- Aug 2024
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most importantly, all of them give the same answer to within an accuracy of about 10%. As we will see, this means we may finally be able to make reliable estimates of the size of the universe.
This is definitely very exciting, but 10% is a lot when it comes to space, that could be a distance of lightyears. I am curious what is missing from the instruments currently available to be able to make more precise measurements.
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most of the material in the universe cannot at present be observed directly in any part of the electromagnetic spectrum. An understanding of the properties and distribution of this invisible matter is crucial to our understanding of galaxies.
Challenging the idea of "seeing is believing" and the idea of invisible matter must have been very controversial at the time and confusing to lots of people, but is now something we take for granted, despite the fact that we don't have a full understanding of it.
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Several simple ideas of this kind were tried, some by Hubble himself, but none stood the test of time (and observation). Because no simple scheme for evolving one type of galaxy into another could be found, astronomers then tended to the opposite point of view. For a while, most astronomers thought that all galaxies formed very early in the history of the universe and that the differences between them had to do with the rate of star formation.
I saw a quote the other day that loosely said that everything sounds crazy until it's proven by science, and I think that really applies here. I also find it interesting that what people think is an impossibility at one point can very quickly become fact later. The idea that science is always evolving and changing is really interesting to me.
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Among Finns, Estonians, and related northern European cultures, the Milky Way is regarded as the “pathway of birds” across the night sky. Having noted that birds seasonally migrate along a north-south route, they identified this byway with the Milky Way. Recent scientific studies have shown that this myth is rooted in fact: the birds of this region use the Milky Way as a guide for their annual migrations.
How many other birds in different regions used the Milky Way to guide themselves but can't anymore? Although I'm curious how much this affects those birds, as they probably know where to go anyways instinctually or because of the many generations of birds flying south.
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Go back a few centuries, and these starlit sights would have been the norm rather than the exception.
I am curious when the conscious decision was made to have protected spaces where development would be kept to a minimum in order to preserve the viewing of the sky.
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In 1785, William Herschel (Figure 25.2) made the first important discovery about the architecture of the Milky Way Galaxy. Using a large reflecting telescope that he had built, William and his sister Caroline counted stars in different directions of the sky. They found that most of the stars they could see lay in a flattened structure encircling the sky, and that the numbers of stars were about the same in any direction around this structure.
I'm curious how many before Herschel and his sister tried and failed to discover how the milky way is laid out, and what set them apart from those before them, allowing them to get the job done.
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