×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Nearby Galaxy Surprisingly Young

michael posted more than 9 years ago | from the fake-id dept.

Space 63

Pi_0's don't shower writes "The hubblesite is reporting that a galaxy discovered 70 years ago, I Zwicky 18, has been confirmed to be one of the youngest galaxies in the universe, at only 500 million years old. By contrast, our Milky Way, Andromeda, and most other nearby galaxies are 12 billion years old. This galaxy is the closest newly-formed galaxy, at only 45 million light years away, which has rather interesting implications for galaxy formation."

cancel ×
This is a preview of your comment

No Comment Title Entered

Anonymous Coward 1 minute ago

No Comment Entered

63 comments

This is (-1, Offtopic)

Anonymous Coward | more than 9 years ago | (#10980323)

An early post, Perhaps even the first.

Interactions (4, Funny)

Anonymous Coward | more than 9 years ago | (#10980381)

So if the Milky Way exchanges some interstellar material with this youngster, can it get busted for transporting a minor across intergalactic borders?

Re:Interactions (1)

OAB_X (818333) | more than 9 years ago | (#10981789)

Yes, but you will spend millions of years in court first before you recieve a several billion year prison sentence. After spending several million light years being deported back to the original galaxy of departure.

Galactic ignition (3, Interesting)

Mark of THE CITY (97325) | more than 9 years ago | (#10980424)

My understanding is that old galaxies had enough fuel in a small enough space to condense into masses that became stars by gravitational compression. Are young galaxies simply areas where this process took much longer, or is there more to it?

Experts only, not Trekkie wannabees! :)

Re:Galactic ignition (4, Informative)

u19925 (613350) | more than 9 years ago | (#10980948)

in the beginning everything is assumed to be lumps of gas. due to some intial asymmetry, the otherwise uniform distribution of gas started forming lumps. once the lumps formed, it was a self sustaining chain reaction. as it became more denser, the gravity became strong and pulled gases even close. it still takes time to form the galaxy, because the gravitational collapse produces heat and that regulates the collapse (that is why our sun still shines and not collapsed under its gravity. except that in sun's case, the heat is coming from thermonuclear reaction). once gases start collapsing, they also form small lumps internally. when density of small lumps reaches some critical value we see star formation.

now the rate at which collapse occurs is difficult to calculate. it is non-linear, too many parameters and depends heavily on initial condition that you start. It may be possible, that these galaxy could produce internal lumps only recently which were dense enough to form stars.
in the beginning the stars are massive, since thermonuclear reaction is hard to start in "pristine" gas composed of only primordial hydrogen and helium. However, these large stars are also short lived, since they produce heat very fast and consume internal fuel and then they explode and generate heavy elements as by-products, which helps other smaller start formation like our sun.

Re:Galactic ignition (1)

mazarin5 (309432) | more than 9 years ago | (#10982590)

Close enough, but there are two things I need to chime in on:

I. Gravity does not increase as density increases, you probably were thinking mass.

II. Heat plays no role in Hydrostatic Equillibrium, which is the balance of the inward gravitational force of the star and the outward pressure of it's mass.

Wrong! (1)

hummassa (157160) | more than 9 years ago | (#10984422)

Gravity (on the surface) does increase with density: mass stays the same, radius decreases...

Re:Wrong! (1)

mazarin5 (309432) | more than 9 years ago | (#10985075)

Hardly helpful for a nebulous smattering of gases across the size of a galaxy and lacking any particular surface at all. Although yes, gravitation does increase squarely as distance to center of mass decreases, it neglects our context where the original statement asserted that the pull of an object would be more significant if it simply took up less space. This is absolutely untrue.

Re:Wrong! (1)

drinkypoo (153816) | more than 9 years ago | (#10996276)

Each atom or molecule of the gas has a surface. As they come "together" the "exposed" parts have a new surface. Actually, the smattering of gases has much more surface than the end result...

Re:Wrong! (1)

mazarin5 (309432) | more than 9 years ago | (#10996787)

You would be surprised at what an atom doesn't have. Regardless, the original reply claimed that the gravity of a cloud of gas and dust increases as it contracts and that is simply untrue. Additionally, gravity is not at all related to exposed surface area.

Re:Galactic ignition (0)

Anonymous Coward | more than 9 years ago | (#10990458)

the outward pressure of it's mass

"its".

Melodrama (1)

daeley (126313) | more than 9 years ago | (#10980479)

When Andromeda confronted the Milky Way about I Zwicky 18, Mr. Way professed he was "shocked and hurt you could think I would do such a thing!" and claimed he had "barely said hello to her!"

Meanwhile, in #stellarformations.. (4, Funny)

Bob Cat - NYMPHS (313647) | more than 9 years ago | (#10980544)

Milkyway: a/s/l?

Re:Meanwhile, in #stellarformations.. (3, Funny)

ravenspear (756059) | more than 9 years ago | (#10982556)

Zwicky: Too young for you to bang. Sorry.

