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Friday 14 April 2017

Galactic Archaeology - evidence of an ancient universe written in the stars

YECs are well aware that the evidence from the natural world overwhelmingly attests to an ancient universe, which is why they invest considerable effort in an attempt to explain away this data to preserve their hyperliteral reading of the creation narratives. Of course, this means advancing patently nonsensical ideas such as accelerated rates of radioactive decay and the creation of light in transit for objects more than 6000 light years away from the Earth. The former assertion is readily falsified when we realise that accelerated rates of radioactive decay would release enough heat to melt the crust of the earth, while the latter means what we see of the universe more than 6000 light years away is essentially a universe-sized special effect which may not have even happened. As Charles Kingsley put it when commenting negatively on Philip Gosse's book Omphalos in which he advanced creation with appearance of age as a means of explaining the evidence for an ancient natural history, "I cannot...believe that God has written on the rocks one enormous and superfluous lie for all mankind."

If the universe was created 6000 years ago, then given that the closest stars to us outside our solar system are a little over four light years away, then apart from the moon and planets, the night sky would have been completely barren for around four years, with the night sky slowly waking up as the light from progressively further stars reached Earth. That ancient records record the night sky - apart from occasional supernovae - as being essentially the same as we see now alone points out that the YEC worldview requires the creation of the universe to involve the creation of light in transit, a view which is more than a little deceptive, to say the least as it involves the creation of a history that never happened as that light created in transit never originated from the stars.

When one examines the astronomical data in detail, the evidence is more than just the mere existence of stars, nebulae, and galaxies considerably further away than 6000 light years. Rather, it is evidence for change over time. One recent example is SN1987A, a former blue giant which went supernova around 168,000 years ago and was first detected in 1987 when the first light of that stellar explosion first reached Earth. If we take the YEC argument that light from stars and galaxies was created in transit so that from the moment of creation, the heavens would be able to 'declare the glory of God' by being visible to ancient humans, that means SN1987A was created with a light stream approximately 6000 light years long corresponding to its existence as a blue giant, followed by (to date) thirty years of light corresponding to an emerging supernova. The point to keep in mind here is that, given the YEC worldview,  neither the 6000 light year long beam of light corresponding to a blue supergiant or the 30 light year long beam corresponding to a supernovae never came from the star but was created in transit, what we see never truly represented reality but is essentially a galactic-scale special effect.  Does SN1987A even exist, or is there nothing but a long beam of light created to give the illusion of a star and supernova? It's one thing to create a light stream of a star in order for its light to appear instantaneously on Earth following its recent creation. It's another thing altogether to create a history of stellar evolution and argue that it has any meaningful link to reality.


SN1987a. By ESA/Hubble & NASA - http://www.spacetelescope.org/images/potw1142a/, 
CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=17014663

It's not just supernovae and the creation of light representing a history that may or may not have happened that poses a considerable problem for YECs who have to reconcile the fact of a vast universe with their belief in a 6000 year old creation. Rather, it's the evidence for galactic-scale events, such as the merger of galaxies in the distant past. Astrophysics graduate student Casper Hesp writes on this problem in a recent BioLogos post, pointing out how we know these events happened:
Firstly, we know exactly what kind of features such events should leave behind: stellar streams. Imagine a dwarf galaxy as a clump of about 100 million stars, entering close to the Milky Way. All of its stars are getting pulled into orbits around the center of our galaxy (which consists of a  supermassive black hole). The orbit of every individual star ends up being very similar to, yet a little bit different from its brothers and sisters. The result is that these stars start smearing out across space, forming streams of stars draped around the galaxy. Because they started out as a single clump, you should still be able to see from their movement and other properties that they used to belong together.
 
Secondly, if this picture is correct, we know how many of such events have taken place in the past. We know the current mass of our Milky Way (100 billion solar masses) and the typical mass of those galactic snacks (about 100 million solar masses). It’s a straightforward calculation to estimate how many merger events have taken place. Based on this number (~1,000), the leftovers from recent galactic dinners should be all over the place in the form of stellar streams!

