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Copernicus in Cleveland

The views expressed are those of the author and are not necessarily those of Scientific American.


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What is our cosmic significance?

Does it even make sense to ask a question like that?

If you happen to find yourself in Cleveland, Ohio this coming Thursday evening, and stop by the Cleveland Museum of Natural History at 8pm you can catch me talking about this. As part of their Frontiers of Astronomy series I’ll be discussing one of the biggest conundrums that we face as a species trying to make sense of its place in the universe.

Since Copernicus laid out the mechanical circumstances of our heliocentric solar system, and proposed that the universe has no single center, we’ve adopted a principle of ‘cosmic mediocrity’ – that we’re not special, nor is our place in the cosmos. This idea is exceedingly important, and has helped science make tremendous progress. It’s also consistent with a wealth of evidence that the opportunities for life are abundant – from the all-pervasive nature of carbon chemistry to the enormous number of planets we know exist around stars in our galaxy.

Yet there’s a catch. If we look a little closer we can also find reasons to think that our place in the cosmos, our circumstances are not so mediocre, that they are unusual to a certain degree. From the architecture of the solar system, to the quirks of terrestrial biology, to this specific point in cosmic history, there are a lot of seemingly ‘special’ characteristics about life on Earth.

So how does science resolve these apparently conflicting bits of evidence, and where is this taking us?

You’ll have to come and see (or you can – hint, hint – take a look at my new book, The Copernicus Complex, when it hits the stands in September 2014).

Caleb A. Scharf About the Author: Caleb Scharf is the director of Columbia University's multidisciplinary Astrobiology Center. He has worked in the fields of observational cosmology, X-ray astronomy, and more recently exoplanetary science. His books include Gravity's Engines (2012) and The Copernicus Complex (2014) (both from Scientific American / Farrar, Straus and Giroux.) Follow on Twitter @caleb_scharf.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Bill_Crofut 10:33 am 04/14/2014

    Re: “If we look a little closer we can also find reasons to think that our place in the cosmos, our circumstances are not so mediocre, that they are unusual to a certain degree.”

    A world class astronomer reported what would seem to be more than “a certain degree” of specialness to our place in the cosmos:

    “ The assumption of uniformity (of nebular distribution) has much to be said in its favour. If the distribution were not uniform, it would either increase with distance, or decrease. But we would not expect to find a distribution in which the density increases with distance, symmetrically in all directions. Such a condition would imply that we occupy a unique position in the universe, analogous, in a sense, to the ancient conception of a central earth. The hypothesis cannot be disproved but it is unwelcome and would be accepted only as a last resort in order to save the phenomena. Therefore, we disregard this possibility and consider the alternative, namely, a distribution which thins out with distance…readily explained in either of two ways….Both explanations seem plausible but neither is permitted by the observations. The apparent departures from uniformity in the World Picture are fully compensated by the minimum possible corrections for red-shifts on any interpretation. No margin is left for a thinning out. The true distribution must either be uniform or increase outward, leaving the observer in a unique position. But the unwelcome supposition of a favoured location must be avoided at all costs. Therefore, we accept the uniform distribution, and assume that space is sensibly transparent. Then the data from the surveys are simply and fully accounted for by the energy corrections alone–without the additional postulate of an expanding universe.”

    [Edwin P. Hubble, Ph.D. 1937. The Observational Approach to Cosmology. Oxford at the Clarendon Press, pp. 50, 51]

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  2. 2. M Tucker 2:19 pm 04/14/2014

    “Since Copernicus laid out the mechanical circumstances of our heliocentric solar system, and proposed that the universe has no single center…”

    Really? Copernicus “proposed that the universe has no single center?” Copernicus was considering the whole universe? How much of the universe was Copernicus aware of?

    Let’s suppose the “universe has no single center” idea was developed over several hundred years by many astronomers… “This idea is exceedingly important, and has helped science make tremendous progress.” This statement needs supporting evidence otherwise it is a throw away statement that I am tempted to chalk up to hyperbole.

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  3. 3. Caleb A. Scharf in reply to Caleb A. Scharf 3:12 pm 04/14/2014

    @mtucker707 – yes, this is in fact one of the ‘axioms’ that Copernicus laid out in his Commentariolus around the year 1514 (there were 7 in total). Of course, what he thought of as ‘the universe’ was different than what we associate the word with today, but the core of the idea, the full displacement of the Earth from the center of anything was profound. As for the progress this enabled – it was part of a dramatic shift of thought, remember at this point in history the nature of something like mathematical physics was very different, we barely used ‘equations’. The idea of mediocrity was critical, and it carried through to modern cosmology, allowing Einstein and other to justify applying physics like general relativity to the whole universe. It also helped people like Galileo to come up with the concept of relative motion (yes, long before Einstein).

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  4. 4. M Tucker 4:09 pm 04/14/2014

    You would need to show that Galileo’s work on motion was influenced by Copernicus. That could be a simple quote from a writing by Galileo, regarding his work on motion, referencing Copernicus.

    I’m sure you read “The Case against Copernicus” by Dennis Danielson and Christopher M. Graney in the January issue. Excellent article and it shows a very slow adoption of geocentrism, with regard to the solar system, by astronomers of the day. Hardly “dramatic.” I think you ought to remind the reader that the concept of what constitutes the universe has also undergone a transformation. The actual story is much more interesting if less dramatic and revolutionary than most modern writers, who venture into history, are willing to admit.

    I am fully aware of the importance of geocentrism to some peoples world view but that is not why astronomers continued to advocate for it. It is not the reason that geo-heliocentrism was advocated by Tycho Brahe. What prominent astronomer or philosopher advocated that Earth was the center of the known universe? I cannot think of one. Why did astronomers not suddenly agree with Herschel when he proposed that the Andromeda nebula lay outside the Milky Way? Why is the Great Debate of 1920, held at the Smithsonian between Harlow Shapley and Heber Curtis, largely ignored by most popular science writers today? Hubble is always mentioned as vanquishing the idea that the Milky Way was the entire universe but no popular science writer mentions that his observations were not immediately accepted by all. Shapely, for one, opposed them for many years.

    Why is the opposition to general relativity largely forgotten? Why do popular science writers want to make it seem like these important developments happened suddenly in a dramatic fashion and ignore the controversy and the time it always takes for something new to be adopted by the scientific community?

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