Zwicky: But if you want some inside info, I heard NGC-4725 really has the hots for you. Her center hole has been getting larger with each passing millennia.

Zwicky 18 is predominated... (0)

Anonymous Coward | more than 9 years ago | (#10980761)

...by swollen red giant stars sprinkled across its surface. Zwicky 18 is actually quite self-conscious about its red stars, and is quite awkward around other galaxies, especially of the spiral type.

How accurate is this? (1)

ravenspear (756059) | more than 9 years ago | (#10982262)

Ok, I'm not an astronomer, but how can someone reliably determine that a region of space 45 million light years away is 500 million years old? It's not like we can go there and conduct tests. Is the light we receive from that galazy somehow different from light elsewhere? Does light have an "age" that can be detected by some instrument?

Given that there is still considerable dispute about the range of accuracy of various dating methods here on earth that use laboratory equipment to examine objects extremely closely, how can this ultra-remote dating be considered reliable?

Re:How accurate is this? (1)

Seraphim1982 (813899) | more than 9 years ago | (#10982501)

Did you read the article at all or is there some part of this that you don't understand?
Hubble's exquisite sensitivity allowed astronomers to do a reliable census of the total stellar population in the galaxy. This allowed them to reliably identify the oldest stars inhabiting the galaxy, thereby setting an upper limit on the galaxy's age

Re:How accurate is this? (1)

ravenspear (756059) | more than 9 years ago | (#10982577)

Right but how were they able to "reliably identify the oldest stars inhabiting the galaxy." How can they reliably say what the age of a star millions of light years away is?

Re:How accurate is this? (4, Informative)

forkazoo (138186) | more than 9 years ago | (#10983079)

Well, science starts with one major assumption. We hope that the laws of physics are the same everywhere. That's not a guarantee, because we have never been outside our solar system, but we have no reason to suspect otherwise.

So, here on earth, we can do all sorts of laboratory tests. We can figure out under what conditions Hydrogen fuses. We can test the strength of gravity. We can test the way various elements react at various tempuratures and pressures. So, while there isn't a 100% guarantee that we have a good handle on how stellar evolution works in another galaxy, we can be pretty confident that we have a very good handle on it. Accurate to many decimal places.

Based on what we know about how the elements, we can make some calculations about stellar evolution in general. We can figure out how far away nearby stars are by using parallax while the earth goes around the sun. The nearby stars are the ones we can use to best test our theories, because we can be very very sure how far away they are. Because we know how far away they are, and how bright they appear, we can figure out how bright they actually are (as if they were all the same distance). We can also use spectrography to figure out what elements are giving off the starlight (which we can double check by heating up the elements in a lab and using the same spectroscope). Thankfully, our mathematical models of how bright a star should be with a certain element mixture line up perfectly with what we actually see, so we can safely apply our models to stars so far away that we can't use parallax to measure the brightness.

So, if you are still with me... We can look at a star, analyse the spectra emitted, and plug it into our mathematical models of stellar evolution. It seems like crazy guessing, and there is certainly some guessing involved, but the theories we use on distant stars have been tested in laboratories, and on nearby stars, with everything being double checked for crazy shit as the tests get farther out.

Given that this galaxy is so unusual, it is possible that somewhere along the line, we may need to update our models. It's possible our models are just giving us a wrong answer. It's wildly unlikely. But, science is the unending quest for a less-wrong answer. That's the difference between dogma and science. Science will freely admit it is wrong, but it usually turns out to be only slightly so. Dogma just finds ways to explain away new information in terms of the existing dogma, or dismisses it entirely.

Re:How accurate is this? (0)

aubreyTF (822544) | more than 9 years ago | (#10989318)

That was a good example, and it was explained concisely.

However, one point I would like to make is the extremely unlikelyness of the evolution of the elements happening the same everywhere in the entire universe. The chances of the elements actually evolving from nothing is very slim, but the chances of the elements evolving from nothing everywhere in the universe is very, VERY slim. A more logical explination would be to assume that God created the elements (and everything else, for that matter). I agree, some people do not like this idea because it would emply a God, but the more you look it is the only plausible explanation. I am very glad to see you admit that this is an assumption, most evolutionists treat everyhting with a "dogma" attitude.

Secondly, I would like to point out that stellar evolution is absolutely impossible. This may sound crazy, but I am willing to back up my statement. In order to create a star (according to evolution), gas must be compressed enough for fusion to take place. The problem with this theory is that gas just can't be compressed that much by anything except (possibly) a bunch of stars blowing up at the same time near each other. Obviously, if you have to loose a bunch of stars to gain a new one, pretty soon, you won't have any stars!
Finally, I would like to point out that, by your own definition, evolution is a complete dogma.
In order to explain the creation of the universe, they have imagined something called the "big bang". By their own definition (read any modern public school textbook), the big bang was caused by the explosion of a dot which either 1 - always existed (the dot is basically god) or 2 - somehow created itself out of nothing (the dot is basically god). I belive that I have proved my point: evolution is a dogma, and will always be a dogma because it is impossible to escape the fact that there is a God! The only reason for coming to the illogical conclusion that the dot is god is that you cannot accept the fact that God is God!


