Milky Way’s Magnetic Field Mapped

If the Milky Way were one giant magnet, sprinkling iron filings around it would trace the galaxy’s magnetic field. Scientists have found a more practical way to map the field using the Planck telescope. Planck measured the polarization of microwave light that permeates space. When light is polarized, its electric fields all point in the same direction. Light reflecting off interstellar dust grains becomes polarized in the direction the grains are aligned; that direction, in turn, is steered by the galaxy’s magnetic field. Planck’s map, reported in four papers posted May 5 at, shows the entire sky with a dark band through the center representing the plane of the galaxy. Darker shading reflects more-polarized light. The lines mark the direction of the magnetic field. The galactic magnetic field is about 100 million times as weak as a refrigerator magnet, and yet it may be crucial to the formation of stars. The field map is also important for understanding the polarization of the cosmic microwave background, the flash of light emitted 380,000 years after the Big Bang, which the BICEP2 team recently used to see gravitational waves from the primordial universe (SN: 4/5/14, p. 6).

Now a little more about science and what people know and do not know about it.

Take the origin of the universe question. Asked if the universe began with a big explosion, 39 percent of Americans polled (in 2012) said yes. But if you said “according to astronomers, the universe began with a big explosion,” the correct response rate jumped to 60 percent.

It’s well-known, of course, that the phrasing of a question can greatly influence polling results, which is one of the reasons why all such surveys should be evaluated skeptically. So it might be a good idea to rethink the relationship between polling questions and the scientific knowledge that members of the public really ought to have. Is it really necessary for the ordinary citizen to understand cosmologists’ consensus on the universe’s origins, or how lasers work? Well, maybe not. But pollsters point out that such questions are merely meant to be indicators of broader comprehension of science and its principles. Trumpeting concerns about ignorance on any specific question misses the point. It’s the more general understanding and appreciation of science and its methods that’s really important — and that really should be the emphasis of general science education.

In fact, I’d contend that the problem with science education is not that it fails to inculcate enough facts, but that it tries to inculcate too many. Science classes in high school and intro classes in college seem to be taught as though everyone needed preparation to pursue a Ph.D. Seriously, calculating solubility constants in high school chemistry classes is about as useful as teaching drivers’ ed students how to maneuver an F-16 fighter jet. Important general principles that could (and should) be retained for a lifetime are diluted to the point of homeopathic impotence by a flood of excessive technical detail. Same hold true for  a basic understanding of fiscal knowledge. Our current youth have no idea how destructive debt and consumption will be in their life.

This science topic was inspired by the physicist Richard Feynman’s famous remarks on the one sentence about science that would be most important to pass down to future generations.

He said “All things are made of atoms — little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another.” Everybody should know that much about science.

And here are a few more basics that are useful to know.

  1. Science successfully explains natural phenomena through rational investigation and logical reasoning rather than by recourse to superstition and mysticism.
  2. When scientific disputes arise, the ultimate arbiter is not expert authority or common sense but experimental evidence, guided by theory.
  3. Scientific theories are not “guesses” but are logi­cally rigorous attempts to explain the observed facts of nature and to predict the results of new observations.
  4. When a theory’s predictions are confirmed, it becomes an essential tool in the further practice of science, but even good theories may someday be superseded by theories more comprehensive or more accurate. In other words, we never know as much as we think!
  5. The universe is vast and old, with our sun only one of bil­lions of stars in a local galaxy, joined by billions of similar galaxies occupying the depths of space beyond.
  6. Life has changed over the eons, with complex creatures evolving from simpler precursors, and human beings therefore occupy one branch of an immense fam­ily tree of living organisms — all sharing attractor fields, and a common molecular machinery driving basic life processes.
  7. As Einstein demonstrated, conceptions of time and space based on everyday life don’t apply accurately to all speeds and all realms of space.
  8. The microworld of the atom, and realms even smaller, obey “quantum” laws completely at odds with common sense, and notions of cause and effect and the very nature of reality are inherently blurred on that scale. ( I like to call these “God’s Laws” that we still know very little about )
  9. The way a thing works is often influenced by its connections to other things and the ways that they work, a principle that applies to everything from the networks of cells in the brain and the body’s other organs, to ecological and economic systems, to human interactions and social institutions. ( Yes it’s all very complex and there is beauty in that )
  10. Little is certain in science but much is highly probable, and the proper quantification of probabilities is essential for inferring facts, drawing conclusions and formulating sound judgments.

Finally for me, I think we all need to stop arguing about things we don’t yet understand, and instead focus our attention on how we can work together to solve the glaring problems of our world like war, famine and greed.

Be well everyone.


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