First Ever Image of Orion (left) & Most Advanced Image Ever (right):
Want to see how much technology has advanced in 100 years?
Look no further…
We recently posted an image of the Orion nebula across all our social media sites. This image compared the first ever photograph of Orion (taken in 1880) with an image taken in 2013 on an iPhone.
Most people seemed to enjoy the comparison. However, there was a bit of a kerfuffle.
Some people asserted that, to be accurate and fair, we should compare the most detailed image pf Orion with Draper’s image from 1880. Your wish is our command….
First ever image of Orion by Henry Draper in 1880 (left) and most detailed image of Orion ever taken (right). Image compiled by From Quarks to Quasars
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Want to know how much technology has progressed in 100 years?
Look no further…
For comparison, see the most detailed image ever taken of Orion at:http://www.fromquarkstoquasars.com/apotd-glorious-image-of-orion/
iPhone image via: Andrew Symes
Find him at: https://twitter.com/FailedProtostar
Happy 86th birthday to Vera Rubin (b. July 23, 1928), a pioneering astronomer who uncovered the galaxy rotation problem. While attempting to explain the galaxy rotation problem, she encountered some of the most firm evidence up to that time of dark matter.
Landing on the moon, July 20, 1969.
Time for an experiment! Find a book and secure it shut using tape or a rubber band. Now experiment with spinning the book while tossing it into the air. You’ll notice that when the book is spun about its longest or shortest axis it rotates stably, but when spun about its intermediate-length axis it quickly wobbles out of control.
Every rigid body has three special, or principal axes about which it can rotate. For a rectangular prism — like the book in our experiment — the principal axes run parallel to the shortest, intermediate-length, and longest edges, each going through the prism’s center of mass. These axes have the highest, intermediate, and lowest moments of inertia, respectively.
When the book is tossed into the air and spun, either about its shortest or longest principal axis, it continues to rotate about that axis forever (or until it hits the floor). For these axes, this indefinite, stable rotation occurs even when the axis of rotation is slightly perturbed.
When spun about its intermediate principal axis, though, the book also continues to rotate about that axis indefinitely, but only if the axis of rotation is exactly in the same direction as the intermediate principal axis. In this case, even the slightest perturbation causes the book to wobble out of control.
The first simulation above shows a rotation about the unstable intermediate axis, where a slight perturbation causes the book to wobble out of control. The second and third simulations show rotations about the two stable axes.
Unfortunately, as far as my understanding goes, there’s no intuitive, non-mathematical explanation as to why rotations about the intermediate principal axis are unstable. If you’re interested, you can find the stability analysis here.Mathematica code posted here.