Anyway, I kind of did stray off topic, but I hope you'll forgive me because I belive it was necessary to explain the entire context of my message.

Re:How accurate is this? (1)

680x0 (467210) | more than 9 years ago | (#10990851)

Secondly, I would like to point out that stellar evolution is absolutely impossible. This may sound crazy, but I am willing to back up my statement. In order to create a star (according to evolution), gas must be compressed enough for fusion to take place. The problem with this theory is that gas just can't be compressed that much by anything except (possibly) a bunch of stars blowing up at the same time near each other.
I can prove you wrong. Humans have created very small stars (fusion of hydrogen and other light elements like helium and lithium) in several ways. See fusion reactors [pppl.gov] and H-Bombs [zvis.com] . If we can do it, the forces of nature can do it.

As for the "big bang", you seem to be under the impression that science and religion are mutually exclusive. Science can only say that "the universe is expanding outward in all directions, so presumably it came from the same place". It can't trace back further than the evidence will support, and so rather than making stuff up, scientists wisely say "and where this 'cosmic egg' came from, we can't say".

Re:How accurate is this? (1)

aubreyTF (822544) | more than 9 years ago | (#10992513)

I can prove you wrong. Humans have created very small stars (fusion of hydrogen and other light elements like helium and lithium) in several ways. See fusion reactors and H-Bombs. If we can do it, the forces of nature can do it.
Your statement about proving me wrong is flawed.

As regards the hydrogen bomb, this is exactly what I was talking about. It uses the pressure and heat from the reaction of a critical mass of uranium or plutonium to fuse lithium duride into helium! This is exactly what I said before, only in my previous example substitute exploding plutonium for a couple stars blowing up near each other, and the lithium deuride fusing into hydrogen for gas being compressed into a new star!
the reactor you mentioned runs along the same basic principles.

By the way, "If we can do it, the forces of nature can do it", is a nonscientific statement. Assuming that something can happen long ago and far away is a very evolutionist way of thinking. :-)

By my way of thinking, science and religion ARE mutually exclusive. Evolution is a religion, not theory. For example, evolutionists would have to do a lot of "tracing back further than the evidence will support" to come up with the big bang in the first place. Did you know that Venus, Uranus, and Pluto rotate backwards from all the other planets? If the "big bang" had really happened, (because of a law known as the conservation of angular momentum), all the planets would be spinning the same direction!

P.S. Contrary to popular opinion, there are many demonstrable evidences that indicate that the universe is quite young.

Re:How accurate is this? (1)

680x0 (467210) | more than 9 years ago | (#10992725)

Apparently, I missed the part of the bible where it says "And God saw all the planets spinning in the same direction, and said 'This is boring.... You three! Reverse direction please.'"

There are plenty of reasons why planets might rotate in the opposite direction (and Neptune is on its "side", don't forget). The early solar system was a busy place, with lots of collisions going on.

Gravity is an interesting force. Most forces (such as magnetism) have an opposite force (like charges repel, opposite charges attract). Gravity, the most far reaching of the forces, only attracts. The more mass you have, the more it attracts. Over vast periods of time, it can draw huge amounts of matter together. The more matter, the more it attracts, and the denser the resulting accumulation. As humans didn't feel like waiting millions or billions of years, they had to "cheat" to create their stars.

Anyway, I'm not going to convince you, since your definition of religion, making it the opposite of "logical thought" (science), makes it entirely irrational, and impervious to debate.

Re:How accurate is this? (2, Informative)

forkazoo (138186) | more than 9 years ago | (#10993525)

Secondly, I would like to point out that stellar evolution is absolutely impossible. This may sound crazy, but I am willing to back up my statement. In order to create a star (according to evolution), gas must be compressed enough for fusion to take place. The problem with this theory is that gas just can't be compressed that much by anything except (possibly) a bunch of stars blowing up at the same time near each other. Obviously, if you have to loose a bunch of stars to gain a new one, pretty soon, you won't have any stars!

Ummm, care to share your calculations about how it's impossible for a could of Hydrogen gas to begin fusion due to gravitational compression? Seriously, if you have a gas cloud the size of the sun, it will eventually be attracted to itself, due to gravity, and form into a smaller and smaller cloud, until eventually it is the size of a star. A gas cloud the size and mass of a star means that the center of that cloud is as compressed as the core of a star, and so it is a place where fusion will start happening. No explosions needed, though they can certainly impact the process.

What *exactly* do you suppose prevents gravity from compressing the gas cloud, making a stellar birth "impossible?"


Finally, I would like to point out that, by your own definition, evolution is a complete dogma.

