Someone just made a thread about a fake lunar impact video, which reminded me I have a question about real lunar impacts.
There are some smart people on ATS and hopefully someone has an explanation that makes sense, but if nobody here can come up with a good answer I
might ask NASA. I tried searching for an explanation but wasn't able to find one, at least not one that made sense to me.
Please refer to this page which shows where lunar impacts have been recorded:
If you scroll down a bit at that link, there is a map of impacts but I'll just post it here:
My question is this:
Does anybody have a good explanation for the pattern of impacts, and specifically, the big gap in the middle?
One person suggested that perhaps the Earth was intercepting some objects before they impacted the moon. I have no doubt this is true, but here is the
reason I don't think that can explain the gap in the middle.
Consider how the Earth casts a shadow on the moon during a lunar eclipse. The rays from the sun aren't exactly parallel from one end of the shadow on
the moon to the other end, but the angular difference is very small, less than one degree, right? So nearly parallel for the sake of this particular
Now in contrast, consider that impactors can approach the moon's surface from any angle, let's say 0 to almost 90 degrees. So in contrast to the
Earth's shadow made by nearly parallel rays from the sun, the trajectories of the impactors cannot be assumed to be parallel. I'm not sure if we know
the actual trajectories because for many impacts all we see is a flash of light and we don't really know what direction or angle the impactor came
So if we reject the idea that the gap in the middle is caused by Earth blocking the impacts, what other explanation remains? I can think of a couple
1. Maybe the Earth's gravitational influence which extends beyond direct blocking can explain how near misses with Earth are deflected in a way that
results in such a pattern. While this idea may be more plausible than just direct impacts on Earth casting an "impact shadow", I'm still very
skeptical of this explanation, though if someone has modeled this I could be convinced.
2. By process of elimination since the above explanations don't seem to explain the pattern, I have to wonder if the flashes we see depend on the
angle of the moon's surface relative to the observer? In other words, if looking directly down at an impact site made the flash difficult to observe
because the light from the flash was minimal in a direction perpendicular to the surface, that might explain the gap. However there are problems with
this idea such as the gap extends vertically, and the impacts don't form a circle around a gap in the middle. However I think this might be explained
if the trajectories of the impactors is limited to roughly the plane of our solar system.
The bigger problem with this idea about only seeing the flashes from certain surface angles is that I'm not aware of the physical process which would
cause this directionality in how the impact flashes could be observed, and I would have thought they could be observed from most angles. In fact the
NASA site says this:
The flash of light comes not from combustion but rather from the thermal glow of molten rock and hot vapors at the impact site.
If that were
to be directional I'd expect it to be easier to see from straight down, because then you wouldn't have the walls of the crater blocking the view of
the inner part of the crater.
I'd appreciate some help in figuring this out. The pattern is so clear there must be an explanation, but I don't know what it is.
12-4-2014 by Arbitrageur because: resized image