Lunar crater

[neufer]

Click to play embedded YouTube video.

Bright Explosion on the Moon
NASA Science News | Dr. Tony Phillips | 2013 May 16

[orin stepanek]

If you're out walking on the moon; and is starts showering, you need to get indoors quick! Unless you have a meteor shower umbrella.

Click to view full size image

[neufer]

[b][color=#0000FF][size=150]Giordano Bruno[/size]: NASA photo[/color][/b]

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<<Giordano Bruno is a 22 km lunar impact crater named after the Italian philosopher 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 craters Harkhebi to the northwest and Szilard 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 as the crater Boss, 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.

Five monks from Canterbury reported to the abbey's chronicler, Gervase, that shortly after sunset on June 18, 1178, (25 June on the proleptic Gregorian calendar) they saw "the upper horn [of the moon] split in two". Furthermore, Gervase writes:

From the midpoint of the division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals and sparks. Meanwhile the body of the Moon which was below writhed, as it were in anxiety, and to put it in the words of those who reported it to me and saw it with their own eyes, the Moon throbbed like a wounded snake. Afterwards it resumed its proper state. This phenomenon was repeated a dozen times or more, the flame assuming various twisting shapes at random and then returning to normal. Then, after these transformations, the Moon from horn to horn, that is along its whole length, took on a blackish appearance.

In 1976, the geologist Jack B. Hartung proposed that this described the formation of the crater Giordano Bruno.

Modern theories predict that a (conjectural) asteroid or comet impact on the Moon would cause a plume of molten matter rising up from the surface, which is consistent with the monks' description. In addition, the location recorded fits in well with the crater's location. Additional evidence of Giordano 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 it can be reasonably hypothesized that Giordano Bruno was formed during the span of human history, perhaps in June 1178.

However, the question of the crater's age is not that simple. The impact creating the 22-km-wide crater would have kicked up 10 million tons of debris, triggering 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. This discrepancy is a major objection to the theory that Giordano Bruno was formed at that time.

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. This would explain why the monks were the only people known to have witnessed the event; such an alignment would only be observable from a specific spot on the Earth's surface.

[THX1138]

Those holes aren't from falling meteors or asteroids, they are crater-chains which are the results of an intergalactic war that happened eons ago.
Good old craterchains i wonder what happened to that character..............In a rubber room now perhaps?

[Nitpicker]

Call me slow if I missed it, but does anyone know if the LROC ever detected the new crater (from the March 17 meteoroid this year)?

I found this article:
http://lroc.sese.asu.edu/news/index.php ... -Time.html

The article mentions this particular big meteoroid, but suggests the crater it formed hasn't yet been found (and may never be).

[neufer]

Call me slow if I missed it, but does anyone know if the LROC ever detected the new crater (from the March 17 meteoroid this year)?

I found this article: http://lroc.sese.asu.edu/news/index.php ... -Time.html

The article mentions this particular big meteoroid, but suggests the crater it formed hasn't yet been found (and may never be).

Smack! A New Crater Appears on the Moon
by Bob King on December 18, 2013

[b][color=#0000FF]Before and after views of the March 17, 2013 impact taken by the LRO camera. Credit: NASA/GSFC/Arizona State University[/color][/b]

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<<Where there’s smoke, there’s fire, or in this instance, a new hole in the moon. NASA’s Lunar Impact Monitoring Program recorded the brightest meteoroid impact ever in its 8-year history on March 17 this year. The flash of light, as luminous as a 4th magnitude star and lasting about one second, was caught on video striking the moon in the Sea of Rains (Mare Imbrium) not far from the prominent crater Copernicus. Some time after the event, the Lunar Reconnaissance Orbiter (LRO) swept in for a closer look and spied a brand new impact crater. Since 2005 the program has detected over 300 flashes which are presumed to be from meteoroid impacts.

Based on the flash brightness and duration of the St. Pat’s Day smack, the space boulder measured between one to 0.3-0.4 meters and struck the moon traveling at 56,000 mph with a force of 5 tons of TNT. Scientists predicted then that the impact could produce a crater up to 20 meters in diameter. Well, guess what? When LRO dropped by for a look and compared images taken of the flash site before and after March 17. Staring it in the face was a brand new crater 18 meters across. Wow! Just look at how reflective the crater and its rays of ejecta appear. That’s all unweathered, fresh dust and rock excavated from beneath the surface courtesy of 5 tons of extraterrestrial TNT. While impressive from LRO’s 31-mile altitude, the “St. Pat” crater is unfortunately invisible in even the largest telescopes from Earth.

Over time, cosmic rays, solar irradiation and micrometeoroids darken and redden the lunar soil. Millions of years from now, the once brilliant crater will blend into the moonscape. Can you imagine how bright larger craters like Tycho and Copernicus must have looked once upon a time?

The March 17 impact wasn’t the first new crater seen by LRO, but it does appear to be one of the largest. The LRO camera team has been systematically searching its archive of before and after images for many more lunar landscape changes. Some of those results – including these photos – were presented at the American Geophysical Union Fall Meeting last week; more new craters will be announced in the near future.>>

[Nitpicker]

Thank you. Would love to record one of these flashes one day.

Can you imagine how bright larger craters like Tycho and Copernicus must have looked once upon a time?

Can you imagine how big the impact flashes must have been for Tycho and Copernicus?