In order to explain the creation of the universe, they have imagined something called the "big bang". By their own definition (read any modern public school textbook), the big bang was caused by the explosion of a dot which either 1 - always existed (the dot is basically god) or 2 - somehow created itself out of nothing (the dot is basically god). I belive that I have proved my point: evolution is a dogma, and will always be a dogma because it is impossible to escape the fact that there is a God! The only reason for coming to the illogical conclusion that the dot is god is that you cannot accept the fact that God is God!

I can't imagine what would cause one to suppose that thinking a very hot dense gas cloud can start fusion somehow precludes the existence of God. The two questions are quite independant. Frankly, I think there are a lot of cosmologists that have no personal problem with the idea that God created that which went bang in the big bang. It doesn't effect the cosmology in any way.

My own supposition is that God was sitting around one day, and he wondered to himself, "I wonder if I can microwave a burrito so hot that even I couldn't eat it..." Lacking an answer to this question, God went into an infinite loop, and he exploded from thinking too hard.

My supposition fits the available evidence as well as supposing that god created the universe, or that there is no God. None of those answers about what was around before the universe effect the laws of physics in any way, because nobody has ever come up with a test or experiment that could demonstrably be effected by what came before the universe.

While stellar evolution is a Dogma, and it is possible that God created the universe 500 years ago, and just made it look really really old, that's no reason to abandon cosmology.

BTW, what created God? Isn't it actually simpler to suppose that a point singularity sprang into being one day? God is an extremely complex entity. I find it more difficult to believe that God sprang into being intact and whole and infinitely wise. If anything, God sounds like he requires the "theory of intelligent design" moreso than the universe. :)

Re:How accurate is this? (1)

evilviper (135110) | more than 9 years ago | (#11005731)

it is possible that God created the universe 500 years ago, and just made it look really really old

If you don't have any objections, I'm making that my new .sig!

Re:How accurate is this? (1)

forkazoo (138186) | more than 9 years ago | (#11013443)

No, no objections. I can't really claim credit for the idea. I'm sure it's been bouncing around for millenia. Oh, BTW, reasonable donations are accepted if you find me quotable!

Re:How accurate is this? (0)

Anonymous Coward | more than 9 years ago | (#10982812)

Amazing I could tell how old I Zwicky 18 is by,

are you ready for this,
begin drum-roll ..BY READING THE ARTICLE!!!!

end drum-roll rimshot

Re:How accurate is this? (1)

aubreyTF (822544) | more than 9 years ago | (#10982849)

I totally agree with you.
Up front, I will state that I am a young earth creationist, and believe that the universe is only around 6000-7000 years old.

I am very interested in any suggestions as to HOW you would determine the age of a galaxy which is far off in space, when you can't take into a lab and anylise it.

Speaking of galaxies, doesn't the existence of spiral galixies prove that the universe is relatively "young"?
I mean, if the universe was older wouldn't the galixies have had enough time to spin around so much that their "arms" would be indistinguishable?

comments welcome :-

Re:How accurate is this? (1)

SHEENmaster (581283) | more than 9 years ago | (#10983182)

As a young earth creationist, why do you believe that the universe is only 6,000-7,000 years old? What in the Bible, or whichever religious text you follow, gives you cause to believe this? Do any of the gospels quote Jesus as claiming that he was born X many years after the creation? I ask because I have never understood where that particular belief comes from or why it is so prevalent.

As for your question, google found this [stsci.edu] .

Re:How accurate is this? (1)

the morgawr (670303) | more than 9 years ago | (#10986772)

Not a creationist, but I did sleep at a Holiday Inn Express!

Seriously, here's an educated guess: The Bible spends quit a bit of time on family geneologies. Because of that you know how many generations of people were born between Adam and the end of the end of the biblical period (a date we know). Making an estimate for the time span per generation would yeild something in the 5000-8000 year neighborhood.

Re:How accurate is this? (1)

aubreyTF (822544) | more than 9 years ago | (#10987195)

Correct.

The Bible is an incredible God inspired book, which contains, among other things, a genialogy trail which when added up, gives a fairly exact date for the creation of the universe.
There are also many tests that you can do to demonstrate that the universe can't be as old as some people claim.
But anyway, this coonversaation is beginning to stray off topic. :-)

Re:How accurate is this? (1)

the morgawr (670303) | more than 9 years ago | (#10994129)

There are also many tests that you can do to demonstrate that the universe can't be as old as some people claim.

I'd be interested to hear about them. The method I discribed above isn't terribly convincing.

Re:How accurate is this? (1)

tjstork (137384) | more than 9 years ago | (#10997475)

By your standard, then, I should be able to haul Adam into the lab and measure the age of his bones. Touche. There's been no proof of Noah's ark. There's been no proof of even the existence of jews as slaves in egypt. There's been no proof of the plagues and there is no mausoleum for moses. There's no proof of the existence of Jesus, no proof, in fact, for the existence of any of the Judaeo Christian heros.

Finally, Egyptians have been proved to have been writing about the world before your calculations show that it was made.

