Grand Canyon-Sized Valleys On the Moon Formed Within 10 Minutes (space.com) 3
A new study reveals that two Grand Canyon-sized valleys were formed in less than 10 minutes by "floods of rocks traveling as fast as bullets," reports Space.com. From the report: Scientists analyzed the lunar canyons, named Vallis Schrodinger and Vallis Planck, to find that these huge valleys measure 167 miles long (270 kilometers) and nearly 1.7 miles (2.7 km) deep, and 174 miles long (280 km) and nearly 2.2 miles deep (3.5 km), respectively. In comparison, the Grand Canyon is 277 miles long (446 km) and is, at most, about 1.2 miles deep (1.9 km), the researchers noted. [...] This pair of lunar canyons represents two of many valleys radiating out from Schrodinger basin, a crater about 200 miles wide (320 km) that was blasted out of the lunar crust by a cosmic impact about 3.81 billion years ago. This structure is located in the outer margin of the moon's largest and oldest remaining impact crater, the South Pole-Aitken basin, which measures about 1,490 miles wide (2,400 km) and dates about 4.2 billion to 4.3 billion years old.
[...] The scientists estimate that rocky debris flew out from the impact at speeds between 2,125 to 2,860 miles per hour (3,420 to 4,600 km/h). In comparison, a bullet from a 9mm Luger handgun might fly at speeds of about 1,360 mph (2,200 km/h). The researchers suggest the energy needed to create both of these canyons would have been more than 130 times the energy in the current global inventory of nuclear weapons. "The lunar canyons we describe are produced by streams of rock, whereas the Grand Canyon was produced by a river of water," [said David Kring, a geologist at the Lunar and Planetary Institute of the Universities Space Research Association]. "The streams of rock were far more energetic than the river of water, which is why the lunar canyons were produced in minutes and the Grand Canyon produced over millions of years." The findings have been published in the journal Nature.
[...] The scientists estimate that rocky debris flew out from the impact at speeds between 2,125 to 2,860 miles per hour (3,420 to 4,600 km/h). In comparison, a bullet from a 9mm Luger handgun might fly at speeds of about 1,360 mph (2,200 km/h). The researchers suggest the energy needed to create both of these canyons would have been more than 130 times the energy in the current global inventory of nuclear weapons. "The lunar canyons we describe are produced by streams of rock, whereas the Grand Canyon was produced by a river of water," [said David Kring, a geologist at the Lunar and Planetary Institute of the Universities Space Research Association]. "The streams of rock were far more energetic than the river of water, which is why the lunar canyons were produced in minutes and the Grand Canyon produced over millions of years." The findings have been published in the journal Nature.
Why the obsession with metaphors for scale? (Score:2)
It may not be libraries of congress per square yard or the like, but the obsession with finding metaphors to explain large amounts of speed, mass or distance is only comparable to the obsession with people respecting a certain brand of handgun. I'd like to *not* use weapons to explain things and that goes for measuring craters in the number of nuclear bombs needed to reproduce them too. Look, if it is around 3600 km/h that and there are 3600 seconds/h it sounds like about 1 km/s. That's enough! Yes, faster
Re: (Score:1)
10 minutes (Score:2)
I need to know what that is in terms of bicycle wheel turns at 25 mph.
Wouldn't the rocks just shatter? (Score:2)
Surely travelling at that speed and hitting the ground they'd simply shatter (or if hot from the impact just squash) or at least be deflected in random directions, they wouldn't all carry on for miles and miles in a dead straight line all in exactly the same direction with a few degrees digging a huge valley as they went. This theory seems a very odd way to explain these features.