A while back, I posted a link to a remarkable surface wind map that, while not particular good at providing detailed scientific information, nevertheless gives an interesting animated look at current winds in the United States. Now, using the same concept, a map of surface currents in the oceans surrounding the U.S. has been made. See it here.
As it turns out, the Moon matches the composition of the Earth’s crust and mantle fairly well, while overall the Moon lacks the Earth’s iron content—and on Earth, the most iron-rich portion of the planet is its interior.
The most commonly accepted theory is that a hypothetical, approximately Mars-sized body called Thea struck the Earth obliquely early in the solar system’s formation, knocking off a significant portion of the mantle, while leaving the iron-rich core relatively intact. The resulting debris from the Earth’s mantle and the remnants of Thea formed the Moon and settled back on the Earth’s remaining surface, accounting for the similarity between the two.
Sounds good as far as it goes, but to stand up, the theory needs to account for the Earth’s rotation and the Moon’s orbit, as well as allow for sufficient mixing between Thea and the material blasted off the early Earth so as to eliminate any noticeable difference in composition.
Meanwhile, the Juno spacecraft has returned a new video, shown above, of the Earth-Moon system, showing both objects in motion. Juno is heading for Jupiter, but used an Earth flyby on October 9th to gain speed on its way. Read more about the video here.
M. Anthony Mills, by way of writing about Chesterton, Pascal, Duhem, and conspiracy theories at RealClearReligion, gets at the reason that I support a modest, moderate, considered, cautious, or otherwise qualified scientific realism:
“Duhem thought that “underdetermination” applied only to certain experimental sciences such as physics and chemistry. In fact, Chesterton’s conspiracy theorist reminds us that these considerations come into play not only in the philosophy of science, but also in the dilemmas that face us in social, political, and moral life. Contemporary culture holds scientific knowledge up as the final arbiter of Fact. But if scientific inquiry is not itself a simple matter of accumulating indisputable facts, but a subtle process of interpreting, weighing, and explaining them, how could the messy and complex choices we face in our daily lives be any different?”
Just so, and a good reminder to those who would make an idol of scientific knowledge. But there’s a flip side—if science is as messy as regular-life knowledge, then regular-life knowledge is as messy as science. We nevertheless manage to make our way through daily life with a sense of reasonable certainty about most things we encounter.
My basic point is this: that science is not special. Aside from those things that are present to us most immediately, through the senses, most things are known through various steps of abstraction, deduction, induction, and all the various operations of the intellect in varying degrees. This is true in other “academic” fields besides science, such as history, and it is even true in the activities of daily life.
For example, there are at least two possible explanations for why my trash can was knocked over during the night and its contents scattered and scavenged. One is that the neighbor’s dog did it; the other is that alien sasquatches pilfered my trash for some nefarious reason known only to them. The empirical evidence, claw marks and hairs left behind, supports both interpretations. But add to it that there was also that weird and startling flash of light last evening. Coincidence, or alien spacecraft? When my neighbor informs me that his dog disappeared from his fenced backyard last night, however, one of the competing explanations clearly becomes more likely: the dog was abducted by the aliens.
Joking aside, the point is that the philosophy of science is really just a special case of epistemology, and if we can overcome epistemological objections and reach reasonable approximations of the truth in our daily lives (reasonably discounting aliens and concluding it was the dog instead), there is no reason in principle why we can’t at least sometimes do the same thing in science.
In Defense of a Modest Scientific Realism (PDF), Jean Bricmont and Alan Sokal write:
“Unless one is a solipsist or a radical skeptic—which nobody really is—one has to be a realist about something: about objects in everyday life, or about the past, dinosaurs, stars, viruses, whatever. But there is no natural border where one could somehow radically change one’s basic attitude and become thoroughly instrumentalist or pragmatist (say, about atoms or quarks or whatever)….
In fact, there are vast domains in physics, chemistry, and biology where there is only one known non-crazy theory that accounts for the known facts and where many alternative theories have tried and failed because their predictions contradicted experiments. In those domains, one can reasonably think that our present-day theories are at least approximately true, in some sense or other.”
Just as in daily life, or history, or law (like a jury making a judgment), there is no need to accept that every proposition we can come up with accurately describes true reality, or to conclude that all are mere attempts to “save the appearances”; all these “theories” are to some degree tentative or revisable, but some propositions are sounder than others, and some are sound enough as to warrant moral certainty as truth. Science’s judgments, while perhaps much more difficult to obtain because of the nature of the things investigated, aren’t fundamentally different. No theory is entirely and precisely accurate, but some theories – the ones that continuously stand up to test — are at least approximately truer than others.
In The Modeling of Nature, Fr. William Wallace, OP, sums it up thusly:
“For realists, all theoretical entities have existence outside of the mind; for non-realists, all are mental constructs. [Arthur] Fine rightfully refuses to take sides in a debate of this kind. In so doing, he clearly accords with the practice of scientists. It would be difficult to find a theoretical physicist who believes that every term in every equation he writes stands for a real entity. Even more difficult would be to find an experimentalist who systematically doubts all of his results and is willing to write them all off as figments of his imagination.”