Re:How accurate is this? (5, Informative)

Teancum (67324) | more than 9 years ago | (#10983045)

There are a number of ways to do this. Perhaps the #1 way is through what is called a
Hertzsprung-Russell diagram, named after the two astronomers who came up with this method of classification.

There are two primary aspects that allow you to plot an individual star on this diagram: Its spectral color (litterally, what color you see the star as) This can be assigned a number as a specific peak color frequency. This also can be interpreted as the temperature of the "surface" of the star. The other axis is the absolute brightness of the star. This is the number of photons you can count in a given period of time relative to how far away it is. For measuring stars in a galaxy, distance measurements can pretty much assume that all of the stars are roughly the same distance away, thus simplifying this task. Close stars will obviously be brighter, but stars like Alpha Centari, an ordinary yellow star, are apparently as bright as Betelguese, a star almost 100 times further away.

Keep in mind that only until the Hubble telescope was able to resolve the individual stars in this galaxy, this study wasn't able to happen for this particular galaxy... which is why this is now news. Really a neat project on the whole.

The point here is that young stars fall onto what is called "The Main Sequence". These are stars like our sun that are still mostly converting Hydrogen to Helium as the primary source of nuclear energy. This relationship is quite well defined, and has been observed in not only the Milky Way Galaxy, but in other galaxies where individual stars have been able to be identified.

Stars that run out of Hydrogen fall into a very different pattern. Like I mentioned with Betelguese (in the constellation Orion), it is much further away but yet just as bright. Also, its color is more Red (in a clear rural sky you can even see this reddish color), which puts it outside of the Main Sequence. That is because (according to current theory) it has run out of Hydrogen and is now in the process of turning Helium into Carbon. This group of stars, known as "Red Giants" play a huge role in determining the age of a galaxy or other group of stars.

When stars finally run out of Helium, the rest of the elemental transmutation takes place rather quickly, or the fusion simply stops. Without going through the subsequent steps, the star eventually turns into a Super Nova (if there is enough stuff in the star to produce it) and leaves behind a white dwarf or neutron star (for really big stars... black holes are yet more stuff). A white dwarf is quite dim even for its distance, but yet its surface temperature is quite hot. These give yet another very distinctive plot on the HR Diagram.

So the whole point here is that you can measure the age of a group of stars based on the relative brightness of the stars in that group. Very large stars tend to live very short lifespans because they do a very efficient job of doing the fusion. Small stars (like Wolf 359) will be still doing the hydrogen fusion 20 billion years from now. Over time (and based on considerable observation examples... not just this galaxy in the article but also concrete parallax measurements of close stars to our own as well) you will see fewer and fewer stars on the very blue end of the HR diagram and more and more Red Dwarfs, with white dwarves showing up in increasing numbers as well.

One other critical tool for measurement is also trying to determine what elements are in the spectra of the stars. Different elements show up in stars and can be measured based on if they are absorbing or emitting light from the surface of the star. Mind you, this doesn't indicate much in terms of what is happening in the center of the star, but rather what is on the surface of the star. The current assumption is that the Universe started out with mainly Hydrogen and Helium, and only very small amounts of other elements. If you find large quantities of other elements in a star (like significant quantities of Iron on the surface of our sun), you know that it didn't get produced by nuclear transmutation by that star. Instead, it came from other stars that exploded, and has been recycled to form new stars. Our sun is suspected of being the 3rd or 4th generation of such explosions. All of that can be calculated based predicted rates of supernova exploding in galaxies.

In short, yes, you can predict with at least an order of magnatude range about how "old" a galaxy should be, and just by "measuring" the "light", although more science does go into it.

BTW, if you look at the photo, you can also see that it is considerably more "blue" than the surrounding galaxies seen behind it. That is in part due to the fact it is quite close to us (There is some serious red-shifting [wikipedia.org] going on behind there... read more about Hubble the astronomer [wikipedia.org] , not telescope to get more details about that.) That also should give a quick visual clue to suggest there are many blue-white stars producing light in that galaxy. Individual stars are discernable in that photo as well, and frankly would make a great textbook example for calculating and plotting an HR diagram.

I hope I havn't overwhelmed you with this answer, and sorry about the rant. I probably should update the Wikipedia entry for that matter.

Re:How accurate is this? (1)

ravenspear (756059) | more than 9 years ago | (#10983304)

Thank you for that very informative answer. I guess what I'm still unclear on is that all the measurements we take on the light, composition, distance, etc. still have to be interpreted by models that attempt to predict how stars behave over billions of years. What assurances do we have that those models are accurate, given the incredibly short (in comparison) span of time we have been collecting detailed data on star characteristics?

Re:How accurate is this? (4, Informative)

Teancum (67324) | more than 9 years ago | (#10983584)

There are a few astronomical measurements that take place over the course of just a few months or years. Supernova in particular happen in just a matter of a few days, which is where they get their name: They appear in the sky as a "new" (Latin form is "Novo" or "Nova") star that wasn't visible before.

