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Dance of the Hundred Thousand Asteroids


Stephen Luntz

Stephen has a science degree with a major in physics, an arts degree with majors in English Literature and History and Philosophy of Science and a Graduate Diploma in Science Communication.

Freelance Writer

355 Dance of the Hundred Thousand Asteroids
A still from Alex Parker's animation of the orbits of every asteroid tracked by the Sloan Digital Sky Survey
You can watch this video and just be mesmerized by the depiction of every asteroid observed by the Sloan Digital Sky Survey. On the other hand, you can also use it as a way to understand important facts about the solar system and the way gravity affects objects.
For a start, the video gives you some sense of just how many objects there are out there large enough to be tracked, in a way the dry figure of “more than 100,000” probably doesn't. Yet the video only represents those objects whose orbits are known precisely. Others await discovery, or have been observed so fleetingly that we do not know their true orbits.
It also becomes clear that most inner solar system objects sit in the asteroid belt, not only lying between Mars and Jupiter, but in a relatively flat plane. Just this week data from the Kepler Space Telescope has confirmed that something similar is true for other planetary systems as well, a product both of the motion of the clouds from which stars form and the insistent gravitational tugging of the largest planets. However, the fact that such behavior is not inevitable can be seen from the fact that a few asteroids do manage to travel at a large angle to the plane formed by the planets and most of the other  smaller objects.
The Trojan asteroids are also visible, their clumping a puzzle until you realize that Jupiter lies between the two groups, with one 60 degrees ahead and the other 60 degrees apart. These spots are highly stable when a massive object orbits an even larger one. The Earth is known to have one such distant companion, 2010 TK7, which leads us through our orbit. You may be able to spot it in the video.
The video's maker, Alex Parker, has color coded the asteroids by families, for example with Jupiter's Trojans in red and the inner main belt in green. The choice of colors is not arbitrary. Although all asteroids look grey to our eyes, each has a frequency where it is brightest when viewed through an appropriate filter. Parker published a paper  in 2008 showing that asteroids with common orbits also tend to be brightest in the same color filter. This may indicate that they have a common origin, resulting from the break-up of a larger object.
Parker's day job is at the University of California, Berkeley, studying the Kuiper Belt, the area beyond Neptune that forms a sort of second asteroid belt. However, he has made a name for himself turning data into videos of this sort. Other examples are below. 

The Supernova Sonata takes scientific data and turns it into music, with each note representing a Type Ia supernova, with pitch indicating the time it took to peak and fade, and volume the distance to the star. Type Ia supernovae are used to measure distances to galaxies, as features of their light curve tell us their intrinsic brightness, and were essential to the discovery of dark energy

Worlds: The Kepler Planet Candidates from Alex Parker on Vimeo.


Worlds: The Kepler Planet Candidates shows what all the potential candidates discovered by the Kepler Space Telescope at the time would look like if they orbited one star. Some of these have since been found to be false positives, while new candidates have been detected since. However, it gives a sense of the fact that at any moment there are likely to be several candidates transiting in front of stars.

HT Phil Plait at Slate


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