Sentences with phrase «number of impact craters»
Studying the number of impact craters to calculate the age of these regions on the surface, scientists estimated that the planet's magnetic field is very ancient — at least 3.7 billion to 3.9 billion years old.
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Scientists record the size and number of impact craters — and how eroded they are — to determine the ages and histories of different planetary surfaces.
Not exact matches
That's potentially problematic, because planetary scientists use the number of small impact craters to estimate the age of the lunar surface.
«By comparing the measured craters to the number and spatial distribution of large impact basins on Mercury, we found that they started to accumulate at about the same time, suggesting that the resetting of Mercury's surface was global and likely due to volcanism,» said lead author Dr. Simone Marchi, who has a joint appointment between two of NASA's Lunar Science Institutes, one at the SwRI in Boulder and another at the Lunar and Planetary Institute in Houston.
The number of new craters found by Speyerer and colleagues is greater than anticipated by standard impact - modeling rates used by lunar scientists.
«In addition to the new impact craters and starburst debris patterns, we observed a surprising number of small surface changes which we call splotches,» Speyerer said.
Stothers, R.B., 1998: Galactic disc dark matter, terrestrial impact cratering and the law of large numbers.