Do we observe such streams? Yes, dozens of them have been observed and more are being found as we launch better space telescopes. We are essentially looking at all the scars our galaxy has from its dynamic history. This field of study has been labeled “galactic archeology.” From the laws of gravity, computer simulations can directly trace back how those streams originated in small dwarf galaxies, and even how much time ago those dwarf galaxies were devoured by our Milky Way. One notable example is the Aquarius stellar stream, its size on the sky is 1300 times (!) the size of the moon. It turns out this stream is the aftermath from a meal our galaxy had 700 million years ago; and this is a relatively recent one! The positions and velocities of the stars of the much older Sagittarius stream (~3 billion years) were measured so precisely that astronomers were able to use them for estimating the overall shape of our galaxy. [1]
Emphasis mine
Of course, if the universe is only 6000 years old, then all of this light was created in transit, and never really came from these stars and galaxies in the first place, which raises the question of why, in a young universe, would a creator create such a detailed history of events that never happened in the first place. As Kingsley would no doubt have said, this means God has written in the very stars one enormous and superfluous lie for all humanity. Hesp puts it well in his conclusion:
The foundations of young-earth cosmologies can be strongly critiqued on observational and theoretical grounds. However, for the sake of the argument, we have only tested the claim that nearby galaxies were created “mature and fully functional.” It led us to examine what we know about the history of the galaxy closest to us, our own galaxy. When we take a closer at our Milky Way, we are confronted with evidence of a multitude of past events, indicating a very dynamic event history. To the present day, stellar streams are direct evidence of the meals our galaxy has consumed over the course of billions of years. Anyone who acknowledges the basic principles of gravity is led to this conclusion.
Assuming mature creation of all stellar streams would mean that the implied event histories were completely fabricated. There is a huge difference between God creating our galaxy fully formed, and God including strong evidence of an assembly process occurring over the course of billions of years (stellar streams). More generally, mature creation is unable to avoid the inclusion of false event histories that are still visible to this day. Yet, according to many in the YEC movement, this is the only way God’s Creation should be understood.
The irony here is that fundamentalists, who constantly declare that the creation narratives must be read literally [2] are determined to avoid the plain obvious reading of the book of nature which attests to an ancient, evolving universe.

References

1. Hesp C "Galactic Archaeology: Uncovering the History Written in the Stars" BioLogos  April 12 2017
2, Of course, if they were truly consistent with their literalism, they would believe in a flat earth covered by a solid firmament in which were set the sun, moon and stars. Their literalism is decidedly selective.
Firstly, we know exactly what kind of features such events should leave behind: stellar streams. Imagine a dwarf galaxy as a clump of about 100 million stars, entering close to the Milky Way. All of its stars are getting pulled into orbits around the center of our galaxy (which consists of a  supermassive black hole). The orbit of every individual star ends up being very similar to, yet a little bit different from its brothers and sisters. The result is that these stars start smearing out across space, forming streams of stars draped around the galaxy. Because they started out as a single clump, you should still be able to see from their movement and other properties that they used to belong together.
Secondly, if this picture is correct, we know how many of such events have taken place in the past. We know the current mass of our Milky Way (100 billion solar masses) and the typical mass of those galactic snacks (about 100 million solar masses). It’s a straightforward calculation to estimate how many merger events have taken place. Based on this number (~1,000), the leftovers from recent galactic dinners should be all over the place in the form of stellar streams!
Do we observe such streams? Yes, dozens of them have been observed and more are being found as we launch better space telescopes. We are essentially looking at all the scars our galaxy has from its dynamic history. This field of study has been labeled “galactic archeology.” From the laws of gravity, computer simulations can directly trace back how those streams originated in small dwarf galaxies, and even how much time ago those dwarf galaxies were devoured by our Milky Way. One notable example is the Aquarius stellar stream, its size on the sky is 1300 times (!) the size of the moon. It turns out this stream is the aftermath from a meal our galaxy had 700 million years ago; and this is a relatively recent one! The positions and velocities of the stars of the much older Sagittarius stream (~3 billion years) were measured so precisely that astronomers were able to use them for estimating the overall shape of our galaxy.
- See more at: http://biologos.org/blogs/guest/galactic-archaeology-uncovering-the-history-written-in-the-stars#sthash.ffIda07B.dpuf
Firstly, we know exactly what kind of features such events should leave behind: stellar streams. Imagine a dwarf galaxy as a clump of about 100 million stars, entering close to the Milky Way. All of its stars are getting pulled into orbits around the center of our galaxy (which consists of a  supermassive black hole). The orbit of every individual star ends up being very similar to, yet a little bit different from its brothers and sisters. The result is that these stars start smearing out across space, forming streams of stars draped around the galaxy. Because they started out as a single clump, you should still be able to see from their movement and other properties that they used to belong together.
Secondly, if this picture is correct, we know how many of such events have taken place in the past. We know the current mass of our Milky Way (100 billion solar masses) and the typical mass of those galactic snacks (about 100 million solar masses). It’s a straightforward calculation to estimate how many merger events have taken place. Based on this number (~1,000), the leftovers from recent galactic dinners should be all over the place in the form of stellar streams!
Do we observe such streams? Yes, dozens of them have been observed and more are being found as we launch better space telescopes. We are essentially looking at all the scars our galaxy has from its dynamic history. This field of study has been labeled “galactic archeology.” From the laws of gravity, computer simulations can directly trace back how those streams originated in small dwarf galaxies, and even how much time ago those dwarf galaxies were devoured by our Milky Way. One notable example is the Aquarius stellar stream, its size on the sky is 1300 times (!) the size of the moon. It turns out this stream is the aftermath from a meal our galaxy had 700 million years ago; and this is a relatively recent one! The positions and velocities of the stars of the much older Sagittarius stream (~3 billion years) were measured so precisely that astronomers were able to use them for estimating the overall shape of our galaxy.
- See more at: http://biologos.org/blogs/guest/galactic-archaeology-uncovering-the-history-written-in-the-stars#sthash.ffIda07B.dpuf