In 1987 a supernova was extensively sutidied in one of the Magenellic clouds (galaxies very close to our own that are so close that their apparent size takes up a significant portion of the southern hemesphere's sky). Previous sky survey's demonstrated that it was in the Red Dwarf stage of its life, and after the explosion a pulsar was found in the same physical position. That was pretty convincing evidence that at least that portion of stellar evolution is quite accurate, and can still be verified with current measurements.

Another major scientific measurement took place with the "Eagle Nebula" [wikipedia.org] , which is the one that has the really cool columns of gases and has been done as poster you can buy in Wal-Mart and put on T-Shirts. In this case over the course of just a few years you can see stars litterally form right out of the gasses of the nebula. These new stars demonstrate that they are right on the "Main Sequence" after their formation. This certainly was a major plus to confirming these theories.

There are some suspected stars that are in transition from Main Sequence to Red Giant, but that takes considerably longer to happen.

With some very recent sky surveys, there have also been some significant confirmation of these theories, if simply from the huge amount of data that simply confirms this information. Keep in mind that many of these theories started out simply as a way to try and come up with a classification system of any kind, and have evloved from there.

The spectral classification originally started out when a bunch of researchers at Harvard University put star names and coordinates on a bunch of 3" x 5" cards and based on the spectrum lines and measured brightness, they litterally dropped these cards into boxes labeled "A", "B", "C", ect. After some more research the boxes were rearranged by temperature to become "O","B","A","F","G","K","M","R","N","S" ("Oh, Be A Fine Girl, Kiss Me") As can be seen, the original classification was very arbitrary, but based on formal measurements. Our sun is of type "G", and blue stars as type "O".

We know about spectral lines because we can do that in laboratories here on the Earth. Really quite cool to do as well, and each element puts out its own specrum. I'm sure you've seen a Neon sign with its pink glow, which is exactly what is done with other elements to identify their spectra as well. BTW, this spectra is also critical to understanding the atomic structure of each element, but that is another story to itself.

The distance measurements are calculated from steallar parallax as the base measurement. We know from several other measurements how far the Earth is away from the Sun, and when the Earth travels around the Sun, stars appear to move relative to each other. This is like taking two photographs a few feet apart and seeing stuff in the background at different angles. Doing this you can directly measure how far away something is from where you are at. This measurement is accurate to about 1000 light years with the Hubble Telescope. Other techniques try to approximate distances based on similar looking stars to ones that are close to us and assuming that stars next to those are probably about the same distance. Obviously that means even further distances are less accurate as you go further away from us. These distance measurements are IMHO very accurate, and their accuracy can be expressed precisely to a certain range of accuracy as well.

Stellar color is pretty easy, as you just have to have filters at different wavelengths when you take pictures of the stars. That is what gives the color to the photo in this article, and you can see both red and blue stars in that galaxy quite clearly.

So yes the basic measurements are all based on scientific principles that are from scientific disciplines outside of astronomy (navigation, chemistry, and optics including multimedia computing). The models are just that, models, but I would dare you to take the amount of scientific data that has been gathered (most of it is available on-line as well) about stars and try and come up with a reasonable alternative to stellar evolution that has been proposed. Minor tweaks to happen all of the time, but the basic process is pretty much accecpted as a very hard fact that has stronger proof than what convicted Timothy McVeigh on his bombing of Oklahoma City.

The only way to get still more convincing evidence is to wait a few million years, which I will never get to during my lifetime. BTW, there is still more emperical evidence about some of this from ancient Chinese and Greek astronomers and some of the records they kept, particular regarding Novas, and specifically with a Nova that is suspected as giving birth to the Crab Nebula. Some ancient star charts do have some minor value, and observers like Tycho Brahe had some incredibly accurate positional measurements... without the aid of even a telescope.

Re:How accurate is this? (3, Insightful)

Anonymous Coward | more than 9 years ago | (#10983714)

If you think about systematically studying people, you can group them according to various similar characteristics -- all those with gray hair over here, all those with bald heads there, all those who are very small, etc.

Then, you can try to look for connections between these groups -- you don't have to live out an entire 100 years and watch them change in order to develop a theory about their characteristics and how they relate to each other. By studying some of the subtle changes over a year's time, you can get some clues.

In the same way, we see stars in all different colors, etc., and brightness and we piece it together as to their relationship. We don'thave to wait a 100 Million years. One can say that the theory is a myth (a story that we tell ourselves) but the crucial thing is that it is myth which makes many predictions as to what we should see if we made additional observations. The predictions can be independently examined by many different groups of people and their predicted observations found or not. It is that characteristic of being a myth that accurately predicts other information that we then confirm to be the case that makes us willing to consider it true (this is almost a definition of truth) even though we haven't waited around the billions and billions of years to witness it.

Re:How accurate is this? (3, Insightful)

Teancum (67324) | more than 9 years ago | (#10983839)

Not bad from an AC. This should be modded up.

