Tag: Kepler-11

Piano sonata in the key of Kepler-11

By Phil Plait | July 1, 2012 7:00 am

Via reddit (if you’re a redditor, go there and upboat!) I found a very interesting use of astronomical data in music. The composer [Update: Astronomer Alex Parker created this!] took the orbital information from the six-planet system called Kepler 11 and codified it into musical notes! From the YouTube notes:

Here, I’ve taken each transit seen by the observatory and assigned a pitch and volume to it. The pitch (note) is determined by the planet’s distance from its star (closer=higher), and they are drawn from a minor 11 chord. The volume is determined by the size of the planet (larger=louder).

The result is actually quite listenable!

That’s lovely, and oddly compelling. It’s like the notes are trying to reach some sort of coherence, straining to achieve a melody, but don’t quite make it. I find this interesting: after listening, and without having to check, I knew the planets weren’t in orbital resonance.

A resonance is when one planet’s orbit is a simple fraction of another’s; for example, one planet might circle the star every 2 days, and the next one out in 4 days. Resonances take many ratios, like 3:2, or 5:3. The planets in Kepler-11 don’t do this (though two of them are near a 5:4 resonance). If they did, then eventually the sonata’s melody, such as it is, would repeat. But I didn’t get a sense of that listening to it.

Isn’t that amazing? You can take data using light, convert it to sound, and actually be able to get insight into it. In this case, of course, you could just make a spreadsheet with the planetary periods in it and start dividing away, but that’s no fun!

Perhaps this is just an oddity with no real impact. But I wonder. We convert data into charts and graphs so that we can look for trends, correlations, compare one datum to another visually. In a sense — haha, "sense"! — this is just another case of that, appealing to hearing instead of sight. I’m not a musician per se* so I don’t know if this method has real use or not.

But it’s still cool. And rather pleasant, don’t you think?

* 20+ years of playing bass trombone may be used to argue my musicianship either way, I suspect.

Related Posts:

Singing the praises of Carl Sagan
Wheel of stars
Laying down the pulsar beat
Music of the spheres

CATEGORIZED UNDER: Astronomy, Cool stuff

Kepler finds a mini solar system!

By Phil Plait | February 2, 2011 11:07 am

Using NASA’s orbiting Kepler observatory, astronomers have found a complete solar system of six planets orbiting a sun-like star… and it’s really weird: five of the six planets huddle closer to their star than Mercury does to the Sun!

None of them is what I would call precisely earth-like — they’re all more massive and much hotter than Earth — but their properties are intriguing, and promise that more wonderful discoveries from Kepler are coming.

The star, called Kepler-11 for convenience, is very sun-like, with a mass, size, age, and temperature very close to that of our own Sun. Located 2000 light years away, it’s way too faint to be seen without a good telescope, though. The planets, called Kepler-11 b, c, d, e, f, and g, were detected using the transit method: their orbits are edge-on as seen from Earth, so when they pass in front of (transit) their star they block a bit of its light. That dip in brightness is what Kepler detects. Over time, multiple dips are seen and those are used to determine the periods of the planets. The amount of light blocked by the planet gives you its size; the bigger the planet the more light it blocks. So the transit method tells you how many planets there are, how long it takes them to orbit, and their size.

But in the case of the minisystem Kepler-11, the planets are huddled together near their star like a close-knit family. And like any such family, the kids poke and prod each other: the planets are so tightly packed near the star that they all interact gravitationally! Each one pulls and tugs on the others, subtly changing their orbits, which in turn affects the timing of the transits. Applying a complex mathematical model to the timings allowed the astronomers to actually calculate the masses of the planets, something usually not possible in systems with fewer planets or more widely spaced orbits. What they found was that the five inner planets have periods from 10 to 46 days (Mercury, by comparison, takes 88 days to orbit the Sun), meaning they lie from 13.6 million to 37.4 million km (8.4 million to 23 million miles) from the star. The planet sizes range from twice the Earth’s size to 4.5 times, and have 4 to 14 times the Earth’s mass.

Once you have the size and mass, you can calculate the density, and that’s where things get interesting. Read More


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