Clues in the Blood Splatter Patterns

This is the penultimate line in an article today in the Science Times:

“Sometimes how the blood is splattered on the wall tells you more about what happened than the body,”

It is a quote from Harold Levison of the Southwest Research Institute, in the context of understanding the origins and dynamics of our Solar System. The article is by Kenneth Chang, and a link to it is here.

It is a lovely article, focusing on the continuing series of discoveries being made about Kuiper Belt objects (e.g. Sedna, “Xena”, etc…), those cousins of Pluto that, thanks for better detection technology, have turned out to be quite numerous (click on image above… more of it at the NYT site):

More than 1,100 Kuiper Belt objects have been found so far. Astronomers estimate that half a million bodies larger than 20 miles wide are floating out there. At least one appears to be mostly rock with a coating of ice. Some are mostly ice. Some are less dense than ice, indicating a Swiss-cheese-like structure. A surprising number of them have moons.

Levison says:

“The more we learn, the weirder it looks.”

It is quite a fascinating subject, a detective story full of wonderful science, and illustrates -as I have said earlier in the post called “Spinach Blogging”– how the “demotion of Pluto” story opens the door to so much active planetary science. It also illustrates why it it is interesting to keep an eye on the debate about the “demotion”. which is still ongoing. The nature of the Kuiper belt is teaching us a huge amount about the other bodies in the solar system. For example:

The distribution of Kuiper Belt objects has already provided decisive evidence that Neptune was once perhaps nearly a billion miles closer to the Sun and was then gravitationally nudged outward. Astronomers also hope that the Kuiper Belt preserves a frozen record of the earliest building materials of the solar system.

Another nice analogy from S. Alan Stern (of the Southwest Research Institute and principal investigator of NASA’s New Horizon spacecraft, which is currently heading to Pluto):

“It’s kind of like the solar system’s attic,” Dr. Stern said. “It’s like an archaeological dig into the history of our solar system.”

The article talks about the science before the discovery of the belt, and the conjectures (going back to Kuiper in 1951, and Edgeworth a few years earlier), clues (such as short-period comets like Halley) and computations that suggested its existence. One set of computations, by showed that there would exist a large amount of “resonant” objects in the belt (Pluto has an orbit resonant with Neptunes, meaning its duration is a rational number times that of Neptunes. The ration is 3:2 in that case), as a result of Neptune sweeping lots of them into such orbits as it migrated outward. Soon after the first Kuiper belt object was discovered in 1992 (“QB1”, by David Jewitt (Hawaii) and Jane X. Luu):

Renu Malhotra, a professor of astronomy at the University of Arizona, was calculating the effects of Neptune’s migrating outward, as some had hypothesized, early in the history of the solar system. Her calculations indicated that Neptune would effectively snowplow smaller objects into resonant orbits.

The first Kuiper Belt objects in resonant orbits were discovered in 1993. The distribution of resonant Kuiper Belt objects fit with what she predicted, and now planetary scientists uniformly agree that the giant planets were not born in their current orbits but migrated there.

There’s much more in the article, so have a look. I find it fascinating. I particularly like the image of the planets migrating outwards over the course of the evolution of the solar system, and especially the speculation that perhaps our sun had more gas giants orbiting it, and they simply were ejected from the system over time.

Oh, and in case you did not get the crime scene analogy: The solar system (especially the large planets) are supposed to be the body we’re trying to understand, and the myriad tiny Kuiper belt objects are the blood splatter. From Levison:

The Kuiper Belt, Dr. Levison said, is “the blood splattering on the wall,’’ adding, “If we’re going to understand what happened, it’s going to be by studying the Kuiper Belt.”

-cvj