What I was trying to point out (unfortunately not too clearly) was that in addition to this sort of classification, we have seen some glimpses of stellar transitions to help confirm the theories. And when new scientific tools come around and used in astronomy, the results tend to confirm rather than debunk the stellar evolution theories. You know that you have a solid scientific theory when it gets confirmation from addition kinds of observations, and better yet if you make a prediction of some future result that actually shows up (like how black holes were described mathmatically before they were actually observed.)

This is exactly the problem with Cold Fusion (to give a current scientific theory that is strongly questioned at the moment), because that theory tends to get conflicting results based on how you are measuring the effect, or even who is doing the measurement. It is almost an embaressment to mention Cold Fusion and Stellar Evolution in the same sentance, because the theories of star development have so much of a sound theory behind them that it is more like the yardstick to compare other scientific theories to.

Re:How accurate is this? (1)

aubreyTF (822544) | more than 9 years ago | (#10988687)

I would agree with your model, to a certain degree.

The part I would disagree with is about star formation. For you see, it would take tremendous pressure to compress gas into a star. I have read calculations before which stated it would take around twenty stars exploding near each other to create enough pressure for a new star to form. I agree, these calculations may not be accurate, but still, I am sure it would take more that one star, and at that rate someday all the stars will be gone! (Not good for your model) :-) In Fact, I belive that this alone would disprove Stellar evolution, because it is impossible to explain the origin of the stars without some theoritical, unprovable idea such as the oort cloud (Imagined to exist as it's the only way evolutionists can explain the existence of commets after the some {a bunch of billions} of years that the universe has supposedly undergone since its creation)

Anyway, my theory is that God created all the stars along with the rest of creation, and, because of man's sin (See genesis for details), the stars have been dying out ever since.


P.S. Funny you chould mention the oklahama bombing.... http://www.apfn.org/apfn/okc_coverup.htm [apfn.org]

Re:How accurate is this? (2, Informative)

beeplet (735701) | more than 9 years ago | (#10992848)

This is nonsense.

Straightforward calculations, starting from equations of gas pressure and gravtational attraction, show that any overdense region in a gas cloud, larger than a certain critical mass (called the Jeans mass), will collapse in on itself. It is true that the simplest calculation of the Jeans mass gives 10^5 solar masses, much larger than any star; but if you take into account that a cloud will fragment as it collapses, the Jeans mass becomes much smaller. For typical conditions, the critical mass is ~1/3 the mass of the sun.

Supernova shocks might help start the process of gravitational collapse, but there is no reason to think 20 or more are necessary.

Re:How accurate is this? (1)

lazy genes (741633) | more than 9 years ago | (#10995925)

Could a sun form around a steller black hole?

Re:How accurate is this? (1)

beeplet (735701) | more than 9 years ago | (#10998483)

I don't think so. The tidal foces would probably tear the star apart before it could collapse. But you might be able to get a binary system with a star and a stellar-mass black hole if it started out as a two-star system, and one star went supernova.

Re:How accurate is this? (1)

bobster45 (816998) | more than 9 years ago | (#10992947)

Your faith based conclusion has little foundation, other than your faith. The current "theory" of stellar and galatic evolution has a foundation built on science that has a huge amount of empiracal data and tons of tangible evidence. Your god is only tangible to you, and is not a measurable entity, has no evidence or proof of existance other than your faith. To wave your faith flag in a discussion of science is tantamount to flamebait. I suggest you bury your ignorace to science with your wimpy arguments on physics that are free of any foundation into your book of mythology (The Bible) and leave science free of your faith babble. You would love to believe that Man was created by some supreme being using some type of explanation of omnipotence. Since you wish to share your theory of your God I will share what my theory is: I believe man created his God by some act of ignorance because there was less knowledge at the time(s) it was put together. Ignorance is a state of having yet to possess knowledge, Stupidity, on the other hand, is knowing the facts and sticking to a frame of thought that is wrong. Since the writing of the Bible much has been discovered: The Earth is NOT the center of the universe, Infections are caused by bacteria and viruses to mention just a few. People who think like you would have been much happier if Galileo never had lived. Give us a break.

More reason to keep Hubble ... (1)

gstoddart (321705) | more than 9 years ago | (#10985099)

Keep in mind that only until the Hubble telescope was able to resolve the individual stars in this galaxy, this study wasn't able to happen for this particular galaxy... which is why this is now news. Really a neat project on the whole.


As little as I understand all of the particulars of the parent post, the fact that we keep getting new science out of Hubble like this tells me that we definitely need to keep Hubble going and not just abandon it.

We're still learning too much from it to just throw it away.

Yet more proof (3, Funny)

aminorex (141494) | more than 9 years ago | (#10984090)

that redshift is not a clock. The whole big bang thing is falling apart awfully fast, and everybody seems to be in denial.

