Giordano Bruno (crater)

lunar crater data


caption=Giordano Bruno. "NASA photo".
latitude=35.9
N_or_S=N
longitude=102.8
E_or_W=E
diameter=22 km
depth="Unknown"
colong=258
eponym=Giordano Bruno

Giordano Bruno is a small lunar impact crater on the far side of the Moon, just beyond the northeastern limb. At this location it lies in an area that can be viewed during a favorable libration, although at such times the area is viewed from the side and not much detail can be seen. It lies between the Harkhebi crater to the northwest and Szilard crater to the southeast.

When viewed from orbit, Giordano Bruno is at the center of a symmetrical ray system of "ejecta" that has a higher albedo than the surrounding surface. The ray material extends for over 150 kilometers and has not been significantly darkened by space erosion. Some of the "ejecta" appears to extend as far away as the Boss crater, over 300 km to the northwest. The outer rim of the crater is especially bright, compared to its surroundings. To all appearances this is a young formation that was created in the relatively recent past, geologically-speaking. The actual age is unknown, but is estimated to be less than 350 million years.

This feature was named after the Italian philosopher Giordano Bruno.

Formation

Five monks from Canterbury reported to the abbey's chronicler, Gervase, that shortly after sunset on June 18, 1178, they saw "two horns of light" on the shaded part of the moon. In 1976 the geologist Jack B. Hartung proposed that this described the formation of the Giordano Bruno crater.

Modern theories predict that there would be a plume of molten matter rising up from the surface of the moon, which is consistent with the monks' description. In addition, the location they recorded fits in well with Bruno's location. Additional evidence of Bruno's youth is its spectacular ray system: because micrometeorites constantly rain down, they kick up enough dust to quickly (in geological terms) erode a ray system. So there is probably enough circumstantial evidence to hold that Giordano Bruno was formed during human history.

More circumstantial evidence that Giordano Bruno was formed by a meteor is the fact that the monks' observation took place during the Taurid meteor shower. This meteor shower, which happens in late June, was possibly responsible for the Tunguska event.Fact|date=February 2007

However, the question of Bruno's age is not that simple. The impact creating the 22 km wide crater would have kicked up enough debris to trigger a week-long, blizzard-like meteor storm on Earth -- yet no accounts of such a noteworthy storm of unprecedented intensity are found in any known historical records, including the European, Chinese, Arabic, Japanese and Korean astronomical archives. [http://science.nasa.gov/headlines/y2001/ast26apr_1.htm] This discrepancy is a major objection to the theory that Bruno was formed at that time.

All this raises the question of what the monks saw. An alternative theory holds that the monks just happened to be in the right place at the right time to see an exploding meteor coming at them and aligned with the Moon. Because meteors appear about 45 to 75 miles up in the atmosphere, [http://www.nasa.gov/worldbook/meteor_worldbook.html] the laws of geometric perspective dictate that only a relatively small area in Britain would have the perfect geometry to make it look like it was on the Moon.

References

* cite journal
last = Jack B. | first = Hartung
title=Was the Formation of a 20-km Diameter Impact Crater on the Moon Observed on June 18, 1178?
journal=Meteoritics | year=1976 | volume=11 | issue=3
pages=187
url=http://adsabs.harvard.edu/abs/1976Metic..11..187H
accessdate = 2007-08-09
* cite journal
author=Camale, O.; Mulholland, J. D.
title=Lunar Crater Giordano Bruno: A.D. 1178 Impact Observations Consistent with Laser Ranging Results
journal=Science | year=1978 | volume=199
issue=4331 | pages=875–87
url=http://adsabs.harvard.edu/abs/1998RPPh...61...77K
accessdate = 2007-08-09
doi=10.1126/science.199.4331.875
pmid=17757584
* cite web
last = Stiles | first = Lori | date = April 20, 2001
url = http://uanews.opi.arizona.edu/cgi-bin/WebObjects/UANews.woa/wa/SRStoryDetails?ArticleID=3561
title = What Medieval Witnesses Saw Was Not Big Lunar Impact, Grad Student Says
publisher = University of Arizona | accessdate = 2007-08-09
* cite news
first=Mark | last=Sincell | title=Nothing But Moonshine
publisher=American Association for the Advancement of Science
date=May 7, 2001
url=http://sciencenow.sciencemag.org/cgi/content/full/2001/507/3?ck=nck
accessdate=2006-05-24

External links

* [http://science.nasa.gov/headlines/y2001/ast26apr_1.htm NASA: The Mysterious Case of Crater Giordano Bruno]