|Grooves around Vesta's Equator|
As you know, in science a hypothesis is the first step in a process that progresses into a theory, and finally into a law, so long as there is more evidence along the way for a valid elevation to a theory from a hypothesis, and thereafter for a valid elevation to a law from a theory.
Some of these Dredd Blog science excursions have involved a hypothesis that is linked to one of the Exploded Planet Hypotheses (EPH), specifically one set forth by an astronomer Dr. Thomas C. Van Flandern, who worked for the United States Naval Observatory for ~21 years, and who was not afraid to question status quo scientific dogma when he thought that there was sufficient evidence for a hypothesis (peer reviewed paper: The Challenge of the Exploded Planet Hypothesis, Cambridge Journals Online, International Journal of Astrobiology / Volume 6 / Issue 03 / July 2007, pp 185-197).
The EPH holds that the asteroids are debris left over from a planet that exploded, and is in scientific friction with the mainstream hypothesis which holds that the asteroids are material that did not bind together to form a planet for some reason.
Concerning the grooves around Vesta, our hypothesis is that they are strata in a chunk of the ancient planet that exploded.
This also indicates that the planet had oceans which had built up the strata over eons of time, like at the Grand Canyon, which water laid layers of strata now show up as dust covered grooves along Vesta's equator.
New data have been released by NASA which have given this hypothetical analysis of the equatorial strata of Vesta support, and have bolstered the hypothesis that those strata originally had water in them:
Two new papers based on observations from the low-altitude mapping orbit of the Dawn mission show that volatile, or easily evaporated materials, have colored Vesta's surface in a broad swath around its equator.(NASA - Dawn, emphasis added). The scientists who wrote the recent papers think the water was delivered by meteorites hitting Vesta's surface.
The strongest signature for hydrogen in the latest data came from regions near the equator, where water ice is not stable.
The holes that were left as the water escaped stretch as much as 0.6 miles (1 kilometer) across and go down as deep as 700 feet (200 meters). Seen in images from Dawn's framing camera, this pitted terrain is best preserved in sections of Marcia crater.
"The pits look just like features seen on Mars, but while water was common on Mars, it was totally unexpected on Vesta in these high abundances," said Denevi. "These results provide evidence that not only were hydrated materials present, but they played an important role in shaping the asteroid's geology and the surface we see today."
However, once again our hypothesis is that Vesta is a chunk from a planet that had large oceans, and when it exploded those chunks that had water in them vented that water when those chunks became debris.
Specifically, when the hot explosion shot the Vesta chunk of the planet into the vacuum of space, it caused the venting of the water from the strata.
There were then violent ejections of water from the Vesta chunk along its strata lines that held water, somewhat like those from Enceladus, a moon of Saturn.
Except in this case the escape holes where water vented are found in the strata along what is now Vesta's equatorial area.
The violent ejections marked those strata with the "holes that were left as the water escaped" which after all these billions of years, still "stretch as much as 0.6 miles (1 kilometer) across and go down as deep as 700 feet (200 meters)."
For illustration only, the amount of water to fill just one of those cone shaped surface vents would be:
vent diameter = 1 kilometer (3280.8 ft)I don't think meteorites would have the volume of water to cause such focused, and violent ejections to make cone-shaped vents a kilometer across and 700 feet deep, because among other things, the meteorite types with the most water are carbonaceous chondrite types, having 3% - 22% water by weight.
radius (r) = 3280.8 / 2
r = ~1640 ft
height (h) = 700 feet
cone volume formula: v = 1/3 * 3.14 * r2 * h
v = .33 * 3.14 * 2,689,600 * 700
v = 1,950,874,464 ft3
assume there are 7.48 gallons of water per ft3
water in cone = 1,950,874,464 ft3 / 7.48 ft3
gallons of water = ~260,812,094 gal (for 1 vent)
Depending on the type of carbonaceous chondrite meteorite, this calculates out to a lot of weight because water (on Earth) weighs ~8.34 pounds per gallon, so 260,812,094 * 8.34 = ~2,175,172,864 lbs, or ~1,087,586 tons (2,000 lbs = 1 ton) of water in just one cone.
Furthermore, the water in each meteorite would be vented as steam upon impact with Vesta, and would go in all directions, not just toward the surface in that one direction to make a large vent cone.
Nor, as is obvious, do meteorites make craters only along the equator of orbs they impact (craters are everywhere on Vesta, not just at the equator).
The evidence shows that this violent venting took place in the strata lines along the equator, indicating that the concentration of the water was in the strata.
Other Weekend Rebel Science Excursion posts are linked to on the Series Posts tab above under "SCIENCE (of the rebellion)."
For another detailed theoretical discussion of where the mass of the exploded planet went, besides the asteroids that is, read Exploded Planet, by Rich Anders (2nd of two).
The following video shows Vesta rotating with the strata shown to go all the way through the asteroid because they go all around the sphere, from one side to the other.
The next post in this series is here, the previous post in this series is here.