APOD: La Palma Eclipse Sequence (2015 Oct 07)

[APOD Robot]

La Palma Eclipse Sequence

Explanation: At left, a dramatic image sequence follows late September's total lunar eclipse above a rugged landscape and sea of clouds from the Canary island of La Palma. Composited in a circular fisheye projection, the brightness of the Full Perigee Moon changes drastically in transition from outside the total eclipse phase compared to its dim glow during the 72 minute long totality. At right, a single frame captures the dark red lunar disk in a moment during the total eclipse phase, the Moon deep within Earth's shadow. In fact, the size of the eclipsed Moon image at right approximately illustrates the relative size of Earth and Moon, when compared to the circular projection of the eclipse sequence.

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[Ann]

So the size of the blue, white and brown "ball" on the left in today's APOD, versus the size of the eclipsed red Moon on the right, closely approximates the relative sizes of the Earth and the Moon.

We do have a large moon, although the size of Charon compared with the size of Pluto makes Charon a larger moon than Luna, relatively speaking. But Luna is larger than Charon when it comes to the actual sizes of these two moons, measured in kilometers. (Or measured in miles for the Americans.) If that makes sense.

Very nice image!

Ann

[tomatoherd]

what I notice in the eclipse sequence is that the moon's path slightly diverges across the star trails, i.e. not parallel. I presume this is due to the moon's own motion/orbit not being in the same plane as earth's (?the celestial equator?). Is this correct?

[neufer]

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what I notice in the eclipse sequence is that the moon's path slightly diverges across the star trails, i.e. not parallel. I presume this is due to the moon's own motion/orbit not being in the same plane as earth's (?the celestial equator?). Is this correct?

Yes.

[Ron-Astro Pharmacist]

Wow. Is this what our sky would look like if time was quantized? It would have quite a different look. Thanks for the unique perspective!

[neufer]

Wow. Is this what our sky would look like if time was quantized?

It would have quite a different look.

<<Frame rate is the frequency (rate) at which an imaging device displays consecutive images. The human eye and its brain interface, the human visual system, can process 10 to 12 separate images per second, perceiving them individually. Persistence of vision creates an illusion of continuity, allowing a sequence of still images to give the impression of motion.

Early silent films had stated frame rates anywhere from 16 to 24 FPS. These frame rates were enough for the sense of motion, but it was perceived as jerky motion. By using projectors with dual- and triple-blade shutters, the rate was multiplied two or three times as seen by the audience. Thomas Edison said that 46 frames per second was the minimum needed by the visual cortex: "Anything less will strain the eye."

When sound film was introduced in 1926, variations in film speed were no longer tolerated as the human ear is more sensitive to changes in audio frequency. Many theaters were then showing silent films at 22 to 26 FPS which is why 24 FPS was chosen for sound. From 1927 to 1930, as various studios updated equipment, the rate of 24 FPS became standard for 35 mm sound film. At 24 FPS the film travels through the projector at a rate of 456 millimetres (18.0 in) per second. This allowed for simple two-blade shutters to give a projected series of images at 48 per second, satisfying Edison's recommendation. Many modern 35 mm film projectors use three-blade shutters to give 72 images per second—each frame is flashed on screen three times. Historical experiments in frame rates that were not widely accepted were Maxivision 48 and Showscan, developed by 2001: A Space Odyssey special effects creator Douglas Trumbull.>>

<<A chronon is a proposed quantum of time, that is, a discrete and indivisible "unit" of time as part of a hypothesis that proposes that time is not continuous. The term was introduced in this sense by Robert Lévi in 1927. Many physicists have suggested that a discrete model of time might work, especially when considering the combination of quantum mechanics with general relativity to produce a theory of quantum gravity. Henry Margenau in 1950 suggested that the chronon might be the time [9.41×10⁻²⁴ seconds] for light to travel the classical radius of an electron:

In Piero Caldirola's model, one chronon corresponds to about 6.27×10⁻²⁴ seconds for an electron. This is much longer than the Planck time, which is only about 5.39×10^-44 seconds. The Planck time is a theoretical lower-bound on the length of time that could exist between two connected events, but it is not a quantization of time itself since there is no requirement that the time between two events be separated by a discrete number of Planck times. For example, ordered pairs of events (A, B) and (B, C) could each be separated by slightly more than 1 Planck time: this would produce a measurement limit of 1 Planck time between A and B or B and C, but a limit of 3 Planck times between A and C. Additionally, the Planck time is a universal quantization of time itself, whereas the chronon is a quantization of the evolution in a system along its world line. Consequently, the value of the chronon, like other quantized observables in quantum mechanics, is a function of the system under consideration, particularly its boundary conditions. The value for the chronon, θ₀, is calculated from:

From this formula, it can be seen that the nature of the moving particle being considered must be specified since the value of the chronon depends on the particle's charge and mass.

Caldirola claims the chronon has important implications for quantum mechanics, in particular that it allows for a clear answer to the question of whether a free-falling charged particle does or does not emit radiation. This model supposedly avoids the difficulties met by Abraham–Lorentz's and Dirac's approaches to the problem, and provides a natural explication of quantum decoherence.>>

[Ron-Astro Pharmacist]

The idea of a quantum of time is very enticing and it seems aptly named. If chronons exist it's tempting to speculate, as you say, their relationship to mass and energy. That brings to mind another formula which is quite famous. Is it possible to define a "second" simply by the rearrangement of E²= (mc²)²+ (pc) ² and doing the algebra? The "real" math is quite complex but my way makes it easy to get a charge out of it. Bet it's not that simple.

[neufer]

[b][color=#0000FF][size=135]Nude Descending a Staircase, No. 2 1912 painting by Marcel Duchamp.[/size][/color][/b]

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The idea of a quantum of time is very enticing and it seems aptly named. If chronons exist it's tempting to speculate, as you say, their relationship to mass and energy. That brings to mind another formula which is quite famous. Is it possible to define a "second" simply by the rearrangement of E²= (mc²)²+ (pc)² and doing the algebra? The "real" math is quite complex but my way makes it easy to get a charge out of it. Bet it's not that simple.

The actual equation is:

E²= (m₀c²)²+ (pc)² where m₀ = rest mass

E= mc² is just fine by itself ... just so long as
blue variable: m = {m₀ / sqrt[1-(v/c)²]}

E²= (mc²)² = (m₀c²)²/[1-(v/c)²]

E²[1-(v/c)²] = (m₀c²)²

E² - (Ev/c)² = (m₀c²)²

E² = (m₀c²)² + (Ev/c)²

E² = (m₀c²)² + {(mc²)v/c}²

E² = (m₀c²)² + (mvc)²

E² = (m₀c²)² + (pc)²

[Pianosorplanets]

Does anybody have a clue whether the nude descending the staircase was a male or a female? Perhaps I would do better to ask if it is a terrestrial being?

[Beyond]

I didn't know they had 'LSD' back then.

[neufer]

Click to play embedded YouTube video.

Does anybody have a clue whether the nude descending the staircase was a male or a female? Perhaps I would do better to ask if it is a terrestrial being?

It's Neil deGrasse Tyson
in a dust storm descending
from his spaceship
as The Martian

[BMAONE23]

Does anybody have a clue whether the nude descending the staircase was a male or a female? Perhaps I would do better to ask if it is a terrestrial being?

Given the size and configuration of the hips, I would say...Female