America, when a person becomes more intolerant and greedy through the teachings of their christan church. Of course these people and their churches are missing the point: I hope you get it.

Philip

[tofu]

Yeah, it's too bad that this board has a prohibition on political discussion, because although I know that you mean well, a lot of what you believe shows ignorance or misunderstanding (and probably isn't even your fault). As a quick example:

keeping down minimum wage

The minimum wage is a bad thing. But even so, it can't be "kept down" because it is not possible to raise the minimum wage. It just isn't possible. A gallon of milk costs whatever it costs in large part because of the minimum wage. What would happen if the minimum wage was 200 million dollars an hour? Well guess what, you're going to have to pay someone 200 million dollars an hour to go out at 6AM and milk those cows. And guess what, you're going to have to charge more for the milk now so that you can pay your employee 200M an hour.

So before you raised the minimum wage, a person making minimum wage could just barely afford a gallon of milk. After you raised the minimum wage, a person making minimum wage can just barely afford a gallon of milk. Great job. That was really helpful.

tax breaks for the wealthy

Impossible. We do not tax wealth in this country. We tax income. You couldn't give a tax break to the wealthy even if you tried.

Paris Hilton is rich. How much income tax does she pay on that wealth? Little or none. When you say, "we need to stick it to those rich people" what you're really saying is, "we need to tax the high income earners." To put that another way, "we need to tax people who make our economy work by taking risk and starting businesses and giving people like you a job - yeah, I hate those people, let's make those people pay, let's punish those people!" Once again, great job.

Has it ever occurred to you what an income tax really is? It is a barrier to becoming rich. "The Rich" by and large, are in positions of political power and put up the barriers in order to maintain the exclusivity of their little club. They don't want you to become rich, and ironically you help them accomplish that by supporting an income tax. They prey on negative emotions like envy and we go right along with them.

Raise or lower the income tax all you want. It does nothing to Paris Hilton. Now on the other hand, if you taxed consumption - then she would pay.

But, I've probably said too much already. My point is just that you seem a little angry, and I think that a lot of that anger comes from (to use the examples above) ignorance or misunderstanding of economics.

[Halcyon Dayz]

You are so wrong.

Decorum forbids me to tell you why.

[trinitree88]

In arguing with creationists, you hear a lot of bizarre claims, and reasoning that is completely unburdened by fact or reason. I was recently talking with a creationist who liked to delve into arguments that had more bearing on astronomy than biology (they are quite fond of this, as I`m sure many of you know). He said that if the universe was really billions of years old, the whole night sky should be lit up with supernovae. Of course, I told him that the light from those supernovae takes tens or hundreds of millions of years to reach earth (sometimes longer) and that in and of itself disproves his claim about a young universe. However, even taking into account how long it takes light to reach the earth from distant supernovae, why is it that we don`t see more than we actually see? I understand that they can often oushine whole galaxies when they are spotted. I certainly don`t think this joker`s claims have any merit, but I would like to present him with more evidence than I have so far.

Rachetmouth. Arguing from the relative abundance of galaxies per square degree of sky(Hubble Deep Field), the number of stars per galaxy (OOM), and the supernova rate per galaxy per century(known)...you could make a case for ~ 4 supernovae /sec for the universe. Interestingly, when the Sudbury Neutrino Observatory, SNO, came on line for calibration, they observed about 24 "events " per second....and then turned down the sensitivity of the apparatus...as the "background" was too large.
Pete.

[ppaulk]

One, I see that you are well versed in the diatribes of supply side, "voodoo" economics ( as creationists have their talking points, so do supply side economists), but by concentrating wealth in the hands of the wealthy we do not help them create new businesses or jobs. A person does not start a business because they have extra money to throw around, they start it because there is a demand to be met.

Two, we are not risk taking business people or worker, we can be both or either: this is decided by demand, ingenuity, drive, and opportunity. Most of the risk in business is taken by the banks and government (using the money of the governed ). Very few businesses are started with ones own cash.

Three, raising the minimum wage would not greatly increase the cost of milk, for in the US the supply and demand of milk is stable and will not be greatly change by the increase of minimum wage. Other so called luxury items such as mid-level houses or cars may increase in the short term, but when supply catches up with demand the price will stabilize and even go back down.

Four, as supply is ratcheted up in the areas in which the masses spend their money, new business opportunities will surface. New entrepreneurs will emerge and established entrepreneurs will higher more people and get richer. It would be a snow ball effect of good economic prosperity. No one is saying that people should not be able to get rich from their work or ideas, but they should not be given the power to exploit: balance is the answer ( just a littler socialism goes a long way). A healthy economy is driven through demand, supply then responds.

Five, I suggest you check your own economic fundamentals and anger. I may get angry and frustrated with some things such as hypocrisy (the religious right) and greed for power and money cloaked by religion. Greed helps to drive the economy, but don't use theology to support it (unless you are a hedonist and follow Dionysus: ha ha).

I am easy going, and have enjoyed the scientific discussions I have seen at this sight: this is the first chat room I have ever visited. But I must admit ignorance to the politics ban. You may notice though, that this thread started with science. Others took it to religion and the creationists which in today’s America can't be honestly discussed without politics. I apologize for my faux pax and promise not to respond on this subject no matter what the replies.

Thanks, and I'm sorry to have offended, that was a back lash, for I too have been a little offended.

philip

[tofu]

I am easy going, and have enjoyed the scientific discussions I have seen at this sight: this is the first chat room I have ever visited.

It's all downhill after this :-)

I apologize for my faux pax

I don't think you made any faux pax. I was actually just covering myself because I know that *I* am not supposed to discuss politics. Obviously the mods gave us lots of wiggle room here though. And anyway you're right, we almost can't discuss this issue without getting into politics.

Well at this point, we've both said what we wanted to say and any further discussion between us would be kind of useless, right? So take care. Nice talking to you.