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Thursday, August 21, 2014

Our Galaxy Is “Just About Perfect”

Posted by jlwile on August 16, 2011

A model of what astronomers think the Milky Way galaxy looks like.
(NASA image)

The more we look at our place in the universe, the more we find how special it really is. For example, we are in a solar system that is a part of the spiral galaxy known as the Milky Way. Our place in the Milky Way is quite special, because we are essentially at the corotation distance from the center of the galaxy.1 This means we rotate around the center of the galaxy at the same rate as the spiral arms of stars that make up the galaxy. This produces a very stable environment for our planet, which is necessary in order for it to support life.


There are many, many other things we have learned about our solar system and the earth in particular that make it clear we are on a very special planet that orbits a very special star. If you are interested in learning more about how special our place in the universe is, I strongly recommend the book The Privileged Planet: How Our Place in the Cosmos is Designed for Discovery by Guillermo Gonzalez and Jay Wesley Richards. It details many discoveries in earth and space science that clearly show how special the earth and its solar system are. If even one of the many, many special factors that make life possible in our little corner of the universe were not present, you wouldn’t be around to be reading this blog post.

Even though we have known for a long time that the earth, the star we orbit, and our placement in the Milky Way galaxy are all quite special, we are just now beginning to find out that even the galaxy itself is special.

Thomas Dame and Patrick Thaddeus of the Harvard-Smithsonian center for Astrophysics have discovered what they think is an extension of the Scutum-Centaurus arm of the galaxy (see image above). Now as you might imagine, it is difficult to identify the different parts of a galaxy when you are observing it from the inside. Nevertheless, astronomers can develop models of what our galaxy might look like, and then they can compare those models to the observations that have been made. If you make enough observations, you can eventually winnow away most models until you have only one that is consistent with all observations. That model is pictured above.

Does this mean that the picture above is an accurate representation of the Milky Way? Not necessarily. However, it is the best we can do by making observations from the inside. Assuming the model is correct, there are two main arms in the Milky Way’s spiral – the Perseus arm and the Scutum-Centaurus arm. Until Dame and Thaddeus announced their discovery, it was thought that the Perseus arm was longer than the Scutum-Centaurus arm. However, if Dame and Thaddeus are correct, the two arms are essentially mirror images of one another.

What does this mean? Well, I think the Science News story that I read sums it up best:2

New finding suggests Milky Way has rare symmetry…A new study suggests the Milky Way doesn’t need a makeover: It’s already just about perfect.

So not only is our planet, the star it orbits, and its place in the galaxy special, the very galaxy of which it is a part is also special. It has a rare symmetry that makes it just about perfect.

Now, of course, if you want to force yourself to believe that our special planet that orbits a special star in a special part of a special galaxy is all a result of a bunch of happy coincidences, you are free to do so. However, I just don’t have that kind of faith. I prefer to follow the evidence, which tells me quite clearly that all this “specialness” is the result of careful planning and design.

REFERENCES

1. DMishurov, Y.N. and L. A. Zenina, “Yes, the Sun is Located Near the Corotation Circle,” Astronomy & Astrophysics 341:81-85, 1999.
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2. Ron Cowen, “Galaxy Gets an Arm Extension,” Science News June 18, 2011, p. 14.
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Comments

13 Responses to “Our Galaxy Is “Just About Perfect””
  1. Pyrodin1233321 says:

    Yes, the aliens did a good job! hehe :)

    Peace

  2. jlwile says:

    Hehe Pyrodin. Actually, that’s a much more reasonable position to take than believing it all created itself, as Stephen Hawking and many evolutionists suggest!

  3. Jonathan says:

    Of course, then you have to ask where the aliens came from…

  4. josiah says:

    The aliens come from another planet.
    Everyone knows that.
    :P

  5. Jonathan says:

    Or maybe they just come from another country…

  6. jlwile says:

    Jonathan and Josiah, you crack me up. Besides, we know where they really came from. They transported themselves here from another one of the multiverses!

