RIP Allan SandageFollow

Astronomer, died at the ripe old age of 84. Published a paper last year. Probably the most famous living astronomer.

http://www.nytimes.com/2010/11/17/science/space/17sandage.html?pagewanted=1&ref=science

He was one of the first people to attempt to measure the Hubble constant which gives the age of the Universe (if we assume a big bang like beginning - there were many estimates from other sources earlier). This was the main reason give to build the Hubble Space Telescope (all those pretty pictures are a happy byproduct).

My recollection of his age of the Universe does not agree with the times article, although I could be mistaken. My recollection was Sandage said 20 billion years (which was more consistent with earlier work he had done) and the first Hubble team arrived at about 14 billion (which is still about the best accepted answer).

My favorite anecdote about him goes as follows: Sandage looked at these early "photos" of galaxies and wished to measure distances between them. Effectively the photos had "pixels". He was so careful that when better technology arrived and with improved resolution more accurate measurements were taken, Sandage's results were found to be accurate to less then one pixel. Now if you think about it, that is not insane. Light illuminates a couple pixels and you sort of guess at the center of mass of the object from the relative illuminations of the pixels. But the main reason it was impressive is that loads of other folks were doing the same things and Sandage was by far the most accurate.

Nah, that distinction goes to Edwin Hubble.

Well that's nice, but unless you're an astrophysicist with ample experience in the field, I'll take the available research at face value. As far as a best guess goes, it's the most reasonable, logical conclusion available given the knowledge we have. I'm sure some day that will change as we get smarter, but unless you have evidence to the contrary, an opinion is just that.

Edited, Nov 23rd 2010 12:31am by BrownDuck

That's nice.



Everything you say here is consistent with every scientific theory, meaning everything in science. Except that perhaps by "shortsighted" you mean you have special knowledge that is better but I won't assume you're going that way since I'll wait and see if you fall into the looney bin all by yourself and not try to put you there.

This is worth extrapolating on a bit:

Science is not truth. It is a process. During that process, at any time, there is evidence which probably favors some theory over others. This does not make that theory "right", just the one with the best evidence. This informs and directs future observations. Some theories are better confirmed then others.

Although what yodabunny is saying is sort of technically right here, it betrays a fundamental misunderstanding of science since it implies that other scientific theories are not logical guesses.



So the age of the universe is unquantifiable? I know you don't realize this, but in a scientific context, you are implicitly claiming to have actual evidence that this is so. In a nonscientific context you have a belief which has no place in a scientific discussion. If this is the route you wish to go, be my guest. I have nothing to say about that. You can believe in anything you like in that regard. But I would recommend you get rid of the trappings of science in that case.



Within the big bang model, there are galaxies moving away so fast they are unobservable. If you hear an estimate of the total mass of the universe, it will usually be couched in the phrase "observable" universe for this reason.

What yodabunny says betrays a very common misinterpretation of the expanding universe. It is not that our Universe is expanding into empty space. The model is that space itself is expanding. Think of the galaxies as drawn on the outer surface of a balloon. Now inflate the balloon. The expansion of that 2-d universe on the surface of the balloon is akin to the big bang model of the expansion of our 3-d universe.

The big bang model does not preclude other universes. And there may be ways of detecting them, or even interacting with them, possibly via black holes or some such thing. It is possible, for example, that we are what happens "inside" one of their black holes after the singularity forms. At the moment, with our current knowledge, let me just say it is unlikely we will be able to meaningfully interact with them. Thus if they are far older (which, perhaps is provable) there would be no way to measure it.

There are steady state models of the universe indicating a larger, if not infinite, age. It is not a closed field there is active development on both sides and in totally new directions.

If anyone would like, I can give a brief summary of some of the successes and challenges of the competing theories.

I'm not a cosmologist. Also, the latest, best info I have (e.g. from the horses' mouthes, so to speak) was a few years ago.

That said:

1. Major victories for the theory: The big bang predicts the cosmic microwave background radiation and the ratio of hydrogen to helium in early* stars well.

2. However, there is an excess of lithium in early stars.

3. There are stars in our galaxy which through traditional analysis would seem to be somewhat older then the universe. Generally they are cited as 15-20 billion years old, whereas the universe is about 13.5 billion years old, so they say. There are fixes to this, but they invoke rather exotic events to quickly "age" these stars. However, these kind of issues crop up within our own galaxy which represents only a tiny fraction of all matter in the universe. (My *recollection* was that Sandage knew this and was thus pressing for an older age of the universe so that it was consistent with these results).

4.a. There is no known physics which can get the big bang to expand into the universe we see now. Thus the "inflation" and "hyper-inflation" theories of the big bang which hope to account for some of the details.
4.b. Look, we don't even know what most of the matter in the universe is (see: dark energy). It is asking a bit much of the big bang to account for it all. My understanding since the year 2000 up to now the so called "inflation" theory is consistent with the laws of physics, but not enough to actually get the big bang to go. This generated room for the so called "hyper-inflation" theories which, by definition, account for the universe as we see it, but rely on highly questionable physics.

* What I am calling early stars are first generation stars: which have little to no input from other exploding stars, thus their elemental makeup likely reflects the products of the big bang directly. Stars can be of the first generation either if they are very distant, although it is tough to pick out individual stars at that distance (but since these products: hydrogen helium and lithium are a direct result of the big bang, they are seen in all old things, including Nobby), or if they are very small, thus slow burning.

Or much of a physicist, probably.

I think the certainty with which people discuss theories of origin, especially in light of the creative license they have to employ to get their theories to line up with "laws of physics" or actual observations, is really amusing. All of the theories we have that can't account for dark energy/matter, but they've been proposed by scientists, so they're totally more credible than intelligent design.

Scientist: We've got a great idea on how it all started and it's based on science!

Preacher: So what about the other half of everything?

Scientist: F'uck you, at least it's based on science!

No, but it doesn't decrease it, either.

.

And yet claims of methods of creation can be debunked by scientific findings. In many ways, it has decreased the chance of specific stories.

I think attempts to compare them as though both have equal merit are ridiculous as well but whatcha gonna do?

Yeah. That must be it.

Silly claims of science debunking anything aside (and taking you somewhat seriously in the first place), that's because intelligent design cannot be disproved. That's what makes it not a scientific theory.



Except that one of them is a scientific theory, while the other isn't. Now, if you'd said that it's ridiculous that so many people come to think that the scientific theory in any way debunks or disproves the religious explanation, you'd have had a valid point. Like it or not, the various theories involving early universe creation can at least be trimmed at the edges over time as we discover sub-particle whatsits and background dohickies and other wizbang things floating around us. The simple proposition that an undetectable supreme being just blinked us all into existence as he pleased, when he pleased and at the time rate and in the order he pleased can't ever be challenged, so it's kinda meaningless. I have no issue with one being taught in science class and one being taught in a religious section of a social studies class, but let's not pretend that both are "science".


Of course, we can also debate the importance placed on science versus faith, but that's another topic entirely.

Mars has roughly 1 more hour in a day than we do. That's why the Martians are more advanced than us; they're more productive.