Re:Yet more proof (1)

kettlechips (769541) | more than 9 years ago | (#10984319)

"that redshift is not a clock"

I think that's an important point. The probability of the cosmos presenting us with some optical illusion or other cannot be underestimated. Even the voyager spacecraft leaving the solar system provided us with unexpected data concerning the composition of interstellar space. We really don't know that much beyond that, simply because we are unable to travel these distances and have a look for ourselves. We're left with circumstantial evidence and deduction.

Nevertheless, the idea that this gascloud was somehow isolated over time and simply took very long to produce stars is very plausible. But I wonder how many possible other explanations one can come up with, without violating the general principles of physics we hold true today.

For instance: Light elements are abundantly present, heavy ones are rare. This doesn't mean that the heavy ones were never there in larger numbers. Some process may have sifted them out. Maybe if circumstances caused the gas cloud to accelerate in one direction, the heavier elements simply got left behind over time.

Re:How fast? (1)

ddimas (629883) | more than 9 years ago | (#10984552)

For instance: Light elements are abundantly present, heavy ones are rare. This doesn't mean that the heavy ones were never there in larger numbers. Some process may have sifted them out. Maybe if circumstances caused the gas cloud to accelerate in one direction, the heavier elements simply got left behind over time.


If that was the case you would see some spectral shifting inconsistant with the general expansion of the universe. As far as I know this is not the case. More likely is that the gas cloud comprising this galaxy was simply in a gravitationally flat region, which impeded inital collapse.

Re:Yet more proof (0)

Anonymous Coward | more than 9 years ago | (#10986913)

It's harder to make the heavier elements in thermonuclear fusion. In fact, it's my understanding that without stars blowing up (as in nova's and supernova's) the progression of lighter elements being fused into heavier elements stops at Iron (Fe) because fusing elements heavier than that requires more energy to be put in than one gets out. The ones heavier than Iron have been made in the (smallish) amount of nuclear fusion that occurs as stars explode. The percentages of elements as I remember have been fairly accurately predicted. (Sorry I can't give you exact info or a link but googling for it or going to ask.com ought to pull it up).

By the way, just like the prriodic table of the elements which many people study in high school chemistry, there is a similar "chart of the nuclides" that shows in detail the way the various nuclei (=elements) are related to each other in terms of one thing decaying into another (as in radioactive decay) the reverse (or one thing fusing into another). It is this immense body of data that tends to convince one that we are on the right track as to how the big bang and follow-on activity resulted in the various percentages of different elements.

Re:Yet more proof (1)

aminorex (141494) | more than 9 years ago | (#10987016)

Another possibility is that local expansion has blue-shifted a region of the star field.
The cosmological principle is sheer speculation -- useful, but speculative.

If English was good enough for Jesus... (1)

CodeWanker (534624) | more than 9 years ago | (#10984953)

Everyone who's read Genesis and done the math knows that galaxy is only 4400 years old!

Re:If English was good enough for Jesus... (2, Informative)

aubreyTF (822544) | more than 9 years ago | (#10987435)

Actually, if you would have done your math right you would notice that it was the FLOOD that happened 4400 years ago, not the creation :)

Re:If English was good enough for Jesus... (1)

raider_red (156642) | more than 9 years ago | (#10989691)

Which creation story are you going by? Genesis actually contains two.

Re:If English was good enough for Jesus... (1)

aubreyTF (822544) | more than 9 years ago | (#10990209)

That was a very disceptive statement.

Through careful reading, you will notice that the first account deals with the creation of the world.
The second account deals with creation in the garden of eden, when God created one of each creature for Adam to name.

So really, when you say creation, it should be OBVIOUS that you mean the creation of the entire world. The only way you could come to any other conclusion is by anylising someone's post intentionally looking for ways to confuse them.

Re:If English was good enough for Jesus... (1)

raider_red (156642) | more than 9 years ago | (#10990731)

That's not quite right. Both creation stories cover the creation of the world. Both cover the creation of humanity. (In the first, found in Genesis 1:1 and ending in 2:2, men and women were created at the same time, both in God's image. In the second, starting in Gen. 2:3 and ending in 3:24, Man (Adam) was created first.) Versions of each story of the creation also occur in other Middle Eastern historical documents, such as those found in Mesopotamia and the Arabian peninsula. Both appear to predate written history, and were probably both included when Genesis was first written down because they both tell us something different about the nature of God.

The idea of two discreet creation stories is commonly accepted in modern Christian theology. It's taught as part of the United Methodist Church's core Bible curriculum (Disciple I) and is discussed at most seminaries. It's not a problem for my faith in God or in Christ, and I don't see why it should be such a problem for yours.

It's spelled deceptive, not disceptive.

Re:If English was good enough for Jesus... (1)

raider_red (156642) | more than 9 years ago | (#10990761)

It figures: I decide to play the spelling Nazi, and end up hitting submit with a spelling error in my comment.

Re:If English was good enough for Jesus... (0)

Anonymous Coward | more than 9 years ago | (#10999776)

and where in the bible does it say god created T-Rex???
Check for New Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account

Loading...