  7. Pyrodin says:

    Engage the Infinite Improbability Drive…Haha
    :)

    Peace

  8. Mary says:

    Hi Dr. Wile-

    My son has been reading evolutionary books by Coyne, Dawkins and others. He seems no longer able to form his own opinions and basically parrots every thing he reads. I am unable to answer his questions because I believe what I believe based on faith alone. I am not a scientist, I am a lover of literature.

    His latest challenge to me is that the creation story is impossible because we couldn’t be where we are today by starting out incestuos. Do you have an answer for that? I’d really like to give him something to think about. He has become very hostile towards the Bible so the answer needs to be “scientific.”

    As an aside, he will be using your Biology book along with the Miller/Levine Dragonfly book to prepare for the AP Biolgy test next May.

    Mary

  9. jlwile says:

    Mary, I actually think it is beneficial for students to read Dawkins, Coyne, etc., as long as they read the other side as well. In answer to his specific question, incestuous relationships are bad today because of all the mutations that have accumulated in the genome. Remember, we have two of each gene. If even one of them is dominant, then it is expressed. Thus, you only express the recessive gene if both of the genes you have are recessive. Well, most genetic diseases are the result of mutation, and the mutated gene is recessive. Thus, to get the disease, you must receive a recessive gene from each parent. If the parents are related, it is much more likely that they each have a recessive gene to pass on to their children. Thus, incestuous relationships are bad today because they make having children with genetic disease more likely.

    However, this would not have been a problem early on, because as you go back in time, the human genome had fewer mutations. Adam and Eve were created with ideal genomes. No mutations yet. Their children, grandchildren, etc., would have very few mutations, because there would have been little time for mutations to accumulate. Thus, there is no problem with the human race starting with incestuous relationships. Such relationships are only a problem now because the human genome has had plenty of time to accumulate mutations.

    Please tell him to contact me via my website if he has other such questions. A lot of what Dawkins and Coyne say is nonsense. I can easily help him navigate the nonsense, if he desires.

  10. Eric says:

    “just about” is such a scientific term. Like “ideal”. How do you define “ideal genome”? Can it be a source of genetic treatments for our degraded genomes today?

  11. jlwile says:

    Eric, you would be surprised at how many scientists use terms like “just about.” I use such terms because there are so many variables, you just can’t pin them all down. Thus, virtually any attempt to describe a system becomes an attempt that is only “just about” true.

    I would define an “ideal genome” as one that has no mutations in it. It is the genome of the kind that was originally created. Even if a scientist doesn’t share my views, I think we could say a genome is “just about” ideal if all its genes code for highly-specific proteins and all its regulatory systems work at peak efficiency. By “specific,” we mean that the protein is functional for its specific job and does not participate in any unnecessary reactions. Many mutations degrade proteins so that they are not specific to their job anymore, which causes them to do things they aren’t supposed to do. Of course, given the fact that not too long ago most scientists thought the human genome was mostly “junk DNA,” it’s clear we don’t currently have enough understanding of the genome to determine whether or not one is ideal.

    Once we are able to do so, however, I think the concept can be a source of genetic treatments for our degraded genomes. For example, if we could identify a gene that produces a protein that is not as specific as it could be, we could possibly do gene therapy to correct the problems so that the protein is highly specific again. Of course, such things are a long way off from being real treatments, but the possibility does exist.

  12. Eric says:

    Okay, I get what you’re saying. I meant to refer to Adam and Eve’s genomes (or is it singular genome?). Can we ever figure out what they (it) was? We know the rate of mutation for humans right?

  13. jlwile says:

    Eric, Adam and Eve had different genomes. If nothing else, many of the genes on Adam’s Y chromosome were different from the genes on Eve’s X chromosome. Most likely, their genomes had a lot of differences so as to promote great genetic diversity in the human population.

    I seriously doubt we can ever discover what their original genomes were. As we have learned more about genetics, we have learned that genomes seem to be designed to change. To get to the original genomes, we would have to be able to backtrack through all those changes as well as all the mutations. I would think that would be an almost impossible thing to do.

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