“The natural convincing explanation of the success of science is that it is gaining a tightening grasp of an actual reality. The true goal of scientific endeavor is to understand the structure of the physical world, an understanding which is never complete but ever capable of further improvement. The terms of that understanding are dictated by the way things are.”
“The astonishing thing to me about astronomy is not only that the universe makes sense and I can come up with equations and explain it,” he continued, “but the way it makes sense is beautiful.”
“God chose to create a universe that was at the same time logical and beautiful, one that I can enjoy with my brain and enjoy with my heart,” he stressed, going on to say that this “tells me something about who God is and how He creates and how He’s expecting me to relate to Him.”
Addressing the fact that many are surprised at the existence of the Vatican Observatory, Br. Consolmagno stated that “that’s part of the reason we exist; to surprise people.”
“To make people realize that the church not only supports science, literally… but we support and embrace and promote the use of both our hearts and our brains to come to know how the universe works.”
Image: Catholic News Agency
Dialogue between science and faith also belongs to the work of evangelization at the service of peace. Whereas positivism and scientism “refuse to admit the validity of forms of knowledge other than those of the positive sciences”, the Church proposes another path, which calls for a synthesis between the responsible use of methods proper to the empirical sciences and other areas of knowledge such as philosophy, theology, as well as faith itself, which elevates us to the mystery transcending nature and human intelligence. Faith is not fearful of reason; on the contrary, it seeks and trusts reason, since “the light of reason and the light of faith both come from God” and cannot contradict each other. Evangelization is attentive to scientific advances and wishes to shed on them the light of faith and the natural law so that they will remain respectful of the centrality and supreme value of the human person at every stage of life. All of society can be enriched thanks to this dialogue, which opens up new horizons for thought and expands the possibilities of reason. This too is a path of harmony and peace.
The Church has no wish to hold back the marvellous progress of science. On the contrary, she rejoices and even delights in acknowledging the enormous potential that God has given to the human mind. Whenever the sciences – rigorously focused on their specific field of inquiry – arrive at a conclusion which reason cannot refute, faith does not contradict it. Neither can believers claim that a scientific opinion which is attractive but not sufficiently verified has the same weight as a dogma of faith. At times some scientists have exceeded the limits of their scientific competence by making certain statements or claims. But here the problem is not with reason itself, but with the promotion of a particular ideology which blocks the path to authentic, serene and productive dialogue.
Here are the latest ISON images from SOHO. The comet now definitely appears to have been disrupted by its pass near the Sun, leaving little more than a dust cloud behind. Updates are available from Sky & Telescope.
On August 18th, 1976, the Soviet probe Luna 24 landed safely on the Moon. Using a robotic drill, it obtained a sample of lunar soil; it then launched from the surface, returning to Earth on August 22nd. Since that mission, no probe has returned for a soft landing to the Moon’s surface, although there have been numerous orbital missions and a few probes crashed into the surface to study their impacts. Now, China is set to be the first to return to the Moon with a soft landing.
Chang’e 3, China’s latest lunar probe, is currently expected to launch on Sunday (12:30 p.m. EST, or Monday morning at 1:30 a.m. local time). Chang’e will land a six-wheeled, solar-powered rover that will be used to explore the Moon’s Sinus Iridum region.
Image: Beijing Institute of Spacecraft System Engineering
Comet ISON made its closest approach to the Sun yesterday, and it’s not quite clear yet in just what form the comet has emerged from its close encounter. Comets are composed of conglomerations of ice and rock, and exposure to the Sun’s intense heat and gravity during close passes can tear them apart. The comet’s nucleus orbits the Sun like any other solid solar system body, while the gas and dust of the coma and tail make up the dramatic, visible portion of the comet as they are blasted off the nucleus by solar heat and pressure. During live observations with NASA’s SDO satellite yesterday, observers did not see ISON come back into view as expected—in fact, it was surprisingly not seen by SDO at all. The suspicion began to grow that the comet hadn’t survived in any meaningful state. Later, however, SOHO images (above) revealed that something had survived, as an obvious cloud emerged from near the Sun, following ISON’s orbital path. But there is still not enough evidence to make any confident judgments about what this post-encounter ISON is. Clearly, ISON in some form is now headed away from the Sun, but whether it is ISON’s nucleus, substantially intact, or scattered fragments, like the famous Shoemaker-Levy 9, remains to be seen.
Comet ISON is currently approaching the Sun, and it is now so close that it is no longer visible from the Earth. However, NASA’s SDO satellite has a perfect view of the comet, and they will be monitoring it as it passes through the Sun’s outer atmosphere. The comet will reach its closest point to the Sun on Thanksgiving Day (Thursday, Nov. 28th). NASA will be hosting a live online Google+ discussion about the comet, beginning at 1:00 p.m. EST.
The event will also be broadcast on NASA Television.
Live images will also be posted at the SDO website.
Image: NASA/MSFC/Aaron Kingery